“…Therefore, if the aim of radiation is to characterize the surface, or to generate or keep a specific wave, such a reflected beam is not useful. One of the main concerns in communication (Barker & Schamiloglu, 2001) and high energy accelerators studies (see e.g., Chodorow et al, 1955;Colby, 2004) is the smoothness of a polished metal surface called the waveguide, which is always assumed to be completely smooth. The waveguide is usually covered by a layer of polishing liquid to make it smoother.…”