Skewon-axion medium and SHDB boundary conditions

A novel set of electromagnetic boundary conditions generalizing those of the soft-and-hard boundary and the DB boundary is defined in terms of an interface of a medium belonging to the class of skewon-axion media. The novel conditions are labeled as SHDB boundary conditions. It is shown that for the eigenwaves reflecting from a planar SHDB boundary see the boundary as equivalent PEC and PMC boundaries. The theory is tested with numerical examples.