Our results show that it is possible to actively cancel the fundamental component of a strong interferer in the core of a high sensitivity ferromagnetic-core loop antenna and prevent core saturation. This control signal is phase locked to the offending signal and the two signals destructively combine in the core. Here, a system is presented that actively controls the magnetic flux in the core of the antenna by applying a control signal to an independent set of windings on the same core. However, high-permeability materials are susceptible to saturation in the presence of strong magnetic fields such as those generated by power lines, in research laboratories, or through natural phenomena.
Ferromagnetic-core loop antennas with high-permeability core materials are typically used in size-constrained applications requiring the detection and reception of weak very low frequency and extremely low frequency signals.
