A Simple Bandwidth-Enhanced Magneto-Electric Dipole with L-Shaped Slots

A Simple Bandwidth-Enhanced Magneto-Electric Dipole with L-Shaped Slots | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Engineering Reports This is a preprint and has not been peer reviewed. Data may be preliminary. 3 September 2025 V1 Latest version Share on A Simple Bandwidth-Enhanced Magneto-Electric Dipole with L-Shaped Slots Authors : Rong Li 0009-0005-9430-3399 [email protected] , Yan Yan , Yanhong Xu , Anyi Wang , and Jianqiang Hou Authors Info & Affiliations https://doi.org/10.22541/au.175691978.83759949/v1 Published Engineering Reports Version of record Peer review timeline 288 views 151 downloads Contents Abstract 2.1 Geometry of the Proposed Antenna 2.2 Design Procedures and Parameters Investigation Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract A simple wideband magneto-electric (ME) dipole antenna is presented in this letter. In particular, two pairs of L-shaped slots with different sizes are successively etched out of the pair of horizontal patches of electric dipole, which can enlarge the bandwidth of ME dipole antenna without increasing the antenna size. Two new resonant frequency points are generated respectively at the lower and upper frequency region. To improve the impedance matching characteristics, two vertical rectangular patches are loaded in the middle of the horizontal portion of the Г-shaped feed structure. A prototype is fabricated and measured, and an overlapped bandwidth of 101.3% (from 1.36 GHz to 4.15 GHz) in terms of VSWR≤2 is achieved, which can simultaneously cover the n50 (1.432GHz-1.517GHz), n51(1.427GHz-1.432GHz), and n78 (3.300GHz to 3.800GHz) bands of sub-6G. It should be highlighted that other excellent properties of ME dipole antenna, such as stable radiation pattern, high gain, and low cross-polarization level (CRPL), are maintained, which makes the proposed ME dipole antenna a good candidate for sub-6G applications. Rong Li 1 , Yan Yan 1 , Yanhong Xu 1 , Anyi Wang 1 ，and Jianqiang Hou 2 1. Xi’an Key Laboratory of Network Convergence Communication, College of Communication and Information Engineering, Xi’an University of Science and Technology, Xi’an, 710054, China 2. The National Key Laboratory of Science and Technology on Antenna and Microwave, Xidian University, Xi’an, 710071, China Correspondence: Rong Li, Xi’an Key Laboratory of Network Convergence Communication, College of Communication and Information Engineering, Xi’an University of Science and Technology, Xi’an, 710054, China Email: [email protected] Funding information National Natural Science Foundation of China under Grant 62271386, 61901357 No conflict of interest exits in the submission of this manuscript, and manuscript is approved by all authors for publication. The work described was original research and has not been published previously, and not under consideration for publication elsewhere. Abstract: A simple wideband magneto-electric (ME) dipole antenna is presented in this letter. In particular, two pairs of L-shaped slots with different sizes are successively etched out of the pair of horizontal patches of electric dipole, which can enlarge the bandwidth of ME dipole antenna without increasing the antenna size. Two new resonant frequency points are generated respectively at the lower and upper frequency region. To improve the impedance matching characteristics, two vertical rectangular patches are loaded in the middle of the horizontal portion of the Г-shaped feed structure. A prototype is fabricated and measured, and an overlapped bandwidth of 101.3% (from 1.36 GHz to 4.15 GHz) in terms of VSWR≤2 is achieved, which can simultaneously cover the n50 (1.432GHz-1.517GHz), n51(1.427GHz-1.432GHz), and n78 (3.300GHz to 3.800GHz) bands of sub-6G. It should be highlighted that other excellent properties of ME dipole antenna, such as stable radiation pattern, high gain, and low cross-polarization level (CRPL), are maintained, which makes the proposed ME dipole antenna a good candidate for sub-6G applications. Keywords: Wideband, bandwidth enhancement, L-shaped slots, impedance matching, high gain. 1. Introduction As a crucial component to transmit and receive electromagnetic waves, an antenna with the properties of wideband and high gain is always demanded to support the increasing requirement of higher date rate for