Metallic Reflector-Based X-Band Circularly Polarized Hollow Dielectric Resonator Antenna for High Gain in UWB Applications

Abstract A circularly polarized hollow dielectric resonator antenna (CPHDRA) is designed for X-band applications. Rectangular dielectric resonator (RDR) is used as a radiator element, fed by a quarter-wave transformer (QWT) feedline. By performance of the RDR antenna, an air cylindrical rod structure is extracted from RDR to enhance the gain and impedance bandwidth. Two parasitic strips are placed on the top of the RDR to achieve circular polarization with reported ≤ 3-dB axial ratio (AR) bandwidth for X-band applications. In this article, UWB antenna covers range from 2.74 to 10.4GHz by using asymmetrical defective ground structure (DGS). In near field of the dielectric resonator, three different radiating modes namely HE11δ, HE21δ, HE23δ, and HE32δ are at 4.4, 6, 8.8, and 9.9 GHz. For the generation of circular polarization (CP), two orthogonal modes are generated at 8.8 and 9.9 GHz as per XZ and YZ planes. It has reported 23.8 % (8 to 10.1 GHz) of 3-dB AR bandwidth. The simulated and measured impedance bandwidths are 118.46 % and 121.12 % along with a peak gain of 6.55 dB without the use of a metallic reflector. By using a metallic reflector suspended in the bottom side of the substrate with a distance of 13.1mm is reported along with the peak gain of 9.8 dBi.