Boundary waves along an impedance plane with a linearly varying impedance

A formal and asymptotic solution has been obtained for boundary waves which are supported by an infinite plane impedance boundary with a linearly varying impedance. The asymptotic solution (with respect to large distance from the origin) has three terms which are recognized as an incident, a reflected boundary wave, and a radiated wave. It is found that an increasing rate of change of the boundary impedance corresponds to more tightly bound boundary waves, to a power reflection coefficient approaching unity, and to a radiation efficiency approaching zero.