Analysis and Design of Stacked MOS mm-Wave Power Amplifiers

Thesis event information

Date and time of the thesis defence

Place of the thesis defence

L10, Linnanmaa

Topic of the dissertation

Analysis and Design of Stacked MOS mm-Wave Power Amplifiers

Doctoral candidate

Master of Science Mohammad Hassan Montaseri

Faculty and unit

University of Oulu Graduate School, Faculty of Information Technology and Electrical Engineering, Centre for Wireless Communications

Subject of study

Wireless Communications Engineering


Professor Frank Ellinger, Dresden University of Technology


Professor Aarno Pärssinen, University of Oulu

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Analysis and Design of Stacked MOS mm-Wave Power Amplifiers

Compact mm-wave IC solutions for high data rate 5G/6G wireless communications systems, has postulated stringent design challenge due to MOS transistors scaling for higher operable frequencies, at which the intrinsic performance characteristics of the transistors are drastically deteriorated. The requirements by modern modulation schemes, deployed in the mentioned communications systems, e.g., LTE or 5G NR, also add to the circuit design challenges.

Power amplifier (PA), as the main building block of the transmitters, principally govern the performance of wireless communications systems and must satisfy power level requirements of the system as well as signal integrity. Stacking the transistors on top of each other has been adapted to fulfill such demands. In this respect, this thesis concerns the analysis and design of Stacked MOS PA topologies. The present study not only focuses on the key performance characteristics such as maximum possible operating frequency, output power, and efficiency, but also investigates the mechanisms of amplitude-to-amplitude/phase (AM-AM/PM) conversion distortions. This thesis has successfully reached the following accomplishments:

1) By taking the impact of frequency into account, a more versatile design rule is proposed to retain the performance of the stacked MOS PAs.
2) The maximum number of stacks/stages in the mentioned topologies are determined versus the P_out and/or η.
3) An inter-stage matching is proposed to improve the performance over a wide frequency band.
4) The overall AM – AM/PM conversion distortions are calculated to account for loading variations.
5) A dimensioning rule is proposed based for the stacked MOS PAs to be utilized in the class C scheme for Doherty PA applications.

The abovementioned proposed methods and design techniques in this thesis will support the design of future MOS based PAs for wireless communication systems applications.
Last updated: 23.1.2024