A High Efficiency 39GHz CMOS Cascode Power Amplifier for 5G Applications

We present a 39GHz CMOS cascode power amplifier (PA) with a two-step (L-C and C-L) second harmonic termination. We analyze the distortion mechanism in a cross-coupled capacitor neutralization technique and suggest the termination scheme to enhance both linearity and efficiency of PAs. This scheme can suppress the second harmonic feedback components generated in the middle of the cascode cell and extend the range of linear output power (Pout). Our two-stage PA shows power gain of >24.5dB, saturation output power (Psat) of >16.2dBm and power-added-efficiency (PAE) of >32% over the full 39GHz band from 37 to 40GHz. Under the 5G new radio modulation, the PA achieves linear Pout of 8.2dBm/10.3dBm and PAEs of 11.9%/16.5% at EVMs of -30.0dB/-25.3dB, respectively.