A New Square Cylindrical Dihedral Reflector for Fully Polarimetric Radar Calibration

Traditionally, fully polarimetric channel gain imbalance calibration of a radar system requires a dihedral corner reflector rotating around the radar line of sight (LOS). An extra stepping motor is required to drive the rotation of a traditional dihedral corner reflector, resulting in higher alignment complexity and degraded uncertainty. In this paper, a new square cylindrical dihedral (SCD) calibrator is proposed and manufactured, which is a 22.5° dihedral corner reflector cut from a metal square cylinder. Fully polarimetric channel gain calibration can be accomplished using a single SCD without requirement of a rotating motor. The ultrawideband (UWB) polarimetric scattering matrix (PSM) of a SCD is calculated and analyzed using the method of moment (MoM). In addition, we propose to put a low scattering insulation material (LSIM) between the calibrator and the pylon to supress the calibrator-pylon interaction (CPI) caused by surface travelling waves. An indoor experiment operating over 6-18 GHz frequency band are presented to demonstrate the excellent performance of the proposed SCD calibrator for fully polar-imetric channel gain imbalance calibration of an ultrawideband (UWB) radar.