A New Sub-Millimeter Wave Power Amplifier Topology Using Large Transistors

In this letter, a new power amplifier topology is demonstrated which allows the use of large (120 mum/transistors) at extremely high frequency. This is accomplished by using compact matching networks consisting of coplanar waveguide transmission lines and metal-insulator-metal capacitors to match each of the three amplifier stages. The resulting amplifier achieves a peak gain of 16.5 dB at 260 GHz. Power measurements indicate that the chip achieves >5.9 mW (unsaturated) of output power and 4% power added efficiency at a frequency of 270 GHz, where the output power is limited by the available source drive power. This power level from a single transistor represents a significant improvement at this frequency band.