A Closed-Form Equation for Estimating Capacitance of Signal Vias in Arbitrarily Multilayered PCBs

This paper provides a significant improvement to the coaxial-line equation that is used for analytical estimation of via capacitance in multilayered printed circuit boards (PCBs) Previously, a pure coaxial-line equation is used for estimating via capacitance with a maximized and minimized number of pads in high-density multilayered PCBs. Now, in the via capacitance equation, both the capacitances associated to via body and via pads in multilayered PCBs with arbitrary stackups are included. Laboratory measurements by a vector network analyzer and digital inductance-capacitance-resistance (LCR) meter, as well as quasi-static and full-wave computational simulations, confirm solid accuracy of the derived equation used for estimating the capacitance of arbitrary signal via geometry common in practice.