various applications [1]-[3]. According to the new 5G frequency band issued by the US Federal Communications Commission (FCC), some new frequency bands have been added to sub-6G, i.e., n50 (1.432GHz-1.517GHz), n51(1.427GHz-1.432GHz) and n78 (3.3GHz to 3.8GHz), and this expands the conventional band of 1.710GHz to 2.690GHz, which have been used for modern 2G, 3G, and 4G mobile communication systems, into 1.427GHz to 3.800GHz [4]. Therefore, it is still a research challenge to design such an antenna that can not only cover the above mentioned frequency band, but also exhibit other good properties, such as high gain, low cross-polarization level (CRPL) and etc. First proposed by Prof. Luk in 2006 [5], the magneto-electric (ME) dipole antenna is of significant importance in antenna and propagation field since it can provide wide bandwidth and stable radiation patterns simultaneously. Over the past decades, many investigations have been conducted to design various kinds of ME dipole antennas for many applications since then, including WBAN/WLAN [6], UWB [7], millimeter-wave [8][9], full-duplex [10] and 5G base station [11] applications. In the meantime, several typical designs are presented to further improve the impedance bandwidth of ME dipole [12]-[20]. In [12], the shorted bowtie-shaped patch is adopted, and a impedance of 67% (2.16GHz-4.13GHz) in terms of VSWR <2 is achieved. In [13], a wideband dual-polarized ME dipole antenna is proposed by employing heptagonal patches and loading with inverted L-shaped structures, where 99.2% bandwidth is achieved. Nevertheless, the antenna suffered from design complexity and difficulty in fabrication. A wideband dual-band ME dipole with improved feeding structure is presented in [14], where a U-shaped electric dipole antenna is employed to generated the dual resonant frequencies, i.e., 72% (1.48GHz-3.1GHz) and 21% (4.67GHz-5.78GHz). In [15], a crossed dipole is incorporated with double-printed vacant-quarter rings, and a bandwidth of 59.8% (1.274GHz-2.360GHz) is obtained. In [16], the straight-line edges of the original electric dipoles are replaced with arc-shaped ones, where a bandwidth from 98MHz to 3.03GHz is realized. A wideband ME dipole antenna for 4G/5G communication is presented in [17]. The bandwidth of the antenna is greatly enhanced by loading two pairs of metallic circular loops on the planar electric dipole. In [17], a wideband ME dipole antenna consisting of a pair of Г-shaped metal plates, a Г-shaped fed line and six metal columns is proposed, and its bandwidth is 81.1% (3.3GHz to 7.8GHz). A modified ground plane and a defected ground structure are utilized in [19] and [20], respectively achieving a bandwidth of 91% (from 3.1GHz to 8.3GHz) and 86.9% (1.38GHz-3.5GHz). Inspired by [14], two pairs of L-shaped slots with different size are successively etched out of the two planar patches to generate two resonant frequency points respectively at the lower and upper frequency regions on the basis of [20]. To improve the impedance matching characteristics, two vertical rectangular patches are loaded on the Г-shaped feed structure. Therefore, a bandwidth of 101.3% (1.36GHz-4.15GHz) is achieved in terms of VSWR < 2 without increase the antenna size, which makes it a good candidate for sub-6G applications. 2. Design of Wideband ME Dipole Antenna 2.1 Geometry of the Proposed Antenna As depicted in Figures 1, the proposed bandwidth-enhanced ME dipole antenna consists of a pair of horizontal patches with etched L-slots, shorted walls with etched rectangular slots, a modified Γ-shaped feed structure, and a box-shaped reflector. Figure 1 (b) provide the top view of the wideband ME dipole antenna, and the modified Γ-shaped feed is shown in Figure 1 (c). 