Research On GPS Antennas With Circular Polarization And Miniaturization

With the rapid development of the Global Position System in the world, particularly in the mobile phone business, higher and higher performance has been put forward, not only circular polarization, but also their appearance and system integration requirements, especially in the research on miniaturization. In addition, low cost is the key whether it can be applied widely. In this thesis, some new designs and researches have been done towards these demands in the basis of original design. The detailed processes of designs and experimental results are presented. The thesis mainly consists of following parts.Firstly, a survey of the previous progress in GPS antenna (helix antenna and microstrip antenna), circular polarization and miniaturization apply in these antennas. Secondly, a helix antenna working in RNSS B3 band is proposed, and its feed network is researched and designed.Thirdly, a novel tri-filar helix antenna working in 1.575GHz band has been designed and researched, it can reduce GPS antenna's size with low cost, whose band is 60MHz, and we have discussed the effect on ground. The experimental results are found to be in good agreement with the simulated results.Lastly, the characters of microstrip antenna have been researched. We use the microstrip antenna with slots in order to achieve antenna's miniaturization. Dual-band GPS antenna has been designed. By using a cross slot on the patch, a dual-band can be achieved. The optimal feed position for dual-frequency operation is chosen, which can excite TM₀₁ mode and TM₁₀ mode. At the same time, another dual-band GPS antenna is proposed, which is based on Koch fractal antenna. After simulated, we found it can achieve characters such as dual-band , circular polarization and miniaturization in 1.575GHz band.