Radar ECCM for Time-Modulated Metasurface-Induced Electromagnetic Camouflage via Phase-Domain Decoupling

The multiphase coding time-modulated metasurface (MPC-TMM) can serve as an electromagnetic camouflaged technique to mask the real target, inducing dual interference effects of real-target stealth and false-target deception during radar signal processing. This article proposes an MPC-TMM counter-countermeasure method that suppresses deceptive false targets and detects the real target. The method inverts the MPC-TMM reflection coefficients by separating the metasurface-induced modulation from the target echo through their distinct phase behaviors after dechirping, thereby reconstructing the real time-frequency distribution of the target. The interference mechanisms of real-target stealth and false-target deception in MPC-TMM electromagnetic camouflaged scenarios are first analyzed. Subsequently, an anti-interference and target detection method capable of separating and decoupling the echoes reflected from MPC-TMM targets is developed. Unlike prior anti-interference techniques, the proposed method offers higher flexibility for fast-/slow-time modulation and multibit coding and additionally recovers useful signal energy rather than only suppressing interference. Simulation and experimental results of different scenarios have been used to validate the proposed algorithm. The results show that the radar anti-interference system is able to suppress the deceptive false targets in MPC-TMM scenarios, making the real target well-detectable in the range-Doppler profile.