Study On The EM Characteristics Of Radar Absorbing Structure Based On Phase Modulated Surface

Conventional passive radar absorbing materials (RAM) operate either on the principle of phase cancellation, or use lossy materials to absorb incident electromagnetic energy. Although they are widely used for modifying the radar cross-section (RCS) of current military Platforms, such absorbers may not have adequate performance to satisfy future requirements. The passive radar absorber, once designed and manufactured,has fixed characteristics that are bounded by the electrical thickness at the lowest desired operating wavelength.Active absorbers, however, offer the potential to overcome the Rozanov limit.A phase-modulated surface (PMS) is a novel active radar absorber that can be used to dynamically control the characteristics of a radar signal scattered from a target, then provide real-time control of the RCS. It does this by applying phase modulation to the incident radar signal in such away that on reflection its energy is redistributed into sidebands that lie outside the bandwidth of the radar receiver and so are not detected.This paper investigating the PMS based on topology of a Salisbury screen, but uses an active layer to provide reflectivity tuning. The active layer is a Frequency Selective Surfaces controlled by semiconductor PIN diodes. The reflectivity of the linear polarized PMS together with the circular polarized types is studied by using the software of Ansoft HFSS, Spectral characteristics of reflected signals are also analyzed utilized the simulation results, as well as the behavior of the PMS from the prospect of the radar receiver. The efficacy of the PMS towards the detecting system is demonstrated by the numerical simulation results.