A frequency-division MIMO FMCW radar system using delta-sigma-based transmitters

In this paper, we present a system that allows to realize frequency-division multiplexing multiple-input multiple-output (MIMO) radars which are based on the frequency-modulated continuous-wave (FMCW) principle. Multiple frequency-shifted FMCW signals, which can be separated in the receiver, are used as transmit (TX) signals. The frequency shifting is implemented using digitally generated sinusoids in conjunction with delta-sigma-based transmitters. The proposed principle requires only little adaptions compared to conventional FMCW-setups. Furthermore a fast Fourier-transform stage, being present in many conventional FMCW radars, can be used to separate the TX signals leading to an efficient usage of existing building blocks. Measurements carried out using a prototype system with 48 MIMO channels demonstrate the feasibility of the proposed approach.