Theory 15/Metamaterials

Negative Index Bandwidth Is a Loss Ratio

The claim

The bandwidth over which a metamaterial shows a negative index is set by the ratio of resonance strength to loss rather than by the resonance quality factor.

01The mechanism

Negative index requires the resonant response to exceed the damping over the band; the ratio sets where the real part can turn negative before loss dominates.

02Predictions

P1Bandwidth should track the ratio.
P2High Q alone should not guarantee bandwidth.

03Refutation

Bandwidth tracking Q would remove the loss ratio.