Research On Circularly Polarized Wide Angle Scanning Array Antenna

With the development of satellite communication technology,people have higher and higher requirements for mobile communication systems of satellite ground station,which is required to have higher transmission rate and transmit broadband information during the mobile process.The wide-angle circularly polarized phased array antenna has excellent beam scanning and anti-interference ability,which makes it have broad application prospects in mobile satellite communication systems.Therefore,the circular polarization phased array antenna with wide-angle scanning characteristic has gradually become a hot spot for experts and scholars at home and abroad.Based on the existing phased array antenna technology,the thesis studies the wide-angle circularly polarized array antenna.The main research work is as follows:1.In view of the background and significance of wide-angle scanning array antenna,the status of circularly polarized antenna unit and circularly polarized wide-angle scanning array antenna at home and abroad are investigated.Based on the basic theory of circularly polarized antenna and phased array antenna,the basic principle of circularly polarized array antenna design is studied,and the theoretical basis of the paper is formed.2.The thesis designs a circularly polarized array antenna which is based on the form of a broadband crossed dipole antenna.Firstly,a quarter-ring phase shifter is used to connect the adjacent dipole arms to form a 90° phase difference to realize the design of circularly polarized crossed dipole antenna.Next,by introducing the curved dipole arm structure,the current path is extended,and the antenna is miniaturized.Then,by loading the parasitic patch on the dielectric substrate surface,the impedance bandwidth and the axial ratio bandwidth of the antenna are broadened.Finally,an 8×8 circularly polarized crossed dipole array antenna is fed by small angle sequential rotation to achieve the beam scanning of ±45°.The thesis processes and testes the antenna unit,and the test results are consistent with the simulation results basically,which verifies the effectiveness of the design.3.The thesis designs a wide-angle scanning circularly polarized array antenna,which is based on the wide-beam microstrip circularly polarized antenna.Firstly,the short-circuit probe is used to perturb the current density distribution of the microstrip patch to generate a pair of degenerate mode with a phase difference of 90°,so that it can realize circularly polarized radiation of the wide beam and improve the radiation intensity of the antenna,at the same time,the electrical size of the microstrip patch antenna at the resonant point is enlarged.Then,it forms an 8×8 microstrip circularly polarized array antenna which is fed by sequential rotation to achieve the beam scanning of ±60°.In this thesis,the feed network of 2×8 array antenna is designed and tested.The test results are consistent with the simulation results basically,which verifies the achievability of the design.4.The thesis designs a wideband and wide-angle scanning circularly polarized array antenna which is based on a double-layer microstrip circularly polarized antenna.Firstly,the 90° phase difference of the antenna is generated by the traditional square corner cutting method to achieve the circularly polarized radiation.Next,the impedance bandwidth and the axial ratio bandwidth are widened by using the double-layer structure and the parasitic patch.Then,it forms an 8×8 array antenna which is fed by sequential rotation to achieve the beam scanning of ±60° over a wide frequency range of 2.14GHz–2.36 GHz.The thesis compares the simulation results of CST and HFSS,and the two simulation results agree with the main beam basically,which verifies the accuracy of the design.