On the Uncertainty of Extracted Permittivity From Inhomogeneously Filled Rectangular Waveguides

Error uncertainty is an important metric to assess the reliability of an inversion algorithm that extracts the electromagnetic constitutive parameters from a material sample. In a previous paper, the inversion algorithm for a partially filled waveguide cross section relied on the assumption that the material sample had to be perfectly centered. In this present letter, the effect of having the material sample displaced from the center is evaluated by comparing its extracted constitutive parameters (epsiv, mu) with the values corresponding to the perfectly centered case. Two low-loss cases are studied: (1) low-contrast and (2) high-contrast material. A finite-element model (FEM) is used to generate the forward data.