A low weight S-band quadrifilar helical antenna for satellite communication

In this paper, a new design of an S-band, self-phased, one-turn quadrifilar helical antenna (QHA) has been presented. The antenna has been analyzed in purposed of desired radiation pattern by numerical method. A new matching technique has been used to improve VSWR of the QHA. The experimental results show the radiation pattern has Nadir null of about 6 dB and Axial Ratio is better than 1 dB. In addition, VSWR is less than 2 in frequency bandwidth of 120 MHz. The antenna has low weight, size and cost which is suitable for satellite communication systems.