Field Analyzers in EMC Radiated Immunity Testing

In radiated immunity testing, it is common practice to utilize a radio frequency (RF) field probe to measure the electric field at the location of the unit under test (UUT). Most RF field probes are designed to measure the root mean square (RMS) of a continuous wave (CW) electric field over a broad range of frequencies and amplitudes.

RF field probes are also commonly used to measure modulated fields. In general, this is not a good practice if the RF field probe is diode based. Depending on the analog response time and the sample rate, measuring a modulated field with a diode based RF field probe will be unpredictable and could yield erroneous results.