An Active Metamaterial Antenna with Tunable Zero-order Resonances

Electromagnetic metamaterials are based on artificial design, such as composite left-right-handed structure (CRLH), split ring resonator (SRR) and Mushroom, and the periodical configurations can be taken advantages of to realize tunable properties via integrating active components such as varactor diodes into metamaterial units. In this paper, an active metamaterial antenna with tunable zero-order resonance(ZOR) is proposed with utilizing Mushroom structure to realize the narrow band. Particularly, varactor diodes are utilized in each unit cell, thus, by supplying different voltages, the capacitance of varactor diodes is changed, resulting in tunable ZORs. The measured results of the antenna are consistent with the simulated results. The proposed antenna can be used in 5G narrowband Internet of Things in the near future due to its good narrowband characteristics in Sub-6GHz band.