Improved permittivity and permeability measurement in open or short circuit terminated test fixtures

Abstract

The unknown permittivity and permeability of a material often needs to be measured. Many techniques use two or more samples or configurations in order to provide sufficient data to determine the permittivity and permeability, under teh assumption that the two samples have identical permittivity and permeability. This paper investigates a technique where sufficient data is determined from a single measure of a single sample by examining the first and second derivatives with respect to frequency of the measured data. The scheme is seen to converge with well with 201 data points in the frequency measure fro a sample that is 65 mm in length. The accuracy of the calculated permittivity and permeability is seen to be very good where there is no dispersion present, and still tolerable where there is some dispersion in the permittivity and permeability of the sample.