Analytical modeling and measurement of vias in PCB-Technology up to 20 GHz

In this paper, an efficient analytical method for evaluation of return-path discontinuities (RPD) of interconnects in multilayered PCBs is proposed. There for equivalent circuits were examined and the inductance and capacitance were calculated. Two kinds of simulation approaches were used to quantify the considered closed-form expressions. The intention of this work is to examine the return current path of transiting signal vias with return vias in multilayer printed circuit boards from 100 MHz to 20 GHz. Therefore analytical, numerical-, and measurement-based methods for extracting the inductance and capacitance of via transitions were quantified and compared. Measurements with a PNA are made to verify these results. It could be shown that the analytical approach has a good correlation to the measurements with a deviation of 10% up to 8 GHz and lies within the manufacturing tolerance of the PCB producer. Measurements up to 20 GHz showed that these simplified models are no longer valid.