Scattering characteristics of a domain wall displacement detection (DWDD) disk with a control layer were investigated by finite-difference time-domain (FDTD) analysis. DWDD is one of the high-density storage technologies of magneto-optical (MO) disks and the control layer is used to suppress ghost signals due to a rear process. The effects of the control layer on the scattering characteristics were studied.

The extended version of spectral domain approach (ESDA) is applied to evaluate the scattering characteristics of discontinuities in coaxial line. Discontinuities may be in inner and/or outer conductor of coaxial line. This method secures the high accuracy by considering the singularities of fields near the conductor edge properly. The computational labor of the new method is far lighter than that of FEM, so that novel method is suitable for the time consuming iterative computation such as fitting procedure in material evaluation or optimization of antenna design.

Reactive near field reflection characteristics of commercial RF absorbers are investigated to determine the minimum size of a reactive-field anechoic box necessary for measuring the reactive near field of an ESPAR antenna. The reflectivity of the absorber placed in close proximity to an antenna is inversely proportional to the distance between the antenna and the absorber. For carbon filled urethane foam tapered absorbers, we find that the backscattered reflection characteristics mainly depend on their tapered height rather than the thickness of absorber base. As a result, we show that carbon filled urethane foam pyramidal and wave surface shaped absorbers can be used to make reactive-field anechoic boxes. A prototype of a reactive-field anechoic box is presented and the distance from the absorber to the antenna is reduced to a wavelength. The prototype is verified by comparing its performance with that obtained from a large anechoic chamber.

An efficient full-wave approach for the accurate characterization of a H-plane waveguide π-junction with an inductive post and a waveguide cross-junction is proposed. By employing the port reflection coefficient method (PRCM), the analysis and solution procedures of these complex waveguide junctions are greatly simplified and only the calculation of field reflections caused by the simplest waveguide step-junction discontinuities are required. The reflections are easily determined by the mode-matching technique. Scattering parameters of these junctions are provided and discussed in terms of the working frequency and the geometrical dimensions of the junctions. Calculated results are compared with those of other papers and measurements, all show good agreement.

The scattering characteristics of a waveguide T-junction with an inductive post are analyzed by the port reflection coefficient method (PRCM), combined with the mode-matching technique. Variation behaviors of the scattering parameters are provided as a function of the operating frequency and the dimensions of the junction. The results are helpful for the design of power dividers using this type of T-junction configuration.