A Single-Supply Balun-First Three-Way mm-Wave Doherty PA
Anil Kumar Kumaran, Masoud Pashaeifar, Mats Alexanderson, L.C.N. de Vreede, Morteza S. Alavi
Abstract
This article introduces a single-supply balun-first three-way parallel Doherty power amplifier (PA) tailored for millimeter-wave (mm-wave) fifth-generation (5G) applications. It incorporates a bandwidth enhancement technique that widens the operational frequency range, enhances broadband power back-off (PBO) efficiency, and reduces impedance mismatch between differential PAs. Realized in 40-nm CMOS bulk technology with a core area of 0.77 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{mm}^\text{2}$</tex-math> </inline-formula> , the prototype delivers a saturated power/peak gain surpassing 20 dBm/16 dB, and it demonstrates a drain efficiency (DE) exceeding 15%/22%/33% at 9.5 dB/6 dB/0 dB PBO across a 24–30 GHz band. The proposed mm-wave PA achieves EVM/ACLR values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 24.3 dB/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 30.1 dBc for a 1-GHz 64-QAM OFDM signal, operating at an average output power (Pout) of 9.4 dBm with an average DE of 15%. For a 50-MHz 1024-QAM OFDM signal, it achieves an average Pout/DE of 8.6 dBm/12% with EVM/ACLR of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 30 dB/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 36.3 dBc.