The RF-R 400-1 is a passive near-field probe. In principle it has the same structure as the probes RF-R 50-1 and RF-R 3-2. The near-field probe is small and handy. It has a current attenuating sheath and, therefore, is electrically shielded. It can be connected to a spectrum analyzer or an oscilloscope with a 50 Ω input. The H-field probe does not have an internal terminating resistance of 50 Ω.