Radiation Properties of a 2-D Periodic Leaky-Wave Antenna

Abstract

A study of the radiation characteristics of a 2-D periodic leaky-wave antenna (LWA) [i.e., one that radiates from higher order space harmonics (Floquet waves) instead of the fundamental one] is presented here for the first time, and an optimization to produce maximum radiation at broadside is discussed. The structure consists of a 2-D periodic arrangement of narrow rectangular patches on a grounded dielectric substrate, excited by a simple source such as a slot in the ground plane. A 2-D periodic LWA can be designed to radiate a narrow pencil beam pattern at broadside by adjusting its geometric parameters. The main beam at broadside is narrower in the E-plane than in the H-plane, and there are also grating lobes introduced due to the periodicity. The structure has been analyzed theoretically using the periodic spectral-domain immittance (periodic SDI) method. The proposed antenna has also been simulated using both FEM and method of moments methods and a fabricated design has been measured. A good correlation is observed between the theoretical, simulated, and measured radiation patterns.