8.6-13.6 mW Series-Connected Power Amplifiers Designed at 325 GHz Using 130 nm InP HBT Technology

We report two 325 GHz series-connected power amplifiers (PAs) using 130 nm InP HBT technology. The unit cell, using two series-connected transistors, produces 8.6 mW at 325 GHz and consumes 243 mW DC power. The PA has a 4.3 dB compressed gain and 2.2% power added efficiency (PAE). Two of these cells are then power-combined, and two further cells are used as driver stages, to form the second design, which produces 11.36 mW at 325 GHz with 9.4 dB compressed gain and 1.09% PAE. The peak small signal gain is 16.6 dB at 325 GHz, and the 3-dB bandwidth is 9 GHz. The total power consumed is 1.12 W and the dimensions including the pads are 0.98 mm ×0.98 mm.