X-band FMCW SAR with direct synthesized signal generation via two stage frequency multiplied DDS output

This article is focused on the design of the short range FMCW (Frequency Modulated - Continuous Wave) Synthetic Aperture Radar (SAR) system, in particular, on the design of the transmitting part of this system where the signal generator is based on the direct synthesis via two stage frequency multiplication of DDS (Direct Digital Synthesis) device output. This solution is novel in comparison with commonly used signal generators of present SAR systems. First, the brief overview of several methods of SAR signal generation is presented as a background for following presentation of this new solution. Next, the block diagram of the SAR transmitting part, including proposed direct synthesized signal generator, is described more in detail. Finally, the several results of practical testing of the evaluation SAR system are shown.