Automated near-field EMC/EMI scanning system with active electro-optical field probes

We present an automated near-field scanner for system- to chip-level EMC/EMI evaluations in the RF domain. The scanning system combines a large scanning volume of 500×500×100mm³ with micrometre resolution. A novel optical surface reconstruction system allows measurement of the height map of the device under (DUT) test with better than 20μm uncertainty. This allows scanning at a precise distance above arbitrary electronic components. Key components of the scanning system are novel active miniaturized electro-optical time-domain E- and H-field sensors in the frequency range from 0.01 to >6GHz measuring the complex amplitude with a dynamic range of >120dB. The full optical isolation of the probes eliminates disturbance of the field of the DUT compared to electrically connected probes and offers up to 60dB better sensitivity than passive electro-optical probes.