Compact Circularly Polarized Tri-, Dual- and Single-Band Dielectric Resonator Antennas

Abstract

The Dielectric Resonator Antennas (DRAs) have received wide attention due to low loss, high radiation efficiency, small size, wider bandwidth and simple feed network as compared to the microstrip antennas. Microstrip antennas have many challenges such as low radiation efficiency, high conductor loss, poor polarization purity, multiple frequency bands and multiple polarizations with a large footprint area of the antenna, low gain and narrow bandwidth. The existing design techniques for tri-, dual- and single-band DRAs reported in the literature have various limitations such as ground plane area of DRA, volume of Dielectric Resonator (DR) and DRA not sufficient for small physical area applications, realization of Circular Polarization (CP) over large ground plane area and unavailability of single DR geometry with multi-mode for multi-band applications. In this thesis, compact CP tri-band (L5, L1 and S-bands) staired Rectangular Dielectric Resonator Antennas (RDRAs) (two port, single port) using tri-, dualand single-sections Wilkinson Power Dividers (WPDs) with wide-band 90◦ phase shifters are designed, analyzed, fabricated and tested. These tri-band RDRAs are used in Indian Regional Navigation Satellite System (IRNSS) and GPS-Aided GEO Augmented Navigation (GAGAN) applications. The ground plane footprint areas of tri-band RDRAs and volumes of staired Rectangular Dielectric Resonators (RDRs) are significantly reduced by using high dielectric constant of DR materials and high dielectric constant of dielectric substrates. The broadside radiation patterns of triband RDRAs are produced by TEy 111, TEy 113 and TEy 112 modes for L5, L1 and S-bands, respectively. Various parameters of tri-band RDRAs like return loss, Right Hand Circularly Polarized (RHCP) - Left Hand Circularly Polarized (LHCP) radiation patterns, RHCP gains and axial ratios are analyzed and measured. Compact CP dual-(L5 and L1) and single-band RDRAs are designed, analyzed, fabricated and tested using feed networks of dual- and single-sections WPDs with wide-band 90◦ phase shifters. The miniaturized volumes of RDRs and ground plane areas of dual- and single-bands RDRAs are achieved using high dielectric constant of DR materials and high dielectric constant of dielectric substrates. The broadside radiation patterns of dual-band RDRA are produced by TEy 111 and TEy 113 modes for L5 and L1-bands, respectively. The TEy 111 modes are produced in three single-band RDRAs for L5, L1 and S-bands. The simulated and measured parameters of dualand single-band RDRAs are return loss, RHCP-LHCP far field radiation patterns, RHCP gain and axial ratio. The design and analysis of finite ground plane single-band CP RDRAs using WPD with wide-band 90◦ phase shifter for L1 and L5-bands are carried out by using high dielectric constant of DRs and dielectric substrates. Also, the effect of different radii of finite circular ground planes of single- and dual-band RDRAs are investigated by using the Method of Moments (MoM). The effect of different radii of circular ground plane on single- and dual-band RDRAs are analyzed for return loss and gains.