Performance of a Metamaterial-based 1×2 Microstrip Patch Antenna Array for Wireless Communications Examined by Characteristic Mode Analysis

Abstract

The theory of characteristic modes (TCM) is used to examine the behavior of hexagonal split ring resonator (HSRR) unit cells employed in the ground plane of a 2-element microstrip antenna array. Suppression of higher harmonics and reduction in mutual coupling between the elements as a result of metamaterial loading was investigated using TCM. The novelty of this paper is the use the TCM to investigate the behavior of the HSRR, to reduce this mutual coupling, to significantly enhance the antenna’s performance. The TCM is employed to precisely determine where the HSRR unit cells should be allocated to efficiently block the coupling modes and not to affect the non-coupling modes. The simulation results showed that gains of 5.36 dB and 8.2 dB as well as bandwidths of 628 MHz and 610 MHz are achieved for the single and 2-element array antennas, respectively. The bandwidth of the array antenna was enlarged to 906 MHz by loading the ground plane with five HSRR cells. Prototypes for the proposed antennas were fabricated and the experimental outcomes showed good agreement between the measurements and simulation results. The gain and radiation efficiencies were measured using the SATIMO Starlab anechoic chamber.