a small printed quadrifilar helical antenna for bgan/gps applications

This paper presents an element of a 2×2element array antenna for inmarsat bgan/gps applications. the element is an axial mode printed quadrifilar helical antenna that has been integrated with a compact feed network to provide sequential phase rotation for circular polarization (cp) radiation. the novel integrated lumpedelement feed network is designed to provide a balanced rf power to the four helix arms with a 90° sequential phase difference between them. the design maintains a low cross polarization, and accordingly, a high quality of rhcp up to ±66° over the transmit frequency band of 1616 mhz to 1626 mhz. the gain in this frequency range is higher than 3.5 db with a return loss 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 good candidate in satellite l1band and bgan satellite communications.