Antenna temperature deterioration of aperture calibration due to millimeter wave radiometer non-linearity

A millimeter wave radiometer, which relies on the accurate linearity of its input-power and output-voltage, interpolates antenna temperature with a two-point calibration. By analyzing the square-law detector linear relationship of its input-power to its output-voltage, the nonlinear coefficient and power nonlinearity are reduced. The nonlinear error of antenna temperature is quantitatively given and examples on power nonlinearity for both ground and space remote sensing system are also shown.