Antenna temperature for a scanning microwave radiometer

Expressions for the antenna temperature are derived for a scanning Earth-viewing satellite-borne microwave radiometer. The result is in the form of an integral that includes the antenna gain function and brightness temperature. A composite emissivity term appears in the brightness temperature equation that contains the horizontal and vertical components of surface emissivity weighted by their respective antenna gains. Analysis is performed to obtain the antenna temperature components corresponding to the emission of horizontally and vertically polarized radiation. Calculations are performed showing the effects of beam width and scan angle on the two components of antenna temperature for a linearly polarized antenna. Effects resulting from antenna cross polarization are also analyzed.