Design of Novel Wideband Circularly Polarized Antenna Based on Vivaldi Antenna Structure

This letter presents a novel compact wideband circularly polarized antenna by utilizing Vivaldi antenna structure as the design concept. The proposed antenna consists of four exponentially tapered patches, a circular metal wall and a feed network. Four tapered patches are sequentially rotated and vertically located in the circular metal wall which acts as a vertical ground plane. Slot-coupled feed technique is applied to feed the antenna. Feeding by a corporate feed network, wide impedance bandwidth and axial ratio bandwidth are achieved. Parametric studies are made to optimize the antenna. The experimental results show that the antenna exhibits a 3-dB AR bandwidth of 41.4% (3.45-5.25 GHz) and a 10-dB impedance bandwidth of 57.3% (3.06-5.52 GHz).