Electromagnetic Boundary Conditions Defined by Reflection Properties of Eigen Plane Waves.

In a previous study [1] it was shown that the generalized soft-and-hard/DB (GSHDB) boundary has the unique property that the two eigen plane waves are reflected as from the PEC or PMC boundary, i.e., with reflection coefficients -1 or +1, for any angle of incidence. The present paper discusses a more general class of boundaries by requiring that the reflection coefficients R+ and R-, corresponding to the two eigen plane waves, have opposite values, R±=±R with R independent of the angle of incidence. It turns out that there are two possibilities, R=1 for the class of GSHDB boundaries, and R=j, defining an extension of the class of perfect electromagnetic conductor (PEMC) boundaries. Matched waves at, and plane-waves reflected from, boundaries of the latter class are studied in the paper.