Joint Design of Frequency and Bandwidth for Multifrequency SAR Based on Mutual Information Maximization

— The carrier frequency and bandwidth are vital parameters of radar transmit signals. In this article, a joint design of frequency and bandwidth in multifrequency synthetic aperture radar (SAR) is proposed to improve the target information acquisition capability. First, the target detection mutual information (MI) is considered as the performance metric, and its mathematical expression is derived using the example of decision-level fusion and hypothesis testing. The design is formulated as an optimization problem with multiple engineering constraints based on MI maximization. Then, a modified genetic algorithm (GA) is proposed to find the optimal solution satisfying the constraints via a code adjustment operator. It is shown by simulation results that for a specific scene, the multifrequency SAR with its frequencies and bandwidths designed by the proposed method has higher target information acquisition capability and more accurate target detection performance than existing spaceborne SAR systems.