1. School of Electronics and Communication Engineering, Guangzhou University, Guangzhou, China
2. School of Electrical and Electronic Engineering, Nanyang Technological University, Jurong West, Singapore
3. School of Information and Communication Engineering, University of Electronic Science and Technology of China, Chengdu, China
4. Institute of Electron Devices and Circuits, Ulm University, Ulm, Germany
5. Faculty of Electrical Engineering and Information Technology, Karlsruhe University of Applied Sciences, Karlsruhe, Germany