Ferrite rod antenna for energy harvesting?

How noisy?

It starts looking like a coil of wire in free space.

Tim

I was thinking in the vicinity of transmitters in the > * What happens to the antenna characteristics if an electrical current

Thanks. I take it that's because the effective permittivity is driven down to unity, lowering radiation resistance.

I'm thinking about RF circulators, where ferrites biased with permanent magnets permit waves to travel in one direction while attenuating those in the opposite direction.

A google search showed that ferrites are sometimes used in rectification, but I couldn't find a description of how.

Google the Friis equation, which is the classic equation for determining the power transfer between two conductive radiators. If the ferrite is in the near field of whatever radiator is generating the noisy environment, it could detune it, causing less power transfer than you might expect. I believe (but don't quote me on it), that Friis is only valid in the far field, where the fields are in quadrature.