[He, Hongyu; Zhang, Shengdong] Peking Univ, Shenzhen Grad Sch, Sch Elect & Comp Engn, Shenzhen 518005, Peoples R China.
[He, Hongyu; Zhang, Shengdong] Peking Univ, Inst Microelect, Beijing 100871, Peoples R China.
[He, Hongyu] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.
[Zheng, Xueren] S China Univ Technol, Sch Elect & Informat Engn, Guangzhou 510640, Guangdong, Peoples R China.