High speed cross-point switch using SiGe HBT technology

摘要

A high-speed cross-point switch is built on a preferably silicon substrate and uses bipolar transistor switching elements. Preferably, the bipolar transistors are SiGe bipolar junction transistors. Intersecting conductive input and output microstrips are preferably thinned at their intersections to reduce shunt capacitance between the coupled lines. It is also preferred that the input buffer be connected in cascode fashion with the switching transistors in order to create an amplification stage. The signal and its inverse are carried on balanced microstrip pairs in order to reduce electromagnetic field strength at the center of the balanced line pairs thereby improving isolation between two crossing balanced pairs.