Performance of Millimeter Wave Radiometer with Periodic Calibration

The performance of the radiometer depends on sensitivity, accuracy and stability. The analysis of sensitivi- ty, accuracy and long-time stability are presented in the paper, and a millimeter wave （MMW） radiometer with periodic cali- bration is designed. The MMW radiometer employs direct detection receiver with 33 -38GHz working frequency. The high temperature calibration source is implemented by turning on the active noise source, and low temperature calibration source is implemented by turning off the active noise source. The experiments show that long-time stability of the radiometer is 1.28K, accuracy of the radiometer is 1.71K, sensitivity of the radiometer is better than 0.50K when integration time for scene and calibration source both are 7.7ms.