60 GHz FMCW radar piHat+
An Infineon-based radar module with a range of sample code on github to get you up and running with some fascinating radar projects, including:
Range-Doppler plot
xy plot with tracking and persistence
Doppler-azimuth plot
Doppler-range plot
60 GHz FMCW doppler radar Arduino shield
An exciting module to fire your imagination and allow detection of fine movements over a 1-8 m range, sound alarms, plot the Doppler trend etc. Ideally suited for security applications.