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Gain expressions for resonant inductive wireless power transfer links with one relay element

Published online by Cambridge University Press:  12 October 2017

Franco Mastri
Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, University of Bologna, Bologna, Italy. Phone: +39 0832 29 7365
Mauro Mongiardo
Department of Engineering, University of Perugia, Italy
Giuseppina Monti*
Department of Engineering for Innovation, University of Salento, Italy
Marco Dionigi
Department of Engineering, University of Perugia, Italy
Luciano Tarricone
Department of Engineering for Innovation, University of Salento, Italy
Corresponding author: G. Monti Email:


In this paper, a resonant inductive wireless power transfer link using a relay element is analyzed. Different problems of practical interest are considered and solved by modeling the link as a lossy two-port network. According to the two-port network formalism, the standard gain definition (i.e. the power, the available, and the transducer gains) are used for describing the network behavior. Firstly, the case of a link with given parameters is considered and the analytical expressions of the optimal terminating impedances for maximizing the link gains are derived. Later on, the case of a link with given source and load is analyzed and the possibility of maximizing the performance by acting either on the transmitting or on the receiving side is investigated. It is shown that by using a single relay element, it is not always possible to maximize all the figures of merit that could be of interest in the WPT context. Theoretical data are validated by comparisons with circuital simulation results.

Wirelessly Powering: The Future
Copyright © Cambridge University Press 2017 

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