A Highly Efficient 18-40 GHz Linear Power Amplifier in 40-nm GaN for mm-Wave 5G

• Published in: IEEE microwave and wireless components letters Vol. 31; no. 8; pp. 1008 - 1011
• Main Authors: Mayeda, Jill C., Lie, Donald Y. C., Lopez, Jerry
• Format: Journal Article
• Language: English
• Published: IEEE 01.08.2021
• Subjects: 5G mobile communication; 5G new radio (NR); broadband; Broadband amplifiers; FR2; Frequency measurement; Gain; GaN; Linearity; Load modeling; millimeter-wave (mm-Wave); power amplifier (PA); Radio frequency
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2021.3085241

A medium-power, highly-efficient broadband linear power amplifier (PA) is designed in a 40-nm GaN technology that covers the key 5G FR2 band of 24-40 GHz. Load-pull simulations suggest better device broadband performance and peak power-added-efficiency (PAE) around <inline-formula> <tex-math notation="LaTeX">V_{\text {DD}} =4 </tex-math></inline-formula>-6 V. Measurement data corroborates the simulations and this PA achieves a small-signal 3-dB bandwidth (BW) of 18.0-40.3 GHz, with max. PAE/<inline-formula> <tex-math notation="LaTeX">P_{\text {SAT}} </tex-math></inline-formula> of 42.1%/18.6 dBm at 28 GHz, and 26.0%/17.2 dBm at 38 GHz at <inline-formula> <tex-math notation="LaTeX">V_{\text {DD}} = 4 </tex-math></inline-formula> V. When tested with a 9 MHz <inline-formula> <tex-math notation="LaTeX">\times \,\, 100 </tex-math></inline-formula> MHz 256-quadratic-amplitude modulation (QAM) 5G new radio (NR) signal, it achieves an adjacent-channel-leakage-ratio (ACLR) of −27 dBc with <inline-formula> <tex-math notation="LaTeX">P_{\text {OUT, AVG}} </tex-math></inline-formula>/PAE of 11.3 dBm/13.9% at 28 GHz. When compared with state-of-the-art broadband PAs, it achieves the best <inline-formula> <tex-math notation="LaTeX">S_{21}~3 </tex-math></inline-formula>-dB BW with excellent peak PAE and linearity. This work also reports the best PAE for broadband medium-power millimeter-wave GaN PA at <inline-formula> <tex-math notation="LaTeX">P_{\text {SAT}}~\sim 20 </tex-math></inline-formula> dBm.