Performance Comparison of Reflector- and Planar-Antenna Based Digital Beam-Forming SAR

The trend in the conception of future spaceborneradar remote sensing is clearly toward the use of digital beamformingtechniques. These systems will comprise multiple digitalchannels, where the analog-to-digital converter is moved closer tothe antenna. This dispenses the need for analog beam steeringand by this the used of transmit/receive modules for phase andamplitude control. Digital beam-forming will enable SyntheticAperture Radar (SAR) which overcomes the coverage and resolutionlimitations applicable to state-of-the-art systems. On theother hand, new antenna architectures, such as reflectors, alreadyimplemented in communication satellites, are being considered forSAR applications. An open question is the benefit of combiningdigital beam-forming techniques with reflector antennas. Thepaper answers this question by comparing the system architectureand digital beam-forming requirements of a planar and areflector antenna SAR. Further elaboration yields the resultingSAR performance of both systems. This paper considers multiplenovel aspects of digital beam-forming SAR system design, whichjointly flow into the presented system performance