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

Abstract

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.

Connecting the Automotive Bands of Present and Future With a Tag for Inharmonic Radar at 76–81/134–141 GHz

“…2. It is based on the frequency doubler from the harmonic tag presented in [4], complemented by a /4-divider. Subsequently, a single-sideband (SSB) mixer is used.…”

“…The coupler's output and mixer's input are designed point symmetrically for identical transmission line lengths. An amplifier chain is located in front of the multiplier, as presented in [4]. It is essential as the way to the tag primarily limits the maximum range by defining an R −2 proportionality when achieving P sat instead of R −6 if not [4], [7].…”

“…An amplifier chain is located in front of the multiplier, as presented in [4]. It is essential as the way to the tag primarily limits the maximum range by defining an R −2 proportionality when achieving P sat instead of R −6 if not [4], [7]. Additionally, the sensitivity curve of the introduced divider means that for input powers that are too low, the output power at the desired frequency will equal zero when the divider stops working.…”

“…Accordingly, the safety of vulnerable road users with a small radar cross section (RCS) should be of growing concern. Therefore, we have presented a harmonic radar system in previous research [3], [4], [5]. It allows for detecting vulnerable road users like pedal cyclists in a separate, clutter-free receive channel.…”

A D-Band Vector Network Analyzer Extension Module Based on a SiGe Reflectometer MMIC

“…Due to the large, achievable, absolute bandwidths, millimeter waves are highly interesting for research and industry. The topics currently being worked on, e.g., cover applications in the fields of sensors, imaging, material characterization, and communications [1]- [4].…”