Nondestructive Electromagnetic Characterization of Uniaxial Sheet Media Using a Two-Flanged Rectangular Waveguide Probe

A nondestructive evaluation technique for determining complex permittivities and permeabilities of uniaxial anisotropic sheet media is presented. An existing technique, the two-flanged waveguide measurement technique (tFWMT), has demonstrated good results for the nondestructive electromagnetic characterization of isotropic materials. This article extends the tFWMT for uniaxially anisotropic materials and presents the experimental determination of the permittivity and permeability of uniaxially anisotropic media. The measured scattering parameters are compared to theoretical scattering parameters, and the complex permittivity and permeability are extracted using a nonlinear least squares method. To find theoretical scattering parameters, Love's equivalence principle and the spectral-domain Green's function are used to form a set of coupled magnetic-field integral equations (MFIEs). This set of coupled MFIEs is solved utilizing the method of moments. To validate the new method, electromagnetic characterization of two honeycomb materials is made by using the two-flanged waveguides measurement technique and the results are compared to those obtained using the established methods.