| With the constant development of information technology and the spread ofcommunication business, the application domain of satellite communication becomesincreasingly wide and it gradually becomes an important mode of communication.Therefore, in order to adapt to the development of modern communication, circularlypolarized, wide beam, sloping beam, low sidelobe and beam scanning become theimportant research directions of the development of antenna technology. Combined withthe scientific research projects, this dissertation makes intensive researches on thehelical antenna, the quadrifilar helical antenna, the circularly polarized microstrip slotantenna and the CTS array antenna to meet the needs of satellite communicationsystems. The author’s major contributions are outlined as follows:1. Two helical antennas are studied. In view of the demands of the satellitecommunication system for the miniaturization and tilted beam of antennas, two helicalantennas used in the ground and the carrier satellite communication system are designed,respectively. Firstly, an axial mode helical antenna array with loading plates is designed,which can obtain a higher gain under a lower height by loading the shorted plate.Secondly, a cone mode helical antenna winded by asymmetric helical arms is designed,which achieves radiation characteristics of tilted beam by using the asymmetric currentdistribution of helical arms. The measured results show that both of the designed helicalantennas have good electrical performances.2. Three quadrifilar helix antennas with feeding networks are studied. In view ofthe demands of the satellite communication system for the miniaturization and widebeamwidth of antennas, three wide beam quadrifilar helix antennas integrated withfeeding networks are designed. Firstly, a folding quadrifilar helix antenna using thetechnology of arm folding and its miniaturized feeding network is designed. Secondly, acoupling quadrifilar helix antenna using the technology of bent arm coupling and itscombination of feeding network is designed. Thirdly, a wideband quadrifilar helixantenna using the technology of dobby combination and its wideband feeding networkis designed. The experimental results show that all of the designed quadrifilar helixantennas have good electrical performances.3. Two circularly polarized microstrip slot antennas are studied. In view of thedemands of the satellite communication system for the broadband circularly polarizationof antennas, two circularly polarized slot antenna arrays are designed. Firstly, a broadband coplanar waveguide fed circularly polarized slot antenna arrays with animproved feeding network is designed. Secondly, a broadband circularly polarized slotantenna arrays fed by asymmetrical coplanar waveguide with a novel series feedingnetwork is designed. The experimental results show that the designed circularlypolarized microstrip slot antenna arrays have good electrical performances.4. A low sidelobe CTS antenna array based on SIW is studied. In view of thedemands of the satellite communication system for the low profile and low sidelobeperformances of antennas, a novel SIW-CTS antenna array is designed. Firstly, the basictheory of CTS antenna, the mutual coupling and radiation characteristics betweenantenna elements are studied. Secondly, the low sidelobe optimization is performed byusing the differential evolution algorithm, and then the wideband feed network isdesigned. The simulation results show that the designed CTS antenna array has goodelectrical performances.5. A VICTS antenna array is studied. In view of of the mobile satellitecommunication system for antenna tracking, the VICTS antenna array with the featureof beam scanning is preliminary studied. Firstly, the basic theory and analysis method ofthe VICTS antenna array are discussed. Secondly, the element of the VICTS antenna isdesigned and the array scanning is performed. Finally, some problems arising frombeam scanning are discussed. |
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