New polarimetric calibration technique using a single calibration dihedral

A new polarimetric RCS calibration technique using a dihedral corner reflector as the single calibration target is presented. This scheme is valid for any monostatic or quasi-monostatic radar system and characterised by five aspects: (a) scattering matrix measurements of only a single calibration dihedral at two orientations are needed; (ii) the radiation polarisation effect and the four measurement channels are separated in this new model; (iii) the frequency responses of four measurement channels are modelled as mutually independent and thus, no special care has to be taken for signal paths and nonreciprocal properties in a measurement system; (iv) the calibration procedure is simplified by taking advantage of small cross-polarised terms and no complicated matrix algebra is involved; (v) the calibrated results are valid for wideband applications because no assumptions are made relative to the theoretical solution for the calibration dihedral. This technique has been verified by several 2-18 GHz wideband RCS measurements using various feeds in the compact range at the Ohio State University ElectroScience Laboratory. Based on these measurements, an effective polarisation isolation close to -60 dB has been demonstrated