Temperature is an important parameter for industrial process control. With the usual methods we obtain only an invasive or superficial information about temperature. Microwave radiometry is a non-invasive way to determine the temperature within dissipative body. This paper presents the design of a new radiometer. With this system, the radiometric temperature is independent of the reflection coefficient of the sensor. A simplified calibration takes into account insertion losses of the microwave elements and the frequency bandwidth has been greatly reduced to eliminate the unwanted electromagnetic noise.