Mutual inductance larger than one of the inductors

[abuya7ya]

Can you have a mutual inductance between two inductors which is larger than one of the inductors?

For example: L1= 0.1 nH, L2= 2.5 nH, M=-0.246 nH --> k=-36.2%.
Are these values practical and could the configuration be realized in LTCC or MMIC technologies?

Thanks

 

[kthackst]

Yep, that's certainly physically possible. The max limit on mutual inductance can be proven through energy conservation, but as long as the coupling coefficient is less than 1 (k = M/sqrt(L1 * L2) ) than the mutual inductance is realizable.

Sorry, but I can't offer any advice as to if those values could be implemented in the way you described.

 

[mtwieg]

Doing so requires a large turns ratio between windings. I don't see why it wouldn't be doable so long as you have several metal layers to work with. Can't say what sort of Q to expect though.