Field Uniformity Measurements of Flat Broadband Dipoles Used for Near-Field Immunity Testing

摘要

Near-field immunity tests have become very popular in the last years. Especially in automotive EMC-applications (ISO 11452-9 and many automotive manufacturer standards), new test methods for immunity tests against portable transmitters have been introduced since 2009. In contrast to widely applied radiated immunity tests according to EN 61000-4-3 or MIL-STD-461G, which are typically performed at distances of 1 m to 3 m between antenna tip and equipment under test, the near-field immunity test methods are done at very close spacings of 5 to 50 mm and on component test level only. The small separation between radiating elements and the surface of the equipment under test leads to a very efficient power to fieldstrength conversion. The characterisation of the generated near-field was done using separate miniaturized scanning probes for E-field and H-field. Measurements of the field uniformity are presented in cartesian coordinates with contour lines as “heatmaps”. The frequency range for these near-field tests is 360 MHz to 2.7 GHz, currently (2020) being extended up to 6 GHz.