Variant Characteristic Mode Equations Using Different Power Operators for Material Bodies

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.INDEX TERMS Characteristic modes, material bodies, power operators, spurious modes.

A Study on Characteristic Mode Equations of Radiation Problems Contrasted with Scattering Problems for Dielectric Bodies

“…One example is given to observe which one of the four cases the modes solved from GEE (19) satisfy. A cubic dielectric resonator (DR) (a = b = c = 25.4 mm) in [15] is considered since it has been frequently applied as a verified example [11][12][13][14]. Its constitutive parameters are ε r1 = 9.4 and µ r1 = 1.0, and the background is the air, i.e., ε r2 = 1.0 and µ r2 = 1.0.…”

“…In addition, our previous work [11,14] has addressed scattering problem (A) and proposed adequate formulations. The boundary condition is truly one of the key points.…”

“…Unfortunately, the SIEbased TCM was reported to generate spurious modes [7]. In order to remove these spurious modes, there are some valuable formulations [8][9][10][11][12][13], including building a dependent relationship between equivalent electric and magnetic currents [8][9][10][11][12][13][14] and making the right-hand side of the generalized eigenvalue equation (GEE) related to only radiated power [11][12][13]. Thus far, the spurious modes have almost been suppressed.…”

Electromagnetic Compatibility Study of Quadcopter Uavs: Characteristic Mode Analysis of the Frame's Material and Shape Effect

“…Moreover, we recently employed CMA to study coupling and interference to wires and other 2-D structures [28][29][30]. However, applying CMA for complex shapes composed of one or more dielectric materials is still under development [31][32][33][34][35][36][37].…”