Spectral-Domain Computation of Fields Radiated by Sources in Non-Birefringent Anisotropic Media

TL;DR

This paper develops a robust spectral-domain method for analyzing electromagnetic fields radiated by sources in non-birefringent anisotropic media, addressing challenges posed by their unique eigenstructure and ensuring high accuracy and stability.

Contribution

It introduces alternative spectral-domain field expressions that overcome issues in eigenfunction expansion analysis for NBAM layers, enabling reliable EM field computations.

Findings

The proposed method achieves high accuracy in numerical simulations.

It demonstrates stability even with complex anisotropic properties.

The approach effectively handles sources within NBAM layers.

Abstract

We derive the key expressions to robustly address the eigenfunction expansion-based analysis of electromagnetic (EM) fields produced by current sources within planar non-birefringent anisotropic medium (NBAM) layers. In NBAM, the highly symmetric permeability and permittivity tensors can induce directionally-dependent, but polarization independent, propagation properties supporting "degenerate" characteristic polarizations, i.e. four linearly-independent eigenvectors associated with only two (rather than four) unique, non-defective eigenvalues. We first explain problems that can arise when the source(s) specifically reside within NBAM planar layers when using canonical field expressions. To remedy these problems, we exhibit alternative spectral-domain field expressions, immune to such problems, that form the foundation for a robust eigenfunction expansion-based analysis of time-harmonic EM radiation and scattering within such type of planar-layered media. Numerical results demonstrate the high accuracy and stability achievable using this algorithm.