A Compact Antenna Rotation Concept for Precise Polarimetric SAR Calibration Transponders

For recent and upcoming spaceborne SAR missions based on compact or full polarimetric operation modes, the calibration of these SAR systems becomes more and more complex. In order to reduce the number of reference targets used during the calibration phase it is essential to use polarimetric active radar calibrators - PARC offering a flexible scattering matrix. This paper presents the comparison of two different antenna rotation concepts suitable for the development of precise polarimetric calibration transponders. After a review of the well-proven waveguide approach a novel cable-based approach is introduced and followed by measurement results showing the achieved performance in terms of magnitude and phase stability.