An All-Digital Carrier Synthesis for Stepped OFDM Radars

OFDM-based radars offer the potential to solve inherent limitations of current modulation schemes by shifting the main effort to the digital domain. By combining an OFDM signal with a stepped carrier, the sampling rate and memory constraints, which are limiting the bandwidth and thus the range resolution of digital radars, can be overcome. However, this is at the cost of highly increased demands on carrier synthesis. This paper presents an all-digital carrier frequency synthesis that allows to realize any desired carrier frequency progression and is synchronized to a digital OFDM radar with signal generation based on a Xilinx Zynq RFSoC. Its functionality is demonstrated using a homodyne 4x4 MIMO radar at 77 GHz.