微波辐射计的功率非线性对标定天线温度的影响

Effect of Power-Nonlinearity in a Microwave Radiometer on Antenna Temperature Interpolated with Aperture Calibration

微波辐射计通过两点定标反演天线温度依赖的是辐射计的输入功率与输出电压的线性关系。通过分析平方律检波器的输入功率与输出电压的关系，导出非线性系数与由口面定标法反演的天线温度误差的关系式。定量说明了功率非线性度引入误差的大小．通过计算分析得出两种定标系统（地面遥感和星载遥感）对功率非线性度的要求。

A microwave radiometer which relies on the linearity of its input-power and outputvoltage accurately interpolates antenna temperature with two-point calibration. By analysing therelationship between the input-power of a square-law detector to and its output-voltage, and theequation relating the nonlinearity coefficient to the error of an antenna temperatur interpolated byan aperture calibration is presented in this paper. The error is quantitatively given and therestriction on power-nonlinearity for both the earth and space remote sensing system is alsoshown.