HanxiaoMeow on Twitter: "Found a 24Ghz FMCW radar module on Aliexpress, cost about 25USD. It looks like some sort of FR4, but is that possible to make 24Ghz Antenna on FR4? https://t.co/v93CAhoNP1" /
Sensing motion and distance with 24GHz XENSIV™ radar module | Infineon - YouTube
24GHz radar sensors - Infineon Technologies
Tutorial, Experiment & Teardown of a 24GHz Doppler Radar Module - Electronics-Lab.com