Uniformly Improved Cross-Polar Discrimination in a Dielectric Resonator Antenna by Conduction-Current Control

Abstract

This work, for the first time, investigates the comprehensive sources of cross-polarized (XP) radiation from a dielectric resonator antenna (DRA). The study uses a recently developed theory on DRA radiation and models the XP sources with the help of well-known definition by Ludwig. This eventually focuses on the conduction-current distribution on the metallic ground. The interpretation leads to a concept of synthesizing effective conduction current in order to satisfy the required condition of low XP fields. A representative prototype of a cylindrical DRA on engineered ground plane has been realized to operate in C-band. It exhibits nearly 12% matching bandwidth with more than 25 dB co-to-cross polar discrimination over both orthogonal (H-) and diagonal (D-) planes. Relative improvement in XP level promised by the measured data is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 15 dB in D- and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 10 dB in H-planes. This proof of concept may now be extended to other DRA geometries and for practical applications in the near future.