Patent ID: 8183930

Claim:
A power amplifier device formed over a substrate, comprising: a primary inductor comprising a plurality of inductor elements arranged in a generally circular geometry, when viewed from a direction perpendicular to the substrate; a ground pattern provided to extend from a portion of a region inside the primary inductor which is circular into regions outside the primary inductor, when viewed from the direction perpendicular to the substrate, and grounded at a plurality of points in the regions outside the primary inductor; and a plurality of transistor pairs, each being provided for linking with each of the plurality of inductor elements, wherein, to both ends of each of the plurality of inductor elements, first main electrodes of first and second transistors forming a transistor pair in linkage with the inductor element are coupled respectively, wherein second main electrodes of the first and second transistors are coupled to the ground pattern in the region inside the primary inductor and have electrical conduction to the respective plurality of points, wherein first and second signals in a pair as differential input signals are supplied to control electrodes of the first and second transistors, respectively, and wherein the power amplifier device further includes a secondary inductor which includes one turn of winding or multiple turns of winding, provided circularly so as to surround the primary inductor, and the secondary inductor further combines and outputs combined signals of the first and second signals combined in each of the inductor elements by magnetically coupling to the primary inductor.