Analysis and Design of a Leaky-Wave Bull's-Eye Antenna with a Backward Endfire Property

A planar periodic leaky-wave antenna based on a “bull's-eye” structure on a grounded dielectric slab, for use in generating backward endfire radiation, is proposed and investigated. The TM₀ parallel-plate mode, launched by a vertical coaxial probe in the center, is perturbed into a leaky mode that radiates from the n = -1 space harmonic at backward endfire. The fact that the leaky mode radiates at backward endfire allows for forward endfire radiation from the antenna with a smaller periodicity, and hence a more homogenous structure. The results are verified by simulation and measurement.