Design And Analysis Of Dual-band Left-handed Materials

Left handed material(LHM) is a kind of dielectric material that the relationship among the electric field intensity E, the magnetic field intensity H and the wave vector K presents the left-handed rule, which has the advantages of miniaturization,broadband, low insertion loss, and so on. But at present, the working frequency band of the left hand material mechanism is single frequency band, which is obviously the obvious deficiency in the practical application.The realization methods of left-handed materials(LHMs) can mainly be classified into two different types at present. One is the resonant-type LHMs which is with the theory of equivalent media and uses the SRRs and metal rod combination structure to achieve the negative equivalent permittivity and negative permeability simultaneously. The other is the transmission line type LHMs which is with the theory of the composite left & right-hand transmission line and uses the combination of finger capacitor and ground vias to realize the equivalent LC resonant circuit in the unit structure.A new structure of dual-band LHMs is designed in this paper based on the theory analysis of the resonant-type LHMs which is composed of a resonator with E-type double resonant ring and a metal wire. The dielectric constant, permeability and refractive index of the structure are simulated and extracted. The surface current and electric field distribution of two resonant frequency points are illustrated. The results show that there are two double negative bands existing in the proposed structure.A novel double pass band LHMs structure with microstrip line is proposed in this paper based on a resonant LC unit combination of double pass band structures of left-handed material proposed by C caloz. The transmission line double pass with equivalent circuit model of the left-handed material is analyzed. Through changing the physical dimensions of the structure reasonably and optimizing the frequency range of negative permittivity and negative permeability, the proposed structure is simulated. The results show that there are two double negative bands in the proposed structure.