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

TL;DR

This paper introduces a new surface integral equation-based characteristic mode formulation for patch antennas that effectively eliminates spurious modes without additional post-processing, improving accuracy and reliability.

Contribution

A novel generalized eigenvalue formulation based on EFIE-PMCHWT that avoids spurious modes in characteristic mode analysis of patch antennas.

Findings

Effectively eliminates spurious modes in characteristic mode analysis.

Validated accuracy through numerical comparison with VSIE.

No need for additional post-processing steps.

Abstract

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