A New Via Hole Structure of MLB (Multi-Layered Printed Circuit Board) for RF and High Speed Systems

We propose a new via hole structure that reduces the amount of reflection noise of RF and high speed digital signals in multilayered PCB (printed circuit boards) and compare the electrical characteristics of the proposed via hole with them of conventional vias such as stacked, staggered and through via types. To verify the performance, after extracting RLC (resistance-inductance-capacitance) parameter from the actual structure, II-type equivalent lumped-circuit model including interaction between power and ground planes is established and the deviation of transmission properties for each type is analyzed through S-parameter and eye-diagram. At 5GHz, the reflection noise of the proposed via structure can be 2.3-3.8 times smaller than that of conventional ones. ISI (intersymbol interference) is reduced less than 5ps and TOF (time of flight) is 77ps shorter than any other types. It improves the output voltage efficiency 15-30% and extends the bandwidth 1.5-2 times. The effective density to layout the trace around it can be increased because of shielding signal via holes