Metamaterial inspired electrically small antennas with enhanced bandwidth and multi- band compatibility

Metamaterial inspired electrically small antennas with enhanced bandwidth and multi- band compatibility | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Metamaterial inspired electrically small antennas with enhanced bandwidth and multi- band compatibility Sakib Sadman, Md Abu Huraira This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8626984/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 9 You are reading this latest preprint version Abstract The invention of a miniaturized antenna that can support multiple frequency bands with efficient bandwidth is very crucial for communication applications. In this work, a novel approach is demonstrated wherein the combination of various metamaterial configurations leads to significantly increase the number of frequency bands and also the bandwidth level. Initially, an ordinary patch antenna, exhibiting narrowband performance at 2.8 GHz and 9.5 GHz, is considered and optimized for reference. By applying different metamaterial architectures like a complementary dual negative metamaterial (CDNG-MTM) or its combination with two split-ring resonators (SRR) alongside the patch structure, a rising in number of bands from two to four and then five is observed in a sequential manner. Every time the k a value (indicator of antenna size) is found to be below one and the electrical size as compact. A CDNG-MTM joining with the patch originated four different bands with bandwidths of 1.75GHz, 1.175GHz, 0.185GHz, and 0.54GHz at 2GHz, 6.8GHz, 9.1GHz, and 9.6GHz, respectively, which can be feasible for next generation high-speed wireless communication, high-resolution radar, earth observation satellites etc. Lastly, the addition of SRRs leads to five operational bands along with 22% more enhancement in overall bandwidth. Antenna Bandwidth Metamaterial Multi-Band Patch Split-Ring Resonator Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 1. Introduction Nowadays, the convenience of wireless communication has led to a rapid increase in the use of wireless and compact communication devices. This has created a strong demand for miniature antennas with multi-band capabilities. As a result, electrically small antennas (ESAs) have been a key area of research for quite some time due to their small size, which makes them ideal for a wide range of wireless applications, such as wireless sensor networks, private communications, unmanned devices, and many more [1]. Microstrip patches are among the most widely used conventional antenna types for ESA transformation due to their many benefits, including low cost, minimal complexity of design, and ease of production [2]. ESA is with specific defining electrical characteristics that were first suggested by Wheeler, and then developed by Chu. An antenna will be definitely considered as an ESA if it satisfies the formula ka < 1; whereas k is defined as the wave number and is equal to 2π/λ 0 , λ 0 is the free space wavelength at the resonant frequency and a is the smallest sphere's radius around the antenna [3]. ESA provides simplicity and compact electrical size due to its small ka value. But this smaller ka rises the quality factor ( Q ) to a significant amount. Because of this, a large portion of energy is stored in the antenna structure instead of being radiated. Thus, the ESAs suffer from poor radiation resistance, large loss resistance, and so, limited radiation efficiency. In fact, a decline in the electrical size parameter ka is closely correlated with the decrement in bandwidth as well as gain [1]. Many ways are there to develop ESA from the normal conventional antennas. The two most popular techniques are utilizing defective ground layouts [4] and the metamaterials (MTMs) [5]. Smith et al. [6] practically constructed MTMs, and their special qualities drew antenna designers’ attention [7]. Following that, Erentok and Ziolkowski devised the notion of electrically compact antennas influenced by MTM technology [8]. An ESA often has an excessive reactance due to its small size, so an extensive loss takes place here. Even if this reactance is appropriately corrected, due to the low resistance, the significant resistance mismatch between the source and antenna results in poor radiation. To obtain the remaining resistive match to the source, matching networks for example, the quarter wavelength transformer can be employed. But this transformer violates the ESA criteria along with generates narrower bandwidth. Another type of matching circuit is a compact matching network, made of inductors and L-sections of capacitors [1]. However, it leads to increase the antenna system’s losses and may potentially reduce the ESA bandwidth. But using the MTMs to develop the desired ESA helps to gain exact impedance matching and thus the radiation efficiency gets improved without the help of any matching network [8]. Apart from that, by positioning a unit-cell of MTM next into the antenna element, its attributes are being used to improve the antenna characteristics such as bandwidth, gain magnitude, and number of bands. Here, we focused on transformation of an ordinary antenna into a well-performing ESA by using effective MTM structures. MTM structures are divided broadly as resonant and non-resonant: the later one bears fewer ‘magical’ properties such as left-handed feature, negative and zero refractive index (RI). The resonant MTMs are divided into double positive (µ > 0 and ε > 0), single negative (µ < 0 or ε < 0), and dual negative (DNG) (µ < 0 and ε < 0) structures [9]. While complementary split-ring resonator (CSRR) is a type of epsilon-negative metamaterial (ENG-MTM), SRR is the most widely utilized mu-negative metamaterial (MNG-MTM) [10]. The both MTMs are integrated into patch antennas to convert those into ESAs [11]. CSRRs can be inserted so easily into the ground plane of an antenna without disturbing the patch that radiates. Compared to placing regular SRRs close to the radiator patch, loading the complementary one in the ground can result in a larger size compensation. Generally, an ESA operating in multiple frequency ranges simultaneously with larger bandwidths is difficult to achieve. In [12], successful operation in three different bands with considerable return loss is ensured, but no gain crosses 1.5 dB. Both gain and bandwidth provided are low in [12] and [13]. Some research [14]-[16] make the antenna electrically small but don't have the multi-functional capabilities. For increasing the usable bandwidth and gain, few have broken the condition of an ESA [17]-[19]. So, an ESA operating simultaneously in multiple bands with wider bandwidths is difficult to find. To overcome this problem, in this article, we have tried to build such an ESA that can be tuned to increase its band numbers whenever needed with decent bandwidths. Here, the contributions of double negative metamaterial and MNG metamaterial such as SRR are explored to convert a normal radiating patch antenna into an ESA and enhance its bandwidth, gain, and band numbers as far as possible. The goal of this study was to improve the narrow bandwidth and poor impedance matching of the typical ESAs. To do that task, a unique MTM approach and novel MTM combinations were used. And also, as the first instance, this study ensures five distinct bands from an ESA with sufficient level of bandwidths and gains in each of those bands. 2. Reference Antenna Geometry The first step is the creation of the reference antenna over which, the behavior of metamaterials will be evaluated. Figure 1 (a)-(b) show the antenna structure and the full parametric list of the optimized antenna unit is given in Table 1 . Copper cladding with thickness of 0.035 mm is used at top and under of the substrate. The substrate material here is polyimide having dielectric constant, ε = 3.4, loss tangent, tanδ = 0.006 with 0.1 mm of thickness. This basic antenna measures 38 and 34 mm in length and Table 1 Dimensions needed to sketch the reference antenna structure. Parameters Size (mm) Parameters Size (mm) Thickness 0.1 L2 26 L 38 W3 4.5 W 34 L3 18 W1 4.5 R1 6 L1 32 W2 4.5 breadth, respectively. The antenna's fundamental construction includes a rectangular feeding route having 17 mm of length (LA) and 5.05 mm of width (WA). Antenna's three rectangular bars aid in its efficient operation, and a circular slot inside the patch produces a capacitance effect that helps to get a better impedance matching with the source. The suggested antenna is designed using Electromagnetic Waves, Frequency Domain of the COMSOL Multiphysics software. The designed antenna is found to show three resonances (in Fig. 1 (c)). The value of return loss is almost − 10 dB at 6.6 GHz; this resonance may be ignored by using the − 10 dB criteria [18]. Thus, the antenna is operating in two frequency bands, centered at 2.8 and 9.5 GHz. Though it is a multi-band module, its contributed bandwidth near of 2.8 and 9.5 GHz is too low (nearly zero). This complete resonance curve is a clear indication of too low bandwidth afforded by the primary antenna structure without MTM. These shortcomings are needed to be solved immediately so the tasks are now to make the module an ESA, expand the usable bandwidth and increase the band numbers as can be seen in the following sections. 3. Metamaterial Inspired Antenna Designs, Theories, and Results To fulfill our objectives, Fig. 2 shows the complete road map of our antenna development procedure. At first, a reference antenna is chosen as shown in Fig. 2 (a) of which S-parameter graph is also revealed there. After that, a CDNG-MTM is etched at the ground plane of the reference structure and a MTM based ESA is created (shown in Fig. 2 (b)) which introduces four different resonance bands. Later on, by incorporating the two different MTMs (SRR set and CDNG-MTM) with the patch layout in Fig. 2 (c), resonances at five different frequency bands are ensured with an adequate overall bandwidth level (22% bandwidth increment from the antenna in Fig. 2 (b)) . 