Characterising the baseband impedance of supply modulators using simple modulated signals

Alt, Alexander ORCID: https://orcid.org/0000-0002-7621-4940, Villarruel-Parra, Alejandro, Chen, Peng, Alsahali, Sattam, Forsyth, Andrew, Tasker, Paul J. ORCID: https://orcid.org/0000-0002-6760-7830 and Lees, Jonathan ORCID: https://orcid.org/0000-0002-6217-7552 2020. Characterising the baseband impedance of supply modulators using simple modulated signals. Presented at: 2020 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMiC), Cardiff, Wales, 16-17 July 2020. 2020 International Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits (INMMiC). IEEE, pp. 1-3. 10.1109/INMMiC46721.2020.9160186

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Abstract

Envelope tracking is one of the promising technologies for 5G power amplifiers, providing high power efficiency over a wide output power range by modulating the supply voltage. Although the baseband impedance, the output impedance of the supply modulator, plays a crucial role in the linearity of the PA, it is often not measured or considered during the modulator design. This paper presents a new, simplified approach to characterising this impedance using a PA with a simple multi-tone modulation as a load. It describes the measurement setup and verifies the results by characterising the baseband impedance of a state-of-the-art buck converter and comparing this to its static model. The results demonstrate that multi-tone signals and complex modulations yield comparable results and are both suitable for measuring and modelling the baseband impedance. This shows that using simple multi-tone measurements and basic equipment, the full static impedance characteristic can be obtained.

Item Type:	Conference or Workshop Item (Paper)
Date Type:	Published Online
Status:	Published
Schools:	Engineering
Publisher:	IEEE
ISBN:	9781728126456
Date of First Compliant Deposit:	3 November 2020
Date of Acceptance:	7 April 2020
Last Modified:	05 Jan 2024 08:28
URI:	https://orca.cardiff.ac.uk/id/eprint/135917

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