A Spurious-Free Characteristic Mode Formulation Based on Surface Integral Equation for Patch Antenna Structures

Conventional surface integral equation (SIE)-based characteristic mode formulation for the patch antenna structure with a finite substrate is susceptible to spurious (nonphysical) modes due dielectric part. To avoid contamination of modes, we propose novel generalized eigenvalue based on electric field equation-coupled Poggio–Miller–Chang–Harrington–Wu–Tsai equation. In this formulation, real and imaginary parts exterior operators are chosen construct finalized weighting matrices, connect radiated power current. Compared other SIE-based methods, does not need additional postprocessing since it can effectively modes. Numerical results compared volume-SIE investigated validate accuracy.