From 1993 to 1995 she worked at the Laboratory for High Frequency Techniques, FER-Zagreb, as assistant and technical secretary of the European COST244 project Biomedical Effects of Electromagnetic Fields. In June 1995 she joined the BIOEM/EMC group at the Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, where she conducted her PhD work on optimized probe designs for near-field evaluations in the mobile frequency range. In October 1999, Katja was employed by SPEAG as Laboratory Director and in December 2001, Katja became an executive board member of SPEAG. Katja also advised SPEAG customers in all areas of near-field evaluation and optimization and represented SPEAG in standardization committees.