[1] Gwangju Inst Sci & Technol, Sch Mat Sci & Engn, 123 Cheomdangwagi Ro, Gwangju 61005, South Korea
[2] Korea Inst Ind Technol, Energy & Nano R&D Grp, Cheomdangwagi Ro 208-gil, Gwagju 61012, South Korea
[3] Mokpo Natl Maritime Univ, Div Nav Sci, Mokpo 58628, South Korea
[4] Korea Electrotechnol Res Inst, Appl Electromagnet Wave Res Ctr, Electromed Equipment Res Div, Ansan 15588, South Korea