Electromagnetic power absorption in multilayered tissue media including anisotropic muscle regions whose principal dielectric axes (that is, muscle fibers) have various directions are analyzed by using 44 matrix method. Numerical calculations in 10kHz-10MHz show the effects of orientation of muscle fibers and polarization of incident wave on absorbed power density in tissues.

In the scattering problem of dielectric gratings in conical mounting, we have considered and formulated scattering fields using transverse electric (TE) and transverse magnetic (TM) waves. This paper formulates scattering fields by superpositions of right-circularly (RC) and left-circularly (LC) polarized waves through the matrix eigenvalue method.

In this paper, scattering waves by a strip grating with an anisotropic substrate for the incidence of inclined polarization are analyzed, and polarization characteristics of scatterd waves are calculated. For simplicity, the analysis is limitted to the case of normal incidence and a perfectly conducting strip grating is assumed.

In the shadow theory, a new description and a physical mean at a low grazing limit of incidence on gratings in the two dimensional scattering problem have been discussed. In this paper, by applying the shadow theory to the three dimensional problem of multilayered dielectric periodic gratings, we formulate the oblique primary excitation and introduce the scattering factors through our analytical method, by use of the matrix eigenvalues. In terms of the scattering factors, the diffraction efficiencies are defined for propagating and evanescent waves with linearly and circularly polarized incident waves. Numerical examples show that when an incident angle becomes low grazing, only specular reflection occurs with the reflection coefficient -1, regardless of the incident polarization. It is newly found that in a circularly polarized incidence case, the same circularly polarized wave as the incident wave is specularly reflected at a low grazing limit.

We propose a new analytical method for a composite dielectric grating embedded with conducting strips using scattering factors in the shadow theory. The scattering factor in the shadow theory plays an important role instead of the conventional diffraction amplitude. By specifying the relation between scattering factors and spectral-domain Green's functions, we derive expressions of the Green's functions directly for unit surface electric and magnetic current densities, and apply the spectral Galerkin method to our formulation. From some numerical results, we show that the expressions of the Green's functions are valid, and analyze scattering characteristics by composite gratings.

44 matrix-based analysis of electromagnetic waves scattered by an infinite array of slots with polar-type anisotropic media are presented. In the analysis, the total fields are given as sum of the fields which exist even if the apertured plane are replaced by a ground plane and the fields scattered from the magnetic currents within the apertures. The scattered fields are expanded in terms of two-dimensional Floquet modes. Expression of each fields are obtained through eigenvalue problem for 44 coupled wave matrix. Unknown magnetic currents in the apertures are determined by applying Galerkin's method to the continuity condition about the magnetic fields in the apertures. Calculated results for isotropic cases are compared with other results for the complementary problem available in the literature using Babinet's principle. Further numerical calculations are performed in the case of gratings with polar-type anisotropic slab.

The scattering problem by metallic gratings has become one of fundamental problems in electromagnetics. In this paper, a thin metallic grating placed in conical mounting is treated as a lossy dielectric grating expressed by complex permittivity and thickness. The solution of the metallic grating by using the matrix eigenvalue calculations is compared with that of the plane grating by using the resistive boundary condition and the spectral Galerkin procedure, and the availability of the resistive boundary condition for thin metallic gratings in conical mounting is investigated. In order to improve the convergence of the solutions of thin metallic gratings, the spatial harmonics of flux densities which are continuous function instead of electromagnetic fields are used.

In the scattering problem of periodic gratings, at a low grazing limit of incidence, the incident plane wave is completely cancelled by the reflected wave, and the total wave field vanishes and physically becomes a dark shadow. This problem has received much interest recently. Nakayama et al. have proposed “the shadow theory”. The theory was first applied to the diffraction by perfectly conductive gratings as an example, where a new description and a physical mean at a low grazing limit of incidence for the gratings have been discussed. In this paper, the shadow theory is applied to the analyses of multilayered dielectric periodic gratings, and is shown to be valid on the basis of the behavior of electromagnetic waves through the matrix eigenvalue problem. Then, the representation of field distributions is demonstrated for the cases that the eigenvalues degenerate in the middle regions of multilayered gratings in addition to at a low grazing limit of incidence and some numerical examples are given.

We present a 44 matrix-based analysis of scattering form a two-dimensional rectangular resistive plane gratings placed on an anisotropic dielectric slab. The solution procedure used is formulated by extending the 44 matrix approach. The fields are expanded in terms of two-dimensional Floquet modes. Total fields can be given as sum of primary and secondary fields whose expression are obtained through eigenvalue problem of coupled wave matrix. Unknown currents on resistive patches are determined by applying Galerkin's method to the resistive boundary condition on resistive grating. Results are compared with other numerical examples available in the literature for isotropic cases. Further, numerical calculation are performed in the case of gratings with polar-type anisotropic slab.