Research On Design Technology And Application Of Multi-band Antenna Based On GNSS System

With the development of GNSS (Global Navigation Satellite System) and mobileInternet technology, the applications based on location services are constantly emerging,promoting the combination of global satellite navigation system and terrestrial mobilecommunication system. Antenna, as an important part of compatible systems, plays a key roleon the performance of compatible system. As the antenna used in GNSS system is circularlypolarized and that used in terrestrial mobile communication system is linearly polarized, howto combine these two polarizations in one antenna and ensure the isolation between the twoports is the focal point in the design of multiple systems antenna. This dissertation focus onthe design of multi-band antenna based on GNSS system, and the major contents and creativepoints are as follows.Firstly, the concept of the polarization is described and existing design methods ofcircularly polarized microstrip antennas and the multi-band dual polarized microstrip antennas,are systematically summarized in this dissertation.Secondly, a dual-band dual polarized antenna based on the single point feedingtechnology is proposed. It is simulated and optimized on Ansoft HFSS software. An antennaprototype is made and measured. The measured result shows that the antenna can performwell on both GPS and TD-SCDMA frequencies.Finally, a multi-band dual polarized antenna based on the multiple points feedingtechnology is proposed. The antenna structure simulation and parameter tunings analysis aremade. The simulation results show that the antenna has the10-dB impedance bandwidth of42.5%and the3-dB axial ratio bandwidth of18.2%in the circularly polarized band, also ithas the10-dB impedance bandwidth of3%in the linearly polarized band. In the wholefrequency range, form1.1GHz to2.2GHz, the isolation between two ports is larger than17dB.