3.1. CDNG-MTM Deployed Antenna The basic dual negative metamaterial (DNG-MTM) here was made of two stub lines with a ring. Later, two additional small stubs were added, and the modification of the original DNG structure was carried out (Fig. 3 (b)). Through this event, though the length of each stub increases, but the behavior and overall size are not altered. As a result, DNG-MTM with a ring of metal and gapped L-shaped stubs has made the scope of larger frequency tuning. These stubs, ring as well as gap are to form an LC resonator having a high Q . Based on the concept of duality and Babinet's principle, a DNG-MTM has a complementary or analogous structure (CDNG-MTM) which ensures same operational behavior and properties. CDNG-MTM has been installed by etching the shape in the bottom surface made of copper ((shown in Fig. 3 (b)). Dimensions of this CDNG-MTM for optimum return loss and efficiency have been revealed by parametric analysis and are given in Table 3 . The configurations of this CDNG-MTM installed ESA are revealed in Fig. 3 (a)-(b). The material properties of this CDNG-MTM are recovered by S-parameter retrieval process [20, 21]. A two-port waveguide configuration is set up to find out the S-parameters in Fig. 4 (a). Then by the use of S-parameters, the properties called permeability, permittivity, and refractive index are extracted in CST Microwave Studio. It is observed in Fig. 4 (b) that throughout the 1 to 5.3 GHz range, both µ and ε are negative. Both of them cover this wide frequency with negative values, hence this MTM is referred to as DNG-MTM in this instance. Consequently, here in this band, the generated RI likewise turns negative. The proposed MTM based antenna is modeled, simulated, and optimized in COMSOL Multiphysics software. This antenna shows four return loss dips and operates having four complete bands with their center frequencies of 2 GHz, 6.8 GHz, 9.1 GHz, and 9.6 GHz. Here, it ensures the return loss (S 11 ) values of -15.75 dB, -26.75 dB, -27 dB, and − 21.5 dB at the dips (Fig. 5 (a)). The corresponding gain values of 2.32 dB, 2.82 dB, 5.2 dB, and 3.01 dB are obtained at those frequency regions (indicated in Fig. 5 (b)) and most importantly, found bandwidths are of 1.75 GHz (1.25-3 GHz), 1.175 GHz (6.375–7.55 GHz), 0.185 GHz (9.02–9.205 GHz) as well as 0.54 GHz (9.44–9.98 GHz). The dips of the return loss graph are the clear indications of marvelous impedance match with the source at those frequency locations. While the patch alone was radiating its electromagnetic field, the CDNG-MTM was installed. Consequently, the field was perturbed and supplementary inductive and capacitive outcome made the resonance lower. The patch antenna previously hold larger reactance and due to its high inductive loss, the return loss and bandwidth were too poor. When this antenna is joined with the MTM bearing dual negative characteristics, it made the reactance compensated and eliminated the loss upto a certain level. But there is another problem, in a conventional patch antenna, the resistance is found with a small value and poor impedance matching with the source arises. But here, the ε, µ, and η of the CDNG-MTM are negative in the band from 1 to 5.3 GHz (Fig. 4 (b)), thus the impedance of the full antenna module ( z ) shows significantly greater positive value and better impedance matching in this region. After 5.3 GHz, the parameters all are positive upto 10 GHz and again a preferable impedance matching is ensured. Thus, a more precise impedance matching than the previous antenna module tends to produce more resonances. And finally, the return loss and bandwidth found here are more desirable than the normal patch antenna model. Lastly, VSWR (voltage standing wave ratio) values are 1.4 at 2 GHz, 1.1 at 6.8 GHz, 1.2 at 9.1 GHz, and 1.2 at 9.6 GHz (measured in COMSOL Multiphysics). The VSWR values are nearly 1 which is a sign of better impedance matching and effective radiation but whatever the value of VSWR is, it must be fewer than 2. The formulas needed to calculate the ka value in this case whether it is less than one or not are shown below [22]: $$\:\:a=\frac{F}{\sqrt{1+\frac{2h}{\pi\:{\epsilon\:}_{r}F}\left[\text{ln}\left(\frac{\pi\:F}{2h}\right)+1.7726\right]}}cm\:\:\:\:\:\:$$ 1 $$\:F=\frac{8.791\times\:{10}^{9}}{{f}_{0}\sqrt{{\epsilon\:}_{r}}}$$ 2 here, h = thickness of the antenna structure in cm and f o = resonance frequency in Hz. Using the Eqs. [1–2], a is found to have a value of 2.3 cm and so, the ka value stands 0.9 for the antenna. So, ka < 1 and it satisfies the criteria to be an ESA. The lowest resonance frequency of 2 GHz is assumed as the basis for all mathematical computations. The diffusion of surface current in the designed ESA structure is presented in Fig. 6 . It tells the story of how the current distribution got changed from the lower resonant frequencies to higher ones. The amount of surface current involvement upon the patch decreased significantly from the lower bands to upper bands. Firstly, at 2 and 6.8 GHz, current is dispersed uniformly in patch and CDNG-MTM and that can be a reason of getting somewhat larger bandwidth at those frequency regions. Then gradually the current density is strongly biased in the CDNG-MTM part and thus the bandwidth declined. This change in surface current has a strong effect on the change in the radiation pattern which will be seen in the next image. Antenna radiation patterns at 2, 6.8, 9.1, and 9.6 GHz are plotted in Fig. 7 (a)-(d). Here, the both H-plane and E-plane are showing omni-directional radiation at 2 GHz. In our operational frequency range, the RI of the CDNG-MTM decreases with the decrement in frequency (Fig. 4 (b)). So, consequently the lower bands achieve omni-directional radiation patterns and low gains because of the lower values of the RI. At 6.8 and 9.1 GHz, there is a sign that the radiation is converting from omni-directional to directive whereas at 9.6 GHz, the radiation pattern has nearly become directive. The higher bands achieve quite focused patterns and extensive gains because of the comparatively larger RI values than the lower bands. That results in an elimination of the unnecessary lobes with the enhancement in the radiation efficiency (RE). After installing the CDNG-MTM with the patch antenna, the obtained improvements are illustrated in the Table 2 . While disclosing the overall size of a particular antenna, the unit of measurement used is usually λ o since it expresses the antenna's electrical size operating at various frequencies. As ka size decreased and became less than 1, successful antenna miniaturization is achieved. And also, satisfactory improvements in the mostly required properties (bandwidth, band number) are visible. It was urgent here to pull up the bandwidth from nearly zero as well as increase multi-functionality. To develop more operating bands and band tunability can be a future scope and thus, another unique MTM-Patch combination has been tried in the next section. Table 2 Performance comparison between the CDNG-MTM antenna and the conventional antenna. Antenna Type No. of Bands Resonance Frequency (GHz) Antenna Size ka value BW (GHz) Patch 2 2.8, 9.5 0.32λ 0 × 0.36λ 0 × 0.0009 λ 0 1 Nearly Zero Patch with CDNG-MTM 4 2, 6.8, 9.1, 9.6 0.25λ 0 × 0.23λ 0 × 0.0007 λ 0 0.9 1.75, 1.175, 0.185, 0.54 3.2. Further Extension of the Invented ESA With the successful installation of the proposed CDNG-MTM, notable developments have been delivered on a regularly available antenna. In this subsection, this CDNG-MTM will be integrated with two SRRs to see how the response of the whole ESA module changes. Here, an analysis will be made by keeping the patch, CDNG-MTM, and SRRs all in a single antenna unit. 3.2.1 Antenna with Double MTMs Here an extension is done by applying two metamaterial structures in one single block of antenna just to add more features (resonant band in this case). In detail, a MTM set of two rectangular split-ring resonator (SRR) rings are attached on top beside the patch structure (represented in Fig. 8 (a)). Moreover, a CDNG-MTM is loaded at the antenna bottom surface by etching (in Fig. 8 (b)) like before. The optimized parameters (extracted by parametric sweep) to design this SRRs are shown in Table 3 . The alliance of these two MTM structures generates red shift of resonance as this time the effect of capacitance along with inductance from the MTM structures is more and robust. Table 3 Essential parameters for designing the MTMs used in this article. CDNG-MTM Dimensions Size (mm) SRR Parameters Size (mm) R1 7.6 H5 14.4 R2 8.35 W5 0.4 W3 7.3 H6 12 H3 1.8 W6 13.1 W4 0.5 H7 6.95 H4 7.25 W7 10.35 S1 0.05 H8 5.75 D1 0.6 P1 1.3 Figure 8 (c) shows the return loss (S 11 ) graph with respect to the frequency and it indicates that, there is an increment in the number of bands and the resonances are now at 1.7 GHz, 3.5 GHz, 5 GHz, 7 GHz, and 9.1 GHz. In this module, the SRR set ensures positive and the CDNG-MTM on the same block produces negative RI of high magnitude (Fig. 4 (b)) in the frequency range of 1 to 5.3 GHz. So, due to the combination of the both, the resultant RI generated here is negative. Besides, the both MTMs compositely furnish negative µ and ε, thus, the antenna impedance becomes convincingly positive and impedance matching is arranged quite well before 5.3 GHz. So, there three resonances with impressive return loss dips and bandwidths are managed. After crossing that frequency area, refractive index from SRRs is still positive and CDNG-MTM gives rise to a positive RI which collectively feature of a high magnitude positive RI. Moreover, their jointly developed ε and µ are positive (CDNG-MTM's permeability is more positive than SRR set's negative permeability in this case). Then, those become responsible to make the z (impedance of the antenna module) competently positive again and thus impedance matching happens so well repeatedly that two more resonances at 7 and 9.1 GHz with appreciable return loss are generated. From the point of view of return loss and resonance dip number, this ESA shows obviously promising achievements. Bandwidths of 0.7 GHz (1.4 GHz to 2.1 GHz), 1.2 GHz (2.9 GHz to 4.1 GHz), 0.26 GHz (4.78 GHz to 5.04 GHz), 1.6 GHz (6.4 GHz to 8 GHz), and 0.7 GHz (9 to 9.7 GHz) whereas gain values of 1.38 dB, 2.9 dB, 2.79 dB, 1.52 dB, and 4.87 dB are available at the resonance regions. In this module, 22% of overall bandwidth improvement has been ensured than the previous CDNG-MTM based ESA. In spite of gain abandonment, the increment in overall bandwidth and band number says that this formation can be said to be the best for multi-band operations. Besides, size miniaturization has reached upto 0.22λ 0 × 0.19λ 0 × 0.0006λ 0 and ka = 0.85 this time which made the antenna electrically smaller than the ESA with CDNG-MTM only. As a result, this MTM based ESA introduced five complete operating bands for the first time. The final achievements from the two MTM-based antennas and their corresponding applications are discussed in Table 4 . Table 4 Improvements achieved in both of the MTM-based ESAs. ESA Type No. of Bands Bandwidths (GHz) Relevant Standards Typical Applications CDNG-MTM installed 4 1.75, 1.175, 0.185, 0.54 IEEE 802.16, IEEE 802.11ax, IEEE X-Band WiMAX, Next-gen Wi-Fi (6E), X-band radar, Satellite communication CDNG-MTM + SRR installed 5 0.7, 1.2, 0.26, 1.6, 0.7 LTE Bands,5G NR, IEEE 802.11a, Wi-Fi 6E/7, SATCOM 4G/5G mobile, 5G wireless, High-speed Wi-Fi, Satellite links Table 5 presents a comparison among our proposed CDNG-MTM installed ESA and several MTM-based antennas described in other studies. Here, [23], [25], [19], and [17] are capable to provide only one band in operation. So, they can never be considered in multi-functional devices whereas our prescribed antennas simultaneously can operate in four as well as five bands. However, [24], [18], [26] can ensure only 2 frequency bands but they take up more spaces than our ESAs. And also, [24] cannot operate above 2.9 GHz which is a great concern and its bandwidths are not satisfactory whereas our CDNG-MTM installed antenna resonances upto 9.6 GHz with decent overall bandwidth. The value of ka > 1 for the antenna in [18] so it will not be considered as an ESA. Article [27] introduces a higher VSWR value than us which is a bad sign for effective radiation and it contains a larger antenna size than ours only to contribute just 2 resonances. Lastly, [13] brings 3 bands (still less than us) with a low bandwidth level. Our two ESAs successfully achieved