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

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
$\sim $
15 dB in D- and
$\sim $
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.