Film Mode Attenuation Due to Random Surface Irregularities

A method for the approximate calculation of the attenuation constant of dielectric film modes due to small two dimensional random boundary deviations from eveness is presented. The irregularities are replaced by effective sources, the radiated power of which accounts for the loss, suffered by an incident mode. Results for the H0-and E0-mode are plotted versus their film asymmetry parameters. When the deviations are assumed to be grooves transvers to the propagation direction, the problem becomes two dimensional and the results show good agreement with an earlier more accurate treatment.