smaller sizes, excellent overall bandwidths with multi-band functionalities in four as well as five bands respectively. Electron beam lithography (EBL) fabrication technique can be used to fabricate the antenna prototypes. At first, a substrate layer made of polyimide with the exact size is to be set above the copper ground layer. Then the copper patch should be grown upon the polyimide substrate using the deposition technique. Finally, the SRRs can be placed beside the patch and CDNG-MTM will be etched on the ground plane for manufacturing both of the MTM installed ESAs. Table 4 Comparison of proposed antenna with the related literature. [Ref.] Year No. of Bands Antenna Size (λ 3 ) VSWR Return Loss (dB) Resonant Freq. (GHz) BW (GHz) Permittivity & Thickness (mm) ka value [23] 1 1.035×1.305 ×0.56 - -17 2.65 0.23 3.9 63.3 0.75 [24] 2 0.8×0.8 ×0.013 - -10.25, -30 2.4, 2.9 0, 0.5 4.4 1.6 0.85 [13] 3 0.254×0.207 ×0.013 - -26, -28, -19 2.44, 6.05, 8.54 0.066, 0.42, 0.324 4.3 1.6 0.94 [18] 2 0.38×0.56 ×0.109 - -33, -45 5.5, 20 0.34, 2.86 2.3 5.958 1.02 [25] 1 0.272×0.317 ×0.007 1.1 -28 1.36 0.05 3 1.524 0.79 [26] 2 0.5×0.35 ×0.02 - -25, -17.5 4.7, 8.5 0.45, 0.87 4.4 1.6 0.84 [19] 1 0.51×0.51 ×0.17 - -13 12.5 1.87 2.2 4.83 1.01 [27] 2 0.42×0.42 ×0.019 1.7 -18, -24 3.5, 4.9 0.4, 0.75 4.3 1.6 0.85 [17] 1 1.905×1.429 ×0.048 - -21 28.6 3.8 2.2 0.508 1.11 Our Model 4 0.25×0.23 ×0.0007 1.2 -15.75, -26.75, -27, -21.5 2, 6.8, 9.1, 9.6 1.75, 1.175, 0.185, 0.54 3.4 0.1 0.9 4. Conclusion In summary, our primary objectives were to achieve multi-band operational capability, considerable enlarged bandwidth, and sufficient reduction of antenna size with the help of MTMs. Four individual bands of resonance with notable return loss depths and impressive bandwidths were ensured in an ESA using the CDNG-MTM. Not only that, all the values of VSWR found at these resonances were much smaller than 2 which indicates adequate impedance matching happened here. As the last case, the four band response was upgraded to five band response with an additional resonance band and 22% increased overall bandwidth. Finally, a novel MTM installed ESA is introduced by combining CDNG-MTM, SRRs, and patch in a single block. Due to the beneficial features as discussed, the last ESA device may find application in different areas such as LTE bands, advanced 4G/5G communication, Wi-Fi 6E/7, SATCOM, and many more. Declarations Declaration of generative AI and AI-assisted technologies in the writing process During the preparation of this work, the author(s) used ChatGPT and Grammarly to improve the writing. After using this tool, the author(s) reviewed and edited the content as needed and take full responsibility for the content of the publication. Authors Contributions: Conceptualization , Sakib Sadman, Md Abu Huraiya ; Data curation, Formal analysis, Investigation, Sakib Sadman , Md Abu Huraiya ; Resources, Software, Sakib Sadman , Md Abu Huraiya ; Supervision, Validation, Md Abu Huraiya ; Visualization, Writing - original draft , Sakib Sadman, Md Abu Huraiya ; Writing- review editing, Sakib Sadman, Md Abu Huraiya. Funding: no funding Availability of Data and Material: Not applicable. Code Availability: Not applicable . Ethics Approval: Not applicable. Consent to Participate: Not applicable. Consent for Publication: Not applicable. Conflict of interest: No competing interests. References Jin, P., Ziolkowski, R.W.: Low-q, electrically small, efficient near-field resonant parasitic antennas. IEEE Transactions on Antennas and Propagation 57(9), 2548–2563 (2009) Gao, X., Zhang, Y., Li, S.: High refractive index metamaterial superstrate for microstrip patch antenna performance improvement. Frontiers in Physics 8, 580185 (2020) Wheeler, H.A.: Fundamental limitations of small antennas. Proceedings of the IRE 35(12), 1479–1484 (1947) Patel, R., Desai, A., Upadhyaya, T.K.: An electrically small antenna using defected ground structure for rfid, gps and ieee 802.11 a/b/g/s applications. Progress in electromagnetics research letters 75, 75–81 (2018) Zulfiker Mahmud, M., Islam, M.T., Misran, N., Singh, M.J., Mat, K.: A negative index metamaterial to enhance the performance of miniaturized uwb antenna for microwave imaging applications. Applied Sciences 7(11), 1149 (2017) Smith, D.R., Padilla, W.J., Vier, D., Nemat-Nasser, S.C., Schultz, S.: Composite medium with simultaneously negative permeability and permittivity. Physical review letters 84(18), 4184 (2000) Kumar, P., Ali, T., Pai, M.M.: Electromagnetic metamaterials: A new paradigm of antenna design. IEEE Access 9, 18722–18751 (2021) Erentok, A., Ziolkowski, R.W.: Metamaterial-inspired efficient electrically small antennas. IEEE Transactions on Antennas and Propagation 56(3), 691–707 (2008) Ziolkowski, R.W.: Design, fabrication, and testing of double negative meta materials. IEEE Transactions on antennas and Propagation 51(7), 1516–1529 (2003) Ameen, M., Chaudhary, R.: Metamaterial-based circularly polarised antenna employing eng-tl with enhanced bandwidth for wlan applications. Electronics Letters 54(20), 1152–1154 (2018) Raval, F., Kosta, Y., Joshi, H.: Reduced size patch antenna using complementary split ring resonator as defected ground plane. AEU-International Journal of Electronics and Communications 69(8), 1126–1133 (2015) [12] Patel, R., Desai, A., Upadhyaya, T.K.: An electrically small antenna using defected ground structure for rfid, gps and ieee 802.11 a/b/g/s applications. Progress in electromagnetics research letters 75, 75–81 (2018) Tamim, A.M., Faruque, M.R., Islam, M.T.: Metamaterial-inspired electrically small antenna for microwave applications. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 236(11), 2230–2241 (2022) Chaturvedi, D., Raghavan, S.: Srr-loaded metamaterial-inspired electrically-small monopole antenna. Progress In Electromagnetics Research C 81, 11–19 (2018) Hussain, N., Naqvi, S.I., Awan, W.A., Le, T.T.: A metasurface-based wideband bidirectional same-sense circularly polarized antenna. International Journal of RF and Microwave Computer-Aided Engineering 30(8), 22262 (2020) Marwaha, A., et al.: Csc-sr structure loaded electrically small planar antenna. Applied Computational Electromagnetics Society Journal 31(5), 591 (2016) [17] Esmail, B.A., Koziel, S.: Design and optimization of metamaterial-based highly isolated mimo antenna with high gain and beam tilting ability for 5g millimeter wave applications. Scientific Reports 14(1), 3203 (2024) Asif, M., Sehrai, D.A., Kiani, S.H., Khan, J., Abdullah, M., Ibrar, M., Alibakhshikenari, M., Falcone, F., Limiti, E.: Design of a dual band sng meta material based antenna for lte 46/wlan and ka-band applications. IEEE Access 9, 71553–71562 (2021) [19] Alam, T., Islam, M.T., Hakim, M.L., Alharbi, K.H., Singh, M.S.J., Sheikh, M.M., Aldhaheri, R.W., Islam, M.S., Soliman, M.S.: Metamaterial based ku-band antenna for low earth orbit nanosatellite payload system. Nanomaterials 13(2), 228 (2023) Thankachan, S., Paul, B., Pradeep, A., Moolat, R.: Design and characterisation of simple planar metamaterial structure with double negative properties. In: TEN CON 2019-2019 IEEE Region 10 Conference (TENCON), pp. 1231–1235 (2019). IEEE Li, Z., Aydin, K., Ozbay, E.: Determination of the effective constitutive parame ters of bianisotropic metamaterials from reflection and transmission coefficients. Physical review E 79(2), 026610 (2009) [22] Ibrahim, K.M., Hassan, W.M., Abdallah, E.A., Attiya, A.M., et al.: Wideband octagonal dual circularly polarized sub-array antenna for ku-satellite systems. Applied Computational Electromagnetics Society Journal 35(12), 1500 (2020) Jeong, H., Kim, Y., Tentzeris, M.M., Lim, S.: Gain-enhanced metamaterial absorber-loaded monopole antenna for reduced radar cross-section and back radiation. Materials 13(5), 1247 (2020) Abdalla, M.A., Wahba, W.W., Allam, A.A.: Analysis and design of a compact crlh inspired–defected ground resonators for triple band antenna applications. Engineering Science and Technology, an International Journal 23(1), 114–122 (2020) Kucukoner, E.M., Cinar, A., Kose, U., Ekmekci, E.: Electrical size reduc tion of microstrip antennas by using defected ground structures composed of complementary split ring resonator. Advanced Electromagnetics 10(1), 62–69 (2021) Armghan, A., Patel, S.K., Lavadiya, S., Qamar, S., Alsharari, M., Daher, M.G., Althuwayb, A.A., Alenezi, F., Aliqab, K.: Design and fabrication of compact, multiband, high gain, high isolation, metamaterial-based mimo antennas for wireless communication systems. Micromachines 14(2), 357 (2023) Alsisi, R.H., Karimbu Vallappil, A., Wajid, H.A.: A metamaterial-based double sided bowtie antenna for intelligent transport system communications operating in public safety band. Crystals 13(2), 360 (2023 Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 22 Jan, 2026 Reviews received at journal 22 Jan, 2026 Reviews received at journal 22 Jan, 2026 Reviewers agreed at journal 21 Jan, 2026 Reviewers agreed at journal 21 Jan, 2026 Reviewers invited by journal 21 Jan, 2026 Editor assigned by journal 19 Jan, 2026 Submission checks completed at journal 19 Jan, 2026 First submitted to journal 17 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8626984","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":578770848,"identity":"1c002109-5c05-4d69-b327-659b78fed9f0","order_by":0,"name":"Sakib Sadman","email":"","orcid":"","institution":"Rajshahi University of Engineering \u0026 Technology","correspondingAuthor":false,"prefix":"","firstName":"Sakib","middleName":"","lastName":"Sadman","suffix":""},{"id":578770849,"identity":"a39ccdb9-7c1e-4a70-a0a4-b220072390ac","order_by":1,"name":"Md Abu Huraira","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABEElEQVRIiWNgGAWjYBACAxCRgCzCDxYpIEGLhGQDSMSAgBZkIGFwAKs4AphL5D788LDNjoGfvfkAc2WbTZ3x+dWJHx4YMMjzix3AqsVyRrqxRGJbMoNkz7EExrNtaRJmN95ulgA6zHDm7ASsWgxupDEAtTADGTkGjI1th4Fazm4AaUkwuI1TC/OPxLZ6Bvv77z8AtfyXMJ5xdvMPAlrYgLYcZjCQ4GEAajkgYcDfuw2/LWeesVkknDvOI3EmzeBgw7lkyRk3eLdZJBhI4PbL8TTmmz/KquX42w8/fNhQZsfP3392880fFTby/NLYtYABIxsDD4g+AOZJgFVK4FYOBn+QOfwHCKgeBaNgFIyCkQYA+QpdevLLR8AAAAAASUVORK5CYII=","orcid":"","institution":"Rajshahi University of Engineering \u0026 Technology","correspondingAuthor":true,"prefix":"","firstName":"Md","middleName":"Abu","lastName":"Huraira","suffix":""}],"badges":[],"createdAt":"2026-01-17 15:23:45","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8626984/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8626984/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":100985339,"identity":"83e2ebac-a39f-49ca-b1b9-1a7df71c2156","added_by":"auto","created_at":"2026-01-23 13:07:20","extension":"docx","order_by":0,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":2393899,"visible":true,"origin":"","legend":"","description":"","filename":"Manuscript310725.docx","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/8ae41fc44daafb6cf717754f.docx"},{"id":101204191,"identity":"c6b5167f-b545-4883-8d2a-bec9cea05169","added_by":"auto","created_at":"2026-01-27 09:41:55","extension":"json","order_by":1,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":4172,"visible":true,"origin":"","legend":"","description":"","filename":"8877d2f06dc44548a4a533808016b30f.json","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/d292cc5bec88398131c494b1.json"},{"id":100985335,"identity":"5a53d2c8-0329-4808-b454-d80b0e22d17a","added_by":"auto","created_at":"2026-01-23 