Wideband Vertical Planar Printed Unidirectional Antenna

Abstract

Abstract-A new wideband vertical planar printed unidirectional antenna is presented. The proposed antenna is composed of a bowtie electric dipole, a loop antenna and a microstrip-to-coplanar stripline balun. All of them are printed in the same plane perpendicular to the ground. The antenna has a wide impedance bandwidth of 88.9% for SWR ≤ 2 from 3.3 to 8.58 GHz and a stable gain of 7.3 ± 1.5 dBi over the operating frequencies. Moreover, stable unidirectional radiation pattern with low back-lobe radiation, low cross polarization and nearly identical E-and H-plane patterns is also demonstrated over the frequency of interest. A prototype is fabricated and measured. The measured results indicate that the antenna is suitable for wideband wireless communication system.