Compact X-band FMCW sensor module for fast and accurate vehicle occupancy detection

This paper presents an X-band FMCW sensor module for vehicle occupancy detection with compact size of only 4.5 cm × 4 cm. The transmitting and receiving antenna arrays are co-designed with the sensor to achieve optimal RF performances using less circuit area. Measurement results demonstrate successful and accurate identification of vehicles with fast response time less than 0.5 second.