This paper deals with electromagnetic wave scattering by an infinite plane metallic double grating with three dielectric layers in case of E- and H-waves excitations. The field expressions for this problem are obtained by making use of superposition of the results of the single grating case. The analytical method used here is based on the spectral domain method combined with the sampling theorem. Some numerical results are presented for the near fields such as the surface current distributions on the strips and for the far fields such as the frequency characteristics as well as the insertion loss from the viewpoint of a polarization discriminator.

This paper is concerned with a theoretical study of electromagnetic wave scattering by infinite plane gratings located on both sides of a dielectric slab in case of oblique incidence and arbitrary polarization. In the analysis, we use the spectral domain method combined with the sampling theorem. Infinite sets of simultaneous equations are derived by the method of moments where spherical Bessel functions are used as weighting functions. Numerical results exhibit a good convergence. The use of a resonance phenomenon of a double grating makes it possible to greatly improve the cross polarization discrimination (X. P. D.) compared with the case of a single grating.

This paper is concerned with a point-oriented finite volume time domain (FVTD) method in the Cartesian coordinate system for analyzing electromagnetic wave scattering by arbitrary shaped metallic gratings. The perfectly matched layer (PML) is used for the absorbing boundary conditions (ABC's) in the directions corresponding to transmitted and reflected wave regions. An FVTD version of the Floquet's theorm is described to impose the periodic condition in the direction where conducting rods are located periodically. The boundary conditions for a conductor rod which is not well suited to the Cartesian coordinate system are satisfied in an average fashion by introducing image fields at image points. It is shown that the present method gives accurate numerical results. Numerical calculations are also carried out for thick conducting rods which seem difficult to deal with in an analytical way.

This paper presents a numerical analysis for the plane wave scattering by an infinite plane grating. First, the induced surface currents on conducting strips are expanded in Fourier series with a weighting function corresponding to field singularities near edges of the strips. Second, all the boundary conditions are satisfied in Fourier spectral domain, which leads to infinite sets of algebraic equations. Since the field singularities have been taken into account, the final numerical results show very rapid convergences for the near fields as well as for the far fields. From numerical comparison of the present method with other various methods, it is found that the present method provides us precise values as for transmitted powers. Numerical calculations are also made for distributions of the surface currents.

This paper is concerned with a theoretical analysis of the electromagnetic wave scattering by an infinite rectangular patch array on a dielectric slab. The present analysis is based on the spectral domain method combined with the sampling theorem. The surface current distributions on the patch array are expanded in nonharmonic Fourier series. Numerical examples are given for frequency and polarization characteristics as well as for the surface current distributions.

This letter is concerned with the investigation of electromagnetic wave scattering by an infinite patch grating. The analytical method used here is based on the spectral domain method combined with the sampling theorem. Numerical results are given for transmitted and reflected powers when frequency or polarization angle is changed.

This paper is concerned with a point-oriented finite volume time domain (FVTD) method in the Cartesian coordinate system and its application to the analysis of electro-magnetic wave propagation in a bended waveguide as well as radiation from and receiving by a horn antenna with a flange of arbitrary angle. The perfectly matched layer (PML) is used for the absorbing boundary conditions (ABC's). The boundary conditions for a perfect conductor not well suited to the Cartesian coordinate system are also proposed. According to this algorithm, the boundary conditions are satisfied in an average fashion at the conductor surface without changing the computational scheme. In this sense, numerical computations based on the present method are simple but flexible. Numerical results show good convergence.

This paper is concerned with the theoretical and experimental study of electromagnetic wave excitation in a tunnel with a cross-junction. In the analyses, a surface impedance model is introduced for the boundary conditions on the tunnel walls to take into account their dissipative effect on propagation. Experiments based on a microwave simulation are also performed in order to check whether the surface impedance approximation is valid or not for a bended tunnel. It is found that numerical and experimental results agree well regarding electric field intensity in each tunnel.

By use of a planar grating on a dielectric slab where some strips of different width are placed in one period, polarization- and frequency-selectivities are improved when the thickness of the dielectric slab, its relative permitivity and the location of the strips are chosen appropriately.