Synthetic Aperture Radar Target Feature Modulation Using Active Frequency Selective Surface

Target feature control on the synthetic aperture radar (SAR) image using the passive way is a challenging task in the field of SAR jamming. The conventional passive jamming devices such as corner reflectors and chaffs cannot achieve the flexible modulation of SAR target feature duo to their fixed scattering cross section. As a passive material, active frequency selective surface (AFSS) can dynamically control their electromagnetic characteristics and has been widely applied in the radar target stealth field. In this paper, a target feature modulation method based on AFSS is proposed against SAR. The method intermittently switches the scattering intensity of AFSS material and imposes periodic or random code amplitude modulation onto the radar signal. As a consequence, multi-false targets with verisimilar characteristics or cross-shaped areas are formed when modulated signal is received and processed by the victim SAR. Thus, the protected target is difficult to detect and identify by the SAR system. Microwave anechoic chamber experiments and measured SAR data simulations with different modulating parameters are separately conducted to demonstrate the effectiveness of the proposed method.