1. Anna University, Regional Center, Department of ECE, Tirunelveli, Tamilnadu 627007, India
2. National College of Engineering, Department of ECE, Tirunelveli, Tamilnadu 627151, India
3. University College of Engineering, Department of Physics, Nagercoil, Tamilnadu 629004, India
4. Chikkanna Government Arts College, Department of Physics, Tiruppur, Tamilnadu 641602, India