W-band Radiometer And Its Performance Testing

A W-band radiometer system is studied for the application of target radiation characteristics measurement in this paper. Also the characteristics of the receiver output signal are analyzed and simulated, and performance parameters of this radiometer are measured.Firstly, the principle of W-band K-factor all-power radiometer is discussed. And its calibration method is analyzed and calibration equation is established. Theory measurement methods are theoretically presented for absolute accuracy, linearity, sensitivity and integration time of radiometer system. For different types of noise that may exist in the system, a study of noise characteristics is carried out. The Allan variance analysis is introduced, and finite-length sequences of this algorithm is derived to simulated the characteristics of white noise, flicker noise, shot noise and sinusoidal noise. The curves of correlation time and Allan variance of all four types of noise are obtained through by simulations.Secondly, radiometer system components, such as the multi-mode horn antenna, mixer, local oscillator and modulation noise source, are described and discussed in the paper. IF amplifier and LF amplifier, data acquisition and control circuits, and modulation signal generator are designed, and the measurement software of the radiometer performance parameters is realized to acquire and process the output signals.Finally, the Allan variance is used to analyze the noise characteristics of radiometer system output signals. And performance parameters are measured and measurement results are analyzed.