A shorted cross bowtie patch antenna with a cross dipole for circular polarization

Abstract

A novel circular-polarized antenna composed of bowtie patches, cross dipole and a power combiner is presented. Two air microstrip lines are utilized to feed the bowtie patches orthogonally. A 90-degree phase shift Wilkinson power divider is placed underneath the ground and connected to the feeds to generate circular polarization. The antenna attains an impedance bandwidth of 40.2% for return loss better than -15 dB and 3-dB axial ratio bandwidth of 29% (from 1.62 to 2.17 GHz). Very Stable and symmetric radiation patterns with low cross polarization level have been obtained over the operating frequency range. The 3-dB axial ratio beamwidth is about 90deg and the gain of the antenna is about 6.3 dBi with small variation.