A Novel Vertical Conductive Structure for Printed Circuit Boards and its Scalable Model

This article proposes a new vertical conductive structure (VeCS) to replace the general via structure for signal connection on printed circuit boards (PCBs). Vias have been widely used as interconnects for in-between layers in PCBs. However, vias have limitations due to their discontinuous characteristic impedance. The VeCS consists of a conductive structure shielded vertically by a metal structure, which provides impedance control. Thus, the VeCS has the constant characteristic impedance that can get better signal integrity for the high-speed channel than the general via structure. This article also proposes a scalable 3-D electromagnetic simulation model of the VeCS for signal integrity analysis. Simulated annealing and linear regression revealed that the scalable model accurately represents the VeCS. The electrical performances of a VeCS and a via were compared up to 70 GHz. The measured insertion losses at 70 GHz for the VeCS and the via were 35 dB and 70 dB, respectively, because PCB vias exhibit significant reflection loss above 10 GHz. In conclusion, this article proposes a novel vertical interconnection for PCBs.