A Small Printed Quadrifilar Helical Antenna for BGAN/GPS Applications

This paper presents an element of a 2×2-element array antenna for Inmarsat BGAN/GPS applications. The antenna is composed of a quadrifilar helical element, and an integrated feed network with sequential phase rotation being employed to enhance the CP characteristics. A novel integrated lumped-element feed network is designed to provide an equal amplitude of RF signal power to the four helix arms and 90° sequential phase difference between them. The design maintains a high quality of RHCP up to ±66°, over frequency range of 1616 MHz to 1626 MHz. The gain in this frequency range is higher than 3.5 dB with a reflection coefficient better than -11 dB and a perfect circular polarization performance (axial ratio ~0 dB). The proposed antenna has small size, light weight, low cost, almost hemispherical radiation pattern and excellent circular polarization that can become a better candidate in satellite L1-band and BGAN communications.