A quadrifilar fraction-turn cone type helix antennas with reflector and cross dipole

A quadrifilar fraction-turn cylinder type helix antenna consists of two pairs of antenna elements placed at right angles, to which two signals having the same amplitude and phase difference of 90° are fed, respectively. In this analysis, the design frequency was set to 1575 MHz, which is the center frequency of the higher frequency band used in GPS (Global Positioning System). The length of helix antenna element was 1/2 of the wavelength of the design frequency. A quadrifilar fraction-turn cylinder type helix antenna was constructed by placing at right angles four antenna elements that are bent by 90° along the surface of a circular truncated cone, to which parasitic elements such as infinite reflector, half-wave cross dipoles, quarter-wave radial monopoles were placed. The variation of its characteristics due to the change of these constituent elements was analyzed by means of the moment method or modern analysis methods, and its application to GPS antennas attempted