A 28 GHz Power Amplifier Based on Broadband Adaptive Linearization Technique in 65-nm CMOS

A 28 GHz linear power amplifier (PA) for
$5\mathrm{G}$
multiband application is proposed in this paper. Based on the proposed broadband adaptive linearization technique, properly designed inter-stage power splitting network, and output power combining network, the P A has broadband linearization performance improvement and high power-added efficiency (P AE) within the operating frequency band. The proposed PA is implemented in 65-nm CMOS process and exhibits a 3-dB bandwidth of S21 from 21.5 to 33 GHz, covering n257/n258/n261 bands. The PA shows maximum power gain of 23.3 dB with output 1-dB compression point
$(\mathbf{P}_{1\text{dB}})$
, saturation output power
$(\mathbf{P}_{\text{sat}})$
, and peak P AE of 24.2
$\text{dBm},\ 24.9\ \text{dBm}$
, and 31.8% at 28 GHz, respectively. The 1-dB bandwidth of
$\mathrm{P}_{1\text{dB}}$
is from 21.8 to 35.2 GHz with corresponding PAE exceeding 22%.