A 1.7-12.6 GHz Stage-Scaling Distributed Power Amplifier with High PAE in 0.18-μm CMOS

This article presents a nonuniform distributed amplifier (DA) with a high stage-scaling factor. A 3-stage DA is adopted and three stacked transistors are employed in each stage to improve gain and output power. The transmission lines are achieved with inductors and parasitic capacitance and the line-impedance scales with the same factor as stage-scaling in the reverse direction. The additional capacitances applied at the input port and output port result in flat gain. As a proof of concept, the DA is fabricated in 0.18-μm CMOS process. The proposed circuit achieves a 3-dB small-signal bandwidth of 1.7-12.6 GHz with a maximum gain of 16.1 dB, 18-21 dBm saturated power, with a peak power-added efficiency of 12.9%-27.7% over the entire bandwidth. The DA occupies an area of 1.19 mm
²
.