Electromagnetic scattering by four perfectly conducting rectangular cylinders is analyzed by Point Matching Method. The numerical results are in full agreement with the results for the well known integral solution method. And this letter give not only the field calculated around four cylinders but also model experiments using a line source at 9.6 GHz. The numerical results are in nearly good agreement with the experimental results.

Analytical solutions have been obtained for the electromagnetic scattering by a modified Luneberg lens with the permittivity of arbitrary parabolic function. They are expressed by four spherical vector wave functions for radially stratified medium which were introduced for the Luneberg lens by C. T. Tai. They consist of the confluent hypergeometric function and a "generalized" confluent hypergeometric function, in which the parameters for the permittivity of arbitrary parabolic function are involved. The characteristics of the modified Luneberg lens are numerically investigated using exact solutions in comparison with that of the conventional Luneberg lens. The bistatic cross section, the forward cross section and the radar cross section are studied in detail. The near-field distribution is also investigated in order to study the focal properties of the Luneberg lens. The focal shifts defined by the distance between the geometrical focal point and the electromagnetic focal point are obtained for various ka (k is the wave number and a is the radius of the lens). The focal shift normalized to the radius of the sphere becomes larger as ka is smaller. However it drops down rapidly for ka5 when the peak of the electric field amplitude appears on the surface of sphere.

The problem is deduced to scattering from four conducting rectangular cylinders by using the electric image method and analyzed by Point Matching Method. This letter gives not only near field distribution but also model experiments using a line source at 9.6 GHz. Numerical result is in nearly good agreement with the experimental result.

A new simple formulation of absorbing boundary conditions with higher order approximation is proposed for the solution of Maxwell's equations with the finite-difference time-domain (FD-TD) method. Although this higher order approximation is based on the third order approximation of the one-way wave equations, we have succeeded in reducing it to an equation in a form quite similar to the second order appoximation. Numerical tests exhibit smaller reflection errors than the prevalent second order approximation.

The effects of multiple scattering between two cylinders which have different radii are explicitly evaluated by direct matrix inversion techniques. This letter gives not only the field calculated around two cylinders but also good agreement between theory and experiment.

Reflection and transmission when a Gaussian beam is launched into an anisotropic slab whose optical axis has arbitrary direction is described. This problem is solved by using Fourier transforms. Solutions of reflected and transmitted beams having integral form are numerically calculated by using FFT.