FREE-SPACE AND WAVEGUIDE TECHNIQUE FOR DETERMINING THE RESISTIVITY OF AN R-CARD USING THE FORWARD TRANSMISSION COEFFICIENT

摘要

A free-space and waveguide technique for determining the relative permittivity and ultimately the resistivity of an R-card using the forward transmission coefficient is presented. The exact solutions for S_(21) are derived in sections Ⅱ and Ⅲ. Utilizing the Maclaurin series for sine and cosine, approximations of the exact solutions are made which are simpler to solve than the exact expressions. The accuracy of the approximations is directly related to the R-card's thickness and wave number. Free-space (2 GHz - 18 GHz) and waveguide (8.2 GHz - 12.4 GHz) measurements were made of two R-cards of differing thicknesses and resistivities to demonstrate the method.