1. a Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1 University Road, Tainan City 701, Taiwan, R.O.C.
2. b Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1 University Road, Tainan City 701, Taiwan, R.O.C.
3. c Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1 University Road, Tainan City 701, Taiwan, R.O.C.
4. d Department of Electronic Engineering, I-Shou University No. 1, Sec. 1, Syuecheng Road, Dashu Township, Kaohsiung County 840, Taiwan, R.O.C.;, Email: mphoung@eembox.ncku.edu.tw