Modal polarization current model method and its application to scattering by dielectric bodies

Abstract

SUMMARYThe polarization current model method (PCMM), one of the volume integral equation methods, is used for the analysis of antennas involving dielectric materials and of electromagnetic scattering by dielectric bodies. In the conventional PCMM, the subdomain method of moments is often used. Since the number of unknowns needed is proportional to the number of segmentations of the dielectric body, the computation time is long. In this paper, the M-PCMM method is proposed in which the polarization current density is mode-expanded in common spherical wave functions in the dielectric body, and its coefficients are used as the unknowns. The number of unknowns is unrelated to the number of segmentations of the dielectric body and is of the same order as that in the modal expansion method. Hence, the computation time can be reduced. In order to study the validity of this method, scattering by a cubic dielectric body is carried out. The analysis results of the M-PCMM are compared with those of the conventional PCMM. The results of the scattering directivity and the internal electromagnetic fields obtained by the two methods are in agreement, while the M-PCMM is found to reduce the computation time substantially.

Design of circularly polarized dielectric resonator antennas using modal polarization current model method

“…In this paper, in order to determine the configuration of the excitation structure, the M-PCMM is used. M-PCMM is a variety of the total domain method of moments using the polarization current density and is effective for the analysis of a homogeneous dielectric body with a shape close to a sphere, which the volume integral equation method has difficulty in handling [7]. Further, the method can provide sufficient accuracy relative to the measured value in the analysis of the linearly polarization dielectric resonator antenna [8].…”

“…In the second stage of the design, an optimum structure of the CP-DRA generating a circular polarization with matching to the feed system is determined by iterative analysis of the structure including the excitation section. In the analysis containing the excitation section as the second stage of the design, the modal polarization current model method (M-PCMM), a kind of total domain method of moments [7,8] is found useful.…”

Application of modal polarization current model method to dielectric resonator antennas

“…When the observation point and the source do not coincide but their blocks are adjacent, numerical integration is performed. If they are not adjacent, volume integration is performed analytically by approximating the solid body as a sphere of the same volume [5]. The probe current J a is approximated by the current on the center axis and is expanded by step functions (with a division length of ∆s q ).…”

“…Although the PCMM using the partial domain method of moments is useful for the analysis of spaces containing inhomogeneous dielectric bodies, the computation time for solving the simultaneous equations is extremely long, because the electric fields inside the divided dielectric material are used as unknowns. Hence, the present authors have proposed a modal expansion polarization current model (Modal PCMM) that is a type of total domain method of moments and have applied it to the analysis of scattering by a dielectric body [5]. This method is henceforth called the M-PCMM.…”

Light scattering by a cube: Accuracy limits of the discrete dipole approximation and the T-matrix method

“…were simulated using similar methods [12][13][14], again with several-percent accuracy, when compared against the finite-difference time-domain method (FDTD) [14]. The second step was made by Liou et al [15] and later others [16,17] with geometrical-optics simulation of light scattering by cubes much larger than the wavelength.…”