Miniature Folded Printed Quadrifilar Helical Antenna With Integrated Compact Feeding Network

A miniature folded printed quadrifllar helical antenna (FPQHA) using a novel compact feeding network is proposed. Folding and meandering techniques are used to obtain 66% of size reduction for the axial length of the printed quadrifllar helical antenna. A compact feeding network using an out-of-phase power divider based on double-sided parallel-strip lines and a Wilkinson power divider is designed. A fabricated prototype of the FPQHA employing the compact feeding network is presented. The measured positive gain bandwidth is from 380MHz to 425MHz with a re∞ection coe-cient less than i20dB and an axial ratio below 2dB. The measured maximum gain is 3.08dBic at 395MHz with a half-power beamwidth of 150 - . With good radiation performance and integrated feeding network, the proposed antenna can become a better candidate in satellite and mobile communications.