BILAYERED DIELECTRIC MEASUREMENT WITH AN OPEN-ENDED COAXIAL PROBE

An equivalent circuit of an open-ended coaxial line used as a probe fo r bilayered dielectric measurement which consists of three parallel ca pacitances C(f), C0 is-an-element-of 1 and C1 (is-an-element-of 2 - is -an-element-of 1) is presented. The measurement method, based on both the analytical expression of the probe's equivalent circuit and the bi linear transformation relationships between the equivalent admittance of the probe and the reflection coefficient and between the real refle ction coefficient and the measured reflection coefficient, is describe d. With using this method, the measurements were made in 0.6-2.6 GHz. The results show that the permittivity of either layer of bilayered di electrics can be determined by using the measured reflection coefficie nts without knowledge of equivalent capacitances C(f), C0 and C1(t) or the thickness of the first layer medium.