A tri-band monopole antenna loaded with circular electric–inductive–capacitive metamaterial resonator for wireless application

Abstract

The triband circular electric–inductive–capacitive (ELC)-based monopole antenna for wireless application is proposed. The proposed structure has a closed ring resonator and an ELC metamaterial resonator, which are connected by a small metal stub. ELC, with its unique negative permeability property, modifies the current direction and creates a new resonance that results in multiband characteristics for the proposed antenna. The fabrication of the proposed antenna is done on an FR4 substrate having the dimension 32 × 36 × 1.6 mm3. The measured results show multiband characteristics at 2.23 GHz, 2.56 GHz, and 4.29 GHz with return loss equal to − 34.21 dB, − 25.83 dB, and − 35.89 dB, respectively. The simulated resonant frequency of the proposed circular ELC is validated with quasi-static analysis, and it could be observed that the simulated and quasi-static analysis results comply with each other. Also, the negative permeability and new resonance of the proposed circular ELC metamaterial resonator are verified using the parameter extraction method. The measured and simulated radiation pattern also displays an excellent uniformity between them. The small size, ease in design, minimal return loss, multiband characteristics, and a considerable gain are the significant features of the proposed work.