The Microwave radiometer is a kind of passive microwave remote sensor. Generally microwave radiometer can be considered as passive receptors of radiation from objects with no energyradiated from the antenna to its surroundings practically the components of radiometers have thermal noise and radiate energy in the reverse direction. In another case

the reverse radiation comes from the mismatch of the components between the antenna and the receiver system. The energy radiated to the outside through the antenna is reflected by the objects and received by the antenna again. The value of revising radiative temperature is linked to the noise of the receiver and components of the receiver front-end. The reverse radiative temperature in the system will affect the accuracy of the microwave radiometer calibration and the ground-based microwave radiative measurements near nadir angle.