1. Universiti Malaysia Perlis (UniMAP), Geopolymer & Green Technology, Centre of Excellence (CEGeoGTech), Perlis, Malaysia
2. Universiti Malaysia Perlis (UniMAP), Faculty of Electronic Engineering Technology, Perlis, Malaysia
3. Universiti Putra Malaysia, Faculty of Science, Department of Physic, Applied Electromagnetic Laboratory, 43400 Serdang, Selangor, Malaysia
4. Institut Teknologi Sepuluh Nopember, Faculty of Science and Analytical Data, Department of Physic, Campus ITS Sukolilo-Surabaya 60111, Indonesia