2.2 Design Procedures and Parameters Investigation Figure 2 (a) depict the evolution of the proposed ME dipole antenna from Ant. 1 to Ant. 3. And the corresponding simulated VSWR curves of these three antennas are provided in Figures 2(b) and (c). As depicted in Figure 2 (a), the Ant.1 in [20] is formed of a half-wavelength planar electric dipole and a quarter-wavelength magnetic dipole with two rectangular slots patch portion etched out. After firstly etched a pair of L-shaped slots with the dimension of l 1 + l 2 =35.3mm respectively out of the two planar horizontal patches, Ant. 2 is formed with a new resonant frequency point around 1.4GHz. As shown in Figure 2 (b), it is seen that the bandwidth of the Ant. 1 is 74.8% ranging from 1.65 GHz to 3.62 GHz, and that of Ant. 2 is 86.7% ranging from 1.39GHz to 3.52GHz. In the sequel, to further enhanced the bandwidth of the Ant. 2, two other L-slots with the dimension of l 3 + l 4 = 28mm are etched out of the horizontal patches to generate a new resonant frequency point around 4GHz. Besides, a modified Γ-shaped feed is adopted here to improve the impedance matching characteristics as depicted in Figure 2 (c). The resultant antenna is termed as Ant 3, and a bandwidth of 103.1% (1.33 GHz to 4.16 GHz) is achieved. (a) (b) (c) FIGURE 1 (a) Perspective view. (b) top view. (c) modified Γ-shaped feed. ( G l =140mm, W =63.2mm, L =27.6mm, S =15.5mm, H =27.9mm, a= 11.2mm, b= 17.1mm, d =9.5mm, l 1 =22.3mm, l 2 =13mm, l 3 =8mm, l 4 =20mm, h 1 =28mm, h 2 =6.2mm, t 1 =3.1mm, d 1 =10mm.) (a) TABLE 1 Comparisons between the proposed antenna and others. Reference Structure Antenna size Bandwidth(VSWR≤2) Peak Gain(dBi) Cross-polarization(dB) FBR(dB) [11] Complex 0.83λ×0.83λ×0.18λ 51.0%(3.2GHz-5.4GHz) 8.3 21 [13] Complex 0.79λ×0.79λ×0.24λ 99.2%(1.20GHz-3.56GHz) 11.0 15 [17] Complex 0.98λ×0.57λ×0.26λ 86.8%(1.46GHz-3.71GHz) 9.5 15 [20] Simple 0.59λ×0.53λ×0.23λ 86.9%(1.38GHz-3.5GHz) 8.4 10 This work Simple 0.65λ×0.58λ×0.26λ 101.3%(1.36GHz-4.15GHz) 11.5 20 (b) (c) FIGURE 2 (a) Design procedure of the proposed antenna. (b) simulated VSWRs. (c) input impedance curves of Ants 1-3. In this section, the parameters that are crucial to the performance of the proposed antenna are investigated and analyzed. During the optimization procedure, it is found that l 2 , l 4 , d 1 , and h 2 are the four parameters that have the greatest influence on the impedance bandwidth. Figures 3 plots the input impedance of Ant. 3 separately with respect to l 2 , l 4 , d 1 , and h 2 . Note that other parameters remain unchanged when one parameter is under investigation. From Figure 3 (a), it can be observed that the real part of the input impedance of Ant. 3 shifts downward with the increase of l 2 , while the imaginary part shifts upward. When l 2 =13mm， the real part of the input impedance is closer to 50 ohms, and the imaginary part is closer to 0 ohm. Therefore, l 2 =13mm is chosen. This also implies that the resonance point at 1.4GHz is related to l 2 . As shown in Figure 3 (b), l 4 has a significant impact on the resonance point of Ant.3 at 4GHz. With the increase in l 4 , the real part of the input impedance of Ant. 3 shifts toward higher frequency region, while the imaginary part shifts toward lower frequency region. Taking these factors into consideration, l 4 =20mm is chosen. Whereas, the remaining resonance points are hardly affected by the parameter. This trend also indicates that the resonance point at 4GHz is related to l 4 . It is evident from Figure 3 (c) that the frequency point at 3.6GHz shifts toward higher frequency region as the value of d 1 increases. This implies that the resonance point at 3.6GHz is related to d 1 . The antenna exhibits excellent impedance matching when d 1 =10mm. With reference to Figure 3 (d), h 2 primarily affects the impedance matching in the high frequency region. We finally set h 2 =6.2mm for excellent impedance matching. (a) (b) (c) (d) FIGURE 3 Parametric study of the proposed ME dipole antenna. (a) l 2 . (b) l 4 . (c) d 1 . (d) h 2 . 3. Antenna Performances The prototype photo of the proposed antenna is provided in Figure 4 (a). During the prototype fabrication, the horizontal patches, shorted walls, box-shaped reflector are made of aluminum, while the modified Γ-shaped feed is made of copper. The VSWR and radiation patterns are measured using an Agilent N5244A network analyzer and a far-field measurement system, respectively. Figure 4 (b) provides the simulated and measured VSWRs and gains. It can be seen that the measured impedance bandwidth (VSWR≤2) is about 101.3% ranging from 1.36GHz to 4.15GHz. The peak gain of 11.5dBi is achieved. The measured and simulated radiation patterns at different frequencies are presented in Figures 4 (c). Great agreements between the measured and simulated results are achieved. The measured CRPLs are all below -20dB at these frequencies. (a) (b) (c) FIGURE 4 (a) Photo of antenna prototype. (b) simulated and measured VSWRs and gains. (c) simulated