Compact Omnidirectional Antenna Using SRR for WIFI Application

A compact horizontally polarized omnidirectional WIFI antenna based on split-ring resonators (SRRs) for base station application is proposed. A novel SRR structure is built with (metal-insulator-metal) MIM capacitor and metallic screws. It is analyzed and justified by the equivalent circuit model. Four rotating SRRs are excited in phase by a simple quartile power divider, and an electric loop is generated, leading to the realization of a vertical magnetic dipole. This antenna based on SRR exhibit not only miniaturization flexibility, but also an easy matching. It shows a compact size of 0.29λ
₀
° 0.29 λ
₀
° 0.04 λ
₀
. The measured -10 dB bandwidth, gain and radiation efficiency are 2.40-2.48 GHz (3.3 %), 1.56 dBi and 92 %, respectively.