Investigations on the improvement of different characteristics of dielectric resonator antenna

Abstract

Dielectric resonator antennas (DRAs) are 3-dimensional resonating structures made up of a high permittivity (and#949;r) low loss dielectric material [1]. The dielectric block is placed on a metallic ground plane. The electromagnetic wave is coupled inside the dielectric block using an excitation source similar to the microstrip patch antennas. The resonant frequency of DRA is predominantly a function of size, shape and permittivity (and#949;r) of the dielectric material [2, 3]. Compared to traditional microstrip antennas DRAs exhibit attractive features like low loss, high efficiency, small profile, greater design flexibility and wide impedance bandwidth [4]. As the radiating structure of the DRA is made of low loss dielectric material, DRA offers higher efficiency at higher frequencies in microwave and millimeter bands compared to metal-based antennas [5]. Moreover, DRAs are free from surface waves which may cause degradation in radiation patterns of microstrip antennas [6]. The advantages of DRAs make them an efficient radiator for modern wireless communication systems [7]. However, existing literature suggests that there is scope of improvement in DRA features like cross-polarization, dual-polarization, circular-polarization, gain, and bandwidth. In this thesis, new strategies for improving the performance characteristics of different shapes of DRAs have been investigated. Different types of feeding techniques have also been investigated in this study. newline