1. Department of Self-Powered Radio Systems, Fraunhofer Institute for Integrated Circuits, Nürnberg, Germany
2. Department of Mathematics, Friedrich–Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
3. Department of Integrated Sensor Systems, Fraunhofer Institute for Integrated Circuits, Erlangen, Germany
4. Advanced Electromagnetics Group, Technische Universität Ilmenau, Ilmenau, Germany