Abstract

a non-destructive technique for simultaneously EM-properties determination of planar radar absorbing materials is presented. The technique is based on using waveguide radiating into multilayered structure to produce the needed independent reflection coefficients necessary to extract the unknown EM-properties at X-band of microwave frequency range. The measurement geometry consists of rectangular waveguide with finite flange placed against a combination of the sample under test and a known material layer backed by a PEC to increase measurement accuracy. To account for finite flange, the geometry is numerically modeled via Finite Difference Time Domain (FDTD) method yielding theoretical values for reflection coefficients which is imposed on the measured ones to obtain both complex pemittivty εr and permeability μr by inverse problem. Measurement results of εr and μr for several samples of radar absorbing materials are presented.