Reference-Plane Invariant Method for Measuring Electromagnetic Parameters of Materials

TL;DR

This paper introduces a simple, wideband, and reference-plane invariant method for accurately measuring electromagnetic material parameters like permittivity and permeability, verified through experiments from 2 to 18 GHz.

Contribution

It presents a non-iterative, explicit technique combining scattering parameters and group velocity data for material characterization, applicable to dielectric and magnetic materials.

Findings

Method effectively characterizes materials across 2-18 GHz.

Uncertainty increases at low frequencies and Fabry-Perot resonances.

Experimental validation on PTFE and PVC samples confirms accuracy.

Abstract

This paper presents a simple and effective wideband method for the determination of material properties, such as the complex index of refraction and the complex permittivity and permeability. The method is explicit (non-iterative) and reference-plane invariant: it uses a certain combination of scattering parameters in conjunction with group-velocity data. This technique can be used to characterize both dielectric and magnetic materials. The proposed method is verified experimentally within a frequency range between 2 to 18 GHz on polytetrafluoroethylene and polyvinylchloride samples. A comprehensive error and stability analysis reveals that, similar to other methods based on transmission/reflection measurement, the uncertainties are larger at low frequencies and at the Fabry-Perot resonances.