CSG SAR Electronics Subsystem architectural design

This paper introduces a novel architectural design for wideband spaceborne Earth Observation Synthetic Aperture Radars (SAR). In particular the paper is focused on an innovative architecture conceived for the transmission chain of the internal electronics of the radar. The presented solution has been developed in the frame of the program 'COSMO-SkyMed di Seconda Generazione' (CSG), to address challenging system requirements in terms of transmitted bandwidth and signal quality. This architecture is based on the direct Radio-Frequency (RF) synthesis of the radar signal and relies on the possibility of configuring the impulse response function of high speed Digital-to-Analog-Converters (DACs) to increase the intermediate frequency of the transmitted signal and on the availability of a high performance digital signal generation section with pre-compensation capabilities. For the future, this approach paves the way towards a possible direct conversion at RF of the radar transmitted signal, therefore avoiding the performance limits and the issues typically related to up-conversions. The presented solution drastically simplifies the design of the RF section of spaceborne radars, avoiding most of the typical distortions which impact on SAR systems image quality. © 2016 EuMA.