A miniature dielectrically loaded spiral folded printed quadrifilar helix antenna for GPS dual-band Applications

Owing to its good circular-polarization (CP) radiation characteristics, the printed quadrifilar helical antenna (PQHA) has been shown to be a very promising candidate for broadcasting satellite. It has also many attractive features such as light weight, hemispherical coverage and no requirement of ground plane with reasonable front to back (F/B) ratio. The antenna can be used on satellite platform as well as on hand held devices which require communicating or receiving data from satellite. For this purpose, several related designs of the PQHA with a reduced antenna height providing dual band behaviour have been developed and reported, using meander line technique to obtain square spirals helix arms giving 43% of size reduction of a 3λ/4 conventional PQHA arm length or using coaxially mounted two dielectrically loaded PQHA to obtain 49% of size reduction of a λ/4 conventional PQHA arm length.