28-GHz CMOS Power Amplifier Linearized With Resistive Drain-Body Connection

A 28-GHz two-stage differential cascode power amplifier (PA) linearized with a simple common-source (CS) body network, in which the body of the CS amplifier at the power stage is connected to the drain through a large resistance. The body network is very simple but very effective to linearize the PA. The linearity improvements are explained and shown with the intermodulation distortions (IMD3) and AM-PM characteristics. The PA also shows a wideband gain because the matching networks consist mainly of transmission-line transformers (TLTs) and distributive interstage matching. It has a gain of 20.1 dB with a bandwidth of 10.8 GHz, a saturation output power of 20.25 dBm, and an output 1-dB compression point of 18.3 dBm, which is fabricated in a 40-nm bulk CMOS process with the area of 0.214 mm(2).