Specularity Resistant Millimeter-Wave Imaging with Distributed Repeater Apertures

Electromagnetic imaging at microwave and millimeter-wave bands is sensitive to specular reflections. This means targets reflect incident electromagnetic signals at specific directions depending on the angle of incidence. Mirror-like reflections can hinder radar performance and make detection more challenging as transmitted radar energy does not necessarily reflect back to the radar receiver. This paper discusses an approach to combat the specular responses from millimeter-wave scatterers by utilizing distributed repeater apertures. A low-cost repeater can capture and retransmit the specular wavefront to enhance target detection. In this paper, we discuss the theory behind our work, include simulated results, and verify our approach by building a 36–38 GHz millimeter-wave imaging system. High-contrast experimental imaging results of a highly specular flat-plate target are incorporated.