Seeing Around the Corner with an Airy sub-Terahertz Radar

Abstract

In light of the tremendous possibilities offered by waveform design in the near field, we develop simulations of a sub-THz radar system that senses using Airy beams. Remarkably, this class of waveforms is “self-accelerating”: they trace out parabolic trajectories in free space in the absence of external forces. As such, a radar equipped with such a beam should be capable of around-the-corner sensing. This newfound capability opens entirely new dimensions in traffic sensing (among others), and its deployment in traffic radar may lead to significantly improved safety outcomes. Our central contribution lies in determining that conjugating the complex E-field incident on an obstacle (via an active surface) generates an Airy beam that returns to the transceiver plane by tracing the path taken by the original. This is true regardless of obstacle orientation. We also investigated the effect of (vertical) obstacle length on the link-budget. As expected, the percentage of returned power increases with obstacle length, reaching a plateau at ~ 80%. We determine that an ideal obstacle length might be in the vicinity of 0.4 (twice the aperture size of 0.2), since it provides a robust middle ground between returned power and size. In the same line of inquiry, we also found that the smallest obstacle length should be about 0.05 (a quarter of the aperture size). At this limit, an (unconjugated) specular reflection might, in fact, yield greater power returns in the primary lobe than conjugation.