| With the development of mobile communication technology, especially thewireless communication technology, a variety of terminal devices appear in the world.As an important component of mobile terminal devices, the antenna directlydetermines the performance of the communication link system.Currently, the satellite navigation continues to expand in civilian areas,especially with rapid development of the mobile Internet and the particularity of thesmart phones, which has laid a solid foundation for the satellite positioning services.Because circularly polarized antenna has the advantages of high reception, stronganti-jamming performance and anti-multipath reflections, so recent research onsatellite navigation terminal antennas have mainly focused on terminal antenna withmulti-band, circular polarization and wide frequency band. Fractal antenna isproduced by iteration, it is easier to realize the antenna’s operation in a multi-banddue to its self-similarity. And it’s possible to reduce the antenna size due to itsspace-filling. Applying the fractal antenna characteristics to the design of microstripantenna will greatly improve the performance of the antenna. Therefore, the researchand application of fractal antennas has a very promising prospect inevitably.Here are the main ideas of the paper:Firstly, the basic theory and analysis methods of the microstrip antenna will belisted, and then the circularly polarized implementation and feeding methods of themicrostrip antenna will be discussed. Next, the requirements of circularly polarizedantenna such as mobile terminals which are used in satellite navigation systems willbe described.Secondly, according to the requirement of the satellite navigation antenna, adouble frequency, broadband, circularly polarized, slot antenna which is used insatellite navigation will be designed. It works on the B1/S frequency band of CompassNavigation Satellite System. With the simulation of the antenna by HFSS(electromagnetic simulation software), the measured result is similar to the simulationresult.Thirdly, application of Hilbert fractal antennas in the field of mobilecommunications will be analyzed. And then, for the structural design of a miniaturized Hilbert fractal multiband PIFA antenna, three kinds of optimizationschemes will be presented in order to improve its performance.Fourthly, applying the fractal technology to the design of microstrip antenna,terminal antenna working on the frequency band of GSM900, DCS1800and ISMWLAN2.5GHz will be designed. Circular polarization will be realized in the2.492GHz frequency band, and the receiving antenna of Compass can meet therequirement of simulation result with the application of HFSS(electromagneticsimulation software). |
