Performance Aspects of Large-Deployable Reflector Antennas Based on Surface Deformations Simulated for Tandem-L

Abstract

Based upon the needs of the scientific community, the next generation of Earth observation synthetic aperture radar satellites will focus on comparatively longer wavelengths such as L- or even P-band. Due to operational constraints, instruments currently under development will likely be constructed as a phased array antenna feed paired with a large deployable reflector (LDR) / boom assembly. Compared to traditional planar antenna array based instrument designs, this leads to a series of novel challenges which have to be addressed. In this presentation we discuss several LDR performance aspects related to SAR-based Earth observation from low Earth orbits. Based upon the present reference scenario for Tandem-L, a current proposal for a future high performance SAR mission, we find that expected intra-orbit thermo-elastic deformations should have a tolerable impact on the SAR signal after digital beamforming in terms of gain and phase variations. Furthermore, the potential for reflector shaping opens a trade space which has to be carefully assessed.