A simple measuring method of reflectivity for radar absorbing material

The basic principle of measuring reflectivity for radar absorbing material (RAM) is analyzed. And a simple method for measuring reflectivity of radar absorbing material using vector network analyzer HP8722ET and APC-7mm coaxial line is presented. The results indicate that the reflectivity of the radar absorbing material can be measured in 0.05-18 GHz using this method. Under the ordinary laboratory condition, the reflectivity of the RAM can be measured accurately without microwave darkroom and other strict terms. Measurement results of reflectivity for single-layer RAM indicate that the measured reflectivity accords with the theoretical calculation of the reflectivity. The measured reflectivity using coaxial method is consistent with the reflectivity using arch method. Some errors exit between the measured results using arch method and theoretical calculation results because the sample's size is large and the thickness of the two-layer RAM can hardly be prepared homogeneously. The coaxial sample under test is small and the thickness can be controlled accurately, so the measured reflectivity is consistent with the theoretical calculation of the reflectivity.