Modelling differential via holes

With the ever-increasing frequencies of printed circuit board (PCB) interconnections, the role played by via holes is no longer negligible. Thoughtless design of via holes on a board may seriously degrade signal integrity due to reflections, ground bounce, etc. However, the characterisation of via holes has not drawn much attention until now. This paper presents a method for the characterisation of differential via holes as a cascade of capacitances and inductances. Capacitances are computed using FASTCAP and inductances using simple analytical models.