[1] Suratthani Rajabhat Univ, Fac Sci & Technol, Program Ind Elect Technol, Mueang 841000, Surat Thani, Thailand
[2] Natl Sci & Technol Dev Agcy, Natl Elect & Comp Technol Ctr NECTEC, Pathum Thani 12120, Thailand
[3] Nakhon Ratchasima Rajabhat Univ, Fac Sci & Technol, Dept Phys, Nakhon Ratchasima 30000, Thailand
[4] Srinakharinwirot Univ, Educ Res Dev & Demonstrat Inst, Ongkharak 26120, Nakhon Nayok Pr, Thailand