Nondestructive determination of electromagnetic parameters of dielectric materials at X-band frequencies using a waveguide probe system

An accurate technique used to measure complex permittivity and permeability of isotropic materials simultaneously has been developed by employing a flanged open-ended rectangular waveguide probe over a frequency range of 8-12 GHz. Two coupled integral equations for the aperture electric field are formulated and solved numerically using Galerkin's method. A series of experiments has been conducted, and the calibration of the probe system using an adjustable shorter is explained. The inverse results on the electromagnetic (EM) properties of various materials (including solid and liquid materials) based on the measured reflection coefficients of the incident dominant mode are presented. It is also shown that the EM parameters of isotropic materials having low complex permittivities can be determined accurately, while those with higher complex permittivities cause larger measurement errors.