Cunjun Ruan (M’11–S’17) received aPh.D. degree from Tsinghua University, Beijing, China, in 2003. He has been working with the Institute of Electronics, Chinese Academy of Sciences, Beijing, since 2003, where he is involved in sheet-beam klystrons, extended interaction klystrons, and integrated vacuum electronics. He became a research professor in 2011. He is currently working with the School of Electronics and Information Engineering, Beihang University, Beijing. His main research interests include sheet electron beam SBKs, EIK TWT in millimeter waves and terahertz, and integrated vacuum electronics devices.