Design of the top-loaded quadrifilar helix antenna for low profile applications

A low profile quadrifilar helix antenna based on top-loaded technology for global navigation satellite system is presented in this paper. The top-loaded technology can both be used to reduce the profile of the wire form quadrifilar helix antenna and the printed form. An S-band top-loaded quadrifilar helix antenna has been simulated and possesses the characteristic of wide beam width, high gain at the low elevation, good circular polarization performance and the low profile. This low profile antenna can be an attractive candidate for handset applications.