Patent ID: 6472885
Filing Date: 2002-10-29
Classification: G01N,G01R

Abstract:
A method for making a frequency dependent dielectric material characterization for the purpose of determining the complex permittivity (&egr;=&egr;â€²âˆ’j&egr;â€³) of a dielectric material under test (MUT), comprising the following steps:placing the MUT in a test fixture that guides electromagnetic energy from an input connector at one end of the test fixture to an output connector at an opposite end of the test fixture, wherein the cross-sectional dimensions of the test fixture can be unknown; sequentially placing successive ones of a set comprising 3 or more pre-characterized loads of different impedance values, at the output connector, each impedance value being mismatched with respect to the fixture so as to produce definite reflections at the input and output connectors; measuring the input reflection coefficient, S11 at the input connector of said test fixture over a predetermined frequency range for each one of the pre-characterized loads placed at said output connector, and storing said measured reflection coefficient data; computing first order and second order (i.e., a reflection of a reflection) complex reflection coefficients over said frequency range at connector and/or load interfaces associated with the test fixture, using said measured s-parameter data; processing said first order and second order complex reflection coefficients to calculate complex impedance values of elements of a specified electrical model of the test fixture over said frequency range; and computing the complex permittivity of the MUT over said frequency range based on the calculated complex impedance values of the elements from the specified electrical model.