Shown here are photos of the radar hardware.  The front end is a direct conversion (direct conversion radar systems are sometimes called homodyne, for single conversion) FMCW radar sensor using a 7.8-12.8 GHz Yig oscillator, LNA, mixer, etc etc.  The horns are low-cost MACOM commercial horns for motion sensors (I think).  The linear rail is an old Genie garage door opener screw with a stepper motor coupled to it via a recycled cordless drill planetary gear set transmission.  A National Instruments PCI-6014 data acquisition card triggers radar pulses and digitizes the video data.  The rack shown is houses the Yig oscillator, the data acquisition system, power supply, and motion control.