Addressing Specularity: Millimeter-Wave Radar With Distributed Repeater Apertures

A new method of millimeter-wave (mmWave) radar sensing using distributed repeaters that can address the strong specular reflections is presented in this article. Specular reflections happen when targets reflect incident electromagnetic signals at specific directions depending on the angle of incidence. These mirror-like reflections can degrade radar performance and make detection more challenging as transmitted radar energy does not necessarily reflect back to the radar receiver. This article proposes a way to combat the specular responses from scattering targets by utilizing distributed repeater apertures at mmWave frequencies. Distributed repeaters can capture and retransmit the specular wavefront to improve the target detection and enhance image reconstruction. In this article, we discuss the theory behind our work, include simulated results and verify our approach by building experimental 36–38 GHz mmWave imaging systems with one and two distributed repeaters. The results presented in this article pave the way for accurate detection of highly specular targets.