How to Calculate E-Field Magnitude From an E-Field Probe

[standardengr]

Hi everyone!

Can anyone explain how to use an E-field probe to actually measure magnitude of an E-field? I know a lot of people use E-field probes to pinpoint RF interference but how does the signal received on the probe actually relate to the E-field magnitude? I tried looking at how electric field meters work in hope it would explain it but I'm having a hard time finding material on the subject.

Thanks!

[skipjackrc4]

The probe should have an "antenna factor" supplied by the manufacturer that will give you the conversion between measured voltage and field strength over frequency.  Typically the AF will be supplied in dB and will be added to the measured voltage in dBuV to get dBuV/m.  It's important to note, however, that the presence of the near-field probe influences the field, and the corrected field strength is going to be somewhat approximate.  Even EMI measurements have this problem at low frequencies--the field "measured" by the antenna is not necessarily the actual field strength.

The probe may also be sensitive to polarization, depending on the design.