A Compact Wideband Dipole Antenna With Wide Beamwidth

Abstract

A wideband dipole antenna with wide beamwidth fed by a coaxial balun is presented. The proposed antenna contains a parasitic patch, a U-shaped reflector, and a pair of L-shaped metal arms. The parasitic patch located above the L-shaped metal arms (as an electric dipole) functions as a director. The combination of the U-shaped reflector and the pair of L-shaped metal arms acts as a magnetic dipole. The wideband impedance bandwidth and wide beamwidth are achieved by using the magnetoelectric dipole. The characteristic mode method is used to facilitate the analysis of the antenna. The measured results show that an impedance bandwidth of 0.78-3.05 GHz (118.5%) for VSWR ≤ 2 is obtained. The beamwidth is between 110° and 179° in the band of 0.78-3.05 GHz (118.5%) in the H-plane, and between 83° and 146° in the band of 0.78-2.47 GHz (104%) in the E-plane. The overall size of the antenna is 0.177λ _L × 0.239λ _L × 0.104λ _L (λ _L is the free-space wavelength at the starting frequency).