Accuracy assessment of free-space material reflectivity measurements using a MADRAS Spaceborne Radiometer sample

In this paper, the accuracy of the Quasi-Optical free-space test bench for reflectivity measurements at W-band and 110-170 GHz is evaluated. A sample from the MADRAS (Microwave Analysis and Detection of Rain and Atmospheric Structures) Spaceborne Radiometer already measured at the Institute of Applied Physics of the Russian Academy of Sciences (IAP RAS) (Nizhniy Novgorod, Russia) was used as reference. Two calibration procedures are considered in order to improve the accuracy of the measurements.