Miniaturized guided wave structures and applications

This thesis examines the properties of novel transmission lines and waveguides as well as their practical applications. The research begins with a discussion of metamaterial transmission lines. Two new composite right/left-handed designs formed in shielded striplines are presented and shown to have great left-handed bands.

In the waveguides research, we demonstrate the multilayer, narrowband and half-mode folded waveguide with the benefit of guide miniaturization. Due to the almost half metallic surface reduction of half-mode waveguide, a novel planar half-mode substrate integrated waveguide is presented and its properties are analyzed. It has the great integration with planar components and stops the radiation of conventional open waveguides. One application based on this medium is a novel switchable substrate waveguide that can be switched between two types of mode via the biasing of pin diodes. Another application is a tunable phase shifter that has a maximum phase shift of 50 degrees with acceptable insertion loss.

A theoretical method for the analysis of planar half-mode waveguides using transverse resonance technique is introduced in this thesis. This method is used to locate the cut-off frequency of the waveguide and analyse the equivalent circuit loaded with discrete components. This novel technique has the advantage of simplicity and compares well with results of electromagnetic simulation and measurement.