Expanding the Capabilities of Automotive Radar for Bicycle Detection With Harmonic RFID Tags at 79/158 GHz

Although traffic safety continues to improve overall, fatalities of vulnerable traffic participants and pedal cyclists specifically have reached 30-year highs. While automotive radar sensors continue to advance and are integrated in more and more vehicles, they are not ideally suited to detect pedal cyclists, especially in complicated traffic scenarios. To mitigate the problem of the lower radar-cross Section (RCS) of the cyclist, equipping them with harmonic radio frequency identification (RFID) tags is proposed. The presented system showcases the benefits of this approach by being able to conduct conventional automotive radar measurements and detect tags simultaneously. In this work, we present the printed-circuit boards (PCBs) and the necessary chipset, while especially focusing on the design of a power-efficient harmonic RFID tag. By improving the gain per current of an amplifier chain, the tag enables a range sufficient for urban scenarios while consuming little enough current to be powered by battery-operated lights. This enables the detection of pedal cyclists even in complicated scenarios at a distance of up to 80 m.