Accurate Sub-Structure Characteristic Mode Analysis of Dielectric Resonator Antennas With Finite Ground Plan

In this communication, we develop a surface integral equation-based sub-structure characteristic mode (CM) formulation to accurately analyze the resonant modes of dielectric resonator antennas (DRAs) with finite ground plane (GP). Two numerical examples of practical DRAs with finite GP are presented to compare the differences between the modal results obtained from the conventional full-structure and the proposed sub-structure CM formulations. It is found that the full-structure CM formulation leads to some resonant modes of the finite GP, which are undesirable modes for the DRA design. On the contrary, the proposed sub-structure CM formulation can suppress the undesirable modes. Thus, the sub-structure CMs are more suitable for the modal analysis of the resonant behavior of the DRAs than the full-structure CMs.