Ultra-efficient X-band and linear-efficient Ka-band power amplifiers using indium phosphide double heterojunction bipolar transistors

We report on an ultra-efficient circuit at X-band and a linear-efficient circuit at Ka-band using InP double heterojunction bipolar transistors (DHBTs). The high efficiency circuit employs a transmission line Class-E topology to achieve 61.1% PAE, 20.1-dBm output power, and 9.8-dB gain at 10 GHz. The linear efficient circuit combines four unit cells of 1.5 /spl mu/m /spl times/ 30 /spl mu/m /spl times/ 2 fingers that yielded 25.2 dBm output power, 8.4-dB linear gain, and 35.2% PAE at 28 GHz. This circuit also achieved 31 to 34 dBm output IP3.