[1] Nanjing Univ Posts & Telecommun, Coll Elect & Opt Engn, Nanjing 210023, Jiangsu, Peoples R China
[2] Nanjing Univ Posts & Telecommun, Coll Microelect, Nanjing 210023, Jiangsu, Peoples R China
[3] Pukyong Natl Univ, Dept Phys, Busan 608737, South Korea
[4] Key Lab Radio Frequency & Micronano Elect Jiangsu, Nanjing 201146, Jiangsu, Peoples R China
[5] Jiangsu Univ, Sch Mat Sci & Engn, Zhenjiang 212013, Jiangsu, Peoples R China