Planar Self-Balanced Magnetic Dipole Antenna With Wide Beamwidth Characteristic

Abstract

A design approach to a novel planar self-balanced magnetic dipole antenna with wide beamwidth is proposed. By incorporating a parasitic rectangular strip to a circular sector magnetic dipole at its angular bisector on the bottom layer, a virtual magnetic wall boundary condition is partly introduced within the horizontal plane. In this way, the unbalanced current can be utilized to generate unidirectional radiation behavior, leading to the formulation of a self-balanced antenna with widened beamwidth. As numerically demonstrated and experimentally validated at the 2.45 GHz band, the half-power beamwidth (HPBW) of a planar, air-substrate magnetic dipole antenna can be effectively broadened up to 100° without increasing antenna profile, inquiring symmetrically rotational configurations, utilizing multilayered substrates or periodic loadings. The proposed approach not only provides a clear physical insight but also works out a set of closed-form formulas. As exhibited, the planar wide beamwidth antennas have a simple configuration and wide impedance bandwidth up to 20%.