Research On The Theory Of The Transmission-line Metamaterials And Their Applications

Electromagnetic Metamaterials are defined as artificial composite structure or medium with unusual properties not readily in nature, which is one of the frontiers of Physics and Electromagnetism at present. It may be equivalent described as in terms of medium parameters (electric/magnetic dipole moment, permittivity, permeability), or in terms of transmission-line parameters (impedance/admittance, propagation constant, characteristic impedance). The latter approach is present with the arisen of the transmission-line Metamaterials. The transmission-line Metamaterials exhibits several advantages, such as broad bandwidth, low loss, compatibility with planar circuits and so on, compared to resonant Metamaterials, so the suitable for practical application of the transmission-line Metamterials has focus much more attention of the researchers. The CRLH Metamaterials, which is also named CRLH TL, is the first proposed and studied transmission-line Metamaterials, and its concept and theory has been widely used in microwave devises and systems.Simplified composite right/left handed transmission line (SCRLH TL) is another transmission-line Metamaterials, which is obtained by tacking away the series capacitance or shunt inductance of the CRLH TL. SCRLH TL may be classified into two different categories:SCRLH-C TL is the CRLH TL without the series capacitance, and SCRLH-L TL is the CRLH TL without the shunt inductance. They both exhibit several advantages compared to the CRLH TL for obtaining the infinite-wave length propagation, non-linear phase shift and realizing the SNG medium:simple structure, easer analyzed, more compact, and so on.The thesis introduces the background and research development of the area; according to the effective-medium theory and Bloch-Floquent theory, the frequency responses of the equivalent medium parameters and propagation parameters of the SCRLH-C TL and SCRLH-L TL are investigated; based on the band-pass filtering effect, we design two ultra wideband (UWB) filters using the SCRLH-C TL and SCRLH-L TL, respectively. The feasibility of the novel theory used in UWB filter design is verified by results of circuit simulation, full-wave simulation and measurement; a 4-cell and a 1-cell zeroth-order resonator are fabricated based on the zeroth-order resonant of the open-ended SCRLH-C TL, and the well agreement among the results obtained from circuit simulation, full-wave simulation and measurement demonstrated the validity of designing a compact, high Q resonator using the SCRLH-C TL; the ENG medium and MNG medium are realized in certain frequency range using the SCRLH-C TL and SCRLH-L TL, respectively. Then, the electromagnetism parameters of the two SCRLH TLs are properly selected to make the ENG medium and MNG medium satisfied the conjugate matched condition, and the tunneling properties of the conjugate matched MNG-ENG pairs is verified; finally, we conclude the whole thesis and outline some future research topics.