Microwave Integrated Left-handed Transmission Line Study

Left-handed material (LHM) is a newly discovered artificial metamaterial with negative permittivity and negative permeability simultaneously. In recent years, several methods have been proposed to realize LHM, including planar composite right/left-handed (CRLH) transmission line structures, CRLH transmission line based on split ring resonator and LHM based on back-wave waveguide with periodic structures. This dissertation mainly analyzes two aspects of LHM, research on broadband zero-phase LHM and new structure based on back-wave waveguide, respectively.First, based on LH transmission line theory, the feasibility of broadband zero-phase LH transmission line is validated. A MIM capacitor model and a spiral inductor model are created. These two models are fitted by the equivalent circuit. Based on these work, a MMIC wide-band left-hand transmission line is processed. This transmission line has a wide left-hand transmission band; the measurement fits the simulation well, which testifies the validity of the model. In the process of validation, the author discovers that the microstrip balanced CRLH has a zero Phase-transfer constant in given frequency. When the right-handed parasite parameter is small enough, the slope of the dispersion curve is infinite. At this time ultra-band zero-phase propagation is realized in a certain range with small enough phase change (we can consider that the change of phase is zero). Then the author presents a new type of broadband LH transmission lines with defected ground. This transmission line model analyses right-handed parasite parameter's influence on the bandwidth of zero-phase transmission. The presented inductor model with defected ground can reduce the right-handed parasite parameter effectively. Based on the analysis of theory and the simulation of model, the author presents the idea of ultra-broadband zero-phase power splitter/combiner network. Then author validates the feasibility of this network through simulation of circuit model.After that, this dissertation introduces a new back-wave LH transmission line model based on the theory of slow-wave system theory. This structure is periodically-loaded waveguide. This structure only requires simple process in mechanical fabrication. Through analysis, when the waveguide is excited by TM mode, waveguide is working on LH propagation and waveguide propagates back-wave. Based on this new LH transmission waveguide theory, author presents a new multi-layer LH transmission line based on substrate integrated waveguide (SIW). This structure has some merits such as the small radiation loss of waveguide and the small size of transmission line. Like the producing conception of waveguide transmission line, LH transmission line based on SIW is formed by periodically loading a rectangular waveguide using H-shape metal plates. When the length of each unit is far smaller that 1/4λ, transmission line realizes propagation of no loss and anti-paralleling, which means the direction of group velocity is in reverse with the phase velocity. Then the characteristic of this LH transmission line has been validated. In all, these two new kinds of LH transmission line are valuable preparations for the future research of LHM based on waveguide and SIW.