Broadband printed quadrifilar helix antenna using parasitic strip technique

A circularly polarized (CP) printed quadrifilar helix antenna (QHA) with enhanced bandwidth is proposed in this communication. This QHA is fed by a feeding structure with superior performance, which uses wide-band 90 degrees and 180 degrees planar bulun. The feeding network can simply realize the 90 degrees phase shift and four equal power divisions within a wide band range. Enhanced impedance matching and CP radiation characteristics can be achieved with the parasitic strips between helix arms. The study of proposed antenna performance with different geometric parameters has been conducted. The final antenna exhibits a good impedance bandwidth (IBW) of approximately 37.4% (1.65-2.41 GHz), and the 3-dB axial-ratio bandwidth (ARBW) is over 43.9% (1.6-2.5 GHz). Broad pattern coverage, pure CP radiation at all designed bands and a wide 3 dB axial-ratio beam width of 150 degrees makes this antenna an excellent candidate for satellite communications and navigation systems.