Chung, Jung-TaoJung-TaoChungHsu, Keng-LiKeng-LiHsuChang, Cheng-TeCheng-TeChangFeng, Kai-ChenKai-ChenFengLin, Kun-YouKun-YouLinWu, Chao-HsinChao-HsinWuLi, Jyun-HaoJyun-HaoLiTu, Shan-YuShan-YuTuChou, Tung-YaoTung-YaoChouTsai, Shu-HsiaoShu-HsiaoTsaiLin, Cheng-KuoCheng-KuoLin2025-12-032025-12-032025-06-15https://scholars.lib.ntu.edu.tw/handle/123456789/734289A 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.6G FR3GaAs HBTpower amplifiersthermal management[SDGs]SDG7conference paper10.1109/ims40360.2025.111038282-s2.0-105014240784