Design and Analysis of a Compact CMOS SOI Power Amplifier With 29.2-dBm <i>P</i> <sub>SAT</sub> and 44.4% PAE for FR3 5G-Advanced/6G Beamforming Systems
Yiting Zhang, Nengxu Zhu, Fanyi Meng, Keping Wang, Kaixue Ma, Kiat Seng Yeo
Abstract
This article presents a compact, high-efficiency power amplifier (PA) for frequency range 3 (FR3) beamformer integrated circuits (BFICs) targeting 5G-Advanced and 6G systems. To address the output power, efficiency, and integration challenges of silicon-based PAs in high-density antenna arrays, an extended cascode core (ECC) leveraging floating-body (FB) silicon-on-insulator (SOI) transistors is adopted to provide improved power handling with a stable breakdown margin, and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i>-feedback networks that further enhance broadband stability and output matching. A triple-coupled 4-to-1 folded transformer (FT) with odd-/even-mode co-optimization enables efficient power combining, incorporating an embedded <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $</tex-math> </inline-formula>-network that suppresses the 2nd harmonic (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2{f_{0}}$</tex-math> </inline-formula>) to sustain high output power and efficiency in a compact footprint. Fabricated in the 0.13-<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu $</tex-math> </inline-formula>m CMOS SOI technology, the PA achieves a 3-dB bandwidth of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9.0{-}13.5$</tex-math> </inline-formula> GHz, 29.2dBm saturated output power (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\text {SAT}}$</tex-math> </inline-formula>), and 44.4% peak power-added efficiency (PAE). The core area is 0.697mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, corresponding to a 1193.3 mW/mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> power density (PD). It supports 64-QAM modulation at an average power of 22.6dBm with an error vector magnitude (EVM)/adjacent channel leakage ratio (ACLR) of −25dB and −31dBc, respectively. The PA exhibits amplitude-to-phase (AM–PM) distortion below 2.5°/2.1°/1.8° at 10/11/12GHz up to 1-dB compression point (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\text {1 dB}}$</tex-math> </inline-formula>), and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${\lt } {-}36$</tex-math> </inline-formula> dBc 2nd-/3rd-harmonic suppression across the band. The PA achieves state-of-the-art PAE and PD among FR3-band silicon-based PAs with competitive <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\text {SAT}}$</tex-math> </inline-formula>, offering an integration-friendly, energy-efficient solution for massive multiple-input multiple-output (MIMO) transmitters in next-generation wireless systems.