There are many low cost commodity microwave RADAR proximity sensors in the marketplace, mostly for industrial or automotive applications like those used for self-driving cars.
Most are using the 24 GHz or 60 GHz for narrow band operation, while others are using Ultra-WideBand (UWB) as a spectral sensor mostly for very close proximity and for home gaming applications.
I will explore some of these sensors from various manufacturers.
Banner ;
https://www.bannerengineering.com/us/en/products/sensors/radar-sensors.html?pageNum=1&#all
Baumer :
https://www.baumer.com/us/en/product-overview/distance-measurement/radar-sensors/c/291
Texas Instruments:
https://www.ti.com/sensors/mmwave-radar/overview.html
Innoscent:
https://www.innosent.de/en/index/
SIck :
https://www.sick.com/us/en/radar-sensors/c/g575803?q=:Def_Type:ProductFamily
Novelda:
Infineon :
https://www.infineon.com/cms/en/product/sensor/radar-sensors/radar-sensors-for-iot/
Scionext
http://www.socionext.com/en/products/assp/radar-sensor/
Hella :
https://www.hella.com/techworld/us/Passenger-car-parts/Vehicle-electronics/Radar-sensors-49343/
LSM Technologies :
https://www.lsm.com.au/index.cfm?go=radar-sense-proximity-detection
Sensotek :
https://www.sensotek.com/en/products/radar-sensor/
If you don't receive the email within an hour (and you've checked your Spam folder), email us as confirmation@grabcad.com.