A low-cost 24GHz doppler radar sensor for traffic monitoring implemented in standard discrete-component technology

This paper deals with both the implementation and the real-life characterization of a low-cost 24GHz Doppler radar sensor, purposely designed for the traffic monitoring. To reduce industrial costs as much as possible a discrete-components technology has been adopted for the microwave front-end. Plastic packaged devices and fiberglass reinforced substrate are used in such a way as to fit with standard PCB manufacturing processes and automated assembly procedures. The signal manipulation is based on a state-machine algorithm and has been implemented in a 8051 family micro-controller unit. The realized sensor has a typical output power of 6dBm and mounts a planar antenna with a 3dB beam-width of plusmn4.5 degrees. The real-life measured performances shows a detection range in excess of 300 meters.