The effective permittivity of the two-dimensional multilayered periodic structures which consist of the rectangular dielectric cylinders is examined numerically. The original periodic structure is replaced with a simple structure such as the dielectric slab. By using the reflectance of the periodic structure obtained by the FDTD method, the effective permittivity of the dielectric slab, which has the same reflectance as that of the periodic structure, is obtained by using the transcendental equation. In order to reduce the procedure to obtain the reflectance from the multilayered periodic structures, the reflectance from one-layered structure is used. The range of the application and validity of this procedure is examined.

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.

In this paper, we propose a new technique for the scattering problems of multilayered inhomogeneous columnar dielectric gratings loaded rectangular dielectric constant both TM and TE waves using the combination of improved Fourier series expansion method, the multilayer method, and the eigenvalue matrix method. Numerical results are given for the power transmission coefficients in the parameters ε 3 /ε 0 , c/p, and b/d of rectangular cylinders to obtain the basic characteristic of the power transmission coefficients and reflection coefficients switching or frequency selective devices for both TM and TE waves. The influence of the incident angle and frequency of the transmitted power are also discussed in the connection with the propagation constant β in the free mode.

Multilayered filters with a dielectric distribution along their thickness forming a one-dimensional quasi-fractal structure are theoretically analyzed, focusing on exposing their resonant properties in order to understand a dielectric Menger's sponge resonator [4],[5]. "Quasi-fractal" refers to the triadic Cantor set with finite generation. First, a novel calculation method that has the ability to deal with filters with fine fractal structures is derived. This method takes advantage of Clifford algebra based on the theory of thin-film optics. The method is then applied to classify resonant modes and, especially, to investigate quality factors for them in terms of the following design parameters: a dielectric constant, a loss tangent, and a stage number. The latter determines fractal structure. Finally, behavior of the filters with perfect fractal structure is considered. A crucial finding is that the high quality factor of the modes is not due to the complete self-similarity, but rather to the breaking of such a fractal symmetry.

Power distribution in multilayered periodic waveguides is first analyzed by longitudinal modal transmission-line theory (L-MTLT). Novel effective characteristic impedances of the equivalent network for TE and TM modes are then derived, and a symmetrical grating guide with three layers is rigorously evaluated to clarify the validity of our approach. Excellent agreement between our results and the results due to other methods indicates that our approach is able to not only reveal all the physical meaning embedded in the multilayered and multi-sectional periodic waveguides, but also predict various possible Bragg regimes rigorously and simply.

We report field emission from multilayered cathodes grown on silicon and glass substrates. The cathode consist of a layer of nanoseeded diamond and overlayers of nanocluster carbon (sp2 bonded carbon) and tetrahedral amorphous carbon (predominantly sp3 bonded carbon). These films exhibit good field emission characteristics with an electron emission current density of 1µA/cm2, at a field of 5.1V/µm. The multilayered cathodes on silicon substrates exhibit even lower emission threshold field of about 1-2V/µm for an emission current density of 1µA/cm2. The emission is influenced by the nanoseeded diamond size and concentration and the properties of the nano carbon over layer.

In this paper, the power plane resonance problem in a multi-layered PCB is numerically analyzed by applying the alternating-direction implicit (ADI) FDTD method. This method is extremely suitable for analyzing the power plane resonance problems having locally fine structures of two closely located planes. This paper also analyzes the effect of the decoupling capacitor, which is one of the solutions for reducing the resonance problem. The results of the ADI-FDTD agree well with those of the conventional FDTD and the analytic solutions, and the computational CPU time is reduced to about a half of that of the conventional FDTD.

A large part of our daily lives is spent surrounded by buildings and other structures. In this paper, we used an infinitelength, multilayered cylindrical model to rigorously analyze the microwave specific absorption rate (SAR) of a human standing near a 90corner wall. At frequencies above 1 GHz, the interactions between the microwaves, the human body (including layer resonance), and the corner cause complex changes in the average SAR. We have shown numerically that the SAR with a corner present is up to four times larger than when there is no corner, and that the average SAR of TE waves at frequencies below 1 GHz is up to 10 times greater than when there is no corner.

In this paper, we present an analysis of microstrip line with a trapezoidal dielectric ridge in multilayered media. The method employed in this characterization is called partial-boundary element method (p-BEM) which provides an efficient technique to the analysis of the structures with multilayered media. To improve the convergence of the Green's function used in the analysis with the P-BEM, we employ a technique based on a combination of the Fourier series expansion and the method of images. Treatment on convergence for the boundary integrals is also described. After this treatment, it requires typically one tenth or one hundredth of Fourier terms to obtain the same accuracy compared with the original Green's function. Numerical results are presented for two microstrip lines that have a trapezoidal dielectric ridge placed on a one-layered substrate and a two-layered substrate. These numerical results demonstrate the effects on the characteristics of the microstrip line due to the existence of the dielectric ridge as well as the second layer between the ridge and the fundamental substrate.

In this paper, we present for the first time two three-dimensional analytical electrostatic Green's functions for shielded and open arbitrarily multilayered medium structures. The analytical formulas for the Green's functions are simply expressed in the form of Fourier series and integrals, and are applicable to the arbitrary number of dielectric layers. In combination with the complex image charge method, we demonstrate an efficient application to analyze microstrip discontinuities in a three-layered dielectric structure. Numerical results for the capacitance associated with on open-end discontinuity show good agreement with those from a previous paper and the effectiveness of using the analytical Green's functions to analyze three-dimensional electrostatic problems.

In this paper, we presented an analysis of single and coupled microstrip lines covered with protective dielectric film which is usually used in the microwave integrated circuits. The method employed in the characterization is called partial-boundary element method (p-BEM). The p-BEM provides an efficient means to the analysis of the structures with multilayered media or covered with protective dielectric film. The numerical results show that by changing the thickness of the protective dielectric films such as SiO2, Si and Polyimide covered on these lines on a GaAs substrate, the coupled microstrip lines vary within 10% on the characteristic impedance and within 25% on the effective dielectric constant for the odd mode of coupled microstrip line, respectively, in comparison with the structures without the protective dielectric film. In contrast, the single microstrip lines vary within 4% on the characteristic impedance and within 8% on the effective dielectric constant, respectively. The protective dielectric film affects the odd mode of the coupled lines more strongly than the even mode and the characteristics of the single microstrip lines.

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.