13:07:20","extension":"xml","order_by":2,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72313,"visible":true,"origin":"","legend":"","description":"","filename":"8877d2f06dc44548a4a533808016b30f1enriched.xml","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/3381243949a1e57534ee841d.xml"},{"id":100985346,"identity":"e8488b90-b57b-470c-9b8f-fc54d0e2b89f","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":11,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":49633,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/acbab47ed1ff76e1dae063bc.png"},{"id":101203804,"identity":"0fb74a5e-cdd3-4ed4-b41a-2f1b7eee0de2","added_by":"auto","created_at":"2026-01-27 09:40:42","extension":"png","order_by":12,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":52035,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/ab559e2078d9400550c10f9e.png"},{"id":100985344,"identity":"cb4c1442-b248-4aef-9bda-b6bcdb61a17c","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":13,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":14922,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/4ba276db9b001dcca555b504.png"},{"id":100985348,"identity":"dbafe401-304f-423c-95ac-7687cad63757","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":14,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":19953,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/0221716e0d9f6df76a842275.png"},{"id":101203315,"identity":"93b02bf0-d7de-4579-9b29-b90a9f7f5fbb","added_by":"auto","created_at":"2026-01-27 09:39:22","extension":"png","order_by":15,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":22329,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/8e7cbfb5b9397333565c14f2.png"},{"id":101203536,"identity":"3a515670-ac4c-4c3c-8180-c13fed34588a","added_by":"auto","created_at":"2026-01-27 09:40:01","extension":"png","order_by":16,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":397673,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/d68c0d546c8ac18283d96cad.png"},{"id":100985351,"identity":"db975d56-7dd7-407b-9eaf-6b61e1c7143c","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":17,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":51910,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/0f53aec73d4a74ebd30a64f6.png"},{"id":100985350,"identity":"a75280c7-6782-49fc-987e-9ab31dbe5868","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":18,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":22877,"visible":true,"origin":"","legend":"","description":"","filename":"Onlinefloatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/cf472df3a1b0eeffa9fc01a2.png"},{"id":101203642,"identity":"d7574cca-a6f4-453b-a98c-c5458cda3b9e","added_by":"auto","created_at":"2026-01-27 09:40:18","extension":"xml","order_by":19,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":72796,"visible":true,"origin":"","legend":"","description":"","filename":"8877d2f06dc44548a4a533808016b30f1structuring.xml","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/5fd53dae5d9dd02ea8719e8d.xml"},{"id":100985354,"identity":"62eec5b6-64cf-48d7-8e13-e90498d0a675","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"html","order_by":20,"title":"","display":"","copyAsset":false,"role":"acdc-reference","size":78403,"visible":true,"origin":"","legend":"","description":"","filename":"earlyproof.html","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/c3acbe1f4b33fb6724aadbc6.html"},{"id":100985343,"identity":"2bf0efd6-a486-4863-81c2-fdfaacddebbb","added_by":"auto","created_at":"2026-01-23 13:07:21","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":60090,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Top surface along with dimensions, and (b) bottom surface, of the reference patch antenna where metamaterials have not yet been deployed. (c) Return loss response as the function of frequency.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/0d2a76227992b5861ea56951.png"},{"id":100985336,"identity":"57f8b120-2a1a-43a6-90b1-2a9ab502af7e","added_by":"auto","created_at":"2026-01-23 13:07:20","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":154201,"visible":true,"origin":"","legend":"\u003cp\u003e(a) The primarily used antenna structure with its return loss response (S\u003csub\u003e11\u003c/sub\u003e) in dB, (b) CDNG-MTM installed patch antenna and its return loss, and (c) MTM based antenna using one CDNG-MTM and two SRRs with the corresponding return loss curve.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/1c4ad6cb7aceba07bacd6b97.png"},{"id":100985338,"identity":"f595b35e-532e-48cc-a8d7-a40e2db0e277","added_by":"auto","created_at":"2026-01-23 13:07:20","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":37202,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Top view of CDNG-MTM based antenna holding the patch layout (similar with the upper sight of the previous antenna without MTM), and (b) bottom view where a CDNG-MTM is etched.\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/b258f46b56e42d7f65468265.png"},{"id":101297274,"identity":"5c8c4c6e-49ba-4eea-9759-1a94c3c7b880","added_by":"auto","created_at":"2026-01-28 09:26:17","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":54815,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Two-port waveguide setup with a vision to extract the S-parameters, and (b) graph of the real values of relative permittivity (ε), relative permeability (µ), and refractive index (n) with respect to frequency.\u003c/p\u003e","description":"","filename":"floatimage4.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/28aa3d56ace61d46a462db30.png"},{"id":101204156,"identity":"78e4bf4b-5ca1-4633-b15b-1d124bf5560c","added_by":"auto","created_at":"2026-01-27 09:41:49","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":24122,"visible":true,"origin":"","legend":"\u003cp\u003e(a) Return loss showing total four resonances provided by the ESA unit formed by connecting only one metamaterial (CDNG-MTM) structure with the ordinary patch, (b) gain plot of that corresponding module.\u003c/p\u003e","description":"","filename":"floatimage5.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/015a863a354707898559c45b.png"},{"id":101203519,"identity":"0ead6352-234a-4793-b93b-9d8199159a82","added_by":"auto","created_at":"2026-01-27 09:39:58","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1826909,"visible":true,"origin":"","legend":"\u003cp\u003eScattered surface current at (a) 2 GHz, (b) 6.8 GHz, (c) 9.1 GHz, and finally at (d) 9.6 GHz.\u003c/p\u003e","description":"","filename":"floatimage6.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/38663bc52ddb360a00ef6454.png"},{"id":101203200,"identity":"ed2dd64f-b9af-465b-aa58-87cb0bce5f94","added_by":"auto","created_at":"2026-01-27 09:39:03","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":165386,"visible":true,"origin":"","legend":"\u003cp\u003eVisualization of E-plane and H-plane at (a) 2 GHz, (b) 6.8 GHz, (c) 9.1 GHz, and (d) 9.6 GHz, respectively.\u003c/p\u003e","description":"","filename":"floatimage7.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/2ce48e06f65c4fe54128fe1c.png"},{"id":100985337,"identity":"b130f26a-0a5a-4f97-abd4-5389ac907ec4","added_by":"auto","created_at":"2026-01-23 13:07:20","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":56243,"visible":true,"origin":"","legend":"\u003cp\u003ePatch with double metamaterials in a single antenna element, (a) top of which bearing regular patch shape along with a rectangular SRR set consisting of two rings with a gap of 6.95 mm between them, (b) bottom with the CDNG-MTM etched on the ground, and (c) illustration of the final return loss (S\u003csub\u003e11\u003c/sub\u003e) response after connecting the CDNG-MTM \u0026amp; SRRs with the primary reference antenna unit.\u003c/p\u003e","description":"","filename":"floatimage8.png","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/8a723414763978122abb88a3.png"},{"id":101300505,"identity":"f8dc8475-7f27-4173-9e39-b4a0a3fa4553","added_by":"auto","created_at":"2026-01-28 09:48:53","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3225820,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8626984/v1/90dcde08-7ea9-44d3-885f-d8fadebbfec0.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Metamaterial inspired electrically small antennas with enhanced bandwidth and multi- band compatibility","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eNowadays, the convenience of wireless communication has led to a rapid increase in the use of wireless and compact communication devices. This has created a strong demand for miniature antennas with multi-band capabilities. As a result, electrically small antennas (ESAs) have been a key area of research for quite some time due to their small size, which makes them ideal for a wide range of wireless applications, such as wireless sensor networks, private communications, unmanned devices, and many more [1]. Microstrip patches are among the most widely used conventional antenna types for ESA transformation due to their many benefits, including low cost, minimal complexity of design, and ease of production [2]. ESA is with specific defining electrical characteristics that were first suggested by Wheeler, and then developed by Chu. An antenna will be definitely considered as an ESA if it satisfies the formula \u003cem\u003eka\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;1; whereas \u003cem\u003ek\u003c/em\u003e is defined as the wave number and is equal to 2π/λ\u003csub\u003e0\u003c/sub\u003e, λ\u003csub\u003e0\u003c/sub\u003e is the free space wavelength at the resonant frequency and \u003cem\u003ea\u003c/em\u003e is the smallest sphere's radius around the antenna [3]. ESA provides simplicity and compact electrical size due to its small \u003cem\u003eka\u003c/em\u003e value. But this smaller \u003cem\u003eka\u003c/em\u003e rises the quality factor (\u003cem\u003eQ\u003c/em\u003e) to a significant amount. Because of this, a large portion of energy is stored in the antenna structure instead of being radiated. Thus, the ESAs suffer from poor radiation resistance, large loss resistance, and so, limited radiation efficiency. In fact, a decline in the electrical size parameter \u003cem\u003eka\u003c/em\u003e is closely correlated with the decrement in bandwidth as well as gain [1].\u003c/p\u003e \u003cp\u003eMany ways are there to develop ESA from the normal conventional antennas. The two most popular techniques are utilizing defective ground layouts [4] and the metamaterials (MTMs) [5]. Smith et al. [6] practically constructed MTMs, and their special qualities drew antenna designers\u0026rsquo; attention [7]. Following that, Erentok and Ziolkowski devised the notion of electrically compact antennas influenced by MTM technology [8]. An ESA often has an excessive reactance due to its small size, so an extensive loss takes place here. Even if this reactance is appropriately corrected, due to the low resistance, the significant resistance mismatch between the source and antenna results in poor radiation. To obtain the remaining resistive match to the source, matching networks for example, the quarter wavelength transformer can be employed. But this transformer violates the ESA criteria along with generates narrower bandwidth. Another type of matching circuit is a compact matching network, made of inductors and L-sections of capacitors [1]. However, it leads to increase the antenna system\u0026rsquo;s losses and may potentially reduce the ESA bandwidth. But using the MTMs to develop the desired ESA helps to gain exact impedance matching and thus the radiation efficiency gets improved without the help of any matching network [8]. Apart from that, by positioning a unit-cell of MTM next into the antenna element, its attributes are being used to improve the antenna characteristics such as bandwidth, gain magnitude, and number of bands. Here, we focused on transformation of an ordinary antenna into a well-performing ESA by using effective MTM structures.