Abstract: Taken 23.8 GHz digital auto gain compensative microwave radiometer for example, the receiver calibration technique using low temperature reference noise source and variable precise attenuator is presented and the solutions for calibration equation are analyzed. Via comparison of these three calibration methods, it was found that the equation educed from two-point calibration technique is as well as the regression line method’s results. The conclusion is thus conducted that calibration equation could be achieved using two-point calibration technique with the excellent receiver linearity in dynamic temperature ranges of radiometer receiver.

Key words: microwave radiometer, receiver, calibration, two-point calibration technique