Changing/Controling relative permeability

[jupiter13]

Hey everyone,

I've been looking at metamaterials, and it's quite an overwhelming subtopic to be introduced to. Most of the stuff I'm finding has to do with negative permeabilities. I'm wondering how exactly we control what relative permeability a material has and how fine that control is, not just so that its a negative value, but that it's any value other than what you'd measure if you found it in nature?

 

[Born2bwire]

The most common is to create a resonant structure such that the permeability and permittivity resonate like in a plasma. If you recall, the resonanct behavior causes the imaginary part to peak and the real part to change sign. By controlling the resonances, we can get both the permeability and permittivity to be negative at the same time in addition to hopefully have a small amount of loss. Such resonances can be done naturally by exciting surface plasmons in nanoparticles. If we permeate a material with nanoparticles and excite a surface plasmon on the particles, then the bulk effect is like there is a plasma behavior throughout the material itself. Or we can build a unit cell that exhibits resonant behavior (like an L-C circuit) and build up a material off of these unit cells.

In the end, what we have to do is use distributed effects to get the behavior that we want. So must of the time you will be dealing with periodic structures.