Coherent 24 GHz FMCW radar system for micro-Doppler studies

This paper presents the hardware design of a coherent 24 GHz radar system developed at the University of St Andrews to obtain micro-Doppler data. The system is based on the Analog Devices EV-RADAR-MMIC2 evaluation board which is based around a chipset of three integrated circuits: a two channel transmitter, a four channel receiver and a fractional-N frequency synthesizer. The evaluation board is combined with a number of other components to enable coherent operation with a PC-based data acquisition card and to boost the output power to increase the operational range. Three identical custom-made smooth-walled conical horn antennas for transmit and co-and cross-polar receive signals were designed and built for the radar system. It is shown that the performance of these high gain (24.5 dBi) antennas agrees extremely well with the design simulations. Finally, field trial results comprising human, bird and drone micro-Doppler data are shown to validate the system performance.