Design of Non-linear Electrical Energy Harvesting Circuits for RF Wireless Power Transfer Systems

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The Coordinated Research Center „Empatho-Kinaesthetic Sensory Systems“ (EmpkinS) is working on the development of wearable sensors with limited size for non-invasive detection of biomedical processes. Wireless power transfer (WPT) is a promising technique that enables efficient remote recharging of the batteries of such small devices. However, a practical implementation of RF WPT systems is challenging due to the non-linearity of electrical energy harvesting (EH) circuits. In particular, the EH circuit non-linearity is caused by the presence of non-linear elements (typically, diodes) for the rectification of the received RF signal. Furthermore, to achieve a high conversion efficiency, the non-linear rectifier at the EH circuit has to be well matched to the receiving antenna by an impedance matching circuit, whose design is also a non-trivial problem. The goal of this work is to study different aspects that influence the performance of practical EH circuits, to develop a procedure for the optimization of the components of EH circuits for the maximization of EH efficiency, and to conduct the measurements to evaluate the performance of practical WPT systems.

Guidelines for the project

  • Conduct a literature survey on hardware design of EH circuits
  • Develop an algorithm for the optimization of the EH circuit parameters to maximize the system performance
  • Program firmware for a μC unit at the transmitter of the WPT system
  • Conduct measurements of the designed EH nodes and analyze the performance of the WPT system


  • Interest in communications, signal processing, and hardware design
  • Basic knowledge of digital and mobile communication systems
  • Basics of analog (and digital) circuit technology
  • Experience in Matlab
  • Basics of μC programming