Design of a compact quasi-isotropic antenna for RF energy harvesting

Abstract

In this paper, a compact quasi-isotropic antenna with enhanced bandwidth for radio frequency (RF) energy harvesting applications is presented. The quasi-isotropic pattern is achieved using split ring resonators (SRRs) and the folded dipole structure. Two folded split ring resonators (FSRRs) are implemented orthogonally to reduce the mutual coupling, and each resonance is placed closely to widen the bandwidth. The measured bandwidth is 5% with ka = 0.47. The measured gain deviations (Δ) are 4.6 dB and 4.0 dB at 863 MHz and 888 MHz, respectively.