Research Onthe Left-Handed Waveguide

Left-handed medium (LHM) is defined as an artificial electromagnetic composite medium with simultaneously macroscopic negative permittivity and negative permeability. LHMs behave some unusual properties not readily available in nature: reversal of Snell's low, backward propogation, reversal of Doppler effect and so on, which indicates various potential applications in both microwave and optical engineering fields. However, traditional LHM structures exhibit high loss and narrow bandwidth, which lead to little practical interest of engineering applications. This dissertation is based on the classical LHM theory, the characteristic of a novel left-handed wave guiding structure is studied, and the relational structures are designed and optimized. The backward and forward transmission properties are verifed by both eigenmode and time-domain simulation. The results indicate a great potential application of this novel waveguide.Firstly, the classical LHM theories are presented, focusing on the traditional LHM constructing methods. Then the left-handed transmission conditions in waveguide structures are studied. The phenomena are verified by a perfect effective constitutive parameters method. Secondly, the dispersion characteristics of resonant-slot coupled cavity chain (RSCCC) unit cell are studied by the eigenmode method indicating the composite right/left handed properties. Furthermore, a type of square waveguide based on RSCCC is designed utilizing a novel feeding structure. The time-domain simulation results are also presented. Both forward and backward wave are proved to be able to propagate in the RSCCC waveguide. And a balanced transmission is achieved. Finally, a leaky wave slotted array antenna with continuous beam-scanning ability is proposed in this dissertation, with forward scanning range connected with backward scanning rangeThe analysis method and design technology of the novel left-handed waveguide are developed in this dissertation, which supplies important reference for the following related studies focusing on the engineering applications of left-handed materials.