Wide-band Wide-beam Circular Polarization Cone-plane Composite Helical Millimeter-wave Antenna

In millimeter wave band, the width of the antenna arm of the planar helical antenna is difficult to be sufficiently small because of the processing accuracy. It results in a decrease in the circular polarization performance of the antenna at high frequencies. In this paper, the 3D structure of a conical and planar composite spiral is used. This configuration does not require changing the width of the antenna arm. At the same time, the spiral density of the antenna arm is increased. This makes the Axial Ratio of circular polarization better at high-frequency. Also it can reduce the difficulty in processing the antenna arm.