The maximum phase error of a reflected signal in an active coded transponder

This letter is devoted to investigate the active coded transponder (ACT), which is designed to add a phase shifter to an active transponder (AT). Since a phase shifting error of a phase shifter is inevitable, there is additional phase error in reflected signal from ACT to synthetic aperture radar (SAR). This letter presents the theoretical study of the phase error of reflected signal. A method is proposed to determine the maximum phase error of the reflected signal. Moreover, images of ACT with different maximum phase errors are simulated. Peak-value and integral methods are used also to evaluate the accuracy of SAR radiometric calibration.