| Global Navigation Satellite System (GNSS) is widely uesed in various fields of society. Compare with the traditional single GNSS system, more advantages are owned by multi-frequncy Navigation Satellite System,such as:wider coverage,higher accuration and more stability. All of the merits make multi-frequncy cooperation will be the trend for satellite navigation system in future.As an crucial part of the satellite navigation system,antenna play a key role in performance of the navigation terminal. Therefore, multi-band satellite navigation antenna research have important significance.In the dissertation, an overview of development and direction of quadrifilar helix antenna is given. Current developed and developing satellite navigation systems are introduced. Furthermore the antenna specification of multi constellation satellite navigation is concluded. Structure and operating principle of quadrifilar helix antenna are analyzed. At last, a dual band quadrifilar helix antenna is proposed, which is air loaded. It can be equipped in the boat and vehicle.Research results of the paper are given as follows:Firstly, solution of miniaturization to quadrifilar helix antenna is studied, and the techniques of Multi-and broad-band working and its feeding method are deeply discussed. General requirements for antenna of receiver which is used in multi constellation satellite navigation is summarized. On the basis of those, a novel quadrifilar helix antenna structure is proposed in the paper. It can work in dual frequency band. Simultaneously a broadband feeding network in microstrip is designed.Its size is 25mmx140mm. The dielectric of the quadrifilar helix antenna is 0.5mm thick Polytetrafluoroethene(PTFE). The antenna is printed on the dielectric. The antenna can be compatible of receiving signal of GPS, GALILEO and BD2, because it can work in dual frequency band. The feeding network is located beneath the antenna. It is composed of Wilkinson power divider, Schiffman phase shifter, gap coupled phase shift power divider. It is realized in microstrip. The radius of plate of feeding network is 60mm, placed under the antenna. This kind of architecture is compact and easily fabricated.Simulated and measured results shows that the impedance bandwidth(VSWR<2) is reaching more than 57%. In the entire working band, its gain is higher than-5dB. It can satisfy the requirements of multi band satellite navigation system. |
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