Enlarged half-wavelength resonator antenna with enhanced gain

A concept of gain enhancement by radiation aperture enlargement has been presented. The nonlinear dispersion relation of a CRLH TL has been used to enlarge the antenna length keeping the resonance frequency nearly constant. It has been shown that the gain is strongly dependent on the size of the radiation aperture. This fact supports the idea that the x-component of the electric field in the interdigital capacitors of the unit cells is the main contribution to the radiation aperture and is also in agreement with the far-field polarization. A maximum gain of 10.7 has been reached for the largest antenna with 18 unit cells.