The requirement for a broadband elliptically-polarized antenna which can be flush-mounted on high speed aircraft is common in the aerospace industry. This antenna inherently fulfills the broadband, elliptical polarization requirements. It is also mechanically simple, can be flush-mounted and is relatively small compared to other antennas that could provide similar operation at a given frequency.
The cavity mounted axial-mode wire helix provides good polarization purity and constant on-axis-gain over the operating band, as shown in the following 3D circular polarized gain pattern image at three different frequencies in the operating band.Typical circularly polarized gain patterns at the minimum, center and maximum frequencies. Typical reflection coefficient versus frequency.