An analogue method of studying the angular spectrum of radiation reflected from rough surfaces

The approximate analogy between the angular spectrum of radiation reflected from a one-dimensional rough surface and the frequency spectrum of a burst of carrier, phase modulated by an appropriate waveform which is directly related to the surface profile, is described. In each case, and subject to certain approximations, the relationship is a Fourier transform. A simple analogue computer is described and used to justify the principle and demonstrate a convenient means of studying reflection problems approximately for both regular and random rough surfaces. Use of the analogue method allows changes in the surface parameters to be introduced easily so that their effects on the angular spectrum may be observed. The technique is applicable to normal or oblique incidence.