1. School of Electronic Science and Engineering, University of Electronic Science and Technology of China,National Key Laboratory of Science and Technology on Vacuum Electronics in Chengdu,Chengdu,China,611731
2. Guoli Vacuum (GLVAC) Industrial Technology Research Institute of High Power Devices Co., Ltd.,Suzhou,China,215300
3. Institute of Applied Electronics, China Academy of Engineering Physics,Mianyang,China,621900