\u003c/p\u003e \u003cp\u003eMTM structures are divided broadly as resonant and non-resonant: the later one bears fewer \u0026lsquo;magical\u0026rsquo; properties such as left-handed feature, negative and zero refractive index (RI). The resonant MTMs are divided into double positive (\u0026micro;\u0026thinsp;\u0026gt;\u0026thinsp;0 and ε\u0026thinsp;\u0026gt;\u0026thinsp;0), single negative (\u0026micro;\u0026thinsp;\u0026lt;\u0026thinsp;0 or ε\u0026thinsp;\u0026lt;\u0026thinsp;0), and dual negative (DNG) (\u0026micro;\u0026thinsp;\u0026lt;\u0026thinsp;0 and ε\u0026thinsp;\u0026lt;\u0026thinsp;0) structures [9]. While complementary split-ring resonator (CSRR) is a type of epsilon-negative metamaterial (ENG-MTM), SRR is the most widely utilized mu-negative metamaterial (MNG-MTM) [10]. The both MTMs are integrated into patch antennas to convert those into ESAs [11]. CSRRs can be inserted so easily into the ground plane of an antenna without disturbing the patch that radiates. Compared to placing regular SRRs close to the radiator patch, loading the complementary one in the ground can result in a larger size compensation.\u003c/p\u003e \u003cp\u003eGenerally, an ESA operating in multiple frequency ranges simultaneously with larger bandwidths is difficult to achieve. In [12], successful operation in three different bands with considerable return loss is ensured, but no gain crosses 1.5 dB. Both gain and bandwidth provided are low in [12] and [13]. Some research [14]-[16] make the antenna electrically small but don't have the multi-functional capabilities. For increasing the usable bandwidth and gain, few have broken the condition of an ESA [17]-[19]. So, an ESA operating simultaneously in multiple bands with wider bandwidths is difficult to find.\u003c/p\u003e \u003cp\u003eTo overcome this problem, in this article, we have tried to build such an ESA that can be tuned to increase its band numbers whenever needed with decent bandwidths. Here, the contributions of double negative metamaterial and MNG metamaterial such as SRR are explored to convert a normal radiating patch antenna into an ESA and enhance its bandwidth, gain, and band numbers as far as possible. The goal of this study was to improve the narrow bandwidth and poor impedance matching of the typical ESAs. To do that task, a unique MTM approach and novel MTM combinations were used. And also, as the first instance, this study ensures five distinct bands from an ESA with sufficient level of bandwidths and gains in each of those bands.\u003c/p\u003e"},{"header":"2. Reference Antenna Geometry","content":"\u003cp\u003eThe first step is the creation of the reference antenna over which, the behavior of metamaterials will be evaluated. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(a)-(b) show the antenna structure and the full parametric list of the optimized antenna unit is given in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Copper cladding with thickness of 0.035 mm is used at top and under of the substrate. The substrate material here is polyimide having dielectric constant, ε\u0026thinsp;=\u0026thinsp;3.4, loss tangent, tanδ\u0026thinsp;=\u0026thinsp;0.006 with 0.1 mm of thickness. This basic antenna measures 38 and 34 mm in length and\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eDimensions needed to sketch the reference antenna structure.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSize (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eParameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSize (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThickness\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eL2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e38\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eW\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e34\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eL3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e18\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eW1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eR1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eL1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eW2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e4.5\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003ebreadth, respectively. The antenna's fundamental construction includes a rectangular feeding route having 17 mm of length (LA) and 5.05 mm of width (WA). Antenna's three rectangular bars aid in its efficient operation, and a circular slot inside the patch produces a capacitance effect that helps to get a better impedance matching with the source. The suggested antenna is designed using Electromagnetic Waves, Frequency Domain of the COMSOL Multiphysics software.\u003c/p\u003e \u003cp\u003eThe designed antenna is found to show three resonances (in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e(c)). The value of return loss is almost \u0026minus;\u0026thinsp;10 dB at 6.6 GHz; this resonance may be ignored by using the \u0026minus;\u0026thinsp;10 dB criteria [18]. Thus, the antenna is operating in two frequency bands, centered at 2.8 and 9.5 GHz. Though it is a multi-band module, its contributed bandwidth near of 2.8 and 9.5 GHz is too low (nearly zero). This complete resonance curve is a clear indication of too low bandwidth afforded by the primary antenna structure without MTM. These shortcomings are needed to be solved immediately so the tasks are now to make the module an ESA, expand the usable bandwidth and increase the band numbers as can be seen in the following sections.\u003c/p\u003e"},{"header":"3. Metamaterial Inspired Antenna Designs, Theories, and Results","content":"\u003cp\u003eTo fulfill our objectives, Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e shows the complete road map of our antenna development procedure. At first, a reference antenna is chosen as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(a) of which S-parameter graph is also revealed there. After that, a CDNG-MTM is etched at the ground plane of the reference structure and a MTM based ESA is created (shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b)) which introduces four different resonance bands. Later on, by incorporating the two different MTMs (SRR set and CDNG-MTM) with the patch layout in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(c), resonances at five different frequency bands are ensured with an adequate overall bandwidth level (22% bandwidth increment from the antenna in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e(b)) .\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e3.1. CDNG-MTM Deployed Antenna\u003c/h2\u003e \u003cp\u003eThe basic dual negative metamaterial (DNG-MTM) here was made of two stub lines with a ring. Later, two additional small stubs were added, and the modification of the original DNG structure was carried out (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(b)). Through this event, though the length of each stub increases, but the behavior and overall size are not altered. As a result, DNG-MTM with a ring of metal and gapped L-shaped stubs has made the scope of larger frequency tuning. These stubs, ring as well as gap are to form an LC resonator having a high \u003cem\u003eQ\u003c/em\u003e. Based on the concept of duality and Babinet's principle, a DNG-MTM has a complementary or analogous structure (CDNG-MTM) which ensures same operational behavior and properties. CDNG-MTM has been installed by etching the shape in the bottom surface made of copper ((shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(b)). Dimensions of this CDNG-MTM for optimum return loss and efficiency have been revealed by parametric analysis and are given in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The configurations of this CDNG-MTM installed ESA are revealed in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e(a)-(b).\u003c/p\u003e \u003cp\u003eThe material properties of this CDNG-MTM are recovered by S-parameter retrieval process [20, 21]. A two-port waveguide configuration is set up to find out the S-parameters in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(a). Then by the use of S-parameters, the properties called permeability, permittivity, and refractive index are extracted in CST Microwave Studio. It is observed in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b) that throughout the 1 to 5.3 GHz range, both \u0026micro; and ε are negative. Both of them cover this wide frequency with negative values, hence this MTM is referred to as DNG-MTM in this instance. Consequently, here in this band, the generated RI likewise turns negative.\u003c/p\u003e \u003cp\u003eThe proposed MTM based antenna is modeled, simulated, and optimized in COMSOL Multiphysics software. This antenna shows four return loss dips and operates having four complete bands with their center frequencies of 2 GHz, 6.8\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eGHz, 9.1 GHz, and 9.6 GHz. Here, it ensures the return loss (S\u003csub\u003e11\u003c/sub\u003e) values of -15.75 dB, -26.75 dB, -27 dB, and \u0026minus;\u0026thinsp;21.5 dB at the dips (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(a)). The corresponding gain values of 2.32 dB, 2.82 dB, 5.2 dB, and 3.01 dB are obtained at those frequency regions (indicated in Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e(b)) and most importantly, found bandwidths are of 1.75 GHz (1.25-3 GHz), 1.175 GHz (6.375\u0026ndash;7.55 GHz), 0.185 GHz (9.02\u0026ndash;9.205 GHz) as well as 0.54 GHz (9.44\u0026ndash;9.98 GHz). The dips of the return loss graph are the clear indications of marvelous impedance match with the source at those frequency locations. While the patch alone was radiating its electromagnetic field, the CDNG-MTM was installed. Consequently, the field was perturbed and supplementary inductive and capacitive outcome made the resonance lower.