1. Federal Institute of Metrology, METAS, Lindenweg 50, 3003 Bern-Wabern, Switzerland
2. Biophysics Department, Johannes Kepler University Linz, Gruberstr. 40, 4020 Linz, Austria
3. Institute of Electromagnetic Fields (IEF), ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland
4. Agilent Technologies Austria GmbH, Measurement Research Lab Linz, Gruberstrasse 40, 4020 Linz, Austria