1. National Chung Hsing University, Department of Electrical Engineering, Taichung 402, TaiwanbNational Chung-Shan Institute of Science and Technology, Aeronautical Systems Research Division, Taichung 407, Taiwan
2. National Chung-Shan Institute of Science and Technology, Aeronautical Systems Research Division, Taichung 407, Taiwan
3. National Chung Hsing University, Department of Electrical Engineering, Taichung 402, Taiwan