All gallium nitride envelope-tracking multiband power amplifier using 200MHz switching buck-converter

We report a multiband Envelope-Tracking (ET) Power Amplifier (PA), comprising a very broadband RF-PA stage and a Voltage-Mode class-D (VMCD) buck-converter with 200MHz switching frequency. Both buck-converter and RF-PA were fabricated using a GaN HEMT process. High frequency switching operation of the buck-converter makes it possible to handle broadband signals (20MHz bandwidth). The design of the RF-PA allows operation over a multi-GHz range of carrier frequencies (0.7 to 2.1GHz). The proposed ET-PA achieved DE of 26~49%, Output Power of 29.2~33.0dBm and Gain of 11.1~7.8dB with 28V supply. This is the first report of broadband and multiband ET-PA, fabricated entirely with a GaN HEMT process.