Experimental Characterization of Multi-Polarization Radar Backscatter Response of Vehicles at ${J}$ -Band

Abstract

This paper proposes radar sensors operating at ${J}$ -band (220–320 GHz) for automotive applications. Operating at ${J}$ -band, at about three times higher frequency than the currently available automotive radars operating at 77 GHz, will result in three-fold improvement in cross-range resolution for the same antenna size. Since the characterization of the radar backscatter from different objects on the traffic scenes is necessary for optimizing the design of automotive sensors, the work reported in this paper is the start of a broader study that attempts to fill the lack of knowledge on radar backscatter behavior of road environment at this frequency band. Considering vehicles as the most important object for automotive radars, this paper investigates the response of vehicles from different aspects. A combination of outdoor high-resolution synthetic aperture radar imaging experiments and real-aperture imaging measurements of vehicles are performed using a 222-GHz polarimetric instrumentation radar. The aim of these experiments is to identify the scattering centers on different vehicle bodies and to determine the statistics of the radar return. The results show that significant scattering is due to a limited number of fixtures on the vehicle’s outer surfaces facing the radar. The strongest scattering phase-centers observed are due to specular reflections and, hence, have a strong dependence on the relative look angle. The statistics associated with backscatter from vehicles are found, in most cases, to best fit the Weibull distribution.