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

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 (
$P_{SAT}$
) 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 (
$G_{p}$
) of 20.4-dB at 23 GHz and a measured 3dB small-signal gain bandwidth (
$BW_{3dB}$
) from 20.8 to 41.6 GHz covering the multiple 5G bands with only 39.6-mW quiescent power consumption. The measured
$P_{\mathrm{sat}}$
is 16.1-dBm at 30 GHz with over 50%
$P_{\mathrm{sat}}$
output power 1dB bandwidth (
$BW_{1\mathrm{dB}}$
) from 23 to 38.5-GHz. Also, this PA reports a 35% peak power added efficiency (
$PAE_{\mathrm{MAX}}$
) at 25 GHz and a 13-dBm peak
$OP_{1\mathrm{dB}}$
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.