The Generalized Soft-and-Hard Surface

The well-known soft-and-hard surface (SHS) condition is one example of the ideal boundary condition defined by vanishing of the normal component of the complex Poynting vector at the boundary. It is shown that more general ideal boundary condition leads to a generalised SHS (GSHS) boundary where the real special direction on the surface is replaced by a complex vector. Reflection of the general plane wave incident on a GSHS boundary is derived in a simple form through generalized TE/TM decomposition of fields. Possible realisations of the GSHS boundary and its application in polarisation transformation are suggested.