An investigation of gain enhancement of the wideband dielectric resonator antenna

Dielectric Resonator (DRAs) antennas are commonly used in small size high-frequency applications. In this thesis, a novel stacked cylindrical reflector backed DRA antenna has been designed and investigated. The proposed DRA antenna is axisymmetric and consists of two dielectric material and a rectangular reflector of copper located under the antenna. According to the authors' knowledge, this type of combination of stacked and reflector methods is first investigated in DRA design. Stacked two dielectric materials with different permittivity and reflector techniques help improve the impedance bandwidth and the antenna's gain simultaneously. i.e., the thesis mainly focuses on the improvement in both the impedance bandwidth and the gain of DRA. To achieve the desired DRA antenna, three antennas (standalone cylindrical DRA, stacked-DRA, and stacked DRA with reflector) are designed. Computer Simulation Technology CST program is used to simulate the proposed DRA antenna. The input impedance bandwidth of the desired DRA antenna below -10 dB is from 4.2GHz to 6.8 GHz, with a center frequency of 5.5 GHz. The proposed DRA gives average gain and approximate radiation efficiency of 10 dBi and 85%, respectively, within the operating frequency range. A gain improvement > 4dBi obtained by placing a reflector under the ground plane. The prototype DRA antenna is fabricated and measured. The measured and simulated results show a good agreement. The fabricated DRA is designed to operate at the band from 4.1 GHz to 6.8 GHz. According to the results, this desired DRA antenna can be used for wireless (Wi-MAX) and (WLAN) application bands.