Low Cost, Electrically small, Quasi-Isotropic Antenna Based on Split Ring Resonator

An electrically small, quasi-isotropic antenna is proposed and fabricated. The quasi-isotropic electrically small antenna (ESA) is composed of two driven striplines and a split ring resonator (SSR) with two extended strips printed on the same side of the substrate. The SRR could generate both equivalent electric and magnetic dipoles with almost the same amplitude of the realized gains. The radiation patterns between the equivalent electric and magnetic dipoles are orthogonal to each other. The measurement results agrees well with the simulation values, which revealed that the ESA antenna has a quasi-isotropic radiation pattern possessing the maximum gain difference around 3 dB covering the whole space, an electrically small size ( $ka=0.68$ ), and an overall efficiency 77%.