Frequency tunable metamaterial designs using near field coupled SRR structures in the terahertz region

We present frequency tunable metamaterials at terahertz frequencies using broadside-coupled split ring resonators (BC-SRRs). Frequency tuning, arising from changes in near field coupling, is obtained by in-plane displacement between the SRR layers. For electrical excitation, the resonance frequency continuously redshifts as a function of displacement. A maximum frequency shift occurs for displacement of half a unit cell resulting in a shift of 663 GHz (51% of f₀). We discuss the difference in the BC-SRR response for electrical excitation in comparison to magnetic excitation in terms of hybridization arising from inductive and capacitive coupling.