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe patch antenna previously hold larger reactance and due to its high inductive loss, the return loss and bandwidth were too poor. When this antenna is joined with the MTM bearing dual negative characteristics, it made the reactance compensated and eliminated the loss upto a certain level. But there is another problem, in a conventional patch antenna, the resistance is found with a small value and poor impedance matching with the source arises. But here, the ε, \u0026micro;, and η of the CDNG-MTM are negative in the band from 1 to 5.3 GHz (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b)), thus the impedance of the full antenna module (\u003cem\u003ez\u003c/em\u003e) shows significantly greater positive value and better impedance matching in this region. After 5.3 GHz, the parameters all are positive upto 10 GHz and again a preferable impedance matching is ensured. Thus, a more precise impedance matching than the previous antenna module tends to produce more resonances. And finally, the return loss and bandwidth found here are more desirable than the normal patch antenna model. Lastly, VSWR (voltage standing wave ratio) values are 1.4 at 2 GHz, 1.1 at 6.8 GHz, 1.2 at 9.1 GHz, and 1.2 at 9.6 GHz (measured in COMSOL Multiphysics). The VSWR values are nearly 1 which is a sign of better impedance matching and effective radiation but whatever the value of VSWR is, it must be fewer than 2.\u003c/p\u003e \u003cp\u003eThe formulas needed to calculate the \u003cem\u003eka\u003c/em\u003e value in this case whether it is less than one or not are shown below [22]:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:\\:a=\\frac{F}{\\sqrt{1+\\frac{2h}{\\pi\\:{\\epsilon\\:}_{r}F}\\left[\\text{ln}\\left(\\frac{\\pi\\:F}{2h}\\right)+1.7726\\right]}}cm\\:\\:\\:\\:\\:\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:F=\\frac{8.791\\times\\:{10}^{9}}{{f}_{0}\\sqrt{{\\epsilon\\:}_{r}}}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003ehere, \u003cem\u003eh\u003c/em\u003e\u0026thinsp;=\u0026thinsp;thickness of the antenna structure in cm and \u003cem\u003ef\u003c/em\u003e\u003csub\u003e\u003cem\u003eo\u003c/em\u003e\u003c/sub\u003e = resonance frequency in Hz. Using the Eqs.\u0026nbsp;[1\u0026ndash;2], \u003cem\u003ea\u003c/em\u003e is found to have a value of 2.3 cm and so, the \u003cem\u003eka\u003c/em\u003e value stands 0.9 for the antenna. So, \u003cem\u003eka\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;1 and it satisfies the criteria to be an ESA. The lowest resonance frequency of 2 GHz is assumed as the basis for all mathematical computations. The diffusion of surface current in the designed ESA structure is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. It tells the story of how the current distribution got changed from the lower resonant frequencies to higher ones. The amount of surface current involvement upon the patch decreased significantly from the lower bands to upper bands. Firstly, at 2 and 6.8 GHz, current is dispersed uniformly in patch and CDNG-MTM and that can be a reason of getting somewhat larger bandwidth at those frequency regions. Then gradually the current density is strongly biased in the CDNG-MTM part and thus the bandwidth declined. This change in surface current has a strong effect on the change in the radiation pattern which will be seen in the next image.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eAntenna radiation patterns at 2, 6.8, 9.1, and 9.6 GHz are plotted in Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e(a)-(d). Here, the both H-plane and E-plane are showing omni-directional radiation at 2 GHz. In our operational frequency range, the RI of the CDNG-MTM decreases with the decrement in frequency (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b)). So, consequently the lower bands achieve omni-directional radiation patterns and low gains because of the lower values of the RI. At 6.8 and 9.1 GHz, there is a sign that the radiation is converting from omni-directional to directive whereas at 9.6 GHz, the radiation pattern has nearly become directive. The higher bands achieve quite focused patterns and extensive gains because of the comparatively larger RI values than the lower bands. That results in an elimination of the unnecessary lobes with the enhancement in the radiation efficiency (RE).\u003c/p\u003e \u003cp\u003eAfter installing the CDNG-MTM with the patch antenna, the obtained improvements are illustrated in the Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. While disclosing the overall size of a particular antenna, the unit of measurement used is usually λ\u003csub\u003eo\u003c/sub\u003e since it expresses the antenna's electrical size operating at various frequencies. As \u003cem\u003eka\u003c/em\u003e size decreased and became less than 1, successful antenna miniaturization is achieved. And also, satisfactory improvements in the mostly required properties (bandwidth, band number) are visible. It was urgent here to pull up the bandwidth from nearly zero as well as increase multi-functionality. To develop more operating bands and band tunability can be a future scope and thus, another unique MTM-Patch combination has been tried in the next section.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePerformance comparison between the CDNG-MTM antenna and the conventional antenna.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAntenna Type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo. of\u003c/p\u003e \u003cp\u003eBands\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eResonance Frequency\u003c/p\u003e \u003cp\u003e(GHz)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eAntenna Size\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eka value\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eBW (GHz)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatch\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2.8, 9.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.32λ\u003csub\u003e0\u003c/sub\u003e \u0026thinsp;\u0026times;\u0026thinsp;0.36λ\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e\u0026times; 0.0009 λ\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003eNearly Zero\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePatch with\u003c/p\u003e \u003cp\u003eCDNG-MTM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e2, 6.8, 9.1, 9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.25λ\u003csub\u003e0\u003c/sub\u003e \u0026thinsp;\u0026times;\u0026thinsp;0.23λ\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e \u003cp\u003e\u0026times; 0.0007 λ\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.75, 1.175, 0.185, 0.54\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e3.2. Further Extension of the Invented ESA\u003c/h2\u003e \u003cp\u003eWith the successful installation of the proposed CDNG-MTM, notable developments have been delivered on a regularly available antenna. In this subsection, this CDNG-MTM will be integrated with two SRRs to see how the response of the whole ESA module changes. Here, an analysis will be made by keeping the patch, CDNG-MTM, and SRRs all in a single antenna unit.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e3.2.1 Antenna with Double MTMs\u003c/h2\u003e \u003cp\u003eHere an extension is done by applying two metamaterial structures in one single block of antenna just to add more features (resonant band in this case). In detail, a MTM set of two rectangular split-ring resonator (SRR) rings are attached on top beside the patch structure (represented in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(a)). Moreover, a CDNG-MTM is loaded at the antenna bottom surface by etching (in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(b)) like before. The optimized parameters (extracted by parametric sweep) to design this SRRs are shown in Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. The alliance of these two MTM structures generates red shift of resonance as this time the effect of capacitance along with inductance from the MTM structures is more and robust.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eEssential parameters for designing the MTMs used in this article.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCDNG-MTM Dimensions\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eSize (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSRR Parameters\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSize (mm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eR1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eH5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e14.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eR2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e8.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eW5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eW3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eH6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eW6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e13.1\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eW4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eH7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e6.95\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eH4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e7.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eW7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e10.35\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eS1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eH8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e5.75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eD1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eP1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.3\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eFigure\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e8\u003c/span\u003e(c) shows the return loss (S\u003csub\u003e11\u003c/sub\u003e) graph with respect to the frequency and it indicates that, there is an increment in the number of bands and the resonances are now at 1.7 GHz, 3.5 GHz, 5 GHz, 7 GHz, and 9.1 GHz. In this module, the SRR set ensures positive and the CDNG-MTM on the same block produces negative RI of high magnitude (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e(b)) in the frequency range of 1 to 5.3 GHz. So, due to the combination of the both, the resultant RI generated here is negative. Besides, the both MTMs compositely furnish negative \u0026micro; and ε, thus, the antenna impedance becomes convincingly positive and impedance matching is arranged quite well before 5.3 GHz. So, there three resonances with impressive return loss dips and bandwidths are managed. After crossing that frequency area, refractive index from SRRs is still positive and CDNG-MTM gives rise to a positive RI which collectively feature of a high magnitude positive RI. Moreover, their jointly developed ε and \u0026micro; are positive (CDNG-MTM's permeability is more positive than SRR set's negative permeability in this case). Then, those become responsible to make the \u003cem\u003ez\u003c/em\u003e (impedance of the antenna module) competently positive again and thus impedance matching happens so well repeatedly that two more resonances at 7 and 9.1 GHz with appreciable return loss are generated. From the point of view of return loss and resonance dip number, this ESA shows obviously promising achievements. Bandwidths of 0.7 GHz (1.4 GHz to 2.1 GHz), 1.2 GHz (2.9 GHz to 4.1 GHz), 0.26 GHz (4.78 GHz to 5.04 GHz), 1.6 GHz (6.4 GHz to 8 GHz), and 0.7 GHz (9 to 9.7 GHz) whereas gain values of 1.38 dB, 2.9 dB, 2.79 dB, 1.52 dB, and 4.87 dB are available at the resonance regions. In this module, 22% of overall bandwidth improvement has been ensured than the previous CDNG-MTM based ESA.