Radiation from waves guided by nonuniform active surfaces

The concept of electronically manipulating the complex wavenumbers of waves launched along guiding surfaces is discussed. The concept is based on being able to synthesize surfaces on which the surface impedance boundary condition Z/sub s/ can take on values anywhere in the complex plane. In particular, the author hypothesizes nonuniform surface impedances having a negative real part over some finite portion of the surface. With such a capability, one of several species of guided waves can be propagated at a time and then converted to another species as the wave propagates from one zone to the next having a different Z/sub s/. A number of cases were numerically studied to specify the impedance profiles.<>