Investigation of the coupling between tunable split-ring resonators (article)

This is the author accepted manuscript. The final version is available from American Physical Society via the DOI in this recordThe dataset associated with this article is located in ORE at: https://doi.org/10.24378/exe.743Passive resonant metamaterials are limited by the narrow-band nature of the resonances they support. Here we show that by incorporating an active component into the structure of the commonly used split-ring resonator it is possible to tune the resonance frequency of this type of metamaterial atom. We make use of this tuneability to examine the interaction between two resonators, one passive and one active, as the resonance frequency of the active resonator is swept through that of the passive resonator. The resultant modes of this coupled system exhibit an anti-crossing and, by changing the separation between, and relative orientation of, the split-ring resonators, we investigate how the magnetic and electric coupling terms change. We find that the relative orientation of the resonators significantly effects the strength of the coupling. Through both structural and active tuning we are able to alter the relative sizes and signs of the coupling terms. We hope that the nature of these changes will be of use to those designing large actively tunable metamaterial systems.We acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the United Kingdom, via the EPSRC Centre for Doctoral Training in Metamaterials (Grant No. EP/L015331/1). W.L.B. acknowledges the support of the European Research Council through project Photmat (ERC-2016-AdG-742222). I.R.H. acknowledges support from the EPSRC via the TEAM-A prosperity partnership (Grant No. EP/L015331/1)