Broadband Folded Printed Quadrifilar Helical Antenna

The printed quadrifilar helical antenna (PQHA) represents a very attractive candidate for many applications such as mobile satellite communications, broadcasting satellite systems or global positioning systems, due to hemispherical radiation, circular polarization, good axial ratio, and low cost. Nevertheless, the bandwidth of a conventional PQHA could be insufficient for such applications. Therefore, in this paper, a technique for increasing the bandwidth of a PQHA by adding a shorted parasitic helix is presented. The new folded printed quadrifilar helical antenna (FPQHA) is designed to achieve 30% of bandwidth in axial-mode. Moreover, due to the printed arms on one substrate face, the FPQHA manufacturing is very simple. Measured results are presented to validate the concept