Experimental study on emissivity measurement of 5mm blackbody

The emissivity measurement of 5 mm microwave black is presented. Because the emissivity of microwave blackbody is close to one, namely its reflectance almost equals zero, the directivity error of directional coupler will cause that is difficult to estimate the emissivity. Hence, we use the space reflection method of moving DUT to measure reflectance of microwave blackbody. In this method, the reflectance of measurement system is equivalent to a big standing wave and the reflectance of block body is equivalent to a small standing wave. By using moving block body within half wavelength, we can separate the two stationary waves. The emissivity of black body is given by Friis formula and some calibration parameters including phase center, gain calibration value, effective area of antenna. The measurement results are presented