1. AFFOC Solutions Ltd . 2-58 Jaunibas Str., Kalnciems, LV-3016 , Latvia
2. Communication Technologies Research Center, Institute of Telecommunications , Riga Technical University 12 Azenes Str ., Riga , , Latvia
3. Institute of Microwave Engineering and Electronics , Riga Technical University 6a Kipsalas Str., Riga, LV-1048 , Latvia
4. Institute of Telecommunications , Riga Technical University 12 Azenes Str ., Riga , , Latvia