Bandwidth Enhancement of 2-D Leaky-Wave Antennas With Double-Layer Periodic Surfaces

Broadband high-gain 2-D Fabry-Perot (FP) leaky-wave antennas (LWAs) consisting of two periodic metallodielectric arrays over a ground plane are presented. Full-wave method of moments (MoM) is employed for the estimation of the near fields upon plane wave illumination and the extraction of the far field directivity and radiation patterns of the LWA. This yields a fast and rigorous tool for the characterization of this type of antennas. Qualitative design guidelines to tailor the antenna directivity bandwidth are provided for the first time based on a detailed analysis of the excited modes. Numerical examples are given to demonstrate the technique and prove the improvement in the antenna bandwidth. The proposed antenna exhibits a six-fold bandwidth improvement compared with the single array LWA with the same directivity. Simulated and experimental results from a finite size antenna prototype are presented.