The Performance Analysis of Digital Millimeter-Wave Radiometer

Abstract

Digital millimeter-wave radiometer (DMMWR) has advantages such as simple structure and good stability, of which a wide-band, high speed analog-to-digital converter (ADC) is the key component. However the unavoidable impairments of ADC in DMMWR degrade the sensitivity and accuracy, the main performance parameters of DMMWR. This paper investigates the sensitivity of DMMWR by deriving an expression for the noise-equivalent sensitivity based on the signal statistical property. Also, it analyzes the accuracy of DMMWR by establishing the calibration equation between output signal power and system noise temperature. During the experiment, the methods of multi-point calibration and curve fitting are introduced to calibrate the nonlinearity and fit the calibration equation of DMMWR, respectively. The experimental results show that the sensitivity expression gives predictions in agreement with experimental results and multi-point calibration can improve the measurement accuracy of DMMWR.