A High-efficiency 135 – 155 GHz Power Amplifier with Compact Three-Conductor Power Combiner Balun in 130-nm SiGe BiCMOS

A compact power amplifier (PA) design for D-band applications in 130nm SiGe BiCMOS technology with saturated output power (P
sat
) excess of 13dBm covering 20GHz operation bandwidth is presented. This architecture consisted of a three-stage driver and one-stage power differential configuration, and the compact three-conductor balun is embedded to improve the output power level. The design delivers 13dBm with 40dB gain from 135 - 155GHz, and the maximum P
sat
is 13.9dBm with a peak power-added-efficiency (PAE) of 24% at 145GHz. The proposed three-conductor balun achieves a good performance of transmission loss that is less than 1dB in the range of 130 - 170GHz, and the amplitude/phase imbalance is not more than 1dB / 3° covering 3-dB bandwidth, respectively. The 0.29W PA is capable of providing a good figure of merit (FoM) of 110 while occupying the core active area of 0.49 mm
²
.