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIn spite of gain abandonment, the increment in overall bandwidth and band number says that this formation can be said to be the best for multi-band operations. Besides, size miniaturization has reached upto 0.22λ\u003csub\u003e0\u003c/sub\u003e\u0026thinsp;\u0026times;\u0026thinsp;0.19λ\u003csub\u003e0\u003c/sub\u003e\u0026thinsp;\u0026times;\u0026thinsp;0.0006λ\u003csub\u003e0\u003c/sub\u003e and \u003cem\u003eka\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.85 this time which made the antenna electrically smaller than the ESA with CDNG-MTM only. As a result, this MTM based ESA introduced five complete operating bands for the first time. The final achievements from the two MTM-based antennas and their corresponding applications are discussed in Table\u0026nbsp;\u003cspan refid=\"Tab5\" class=\"InternalRef\"\u003e4\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eImprovements achieved in both of the MTM-based ESAs.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eESA Type\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo. of\u003c/p\u003e \u003cp\u003eBands\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eBandwidths\u003c/p\u003e \u003cp\u003e(GHz)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eRelevant Standards\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eTypical Applications\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCDNG-MTM installed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.75, 1.175, 0.185, 0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eIEEE 802.16, IEEE 802.11ax, IEEE X-Band\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003eWiMAX, Next-gen Wi-Fi (6E), X-band radar, Satellite communication\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCDNG-MTM\u0026thinsp;+\u0026thinsp;SRR installed\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.7, 1.2, 0.26, 1.6, 0.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003eLTE Bands,5G NR, IEEE 802.11a, Wi-Fi 6E/7, SATCOM\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4G/5G mobile, 5G wireless, High-speed Wi-Fi, Satellite links\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eTable\u0026nbsp;5 presents a comparison among our proposed CDNG-MTM installed ESA and several MTM-based antennas described in other studies. Here, [23], [25], [19], and [17] are capable to provide only one band in operation. So, they can never be considered in multi-functional devices whereas our prescribed antennas simultaneously can operate in four as well as five bands. However, [24], [18], [26] can ensure only 2 frequency bands but they take up more spaces than our ESAs. And also, [24] cannot operate above 2.9 GHz which is a great concern and its bandwidths are not satisfactory whereas our CDNG-MTM installed antenna resonances upto 9.6 GHz with decent overall bandwidth. The value of \u003cem\u003eka\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;1 for the antenna in [18] so it will not be considered as an ESA. Article [27] introduces a higher VSWR value than us which is a bad sign for effective radiation and it contains a larger antenna size than ours only to contribute just 2 resonances. Lastly, [13] brings 3 bands (still less than us) with a low bandwidth level. Our two ESAs successfully achieved smaller sizes, excellent overall bandwidths with multi-band functionalities in four as well as five bands respectively. Electron beam lithography (EBL) fabrication technique can be used to fabricate the antenna prototypes. At first, a substrate layer made of polyimide with the exact size is to be set above the copper ground layer. Then the copper patch should be grown upon the polyimide substrate using the deposition technique. Finally, the SRRs can be placed beside the patch and CDNG-MTM will be etched on the ground plane for manufacturing both of the MTM installed ESAs.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab5\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of proposed antenna with the related literature.\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"9\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[Ref.]\u003c/p\u003e \u003cp\u003eYear\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo.\u003c/p\u003e \u003cp\u003eof\u003c/p\u003e \u003cp\u003eBands\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAntenna Size\u003c/p\u003e \u003cp\u003e(λ\u003csup\u003e3\u003c/sup\u003e)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eVSWR\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eReturn Loss\u003c/p\u003e \u003cp\u003e(dB)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eResonant Freq.\u0026nbsp;(GHz)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eBW\u003c/p\u003e \u003cp\u003e(GHz)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003ePermittivity \u0026amp; Thickness (mm)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eka\u003c/p\u003e \u003cp\u003evalue\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[23]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.035\u0026times;1.305\u003c/p\u003e \u003cp\u003e\u0026times;0.56\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.65\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3.9\u003c/p\u003e \u003cp\u003e63.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.75\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[24]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.8\u0026times;0.8\u003c/p\u003e \u003cp\u003e\u0026times;0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-10.25, -30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.4, 2.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0, 0.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[13]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.254\u0026times;0.207\u003c/p\u003e \u003cp\u003e\u0026times;0.013\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-26, -28,\u003c/p\u003e \u003cp\u003e-19\u003c/p\u003e\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.44, 6.05, 8.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.066, 0.42, 0.324\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.94\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[18]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.38\u0026times;0.56\u003c/p\u003e \u003cp\u003e\u0026times;0.109\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-33, -45\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.5, 20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.34, 2.86\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.3\u003c/p\u003e \u003cp\u003e5.958\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.02\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[25]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.272\u0026times;0.317\u003c/p\u003e \u003cp\u003e\u0026times;0.007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-28\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e1.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3\u003c/p\u003e \u003cp\u003e1.524\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.79\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[26]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.5\u0026times;0.35\u003c/p\u003e \u003cp\u003e\u0026times;0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-25, -17.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e4.7, 8.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.45, 0.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.4\u003c/p\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[19]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.51\u0026times;0.51\u003c/p\u003e \u003cp\u003e\u0026times;0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e12.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.87\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003cp\u003e4.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.01\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[27]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.42\u0026times;0.42\u003c/p\u003e \u003cp\u003e\u0026times;0.019\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-18, -24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e3.5, 4.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.4, 0.75\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e4.3\u003c/p\u003e \u003cp\u003e1.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.85\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e[17]\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.905\u0026times;1.429\u003c/p\u003e \u003cp\u003e\u0026times;0.048\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e28.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e2.2\u003c/p\u003e \u003cp\u003e0.508\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e1.11\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOur Model\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.25\u0026times;0.23\u003c/p\u003e \u003cp\u003e\u0026times;0.0007\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e-15.75, -26.75, -27, -21.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2, 6.8, 9.1, 9.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.75, 1.175, 0.185, 0.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e3.4\u003c/p\u003e \u003cp\u003e0.1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c9\"\u003e \u003cp\u003e0.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIn summary, our primary objectives were to achieve multi-band operational capability, considerable enlarged bandwidth, and sufficient reduction of antenna size with the help of MTMs. Four individual bands of resonance with notable return loss depths and impressive bandwidths were ensured in an ESA using the CDNG-MTM. Not only that, all the values of VSWR found at these resonances were much smaller than 2 which indicates adequate impedance matching happened here. As the last case, the four band response was upgraded to five band response with an additional resonance band and 22% increased overall bandwidth. Finally, a novel MTM installed ESA is introduced by combining CDNG-MTM, SRRs, and patch in a single block. Due to the beneficial features as discussed, the last ESA device may find application in different areas such as LTE bands, advanced 4G/5G communication, Wi-Fi 6E/7, SATCOM, and many more.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of generative AI and AI-assisted technologies in the writing process\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDuring the preparation of this work, the author(s) used ChatGPT and Grammarly to improve the writing. After using this tool, the author(s) reviewed and edited the content as needed and take full responsibility for the content of the publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors Contributions:\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization\u003cstrong\u003e,\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Sakib Sadman,\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eMd Abu Huraiya\u003c/strong\u003e\u003cstrong\u003e;\u0026nbsp;\u003c/strong\u003eData curation, Formal analysis, Investigation, \u003cstrong\u003eSakib Sadman\u003c/strong\u003e, \u003cstrong\u003eMd Abu Huraiya\u003c/strong\u003e\u003cstrong\u003e;\u0026nbsp;\u003c/strong\u003eResources, Software,\u003cstrong\u003e\u0026nbsp;Sakib Sadman\u003c/strong\u003e\u003cstrong\u003e, Md Abu Huraiya\u003c/strong\u003e\u003cstrong\u003e;\u003c/strong\u003e Supervision, Validation,\u003cstrong\u003eMd Abu Huraiya\u003c/strong\u003e; Visualization, Writing - original draft\u003cstrong\u003e,\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Sakib Sadman,\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Md Abu Huraiya\u003c/strong\u003e\u003cstrong\u003e;\u003c/strong\u003e Writing- review editing, \u003cstrong\u003eSakib Sadman,\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;Md Abu Huraiya.