Metamaterial superstrate microstrip patch antenna for 5G wireless communication based on the theory of characteristic modes

Metamaterials (MTMs) have received considerable attention due to their novel electromagnetic properties. Their applications include enhancing gain and bandwidth in microstrip antennas. In this article, a dual band microstrip antenna design based on characteristic mode analysis (CMA) using MTM superstrate is proposed for 5G wireless communication. The CMA is used for the modelling, analysis and optimization of the proposed antenna to examine the underlying modal behaviour of the MTM unit cell and to guide mode excitation. The antenna structure consists of a microstrip feed line connected to a rectangular patch. Then triangular split ring resonator unit cell is inserted on the ground of a traditional patch antenna that resonates at 15 GHz to produce additional resonance at 10 GHz. A planar array of 2 x 3 triangle MTM unit cells is used as superstrate to improve the gain and bandwidth at both resonances simultaneously. The optimal distance between MTM superstrate and the antenna patch is determined using the Fabry-Perot cavity theory to maximize power directivity and efficiency of the proposed antenna. The CST microwave studio software is used to model and optimize the proposed antenna. A prototype of the designed antenna that was fabricated showed good agreement between measurement and simulation results.