A metamaterial antenna with frequency-scanning omnidirectional radiation patterns

摘要

A metamaterial antenna exhibiting simultaneously omnidirectional radiation and leaky-wave characteristics is proposed based on a two-dimensional transmission line (TL) made of complementary split ring resonators and capacitive gaps. The backward-wave propagation is demonstrated based on the dispersion characteristics provided by the generic TL theory and full-wave eigenmode analysis. Numerical and experimental results indicate that the frequency-scanning leaky-wave radiation is realized in E-plane, whereas omnidirectional radiation (parallel to H-plane) with considerable antenna gain directs from backward to broadside. The unique dispersion diagram and equivalent long monopole give rise to these abnormal physical phenomena.