Multiband Radar Using Microwave Photonic Time-Frequency Limiter for Real-Time Detection in Interference Scenarios

In this paper, a novel strategy of employing microwave photonic (MWP) time-frequency limiter (TFL) for microwave photonic multiband radar is proposed to suppress the interference, achieving real-time response to the interference scenarios and high-resolution target detection. By mapping the echo signal into optical domain, the time-frequency characteristic is re-constructed through stimulated Brillouin scattering (SBS), realizing the selective suppression on high-power optical signal mapped by the interference. Based on this concept, a MWP TFL system based on the optical spectrum processing is constructed, and proof-of-concept experiments are demonstrated to verify the feasibility of the proposed strategy under different interference scenarios. Employing the proposed MWP TFL, the signal-to-noise ratio of the detection results, which is severely degraded by asynchronous interference, can be improved by 27.97 dB, and the suppression ratio on the false targets generated by the synchronous interference can reach 34.10 dB. The experimental results shows that the strategy can further enhance the survivability of multiband radar without compromising the range resolution for target detection. In addition, experiments are carried out to demonstrate the capability of the proposed strategy under different interference-to-signal ratios, showing a good adaptability to the complex interference scenarios.