Optimal Design of Antenna for Spaceborne SAR Based on Differential Evolution Algorithm

Abstract

An important feature of future spaceborne synthetic aperture radar (SAR) is the adoption of large mesh reflectors fed by arrays. The main advantage of this SAR sensor is the provision of large antenna apertures and reconfigurable feed excitation. A large deployable mesh-reflector antennas combinaed with feed arrays is designed for the application of spaceborne SAR on geosynchronous orbit. To decrease the transmit power of feed element and increase the flexibility, a large scale of two-dimensional feedarray is adopted. An approach based on defocused reflector is used to broaden the beams from feed element, so almost all the feed elements can participate in the pattern synthesis in the complete angular domain. This paper presents a new optimization method of the defocused reflector system. The method aims at getting high gain and low sidebobes by optimizing the reflector parameters together with the feed array. The differential evolution algorithm(DE) is used to get globally optimal solution. The performance of the reflector after optimization is computed to demonstrate the effective of the method presented.