Frequency-Tunable Tri-Band Metamaterial-Inspired Antenna

A frequency-tunable tri-band metamaterial-inspired antenna is proposed. The antenna consists of patches, interdigital capacitors, and meander lines inductors, and loaded with a split ring resonator. The metamaterial-inspired antenna can provide three band operations at 1.575/2.1/2.6 GHz, which cover the GPS band1, LTE band1, and LTE band7 applications. The antenna has three different current flows, which create different resonances. The proposed antenna can adjust each resonant frequency independently by adjusting the antenna parameters, the length of SRR, meander lines, and ground branch line, which can affect each current path. The prototype antenna has been designed and fabricated using the FR4 substrate with a thickness of 1.6 mm and a dielectric constant of 4.3. The measured return loss and far-field radiation patterns of the fabricated antenna have good agreement with the simulated results. The fabricated antenna shows well-matched impedance characteristics with a reasonable bandwidth and has an omnidirectional radiation pattern at each operating band. The proposed antenna has the advantages of multi-band, frequency-tunable characteristics, and easy fabrication, and can be widely used in various wireless mobile communication systems.