Effect of Substrate Dielectric Properties and Tunable Metamaterials

The effect of substrate dielectric properties on the overall performance of split ring resonator (SRR) metamaterials was investigated. Results of a finite element simulation show notable differences of metamaterial properties with different substrate dielectric properties. The resonance frequency change can be used to roughly characterize the effect of the change of the substrate dielectric property. Since the electromagnetic properties of a metamaterial vary largely at the frequencies around the resonance frequency, the metamaterial properties can be effectively tailored by adjusting the substrate properties. This means the substrate provides an additional dimension of flexibility for the design of the metamaterials. On the other hand, considering the tunability of the metamaterials, which is required in many applications, we notice it is a very effective way to achieve tunable metamaterials by tuning the properties of the substrate. Although the change of the geometry or the electromagnetic properties of the metallized structures will result in metamaterials with different properties, it should be noted that the tuning of the size or the metal properties is more difficult and very limited once the geometry is determined. The substrate properties, however, can be tuned relatively easily by, for example, temperature, stress, bias voltages, bias currents, etc. How to tune the substrates is not within the coverage of this paper, but our simulation results show a tunable metamaterial can be implemented by fixed metallized structures on a tunable substrate