Sepehr Kiani

A new method to interconnect PCB layers in GHz frequency range

The main goal of this paper is to demonstrate a novel concept of an any-layer to any-layer interconnection technique in a large high-performance multi-layer board. The proposed technique introduces a true impedance-controlled wave-guide structure for interconnections between various layers, thus significantly reducing and even wholly eliminating the signal discontinuity. In addition, this structure offers good isolation and density characteristics, which enable routing more signals through a multi-layer PCB using the same number of layers. Moreover, the electrical performance of this structure is entirely independent of the hole diameter. The results of our theoretical and experimental studies of the signal performance of this structure show that the proposed technique enables one to improve the performance of circuit boards carrying digital signals at multi-gigabit speeds.

A Predictive Model for Variation in the Pitch Between Stamped Pilot Holes

This paper presents an analytical model for predicting the variation in the pitch distance between pilot holes stamped with a progressive die. The model is useful in designing diesets since it relates pitch variation to dieset parameters such as the quantity of pilot pins clearance in the stripper plate bearings, clearance about the punch, and clearance about the pilot pins. The efficacy of the predictive model is demonstrated with a sensitivity study of design parameters in an exemplary dieset used to stamp electrical contacts. Predictions from the model match previously measured variation within about twenty-four percent.