Super-Resolution Method for Microwave Front-Looking Imaging Using Broadband Signals and Spatial Spectrum Shifting

We propose a super-resolution method for microwave front-looking imaging, which takes advantage of the signal bandwidth to enhance the resolution of imaging. Via spatial spectrum shifting, the distortion introduced by broadband imaging is eliminated. Therefore, the resolution of our method can surpass the Rayleigh diffraction limit defined by the angular aperture. A numerical study shows that, in the case of an angular aperture of 0.22, our method can reach 6 mm for a target located 10 km away without imaging distortion. It is equivalent to the resolution of an angular aperture of 1.38 We derive the relationship between the resolution and the signal bandwidth, which illustrates that our method makes it possible to use the bandwidth dimension for improving front-looking imaging resolution. The proposed method will promote the development of ultralong-distance precision imaging and wide-range microwave surveillance.