Combining FDTD simulations with measurements of microstrip ring resonatorsfor characterization of low- and HIGH-K dielectrics at microwaves

This paper shows how the dielectric constant of alumina and rutile substrat es at microwave frequencies can be accurately determined by fitting the sim ulated S-parameter spectra of microstrip ring resonators, generated via the finite-difference time-domain (FDTD) method, to experimentally measured da ta. The proposed method does not require the determination of the effective dielectric constant and the approximate closed-form expressions to find th e true permittivity of the substrate. This is essential for the characteriz ation of high-K dielectric materials at high frequencies when the closed-fo rm expressions are invalid. (C) 2001 John Wiley & Sons, Inc.