A review of UK facilities for characterizing the performance of radar absorbing material (RAM)

The performance of microwave absorbing materials is commonly expressed in terms of the scattering parameter S₁₁. S₁₁ data (often termed reflectivity) are independent of cross-section dimensions, and performance figures relate solely to the matching and absorption properties of an absorbing material. Measuring one or more scattering parameters may also enable calculation of a sample´s intrinsic properties. As part of its research effort aimed at improving the metrology of RAM the DRA at Malvern organised the RAM performance measurement intercomparison which ran from July to September 1994. The exercise gathered together all UK laboratories which routinely perform free wave reflection measurements. An informal exercise was initiated prior to the 1994 exercise to verify that participating laboratories were following procedures applicable to a one-port free space reflection measurement. The aim of the 1994 exercise was to quantify the variability and absolute error in the magnitude of UK free wave reflection coefficient data. This paper presents an analysis of the 1994 RAM measurement exercise data