and measured radiation patterns. Table 1 provides the performance comparison with several typical ME dipole antennas reported in existing literatures. Compared with the antennas in [11] and [17], the proposed antenna exhibits a bandwidth of 98.6% and 16.7% wider, respectively, with a much smaller structure. Compared with the antenna in [20], the bandwidth of the proposed antenna is 16.6% wider. Referring to the antenna in [13], although a comparable bandwidth is achieved, its size is 52.8% larger than that of the proposed antenna. To summarize, the proposed antenna exhibits not only a wide bandwidth, but also other good performance, including high gain, low CRPL and high front-to-back ratio (FBR). 4.Conclusion In this letter, a simple wideband ME dipole antenna is presented, where a bandwidth of up to 101.3% (1.36 GHz to 4.15 GHz) in terms of VSWR≤2 is achieved without increase the antenna size. In particular, two pairs of L-shaped slots with different size are successively etched out of the two planar patches, which respectively introduces a new resonant frequency point at the lower and upper frequency region. Furthermore, the Г-shaped feed structure is modified to improve the impedance matching characteristics. The proposed ME dipole antenna can simultaneously cover the n50 (1.432GHz-1.517GHz), n51(1.427GHz-1.432GHz), and n78 (3.300GHz to 3.800 GHz) bands of sub-6G. Besides, other excellent properties of ME dipole antenna, such as stable radiation characteristics, high gain, and low CRPL, are maintained, which makes the proposed ME dipole antenna a good candidate for sub-6G applications. References 1. X. Shi, Y. Cao, Y. Hu, X. Luo, H. Yang and L. H. Ye, “A high-gain antipodal vivaldi antenna with director and metamaterial at 1-28 GHz,” IEEE Antennas Wireless Propag. Lett. 2021;20(12): 2432-2436. 2. C. Cao and C. 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Hou. “A novel wideband dual‐polarized heptagonal magnetoelectric dipole antenna loaded with inverted L‐shaped structures”. Microw Opt Technol Lett . 2023;1‐7. 14. K. He, S. -X. Gong and F. Gao, “A wideband dual-band magneto-electric dipole antenna with improved feeding structure,” IEEE Antennas and Wireless Propag. Lett. 2014;13:1729-1732. 15. S. X. Ta an I d. Park, “Crossed dipole loaded with magneto-electric dipole for wideband and wide-beam circularly polarized radiation,” IEEE Antennas and Wireless Propag. Lett. 2015;14: 358-361. 16. Y. Shi, G. Wang, Q. Liu, L. Guo, X. Zou and H. Bai, “An ultrawideband compact magneto-electric dipole antenna and its coupled array,” IEEE Antennas and Wireless Propag. Lett. 2023;22(7):1662-1666. 17. Zhou M, Xu Y, Wang A, Hou J. A wideband magnetoelectric dipole antenna for 4G/5G communication . Microw Opt Technol Lett. 2 023;1‐6. 18. G. Yang, J. Li, J. Yang and S. G. Zhou, “A wide beamwidth and wideband magnetoelectric dipole antenna,” IEEE Trans. Antennas Propag .2018;66(12): 6724-6733. 19. B. Q. Wu and K. -M. Luk, “A magneto-electric dipole with a modified ground plane,” IEEE Antennas and Wireless Propag. Lett. 2009;8: 627-629. 20. J. Zeng and K. -M. Luk, “A simple wideband magnetoelectric dipole antenna with a defected ground structure,” IEEE Antennas and Wireless Propag. Lett. 2018;17(8):2018. Information & Authors Information Version history V1 Version 1 03 September 2025 Peer review timeline Published Engineering Reports Version of Record 11 Aug 2024 Published Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Engineering Reports Keywords bandwidth enhancement high gain impedance matching l-shaped slots Authors Affiliations Rong Li 0009-0005-9430-3399 [email protected] Xi'an University of Science and Technology View all articles by this author Yan Yan Xi'an University of Science and Technology View all articles by this author Yanhong Xu Xi'an University of Science and Technology View all articles by this author Anyi Wang Xi'an University of Science and Technology View all articles by this author Jianqiang Hou Xidian University Key Laboratory of Antennas and Microwave Technology View all articles by this author Metrics & Citations Metrics Article Usage 288 views 151 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Rong Li, Yan Yan, Yanhong Xu, et al. A Simple Bandwidth-Enhanced Magneto-Electric Dipole with L-Shaped Slots. Authorea . 03 September 2025. 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