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Improvement of the absorbing boundary conditions for triangle-hexagonal dual cell grids in the time domain method is described in this paper. The magnetic field components, which are evaluated by the electric fields at the circumcenters of the triangle cells, are conformed to Berenger's perfectly matched layer absorbing boundary conditions. The electric field is linearly interpolated by the fields at the vertices. The lower reflection coefficients in the frequency range for the equilateral and non-equilateral triangle cells are demonstrated.
Masashi HOTTA Tomoyuki INOUE Masahiro KOBAYASHI Mitsuo HANO
Leakage loss of Conductor Backed Coplanar Waveguide (CBCPW) with air-gap-spacing (AGS) dielectric sheets has been analyzed by using the hybrid 2D-FDTD Method and curve-fitting procedure. From numerical results, the proposed CBCPW with AGS dielectric sheets shows even lower leakage loss characteristics than those of conventional and double-layered one over a wide range of operating frequency. Furthermore, the possibility of the optimum air-gap width for leakage loss has been confirmed.
Masashi HOTTA Mitsuo HANO Ikuo AWAI
Eigenvalue equations and expressions of EM fields for volume modes in an anisotropic single-negative slab with tensor material parameters is presented. By the comparison with the eigenvalue equation of surface modes along single-negative slab with negative scalar permeability, the validity of the present study is confirmed. We have also made clear which elements of the material parameter tensors affect existence of TE and TM modes in the slab. Taking the dispersion of material parameters into consideration, we demonstrate in detail that TE modes propagate in a slab with one negative element of the permeability tensor numerically. These TE modes turn out to be the magnetostatic waves (MSWs), which is the first demonstration of the MSW in a nonmagnetic material.
Masashi HOTTA Mitsuo HANO Ikuo AWAI
Existence of a surface wave along the boundary between the semi-infinite materials, one of which is a free-space and the other is a material with either negative permeability or negative permittivity, is theoretically investigated. Surface waves exist in only limited combination of negative and positive signs of the material parameters. In addition, by analyzing the surface wave in a finite-thickness slab with negative permeability, its mode profile has been obtained for two different types of symmetry. From these results, the present paper predicts the possibility of a surface wave directional coupler based on a single slab transmission along its top and bottom surfaces.
We report a magneto-optic analog-to-digital converter for a 2-digit case with a ternary code and a unit distance code using a multiple-reflection Kerr effect in Permalloy thin films. In our experiment, a sampling frequency could be extended up to 30 kHz.
We report a magneto-optic bistable device using a magnetic thin film waveguide modulator. Because of a discontinuous transmission curve of this waveguide, optical bistable operations can be obtained with a wide range of bias field at room temperature.
We have proposed an algorithm to apply perfectly matched layer (PML) absorbing boundary condition to the noncubic cell time-domain method. The extended method has a merit of flexibility in truncating the computational domain by the use of a curvilinear PML. In this paper we apply a circular PML for computing the scattered fields of a dielectric cylinder or cylindrical shell of arbitrary cross section shape. Numerical results are presented to demonstrate the accuracy of this method.
Masashi HOTTA Ryota OGAWA Mitsuo HANO
Existence of backward TE volume modes which are to be identified as Magnetostatic Wave (MSW) in anisotropic single-negative slab with partly negative permeability tensor component have already been revealed by present authors. In this paper, detailed modal analysis has been carried out for this kind of TE volume modes to find out their novel and peculiar properties. From these numerical results, it has been clarified that dispersion curve of the lowest order mode for thicker slab has a frequency of turning point below which both forward and backward waves can be simultaneously observed and also there is a critical slab thickness for each order of TE volume modes to exist.