This invention provides a microwave radiometer to detect the radiated electromagnetic energy of a body. Three low-frequency electronic switches, an integrating network and a timing control system are arranged in its low-frequency circuit system. The three low-frequency electronic switches and two high-frequency electronics switches of input port are simultaneously controlled by the timing control system and act in accordance with the special time sequence, so that the output signals of the microwave radiometer are irrelative to variations of high, middle and low frequency circuital parameters in system. The invention is suitable for various working platforms with multiple wave bands, especially for the applications requiring accurate and stable detecting results, and can easily make self-calibrations. |