Influence of parasitic elements on characteristics and design of ESPAR antenna

In this paper the influence of parasitic elements on characteristics and design of the electronically steerable passive array radiator (ESPAR) antenna is analyzed and discussed. Simulated results of three types of simplified ESPAR antennas are compared. Through the comparison, it is found that if the parasitic element is open to the ground, it has no effect to the radiation characteristics of ESPAR antenna. So the existence of the parasitic elements, which are open to the ground, can be neglected. Only parasitic elements shorted to the ground need to be considered in the design of the ESPAR antenna.