Performance Optimization of the Reflector Antenna for the Digital Beam-Forming SAR System

A novel idea of a realization a Synthetic Aperture Radar (SAR) system combining a reflector antenna with a digital feed array was suggested for the first time in [1]. The new digital beam-forming (DBF) SAR architecture has better overall system performance while being of lower complexity level as compared to the planar antenna based architecture [2]. This innovative idea has driven intensive studies aimed at future space borne SAR missions. Antenna design aspects and performance of the reflector based DBF SAR system have been thoroughly discussed in [2], [3] and [4]. As shown in [3] the initial design of the reflector antenna, aimed to satisfy the main system requirements, may need further optimization to allow better system performance. This paper is dedicated to this problem. The paper starts with the introduction of the initial system design and its operational principle. The discussion is followed by the consideration of several aspects specific for the reflector based DBF SAR and their impact on the system performance. Possible ways to reduce the impact by optimizing the antenna design are suggested. In the end the overall system performance is estimated.