| In recent years, the concept of a medium with both negative permittivity and negative permeability, referred to as a left-handed medium (LHM); has attracted the attention of Physics and Engineering communities. Such a material has many extraordinary properties that are not generally found in nature. In this thesis, we study some of the unusual properties of LHMs, explore new methods to realize left-handed composites, and identify some of the device applications of left-handed structures at microwave and optical frequencies.; We study the physics of multi-layer left-handed slab waveguides (LHSW), and examine the behaviour of the evanescent fields in a multi-layer left-handed configuration. The transmission line matrix (TLM) method is used to verify the unusual properties of the LHSWs, including the existence of the plasmon modes and the dual wavenumber modes (DWMs). Possible device applications of a more practical anisotropic mu-negative SW are investigated by employing both analytical and finite-difference time-domain (FDTD) methods. In the second part of this thesis, new left-handed transmission line (LHTL) structures are introduced. A miniature resonator with a left-handed transmission line (LHTL) section, whose resonant frequency is independent of its physical length, is proposed. A three-pole filter that employs the proposed resonator is designed, fabricated, and tested. The miniature size of the proposed resonator suggests that the structure has an undesirable low quality factor, and therefore, superconductive materials are good candidates for the realization of the proposed left-handed resonator. Consequently, the properties of superconductive left-handed transmission lines (SLHTLs) are examined. The effect of the kinetic inductance of the superconductive materials on the performance of the SLHTL is investigated. Furthermore, the structure of the SLHTL is modified by incorporating arrays of Josephson junctions (JJs) to realize a tunable SLHTL. The harmonic generation of the proposed Josephson left-handed transmission line (JLHTL) is also explored.; In the last part of this dissertation, a new realization of LHTLs by using a coaxial waveguide configuration is proposed. The new structure employs a coaxial waveguide structure to host periodic arrays of split-ring resonators (SRRs) and capacitively loaded strips (CLSs). They are radially mounted on the inner conductor of the coaxial waveguide structure, which provides the necessary polarization for the periodic arrays of SRRs and CLSs to exhibit negative index of refraction over a specific frequency band. The proposed coaxial waveguide left-handed transmission line (CW-LHTL) can model LHM in free space, eliminating the need to fabricate a large number of unit cells to measure the properties of LHM. Lastly, the filtering properties of the CW-LHTL are investigated to develop various filtering functions; including band-pass, band-stop and low-pass filtering functions. |
