Analysis of an Inhomogeneous Circularly Polarized Hollow Dielectric Resonator Antenna Using Perturbation Theory

Neetu Sehrawat,Anshul Agarwal,Gaurav Varshney,Binod Kumar Kanaujia

doi:10.3390/electronics10182273

Abstract

The perturbation approach is presented here for the first time for the analysis of an inhomogeneous circularly polarized rectangular dielectric resonator (DR) antenna (DRA). The inhomogeneous permittivity is created by perturbing a rectangle-shaped region of different material inside the rectangular dielectric resonator antenna (RDRA). The orthogonal degenerate modes with a phase difference of TE111x, and TE111y, are excited simultaneously for achieving circular polarization. A simple expression for the calculation of the resonant frequency and optimal axial ratio point for a circularly polarized (CP) inhomogeneous RDRA is presented here. Theoretical results obtained from the proposed theory are compared with theoretical, simulated, and experimental data available in the literature. The proposed analysis results show optimal axial ratio point calculations within a 1% range of the simulated and experimental data, which is better than the previous transverse transmission line reported method, having an error of approximately 4%. The advantages, accuracy, and simplicity of perturbation theory for DR are discussed in detail. The proposed theory can be easily extended for higher order modes and other shapes of material perturbation and anisotropic DRAs. The proposed technique will help in incorporation of the perturbation in the DR so that CP radiation can be obtained in an easy way.

Highlights

High-frequency wireless applications need an antenna which can suitably be utilized with low losses and improved performance parameters, like gain and radiation efficiency [1]
The symbols used here are as follows: εr and εp are the dielectric constant of the original and perturbed region of the rectangular dielectric resonator antenna (RDRA), respectively; f0x, f0y are the resonant frequencies of the homogeneous RDRA using the dielectric waveguide model (DWM) method; frx, fry are the resonant frequency of the homogeneous RDRA using the perturbation method; fpx, fpy are the resonant frequencies of the inhomogeneous RDRA using the perturbation method; fpc represents the frequency corresponding to the optimal axial ratio point; fm and fm_0.88 are the resonant frequencies of the inhomogeneous RDRA according to the mode matching technique and effective dielectric permittivity approach, respectively; ft represents the resonant frequency of the hollow RDRA using the transverse transmission line model; and fhfss, fmeas represent the simulated and measured resonant frequencies, respectively
The proposed perturbation theory for an inhomogeneous RDRA is compared to the theoretical results available in the literature and validated by comparing the proposed theoretical results with the simulated and measured results available in the literature

Summary

Introduction

High-frequency wireless applications need an antenna which can suitably be utilized with low losses and improved performance parameters, like gain and radiation efficiency [1]. The proposed approach for calculation of the resonant frequencies of orthogonal modes and the optimal axial ratio point is found to be close to the simulated, experimental, and theoretical data available in the literature.

Results

Conclusion