Loop Antennas vs. B-Probes: Similarities and Differences

[Massi]

Hi
the difference between a loop antenna and a magnetic probe (B-Probe) is only that the loop antenna works in far field and B-Probe works in near field? The standard features of magnetic antenna (antenna factor, impedance matching, radiation patterns, efficiency, ecc) have the same definition in the case of the B-Probe?
Thanks !
Regards
Massi

 

[Baluncore]

Welcome to PF.
A loop antenna and a B-probe differ in the external circuit and so in the flow of energy.
The loop antenna extracts the maximum power from the magnetic field and so significantly distorts the local field.
The B-probe senses the voltage induced on the loop, while minimising the current. That reduces the influence of the probe on the field.

 

[Massi]

Thank you!

 

[berkeman]

Hi
the difference between a loop antenna and a magnetic probe (B-Probe) is only that the loop antenna works in far field and B-Probe works in near field? The standard features of magnetic antenna (antenna factor, impedance matching, radiation patterns, efficiency, ecc) have the same definition in the case of the B-Probe?
Thanks !
Regards
Massi

Welcome to the PF.

In addition to Baluncore's comments, keep in mind that there are two different kinds of B-Field probes. The simplest is a small coil that is used to sense AC magnetic fields. It may be a single turn, shielded loop probe, or it can also consist of a number of turns for higher sensitivity (at the expense of lower bandwidth). But to sense DC and AC magnetic fields, a Hall Effect sensor is generally used. Does that make sense?

 

[Massi]

ok I see, thank you!
massi