A Varactor Loaded Tunable Dual-band Left-Handed Metamaterial

摘要

In this paper, we proposed a tunable dual-band left-handed metamaterial (LHM). This dual-band LHM can be regarded as a combination of double-slits split ring resonators (DSSRRs) and rotated 'H-shape' structure loaded with varactors. The 'H-shape' structure functions like arrayed metallic wires, and is only capable of extracting negative permittivity, but with proper loaded capacitors, it can also extract negative permeability. According to the numerical analysis, such character is closely related to the mutual coupling coefficient. We analyzed both the DSSRRs and the 'H-shape' structure through equivalent circuits and simulations, respectively. Later the composed LHM loaded with varactors is also simulated. Dual-band left handed (LH) property can be observed from the retrieved effective parameters, of whom one LH band is stable and wide, approximately from 2GHz to 2.1GHz, while the other one is relatively narrow, shifting from 1.14GHz to 2.36GHz dynamically. Compared to other work where only multi-band technology or tunable method is applied, the combination of both the methods greatly extended the functioning bandwidth.