口面定标源天线温度的相关成分分析

Analysis on Coherent Antenna Temperature of Aperture Calibration Source

口面定标源的天线温度是微波辐射计定标的重要参数，在以往的辐射计定标中都只考虑到它的非相关分量而忽略了相关分量。分析了液氮冷却低温口面定标源和室温源的相关天线温度，导出口面定标源的相关天线温度与辐射计逆向辐射噪声温度、定标源的反射系数和天线口面的反射系数的函数关系。说明减小相关天线温度的有效途径，并举例阐述了这些相关天线温度的大小。

The antenna temperature of a aperture calibration source is a key feature for microwave radiometer calibration,and its coherent part is usually omitted when its incoherent part is used to interpolate the temperature of a measured object.This paper analyses coherent antenna temperature of a low temperature source cooled by liquid nitrogen and a room temperature source.It is given that coherent antenna temperature is a function of an inverse radiating noise temperature from a radiometer,and reflection coefficients of the antenna and calibration sources.A way is obtained to reduce coherent antenna temperature.