Time-Modulated Metasurface-Assisted Moving Target Jamming for Synthetic Aperture Radar

Motivated by the extraordinary modulation capability of the electromagnetic (EM) metasurface technique, a time-modulated metasurface-assisted moving target jamming method is proposed for the synthetic aperture radar (SAR) in this article. A time-modulated metasurface with real-time and flexible manipulation characteristics for the reflection phase of the EM wave under both normal and oblique incidences is designed, fabricated, and measured, respectively. It is capable of achieving composite phase modulation, which combines the advantages of the cosinusoidal-phase and subsection-phase modulations. Based on the designed metasurface, a spectral distribution with a series of discrete harmonic frequency components with varied frequency offsets and amplitudes can be formed. Furthermore, the composite phase modulation signal generated by the time-modulated metasurface is applied to interfere with the ground moving target indication (GMTI) for the SAR system, and the jamming effect of the metasurface on the moving target detection is analyzed in detail. The validity of the proposed jamming method is verified through theoretical analysis, metasurface modulation measurements, and SAR-GMTI experiments. Theoretical analysis and experimental results demonstrate that the adoption of the time-modulated metasurface modulation technique allows for the generation and detection of multiple discrete false moving targets with varying azimuth spacings and amplitudes for the victim SAR-GMTI system. The proposed method achieves effective moving target jamming and deception, expanding the application scenarios of metasurfaces in the field of radar electronic countermeasures.