System design of W-band fully polarimetric radiometer for target identification

For the last few decades, microwave radiometers have played an important role in various remote sensing applications of the earth environment such as atmosphere, ocean and soil. Especially, various polarimetric emission for more accurate estimation. In general, the electromagnetic wave is represented as full Stoke parameters. [1] The Stoke parameters can be defined as the horizontal and vertical polarization for the first and second parameters, and the 45 degree linear and circular polarization for the third and forth parameters, respectively. [2] In this study, we developed the fully polarimetric radiometer to measure full Stokes parameter at 94GHz. For stable and high sensible Stokes parameters measurement, we implemented a wideband analog correlator and a total power type receiver with periodic calibration. In order to measure full Stokes parameters, it needs the calibration by using the additional polarized references. The fully polarimetric calibration standard is composed of a polarizing grid, a retardation plate, and reference sources. The characteristic of calibration standards was measured and evaluated.