Modelli circuitali per l'analisi e l'ottimizzazione della radiazione al broadside da onde leaky in strutture uniformi e periodiche

In this paper a study on one- and two-dimensional leaky-wave antennas is presented, in order to characterize their radiation features and the relevant dispersion properties when a beam pointing at broadside is radiated. This study is aimed at the analysis and optimization of periodic screens allowing for enhanced transmission through subwavelength apertures. Uniform and periodic planar structures are considered, by means of simple transverse and longitudinal network representations, respectively. In both cases, the analysis reveals that a fundamental condition is the equality between the leaky-wave phase and attenuation constants: this determines the splitting of a single radiated beam pointing at broadside into separate beams, and the maximization of power density radiated at broadside. The antenna bandwidth is studied and design formulas are provided for both lossless and lossy structures.