1. Department of Electronics Engineering, Kaunas University of Technology, Studentu St. 50, LT-51368 Kaunas, Lithuania
2. Prof. K. Barsauskas Ultrasound Research Insititute, Kaunas University of Technology, K. Barsausko St. 59, LT-51423 Kaunas, Lithuania
3. Department of Electrical Power Systems, Kaunas University of Technology, Studentu St. 50, LT-51368 Kaunas, Lithuania