A 28GHz Harmonic Injection Doherty Power Amplifier

In this paper, a 28 GHz fully on-chip Doherty power amplifier with harmonic injection is presented in 65 nm CMOS technology. In order to improve the linearity, two injection amplifier stages biased in class C are used. In this method, injection of the second harmonic compensates the gain compression phenomena and improves the output
$\mathrm{P}_{-}1\text{dB}$
and PAE at
$\mathrm{P}_{-}1\text{dB}$
by more than 6 dB and 9 %, respectively. Post-Layout EM (electromagnetic) simulation of PA illustrates maximum PAE of 19.6%, output
$\mathrm{P}_{-}1\text{dB}$
of 15.76 dBm, PAE of 14% at 6dB back-off, 6 dB gain, and 19 dBm saturated output power. The layout area is 0.445 mm
²
.