Tunable planar left-handed metamaterials based on split-ring resonator pairs

A mechanically tunable planar left-handed metamaterial (LHM) using SRR pairs was presented. The two identical SRRs of a SRR pair unit cell are etched on two separate substrates so that the coupling between the two SRRs can be adjusted by slipping one SRR relative to the other. The tunable planar LHM was investigated. The results show that the tunable planar LHM can be tuned within a broad range continuously, reversibly and smoothly by a relative slip under both normal and oblique incidences. This tunable planar LHM is realized by the simple mechanical means, so it is much easier to be fabricated and used in practice.