1. Ph. D. Program in Engineering Science; College of Engineering, Chung Hua University; Hsinchu; 30012; Taiwan; Republic of China
2. Centre for Optical and Electromagnetic Research; State Key Laboratory of Modern Optical Instrumentations; East Building No. 5; Zijingang Campus; Zhejiang University; Hangzhou; 310058; The People's Republic of China
3. Department of Communication Engineering; Chung Hua University; Hsinchu; 30012; Taiwan; Republic of China
4. Department of Electrical Engineering; Chung Hua University; Hsinchu; 30012; Taiwan; Republic of China