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In this paper, a rigorous two‐dimensional full‐vectorial finite difference time domain (2D‐FVFDTD) method is developed for an efficient analysis of nonradiative dielectric waveguide (NRD guide) devices with three‐dimensional structure. A Convolutional perfectly matched layer is employed as an absorbing boundary condition. Furthermore, we have established a rigorous formulation for estimating the modal power of each LSM01 ${\text{LSM}}_{01}$ and LSE01 ${\text{LSE}}_{01}$ mode. We confirmed the validity of the proposed method through the analysis of NRD crossing and T‐branch guide devices. Excellent accuracy is achieved by the cross comparison of 2D‐FVFDTD results with recently developed two‐dimensional full vectorial finite element method. [ABSTRACT FROM AUTHOR]

Recently, we reported on the basic advantages of the complex-type surface impedance boundary condition (CSIBC), however, its validity has not been confirmed for practical problems. In this paper, we show the formulation of CSIBC, which includes corners, and the complex nonstandard finite-difference time-domain (CNS-FDTD) method with the CSIBC is applied to the scattering analysis of a large cavity coated with radar absorbing materials. As a result, it is shown that the CSIBC formulation is highly efficient at reducing the computer load. For our 3-D model, the CSIBC reduced the computer load to roughly 1/[6.sup.4] that of the FDTD method. Index Terms--Cavity scattering, finite-difference time-domain (FDTD) methods, NS-FDTD methods, surface impedance boundary condition (SIBC).

The nonstandard finite difference time domain (NS-FDTD) method is a new high-accuracy FDTD method, but until now, it was applicable only at a single frequency. In this paper, we extend the NS-FDTD method to handle multiple frequencies in one computer run. We apply our new method to analyze the scattering analysis of a large cavity. Index Terms--Finite difference time domain (FDTD) methods, multifrequency analysis, nonstandard finite difference time domain (NS-FDTD) methods, numerical equivalent frequency, phase velocity.

In this paper, the overlap algorithm is applied to the nonstandard finite-difference time-domain (NS-FDTD) method using a nonuniform mesh in a 2-D space. The characteristics of the overlap algorithm are numerically examined and compared with a no overlap algorithm. The results show that the reflection rate from the interface of the two meshes using the overlap algorithm is less than -80 dB, which is smaller than that of the NS-FDTD method without the overlap. Consequently, it is shown that the overlap algorithm is more suitable for the NS-FDTD method when using a nonuniform mesh. The overlap algorithm is successfully applied to the analysis of a dielectric flat panel and a corrugated surface. Index Terms--Finite-difference time-domain (FDTD) method, nonstandard finite-difference time-domain (NS-FDTD) method, nonuniform mesh, numerical analysis, scattering.

This paper investigates the characteristics of evanescent waves in the generalized nonstandard finite-difference time-domain (NS-FDTD) method and derives the dispersion equation and stability condition for two-dimensional space. The validity of the dispersion equation is confirmed by comparison with results of numerical simulations. The NS-FDTD method is applied to the analysis of an optical switching device using a photon tunneling effect. It is shown that the NS-FDTD method has highly accurate characteristics not only for propagating waves, but also for evanescent waves compared with the standard FDTD method. Index Terms--Evanescent wave, finite-difference time-domain (FDTD) methods, nonstandard finite-difference time-domain (NS-FDTD) methods, numerical dispersion, photon tunneling effect, stability condition.

In this paper, a complex nonstandard finite-difference time-domain (CNS-FDTD) method is proposed in order to simulate wave propagation in lossy media. To clarify the characteristics of the method, expressions for the numerical propagation constant and the stability condition are derived. It is found that the CNS-FDTD method is much more accurate and stable than the conventional finite-difference time-domain (FDTD) method. The method is applied to the analysis of a fin ferrite electromagnetic wave absorber with a periodic structure. Index Terms--Complex formulation, FDTD method, NS-FDTD method, phase error, stability condition.

Several high accuracy finite-difference time-domain (FDTD) methods have been developed to overcome the phase velocity errors present in the FDTD method. The nonstandard FDTD method has been developed as one of those. The phase velocity errors of the method are investigated and the characteristics are compared with other high-accuracy FDTD methods. As a result, the numerical dispersion characteristics of the method are clearly shown and the extremely high-accuracy characteristic at the desired frequency is confirmed. Index Terms--FDTD method, high-accuracy FDTD method, nonstandard FDTD, numerical dispersion, phase velocity.

In this paper, the analytical edge condition is proposed for finite difference time domain (FDTD) simulations. The simple and accurate analytical procedure is obtained by referring to Przybyszewski's numerical procedure. The method is applied to analysis of patch antennas and waveguides with a capacitive iris. Calculated results agree well with the measured data and theoretical one. As a result, it is shown that the method is very effective for problems with edges involved. Index Terms--Edge condition, FDTD method, iris, microstrip antennas.

Hyperthermic treatment using a reentrant resonant cavity applicator is investigated. By solving time-dependent electromagnetic field - heat transfer equations for a heterogeneous model, temperature distributions in various organs are obtained. Calculated results show that it is indispensable to consider the blood flow to predict accurate temperature distributions during a hyperthermic treatment. Also, it is found that the necessity of measuring the electrical and thermal properties of the abdominal fat accurately as well as optimizing the heating system to avoid the concentration of electromagnetic energy around the abdominal fat-muscle interface.

This paper investigates the analysis of a hyperthermic treatment. The time dependent electromagnetic-heat transfer equations are solved step-by-step considering the temperature dependences of relative permittivity [[Epsilon].sub.r] and electric conductivity [Sigma]. Close agreement between the calculated and measured temperature distributions is obtained. A technique to direct the electromagnetic energy toward a specific part of a homogeneous torso model is also noted.

The need for small, portable antennas for mobile communications has recently spurred the study of microstrip antennas (MSA). MSA are quite flexible and have been used as conformal antennas on arbitrary curved surfaces. The characteristics of conformal MSA can be expected to differ from those of planar models. Dependable numerical analyses will obviate many of the costs and other inconveniences associated with experiments, but as antennas may be mounted on surfaces of arbitrary topological complexity, analysis methods must have as general applicability as possible. The curvilinear finite-difference time-domain (FD-TD) method has shown excellent versatility. In this paper, the curvilinear FD-TD method is applied to analyze microstrip antennas mounted on curved surfaces. The numerical predictions are compared with the experimental values. The results confirm the predictions within acceptable limits and appear to confirm the validity of the method. As a result, it was confirmed that the input impedance and directivity of MSA on curved surfaces are different from the flat MSA.