Miniaturization of Magnetoelectric Dipole Antenna by Using Metamaterial Loading

This communication presents a novel miniaturized magnetoelectric dipole antenna by introducing magnetic metamaterial loading. The proposed antenna, excited by a Γ-shaped probe, consists of a planar electric dipole and a quarter-wave shorted patch antenna. To miniaturize the antenna, the metamaterial loading is fully arranged inside the shorted patch antenna and the matching portion of the Γ-shaped probe. The loading is formed by a stack of modified rectangular split-ring resonators, which are placed very closely in parallel. With the presence of the metamaterials, the effective permeability of the substrate is increased, and therefore the antenna finds a significant size reduction. Most importantly, the impedance and radiation characteristics of the antenna are not compromised too much. The antenna loaded with metamaterials exhibits an impedance bandwidth of 44% ranging from 1.7 to 2.67 GHz and a boresight gain of about 8.5 dBi. The volume size is reduced by 48% when compared with the original design having an impedance bandwidth of 47%.