[1] Nanjing Univ Aeronaut & Astronaut, Coll Sci, Nanjing 210016, Peoples R China
[2] China Acad Engn Phys, Inst Appl Elect, Mianyang 621900, Sichuan, Peoples R China
[3] China Acad Engn Phys, Key Lab Sci & Technol Complex Electromagnet Envir, Mianyang 621900, Sichuan, Peoples R China