Microwave Photonic Synthetic Aperture Radar: Systems, experiments, and imaging processing

With the development of synthetic aperture radar (SAR) technology, the resolution of SAR images has been improved from tens of meters to centimeters (currently the highest). However, increasing image resolution from centimeters to millimeters will pose a significant challenge to the hardware and signal processing algorithms of traditional radar systems. Fortunately, the emergence of microwave photonic technology assisted SAR systems in recent years is expected to solve this bottleneck. The system is theoretically capable of achieving a signal bandwidth of 10 GHz or even tens of GHz. However, the rapid increase in resolution will also bring new problems and challenges. For example, i) How to address the adverse effects of system instability under ultra-large signal bandwidth; ii) How to improve the imaging efficiency in the case of a sharp increase in data volume; iii) How to overcome the more complex signal characteristics faced by ultra-high-resolution imaging. Although microwave photonic SAR systems and data processing techniques are not yet sufficiently developed, they have great potential and will be a very hot and cutting-edge research field at present and in the future. In this paper, we will make a comprehensive review, summary, and prospect of the related research on microwave photonic SAR from three aspects of systems, experiments, and imaging processing. The purpose of this study is to provide some guiding suggestions and references for relevant researchers to promote the further development of microwave photonic SAR technology.