1. Department of Electrical and Computer Engineering, The University of Alabama, Tuscaloosa, Alabama 35487, USA
2. Department of Physics and Astronomy, The University of Alabama, Tuscaloosa, Alabama 35487, USA
3. Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, USA
4. Samsung Electro-Mechanics, Co. Ltd., Suwon, South Korea
5. Deaprtment of Physics, Sogang University, Seoul, South Korea
6. Institute of Fundamental and Advanced Technology (IFAT), Hyundai Motor Company, Uiwang-si, Gyeonggi-do, South Korea