A High-Efficiency GaAs HBT Power Amplifier for 6G FR3 Applications

A two-stage, single-ended amplifier has been designed for 6G FR3 band handset application in a commercial 6-inch GaAs HBT process. At 12 GHz, the power stage of this amplifier achieves an output power of 32 dBm with power added efficiency (PAE) of 57.9% under 6.5 V operation. Using this HBT array of power stage to fabricate a two-stage amplifier, PAE can be further improved to 55% with a gain of 24 dB. Combining two two-stage PA by power combiner, the measured output power is 34.4 dBm with a gain of 24 dB and PAE of 50%, which is among the highest reported for GaAs HBT amplifiers under mobile handset operation voltage at this frequency.