A 20.8-41.6-GHz Transformer-Based Wideband Power Amplifier with 20.4-dB Peak Gain Using 0.9-V 28-nm CMOS Process
Chieh-Wei Wang, Yi‐Chun Chen, Wen‐Jie Lin, Jeng‐Han Tsai, Tian‐Wei Huang
Abstract
This paper presents a wideband transformer-based power amplifier applicable for the millimeter-wave (MMW) fifth generation (5G) mobile communication. The proposed power amplifier is manufactured in 28-nm HPC-plus CMOS process. The power stage and driver stage amplifiers are biased in deep class-AB to reduce the dc power dissipation in the linear power region and provide a linear operation close to the saturated output power ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P_{SAT}$</tex> ) of the PA. In the output matching network, a transformer with two coupled resonant capacitors is designed for broadband power matching. The proposed PA achieves the peak small-signal power gain ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$G_{p}$</tex> ) of 20.4-dB at 23 GHz and a measured 3dB small-signal gain bandwidth ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$BW_{3dB}$</tex> ) from 20.8 to 41.6 GHz covering the multiple 5G bands with only 39.6-mW quiescent power consumption. The measured <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P_{\mathrm{sat}}$</tex> is 16.1-dBm at 30 GHz with over 50% <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$P_{\mathrm{sat}}$</tex> output power 1dB bandwidth ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$BW_{1\mathrm{dB}}$</tex> ) from 23 to 38.5-GHz. Also, this PA reports a 35% peak power added efficiency ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$PAE_{\mathrm{MAX}}$</tex> ) at 25 GHz and a 13-dBm peak <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$OP_{1\mathrm{dB}}$</tex> at 41 GHz. In the 64-QAM OFDM modulated signal measurement, this power amplifier obtains an output power of 7.2/6.9-dBm and a modulated PAE of 8.5%/8.8% at 23 and 41-GHz respectively when keeping the EVM below -25 dBc.