On The Antennas Design For Beidou Navigation Satellite System

The research works with scientific projects in this thesis. The engineering samplesof the terminal antennas for Beidou navigation satellite system are made.Firstly, the design methods of the terminal antennas for Beidou navigation satellitesystem are discussed . The design of a dual-frequency equal Wilkinson power divider ispresented. This power divider fulfill an equal power split and all the other features of aconventional Wilkinosn power divider simultaneously at two arbitrary frequencies. Thestructure of these power dividers and the formulas used to determine te designparameters have been given. The simulated results are presented to validate theproposed idea. Good experimental performances of the proposed power divider areobtained.Secondly, The approach to the coupling of many microstrip lines to achieve boostup the coupling of the filter. The microwave band-pass filter fulfill all other features of aFilter simultaneously at arbitrary frequencies.The design method of a common-aperture dual-band circularly- polarizedmicrostrip antenna is presented based on the theories of microstrip antenna. Themeasured results show that the antennas are of dual-band circular polarization and highisolation for more than 30dB, and that the design method is valid.At last, The design method of a tri-band antenna including the terminal antennasfor Beidou navigation satellite system and a receiving antenna for GPS is presented. Themicrostrip patch and the feeding networks of the dual-frequency power divider andmicrowave band-pass filter are printed on the same dielectric plate for compactness.The measured results of a sample tri-band antenna show that the antenna is of goodcircular polarization in three bands and high isolations between the feedings ,theterminal antennas for Beidou navigation satellite system achieve wide beam andmaintain a higher gain in low elevations, and that the design method is available andvalid.