A 28 GHz transformer-based Doherty power amplifier for FR2 5G applications in 40 nm CMOS

ABSTRACT

In this paper, a 28 GHz transformer-based Doherty power amplifier (DPA) is designed in Huali Microelectronics (HLMC) 40 nm CMOS process. The impedance inverter is converted into transformer form to calculate and design the power combiner based on the transformer voltage combination. A switchable cap array is added to the auxiliary output to increase the robustness of the active load modulation. The DPA achieves 17.1 dBm saturated power with 33.67% peak power added efficiency ($\mathit{PA}{E}_{\mathit{max}}$) and 19.93% $\mathit{PA}{E}_{\mathit{PBO}6\mathit{dB}}$ at 6 dB power back-off.

KEYWORDS:

• Doherty power amplifier
• millimetre-wave
• impedance inverter
• voltage combination
• switchable cap array

Disclosure statement

No potential conflict of interest was reported by the author(s).