Resonance-cone propagation in continuous transmission-line grids and microwave applications.

摘要

This thesis presents a novel approach to synthesizing a hyperbolically dispersive metamaterial by forming a continuous (unloaded) periodic transmission-line grid with rectangular unit-cells over a ground plane. The dispersion properties of the hyperbolic grids are examined by performing periodic analysis. The hyperbolic dispersive effects occur in second and higher order harmonic bands because the periodicity of the grids is on the order of half-wavelength. Frequency-dependent phenomena associated with the hyperbolic dispersion such as resonance-cone formation and their negative refraction and focusing, are demonstrated by plane-wave and circuit simulations, and are experimentally verified in microstrip-based grids. It is shown that by exploiting the unique dispersion characteristics of the grids, spatial-filtering electromagnetic devices such as passive spectrum analyzers, multiplexers and demultiplexers can be designed. Representative microwave devices including a 3 GHz/6 GHz harmonic splitter and a 5.8/6.2 GHz diplexer are designed and practically implemented. Since these grids are synthesized by simply printing transmission lines, they are easy to fabricate at a low cost and are potentially scalable to millimeter and Tera-hertz frequencies.