A high efficiency, 40dBm, 728-768 MHz MMIC Doherty power amplifier using low-voltage GaAs HBT technology for LTE and active antenna system applications

In this paper we report on the design and measurements of 1.75× 2.45mm² monolithic microwave integrated circuit (MMIC) Doherty power amplifier (DPA) fabricated using low-voltage, low-cost GaAs hetero-junction bipolar transistor (HBT) technology. In measurements, from 31dBm to 40dBm saturated output power higher than 43% drain efficiency is obtained across 728 to 768 MHz band. Moreover, single stage Doherty amplifier exhibits 14dB small signal gain over the band of operation. To the best of our knowledge, with low voltage GaAs HBT, the highest efficiency and saturated output power are reported in this work.