Patent ID: 7737786
Filing Date: 2010-06-15
Classification: H03D,H03F,H03H

Abstract:
1. A reciprocal active balun, comprising: an active splitter balun element having a first transmission line, a second transmission line and a third transmission line, forming a first distributed amplifier structure and a second distributed amplifier structure, wherein the first and second distributed amplifier share a first transmission line, and wherein: an active combiner balun element having a fourth transmission line, a fifth transmission line and a sixth transmission line, forming a third distributed amplifier structure and a fourth distributed amplifier structure, wherein the third and fourth distributed amplifier structures share a fourth transmission line, and wherein: wherein the active splitter balun and active combiner balun elements are arranged in such a way that the first transmission line of the splitter balun element is coupled to the fourth transmission line of the combiner balun element through a first capacitor to form a first combined transmission line, while the third transmission line of the splitter balun element is coupled to the sixth transmission line of the combiner balun element through a second capacitor to form a second combined transmission line, and the second transmission line of the splitter balun element is coupled to the fifth line of the combiner balun element through a third capacitor to form a third combined transmission line; wherein the distributed Darlington amplifier cells and the distributed cascode amplifier cells of the first through fourth distributed amplifier structures can be polarized so as to provide a specific direction of coupling between the first combined transmission line and the second combined transmission line on one hand, and between the first combined transmission line and the third combined transmission line on the other hand; wherein a first active coupling is provided between the first combined transmission line and the second combined transmission line by the distributed cascode amplifier cells of the splitter and combiner baluns; and wherein a second active coupling is provided between the first combined transmission line and the third combined transmission line by the distributed Darlington amplifier cells of the splitter and combiner baluns.