Determination of Dielectric Thickness, Constant, and Loss Tangent from Cavity Resonators

For high-speed digital and high-frequency analog applications, accurate determination of material properties are critical. Technological tolerances on printed circuit boards and packages result in variations of the dielectric thickness, constant, and loss tangent. These properties may also change depending on the process and location on the panel. Hence a methodology is needed where these properties can be measured using test coupons on a panel. Previous research focuses on the determination of dielectric constant and loss tangent using coupons in the form of resonators or transmission lines. However, dielectric thickness also shows significant variation from vendor-supplied values. In this paper, we present a new method that allows to extract the dielectric thickness from resonator measurements as well, hence providing a unique capability for non-destructive monitoring of geometrical as well as electrical properties of printed circuit boards and packages.