1. ENTE Sp. z o.o., Gaudiego 7, 44-100 Gliwice, Poland
2. Faculty of Electrical Engineering, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice, Poland
3. Institute of Physics, Silesian University of Technology, Krzywoustego 2, 44-100 Gliwice, Poland