Abstract: As an asymptotic solution of the wave equation at high, frequency, the complex ray field in lossy media is discussed in detail, and oompai'ed with the case of lossless ones. From these discussions, it is found that the Gaussian beam can also be effectively expressed by the complex ray field in lossy media, and the complex ray approaches developed in the lossless case can also be used in the lossy case. As an example, we give the ROS results obtained by both theoretical and experimental methods for a conducting flat plate with one surface coated with radar absorbing materials. Their good agreement shows the extension of complex rays from lossless media to lossy ones is reasonable.

Key words: complex ray, radar absorbing material, radar cross section