1. Antenna, Propagation, and Millimeter-wave Systems (APMS) Section, Department of Electronic Systems, Faculty of Engineering and Science, Aalborg University, Aalborg, Denmark
2. State Key Lab of Networking and Switching Technology, Beijing University of Posts and Telecommunications, Beijing, China
3. Oulu University, Oulu, Finland
4. National Mobile Communications Research Laboratory, School of Information Science and Engineering, Southeast University, Nanjing, China