Quadrifilar helix antenna for GPS applications

In GPS applications, the antenna requires omnidirectional pattern over entire upper hemisphere where the satellites may be visible. The fractional QHA (FQHA) is a compact size antenna that is suitable in mobile handset for Global Positioning System (GPS) applications. In this paper, we present a FQHA design with square cross section. The effect of dielectric core on travelling-wave QHA is presented. And resonant QHA with square dielectric core is also given.