This paper describes the high-precision electromagnetic field analysis methods that the author has developed (point matching method considering edge condition and modified Fourier series expansion method) and research on their applications. In addition, as a new application of periodic structures, it is discuss the new method for solving scattering problems involving arbitrarily shaped objects in inhomogeneous media.

In this study, the scattering fields by multi-window buildings have been analyzed by using the Kirchhoff approximation method. The scattering fields are obtained by the radiation integrals due to the equivalent current sources excited by the incident plane wave on the exterior of the building and the virtually closed window apertures. The fields in the window region are represented by rectangular waveguide modes, then the reflected fields from window glasses are also converted to the equivalent currents. The validity of our formulation has been confirmed by numerical comparison with the physical optics method and by measurements on scale models. Discussions have been made on the impact of window glass in the context of high-frequency wireless communications.

This paper presents an extension of the Kelvin transformation for high-frequency electromagnetic problems. The Kelvin transformation is a coordinate transformation that maps infinite space to a finite space, acting as a conformal transformation of Maxwell’s equations. We apply concepts of differential geometry to derive the material constant’s metric and spatial dependence in the exterior domain, which was originally proposed for low-frequency eddy current problems. This paper extends the conformal transformation concept to high-frequency problems by introducing a Perfectly Matched Layer (hereafter referred as to PML) in the exterior domain. This technique makes it easy to apply a simple Maxwellian PML.

An optical resonator with two waveguide discontinuities constructed by a metal-dielectric-metal plasmonic waveguide has been analyzed using the finite-difference time-domain (FD-TD) method with the piecewise linear recursive convolution (PLRC) method. The waveguide discontinuity has been expressed as an equivalent transmission line circuit whose circuit parameters are estimated from the reflection coefficients analyzed by the FD-TD method. We have confirmed the validity of the circuit configuration because the reflection characteristics of the equivalent circuit with the circuit parameters agree with those of the FD-TD method. Next, we have analyzed a resonator structure with two waveguide discontinuities and shown that the equivalent circuit gives a good approximation for the structure with a large difference in waveguide width at the discontinuities, in which conventional equivalent circuits had large errors.

This paper proposes directivity synthesis for multimode horns with square-waveguide aperture based on quadratic programming approach using radiation patterns for each mode for obtaining axial-symmetric beam and low cross-polarization components, and also for realizing desired constant beamwidth. As a design example, we present a 11/14/20/30-GHz primary horn with square aperture and also show effectiveness of the proposed method by evaluating electric force lines of aperture distribution and 15-dB beamwidth of radiation patterns.

Power line communication (PLC) technology utilizes the alternating current distribution network to transmit signals, enabling high-speed information exchange in photovoltaic (PV) power systems without the need for additional wiring, thereby saving costs. The use of PV PLC technology may potentially cause radiated emissions that interfere with wireless radiocommunications, consequently leading to electromagnetic compatibility issue. Additionally, conducting accurate radiated emission measurements on-site in PV power systems can be challenging. The paper proposes a methodology utilizing a scaled model for the equivalent radiated emissions of PV PLC. This approach facilitates the execution of equivalent testing for PV PLC radiated emissions under controlled laboratory conditions. Conducting a simulation study using CST to determine the equivalent simulation of actual long-line model through scaled short-line model, three scaled short-line models with different diameters were selected for comparison with the simulated radiated emission results of long-line model. After that, the optimal scaled short-line model was determined, followed by practical testing of the scaled short-line model in an anechoic chamber. Finally, by comparing the results, the accuracy of the simulation model was validated, this further substantiates the feasibility of the research methodology employed in this study. The study serves as a reference for achieving accurate prediction of PV PLC radiated emissions and the determination of associated limits in the future.