Double stub matching in multilayered printed circuit board using vias

In this paper the authors present the application of functional vias to narrowband load matching in the frequency range from 2 up to 20 GHz. The utilization of single and double stub matching is demonstrated. Corresponding network parts basically contain one or two via stubs and transmission line elements, e. g. striplines and microstrips. It is also shown that in most of the given frequency range vias and via stubs can be characterized as transmission lines. Especially the influence of the via configuration on the characteristic impedance and the propagation constant are analyzed in order to investigate their feasibility for matching purposes. Influences are the via length, the number of adjacent ground vias and their distance to the signal via. The analysis is done for open and shorted vias and is based on measurements, full-wave simulations and physics-based via models. Examples include matching networks with inductive loads up to several nH.