1. Hahn-Schickard, Georges-Koehler-Allee 103, 79110 Freiburg, Germany
2. Mast Diagnostica GmbH, Feldstraße 20, 23858 Reinfeld, Germany
3. Laboratory for MEMS Applications, IMTEK−Department of Microsystems Engineering, University of Freiburg, Georges-Koehler-Allee 103, 79110 Freiburg, Germany