Decade Bandwidth Circularly Polarized Antenna Array

A circularly polarized antenna array design comprising of a feed network that splits an input signal into four orthogonal (0°, 90°, 180°, and 270°) phased signals with equal magnitudes and connected to four anti-podal Vivaldi antennas sequentially rotated by 90° is presented. The proposed antenna array yields 10-dB return loss and 3-dB axial ratio bandwidths from 1-10 GHz. The symmetrical structure gives the antenna array almost identical azimuth and elevation radiation patterns. Pulse reception from various angles show equi-amplitude outputs and very little distortion. The proposed design is suited for high-resolution microwave imaging systems.