Patent ID: 8264278

Claim:
An amplifier being a distributed-constant-type amplifier comprising an input-side transmission line and an output-side transmission line, and a plurality of unit circuits coupled between the input-side transmission line and the output-side transmission line, wherein each of the plurality of unit circuits comprises an amplification circuit having a gain equal to or greater than one, wherein each of the plurality of unit circuits includes an input-side amplification stage coupled to the input-side transmission line, an output-side amplification stage coupled to the output-side transmission line and first inductors provided between the input-side amplification stage and the output-side amplification stage, wherein the output-side amplification stage includes differential pair transistors, which is inserted between the first inductors and output terminals of the output-side amplification stage respectively, and a current source transistor coupled to the differential pair transistors, and wherein each of the first inductors is coupled to a gate of each of the differential pair transistors, respectively.