Analysis and Design of Conical Printed Quadrifilar Helical Antenna

A novel conical printed quadrifilar helical antenna for GPS application is presented.The antenna behaves wide beamwidth and circular polarization.Numerical simulations show that the pitch angle and the length of radiating arms are main factors which influence the beamwidth of this kind of antenna.The model antenna designed working at center frequency of 1.57542GHz characterizes: 1) about 200 degrees of 3dB beamwidth which satisfies the requirement of the hemi-sphere radiation,2) about 0.35GHz of 3dB axial-ratio bandwidth,and 3) VSWR under 1.5∶1 covering 1.47~1.6GHz.The measured results agree well with numerical ones.