[paper] 60GHz Class-AB PA in 22nm FD-SOI CMOS

Dimitrios Georgakopoulos, Vasileios Manouras and Ioannis Papananos

A 60-GHz Current Combining Class-AB Power Amplifier in 22 nm FD-SOI CMOS

Microwave 2026, 2(1), 2; DOI: 10.3390/microwave2010002

* School of Electrical and Computer Engineering, National Technical University of Athens, (GR)

Abstract: This work presents a fully integrated, two-stage, deep class-AB power amplifier (PA) operating at a center frequency of 60 GHz. High efficiency and suppression of third-order intermodulation products are targeted, achieving improved linearity compared to reported state-of-the-art designs. A current combining architecture is also employed to enhance the output power capability. The PA is designed in a 22 nm FD-SOI CMOS technology and is optimized through a complete schematic-to-layout design flow. Post-layout simulations indicate that the PA achieves a peak power-added efficiency (PAE) of 28%, a saturated output power ( 𝑃𝑠𝑎𝑡 ) of 20.2 dBm, and a maximum large-signal gain (𝐺𝑚𝑎𝑥 ) of 19.6 dB at 60 GHz, evaluated at an operating temperature of 60 °C. The design maintains high linearity across the targeted output power range, exhibiting effective suppression of third-order intermodulation distortion (IMD3), which enhances its suitability for spectrally efficient modulation schemes. 

FIG: Top-level schematic of the overall mm-Wave PA, including layout of all passive networks

[paper] Processes of AM-PM Distortion in Large-Signal Single-FET Amplifiers

Processes of AM-PM Distortion in Large-Signal Single-FET Amplifiers

S. Golara, S. Moloudi and A. A. Abidi, " 

in IEEE Transactions on Circuits and Systems I: Regular Papers, 

vol. 64, no. 2, pp. 245-260, Feb. 2017; doi: 10.1109/TCSI.2016.2604000

Abstract: Using an appropriate formulation of field-effect transistor (FET) current as a nonlinear function of terminal voltages, and a simplified model of gain compression in common source amplifiers, we are able to identify four principal sources of amplitude-to-phase (AM-PM) distortion. A new analysis shows the varactor effect of gate-source capacitance on AM-PM distortion, and the changing Miller-multiplied gate-drain capacitance as the field-effect transistor (FET) is driven into compression. The phase shift in the load impedance at the frequency of operation and incomplete suppression of 2nd harmonic by a resonant load of limited Q are explained and analyzed. We are able to identify the dominant mechanism of AM-PM distortion in various practical circuits, which then suggests methods of remediation. The analysis was put to test by predicting the measured AM-PM distortion of power amplifiers reported in the literature. Good agreement is found in all cases, with insights gained into the dominant cause of distortion in each case. In this paper, AM-PM distortion is first defined in Section II. In Section III, the EKV model of the MOSFET is briefly presented and dominant mechanisms are explained. In Section IV the analysis is compared against measured data to validate the theory and Section V summarizes the conclusions [read more...]