A novel perturbation approach to dielectric measurements

A new cavity perturbation method for measuring dielectric properties is demonstrated. Transmission line theory is used to analyze a typical cavity perturbation experiment and show that waveguide impedances can be measured by standard resonator techniques. Cavity perturbation measurements of the impedance of a dielectric post provide a useful method for determining dielectric properties, particularly when the dielectric constant and/or conductivity is large. The transmission line analysis is used to evaluate the ‘‘quasistatic’’ field approximation commonly used in cavity perturbation theory. Application to experimental measurements on Si:As near the metal-insulator transition is also discussed.