A Template-Modulation Jamming Against SAR Based on Frequency-Diverse Array

Existing frequency-diverse array (FDA)-based jamming methods against synthetic aperture radar (SAR) still require complex modulation calculations to generate false area targets as the traditional SAR jamming method does and cannot generate them solely without the regular distribution or repetition in range in SAR images. However, such regular distribution or repetition tends to make false area targets easily identifiable. Therefore, in order to create flexible jamming both in range and azimuth, this letter first proposes a method to obtain Doppler-modulation phase using the fast Fourier transform (FFT) of a template along the azimuthal direction, which can help the jammer generate template-based jamming in the azimuth domain. Then, by leveraging the distinctive features of FDA's multifrequency transmission structure, which allows for accurate determination of range positions of false targets within the template, and incorporating the utilization of Doppler-modulation phase, a template-modulation jamming method based on the FDA is proposed. This method can produce solely 2-D template-based deceptive or controllable suppression jamming in SAR images without complex modulation calculation requirements. As the final jamming result is determined by the template constructed, the regular jamming distribution can be avoided. The effectiveness of the proposed method is validated through theoretical analysis and simulation experiments.