A Cross-Shaped 2-D Periodic Leaky-Wave Antenna

Abstract

A 2-D periodic leaky-wave antenna (LWA) is a planar structure that radiates from high-order space harmonics (Floquet waves) of a leaky mode that propagates radially outward on a structure. The structure chosen here consists of a 2-D periodic cross-shaped distribution of metal patches on top of a grounded dielectric substrate and is designed to produce a highly directive elliptical beam at broadside. The beam at broadside is produced by two high-order space harmonics of a leaky TM0 surface-wave mode that propagates radially outward from a dipole source. It is shown here that the structure can be truncated to the shape of a cross, maintaining similar radiation characteristics as the full structure, while reducing undesirable grating beams. The results from theoretical analysis, full-wave simulations, and measurements for a fabricated 2-D periodic cross LWA are presented here and are found to be in good agreement.