Reconstruction of Material Inhomogeneity Profile Using Partially Filled Rectangular Waveguide Measurements

This article presents a novel technique to reconstruct the inhomogeneity profiles of the material using partially filled rectangular waveguide (RWG) measurements. Variation in the sample width is developed to obtain the required independent scattering parameters for accurately reconstructing the inhomogeneity profiles. The electromagnetic parameters of the inhomogeneous sample are obtained, minimizing the difference between the measured and the theoretically calculated scattering parameters. For the first time in this article, the scattering parameters of the inhomogeneous material partially loaded in the RWG are theoretically calculated using the hybrid of mode matching and Taylor’s series expansion. A prototype of the measurement system is fabricated for experimental verification. Through comprehensive examples, experimental verifications are performed for the three types of inhomogeneous materials. The validity and accuracy of the proposed method are verified by comparing the results obtained by the RWG methods. The suggested technique is less expensive and more straightforward than the previously developed RWG method, which uses multiple waveguides and requires a single-time calibration.