First Integration of GaN Low-Voltage PA MMIC into Mobile Handsets with Superior Efficiency Over 50%

The demand for compact, efficient and agile power amplifiers (PAs) continues to rise. GaN-on-Si technologies are anticipated to deliver PAs with superior power performance and smaller form factors. However, their typically high operating voltages are often incompatible with the power control units in current handsets. In this work, we demonstrate a GaN-on-Si low-voltage HEMT technology achieving a peak power-added efficiency (PAE) of over 80% and a saturated output power (P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</inf>) of 2.84 W/mm at drain voltages ≤ 10 V at 2.2 GHz. A microwave monolithic integrated circuit (MMIC) featured as a three-stage PA based on our GaN-on-Si technology is successfully implemented in real handset applications for the first time and its system-level power performance is evaluated on the mainboard of a smartphone. At 2.0 GHz, the MMIC achieves a gain of 37.3 dB, a P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">out</inf> of 38 dBm, and a PAE of 51.4% with required linearity (error vector magnitude < 5%) for efficient handset operation. These outstanding device- and circuit-level power performance surpass those of other technologies for LV RF applications, strongly indicating the potential of GaN-on-Si RF technologies for the next-generation efficient mobile communication systems.