Effect of fabrication imperfections for ground-plane-backed dielectric-resonator antennas

Results of numerical and experimental studies, pertaining to the effect of imperfections such as surface roughness, which could lead to poor mechanical contact between a dielectric resonator and the conducting surfaces on which it resides, are presented. This work simulates the poor-contact effect by introducing air gaps between the dielectric resonator (DR) and the adjacent conducting surfaces. Results are presented which illustrate the effect of air gaps upon the input impedance and resonant frequency of cylindrical-DR antennas, operating in the TM₀₁ and HEM₁₁ modes. Also presented are preliminary results pertaining to the validity of the thin-wire-theory approximation that is used in numerical electromagnetic design codes, to model the coaxial-feed probes, and results pertaining to the effect of an infinite-ground-plane assumption