1. TeraSi AB, 139 33 Stockholm, Sweden
2. Department of Radar Systems, Swedish Defense Research Agency, 583 30 Linköping, Sweden
3. Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412 58 Gothenburg, Sweden
4. Division of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden