Phase Mismatch in Multichannel Beam Steering SAR With Different Azimuth Steering Laws

Azimuth multichannel synthetic aperture radar (SAR) working in beam steering modes can effectively obtain images with wide unambiguous swath and high azimuth resolution. However, azimuth phase center fluctuation (APCF) phenomenon can be induced by the beam rotation in azimuth. Consequently, addition phases will be introduced in echoes of different channels. Different beam steering laws result in different degrees of APCF phenomenon, which lead to different azimuth channel phase errors. These phase errors lead to paired azimuth ambiguities or targets offset in imaging results. In this letter, the effects of different beam steering laws on the imaging results are analyzed, and the total additional wave paths required by different beam steering laws are compared, aiming at providing a reference for the design of the practical beam steering SAR system. The impacts of different beam steering laws on the imaging results are verified by simulation experiments.