Variant Characteristic Mode Equations Using Different Power Operators for Material Bodies

Xing-Yue Guo,Ren-Zun Lian,Ming-Yao Xia

doi:10.1109/access.2021.3073901

Xing-Yue Guo, Ren-Zun Lian + Show 1 more

Open Access

https://doi.org/10.1109/access.2021.3073901

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Abstract

This paper is concerned with the electromagnetic theory of characteristic modes for general homogeneous material bodies using surface integral equations (SIEs), which are computationally more efficient than using volume integral equations (VIEs). However, the generalized eigenvalue equations (GEEs) based on SIEs are prone to generate spurious or extra modes, unlike their counterparts based on VIEs. In this work, several variant SIE-based GEEs are proposed to eliminate the spurious/extra modes and improve the numerical performances. These variant GEEs share a common point that the reactive power operator related to the material domain should be removed from the left-hand sides of GEEs by explicitly enforcing the boundary condition, because it seems sensitive to incur unwanted modes. These variant GEEs are diverse in choosing the active power operator related to the material domain on the right-hand sides to suit different medium parameters, which even can be dropped directly for lossless cases. Numerical results show that these variant GEEs do not generate spurious/extra resonant modes in observed frequency range, and at least one of the variants would have acceptable numerical accuracy.

Highlights

The well-developed theory of characteristic mode (TCM) based on surface electric field integral equation (EFIE) was proposed by Harrington and Mautz in 1971 for perfectly electrical conductor (PEC) [1]
The recognized solutions obtained by using the volume integral equations (VIEs)-based formulations with only 812 tetrahedron meshes are shown in Fig. 2 (a) for both the lossless and lossy cases, where the mode significances (MS) for the first 129 modes are displayed
If we use the generalized eigenvalue equations (GEEs) (A) to solve them, the results are shown in Fig. 2 (b) and Fig. 2 (c) for the lossless and lossy cases, respectively, both of which present many spurious modes

Summary

Introduction

The well-developed theory of characteristic mode (TCM) based on surface electric field integral equation (EFIE) was proposed by Harrington and Mautz in 1971 for perfectly electrical conductor (PEC) [1]. This first choice was reported to generate spurious modes for both lossless and lossy dielectric bodies [5], [6], which did not exist by using the VIE-based formulations.

Results

Conclusion