Space-time analysis of phase-switched screens

A phase-switched screen (PSS) differs from conventional radar absorbers in that an ´ideal´ PSS does not absorb incident electromagnetic energy but redistributes it in the frequency domain so that it is undetectable by interrogating radar systems. The PSS achieves this translation in frequency by imposing phase modulation onto the energy scattered from its surface to produce a signal with a low time-average energy spectral density at the illuminating frequency. Previous work has examined the properties of PSS operating under various scenarios including oblique incidence and pulsed illumination. In all of these studies the analysis has been based on a transmission line analogue in which the PSS is assumed to be an infinite planar structure. Although this approach has proved very successful for modelling specular scattering from a PSS, particularly for back-scatter at normal incidence, it does not predict the angular scattering dependence of finite PSS. Hence in this contribution we present some results obtained from a new technique for modelling finite sized PSS using an approach based on time-switched array theory.