Open-ended zeroth-order resonators using dielectric-based metamaterials

An open-ended zeroth-order resonator using a 1-D dielectric-based CRLH metamatelial structure is proposed, and its radiation characteristics are investigated. The structure is composed of a rectangular waveguide with windows, 1-D array of dielectric resonators, and open circuits at both terminals with a short-circuit λ/4 waveguide. The balanced CRLH structure is designed and fabricated to excite the zeroth-order resonance. The open-ended resonators with different number of unit cells are numerically simulated and measured, especially on the radiation characteristics. It is found that the radiation gain is larger than that for corresponding short-ended resonators and is enhanced by increasing the number of unit cells. In addition, the measured radiation patterns are in good agreement with the numerical results.