Analysis of crosstalk in high speed and high frequency printed circuit board

Abstract

ABSTRACT Numerical analysis of crosstalk between two traces in a printed circuit board is presented using the method of moments (MoM). In the high-frequency range, the attenuation constant is neglected in the theory for its very small values. The width of the trace is accurately determined for the trace impedance of 50 ohm from the charge distribution on the traces without using an approximated empirical formula. Line capacitances are determined from the total charge on the conductors and the line potentials. The coupling capacitance and inductance are determined from in-phase and out-of-phase excitations between the traces. Crosstalk interference is calculated from these coupling parameters. Results of crosstalk obtained from the above technique are verified by comparing with those obtained from four other methods: (1) Ansoft HFSS software tool, (2) even mode and odd mode analysis, (3) empirical formulae of parasitic elements, and (4) measurements using a vector network analyser. All the results agreed well. The results obtained by using the method of moment technique are more stable, reliable, and accurate among all the described different methods. This paper shows that the analytical method using MoM is a useful tool for predicting crosstalk interference in PCB without using expensive simulation software.