Linearity measurements of an accurate transponder for calibrating future spaceborne SAR systems

The requirements on new spaceborne synthetic aperture radar (SAR) missions are always pushed towards better image quality with respect to signal-to-noise ratio, radiometric accuracy, and spatial resolution. Therefore an accurate calibration of the SAR system and the final product is essential. The quality of the calibration depends on the utilized reference target. In this paper a new active calibration target (transponder), currently under development at DLR, and measurement results of the linearity of the high frequency section is presented.