Analysis and Design of Dielectric Resonator Antennas Using Perturbation Technique

Abstract

This thesis deals with the research area related to the theoretical analysis of dielectric resonator (DR) antennas (DRAs). In this thesis, the research work is carried out focussing on the analysis of four perturbed rectangular dielectric resonator antennas (PRDRAs) structures (i) RDRA with rectangular shaped perturbation, (ii) RDRA with (iv) Higher-order mode Perturbed RDRA with rectangular and cylindrical shaped perturbation. Another point that has been focussed on is to use the perturbation technique for computing the accurate resonant frequency of the perturbed structures mentioned above. In order to cover the first issue, a simple RDRA was subjected to rectangular-shaped material perturbation in horizontal and vertical directions named horizontally perturbed RDRA (HPRDRA) and vertically perturbed RDRA (VPRDRA), respectively. These antenna structures are excited in the dominant mode. A theoretical analysis was carried out using the perturbation method to calculate the resonant frequency of HPRDRA and VPRDRA in terms of perturbed region dimension and dielectric constant. The proposed theory is verified using simulated results for different variations in dimension and dielectric constant of the perturbed region. The accuracy of the proposed perturbation formula over other reported methods is validated in terms of percentage error with respect to simulated and experimental data of inhomogeneous and stacked RDRA available in the literature. This theory is extended for RDRA with cylindrical-shaped perturbation in both orthogonal directions. The perturbed rectangular dielectric resonator antenna with centered cylinder (PRDRA_CC) is analyzed using perturbation theory, and the effect of change of radius and permittivity of the cylinder is also investigated. The theoretical resonant frequency of PRDRA_CC is verified using simulated results. This theory was further extended for the analysis of an inhomogeneous circularly polarized rectangular dielectric resonator (DR) antenna (DRA). The inhomogeneous permittivity was