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

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.