Investigation of a 3D Printed Tetrahedral Aligned Sphere Target at 145 GHz for Radar Positioning

A 3D printed tetrahedral aligned sphere target and its effect on FMCW radar measurements at 145 GHz are investigated in this paper. The target itself contains four differently sized metallic spheres connected by cylindrical holders. This yields an unambiguous reflection behaviour over all angles. For the evaluation, sinograms are simulated and measured in order to determine the distance and the angle between radar and target as well as the radar cross section (RCS). This allows for unambiguous angle estimations. One possible field of application is precise 3D industrial robot positioning. The simulations are performed by CST Microwave Studio using a shooting and bouncing ray approach to obtain the simulation results very fast compared to full 3D electromagnetic field simulations. Final measurements with aD-band FMCW radar prove the applicability of the presented 3D printed tetrahedral aligned sphere target.