Influence of number of split rings on the leaky radiation of a metamaterial transmission line based on complementary split ring resonators

Abstract

This article discusses the influence of the number of concentric split rings on the radiation performances of a leaky wave antenna (LWA) created by a microstrip transmission line periodically loaded by series gaps and complementary split ring resonators (CSRRs) in its ground plane.The addition of a second concentric split ring in the CSRR structure strongly modifies the distribution of electric and magnetic currents in each cell of the periodic LWA structure. As a consequence, the far-field radiation pattern of the cell shows a zero in the broadside direction, which is responsible for an apparent split of the LWA radiation pattern at the upper frequency of the backward scanning range, predicted by full-wave simulations and validated by measurements in anechoic chamber.