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u0026nbsp;\u003c/strong\u003eno funding\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of Data and Material:\u0026nbsp;\u003c/strong\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode Availability:\u0026nbsp;\u003c/strong\u003eNot applicable\u003cstrong\u003e.\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for Publication:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest:\u0026nbsp;\u003c/strong\u003eNo competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eJin, P., Ziolkowski, R.W.: Low-q, electrically small, efficient near-field resonant parasitic antennas. IEEE Transactions on Antennas and Propagation 57(9), 2548\u0026ndash;2563 (2009)\u003c/li\u003e\n\u003cli\u003eGao, X., Zhang, Y., Li, S.: High refractive index metamaterial superstrate for microstrip patch antenna performance improvement. Frontiers in Physics 8, 580185 (2020)\u003c/li\u003e\n\u003cli\u003eWheeler, H.A.: Fundamental limitations of small antennas. Proceedings of the IRE 35(12), 1479\u0026ndash;1484 (1947) \u003c/li\u003e\n\u003cli\u003ePatel, R., Desai, A., Upadhyaya, T.K.: An electrically small antenna using defected ground structure for rfid, gps and ieee 802.11 a/b/g/s applications. Progress in electromagnetics research letters 75, 75\u0026ndash;81 (2018) \u003c/li\u003e\n\u003cli\u003eZulfiker Mahmud, M., Islam, M.T., Misran, N., Singh, M.J., Mat, K.: A negative index metamaterial to enhance the performance of miniaturized uwb antenna for microwave imaging applications. Applied Sciences 7(11), 1149 (2017) \u003c/li\u003e\n\u003cli\u003eSmith, D.R., Padilla, W.J., Vier, D., Nemat-Nasser, S.C., Schultz, S.: Composite medium with simultaneously negative permeability and permittivity. Physical review letters 84(18), 4184 (2000) \u003c/li\u003e\n\u003cli\u003eKumar, P., Ali, T., Pai, M.M.: Electromagnetic metamaterials: A new paradigm of antenna design. IEEE Access 9, 18722\u0026ndash;18751 (2021) \u003c/li\u003e\n\u003cli\u003eErentok, A., Ziolkowski, R.W.: Metamaterial-inspired efficient electrically small antennas. IEEE Transactions on Antennas and Propagation 56(3), 691\u0026ndash;707 (2008) \u003c/li\u003e\n\u003cli\u003eZiolkowski, R.W.: Design, fabrication, and testing of double negative meta materials. IEEE Transactions on antennas and Propagation 51(7), 1516\u0026ndash;1529 (2003) \u003c/li\u003e\n\u003cli\u003eAmeen, M., Chaudhary, R.: Metamaterial-based circularly polarised antenna employing eng-tl with enhanced bandwidth for wlan applications. Electronics Letters 54(20), 1152\u0026ndash;1154 (2018) \u003c/li\u003e\n\u003cli\u003eRaval, F., Kosta, Y., Joshi, H.: Reduced size patch antenna using complementary split ring resonator as defected ground plane. AEU-International Journal of Electronics and Communications 69(8), 1126\u0026ndash;1133 (2015)\u003c/li\u003e\n\u003cli\u003e[12] Patel, R., Desai, A., Upadhyaya, T.K.: An electrically small antenna using defected ground structure for rfid, gps and ieee 802.11 a/b/g/s applications. Progress in electromagnetics research letters 75, 75\u0026ndash;81 (2018) \u003c/li\u003e\n\u003cli\u003eTamim, A.M., Faruque, M.R., Islam, M.T.: Metamaterial-inspired electrically small antenna for microwave applications. Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 236(11), 2230\u0026ndash;2241 (2022) \u003c/li\u003e\n\u003cli\u003eChaturvedi, D., Raghavan, S.: Srr-loaded metamaterial-inspired electrically-small monopole antenna. Progress In Electromagnetics Research C 81, 11\u0026ndash;19 (2018)\u003c/li\u003e\n\u003cli\u003eHussain, N., Naqvi, S.I., Awan, W.A., Le, T.T.: A metasurface-based wideband bidirectional same-sense circularly polarized antenna. International Journal of RF and Microwave Computer-Aided Engineering 30(8), 22262 (2020)\u003c/li\u003e\n\u003cli\u003eMarwaha, A., et al.: Csc-sr structure loaded electrically small planar antenna. Applied Computational Electromagnetics Society Journal 31(5), 591 (2016)\u003c/li\u003e\n\u003cli\u003e[17] Esmail, B.A., Koziel, S.: Design and optimization of metamaterial-based highly isolated mimo antenna with high gain and beam tilting ability for 5g millimeter wave applications. Scientific Reports 14(1), 3203 (2024) \u003c/li\u003e\n\u003cli\u003eAsif, M., Sehrai, D.A., Kiani, S.H., Khan, J., Abdullah, M., Ibrar, M., Alibakhshikenari, M., Falcone, F., Limiti, E.: Design of a dual band sng meta material based antenna for lte 46/wlan and ka-band applications. IEEE Access 9, 71553\u0026ndash;71562 (2021)\u003c/li\u003e\n\u003cli\u003e[19] Alam, T., Islam, M.T., Hakim, M.L., Alharbi, K.H., Singh, M.S.J., Sheikh, M.M., Aldhaheri, R.W., Islam, M.S., Soliman, M.S.: Metamaterial based ku-band antenna for low earth orbit nanosatellite payload system. Nanomaterials 13(2), 228 (2023) \u003c/li\u003e\n\u003cli\u003eThankachan, S., Paul, B., Pradeep, A., Moolat, R.: Design and characterisation of simple planar metamaterial structure with double negative properties. In: TEN CON 2019-2019 IEEE Region 10 Conference (TENCON), pp. 1231\u0026ndash;1235 (2019). IEEE \u003c/li\u003e\n\u003cli\u003eLi, Z., Aydin, K., Ozbay, E.: Determination of the effective constitutive parame ters of bianisotropic metamaterials from reflection and transmission coefficients. Physical review E 79(2), 026610 (2009)\u003c/li\u003e\n\u003cli\u003e[22] Ibrahim, K.M., Hassan, W.M., Abdallah, E.A., Attiya, A.M., et al.: Wideband octagonal dual circularly polarized sub-array antenna for ku-satellite systems. Applied Computational Electromagnetics Society Journal 35(12), 1500 (2020) \u003c/li\u003e\n\u003cli\u003eJeong, H., Kim, Y., Tentzeris, M.M., Lim, S.: Gain-enhanced metamaterial absorber-loaded monopole antenna for reduced radar cross-section and back radiation. Materials 13(5), 1247 (2020) \u003c/li\u003e\n\u003cli\u003eAbdalla, M.A., Wahba, W.W., Allam, A.A.: Analysis and design of a compact crlh inspired\u0026ndash;defected ground resonators for triple band antenna applications. Engineering Science and Technology, an International Journal 23(1), 114\u0026ndash;122 (2020)\u003c/li\u003e\n\u003cli\u003eKucukoner, E.M., Cinar, A., Kose, U., Ekmekci, E.: Electrical size reduc tion of microstrip antennas by using defected ground structures composed of complementary split ring resonator. Advanced Electromagnetics 10(1), 62\u0026ndash;69 (2021)\u003c/li\u003e\n\u003cli\u003eArmghan, A., Patel, S.K., Lavadiya, S., Qamar, S., Alsharari, M., Daher, M.G., Althuwayb, A.A., Alenezi, F., Aliqab, K.: Design and fabrication of compact, multiband, high gain, high isolation, metamaterial-based mimo antennas for wireless communication systems. Micromachines 14(2), 357 (2023)\u003c/li\u003e\n\u003cli\u003eAlsisi, R.H., Karimbu Vallappil, A., Wajid, H.A.: A metamaterial-based double sided bowtie antenna for intelligent transport system communications operating in public safety band. Crystals 13(2), 360 (2023\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"advanced-metamaterials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Advanced Metamaterials](https://link.springer.com/journal/44468)","snPcode":"44468","submissionUrl":"https://submission.springernature.com/new-submission/44468/3?","title":"Advanced Metamaterials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Antenna, Bandwidth, Metamaterial, Multi-Band, Patch, Split-Ring Resonator","lastPublishedDoi":"10.21203/rs.3.rs-8626984/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8626984/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eThe invention of a miniaturized antenna that can support multiple frequency bands with efficient bandwidth is very crucial for communication applications. In this work, a novel approach is demonstrated wherein the combination of various metamaterial configurations leads to significantly increase the number of frequency bands and also the bandwidth level. Initially, an ordinary patch antenna, exhibiting narrowband performance at 2.8 GHz and 9.5 GHz, is considered and optimized for reference. By applying different metamaterial architectures like a complementary dual negative metamaterial (CDNG-MTM) or its combination with two split-ring resonators (SRR) alongside the patch structure, a rising in number of bands from two to four and then five is observed in a sequential manner. Every time the \u003cem\u003ek\u003c/em\u003e\u003csub\u003e\u003cem\u003ea\u003c/em\u003e\u003c/sub\u003e value (indicator of antenna size) is found to be below one and the electrical size as compact. A CDNG-MTM joining with the patch originated four different bands with bandwidths of 1.75GHz, 1.175GHz, 0.185GHz, and 0.54GHz at 2GHz, 6.8GHz, 9.1GHz, and 9.6GHz, respectively, which can be feasible for next generation high-speed wireless communication, high-resolution radar, earth observation satellites etc. Lastly, the addition of SRRs leads to five operational bands along with 22% more enhancement in overall bandwidth.\u003c/p\u003e","manuscriptTitle":"Metamaterial inspired electrically small antennas with enhanced bandwidth and multi- band compatibility","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-23 13:07:15","doi":"10.21203/rs.3.rs-8626984/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-01-22T13:06:00+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-22T06:20:45+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-22T05:34:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"257695862896978110185128897605856724757","date":"2026-01-22T04:59:46+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"5446902342637297755719479680388441739","date":"2026-01-22T02:24:25+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-21T19:20:38+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-19T05:08:44+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-19T05:07:55+00:00","index":"","fulltext":""},{"type":"submitted","content":"Advanced Metamaterials","date":"2026-01-17T15:13:31+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"advanced-metamaterials","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"","sideBox":"Learn more about [Advanced Metamaterials](https://link.springer.com/journal/44468)","snPcode":"44468","submissionUrl":"https://submission.springernature.com/new-submission/44468/3?","title":"Advanced Metamaterials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Open","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"89fe3406-b9e7-4124-8869-ce7320875d75","owner":[],"postedDate":"January 23rd, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-01-23T13:07:15+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-23 13:07:15","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8626984","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8626984","identity":"rs-8626984","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}