| This paper focuses on the analysis and research of the high-gain broadband technology of Fabry-Perot cavity antenna.Firstly,the theory of Fabry-Perot resonant cavity and array technology are briefly described,and then the "high-gain broadband" technology of microstrip antenna is emphatically studied.The realization of the main method is what loading the Partially Reflective Surface,constituting a Fabry-Perot cavity antenna.The main research contents of this paper are as follows:Firstly,the working principle of Fabry-Perot cavity antenna is analyzed,it is concluded that the reason for the narrow gain bandwidth of the traditional Partially Reflective Surface is that the phase of the reflection coefficient decreases with the increase of the frequency.Then a Partially Reflective Surface with positive reflection phase gradient is designed and its advantages are explained.Through the simulation of electromagnetic simulation software HFSS,the influence of various parameters of the reflective surface on its performance was analyzed.Finally,it is concluded that the amplitude of the reflection coefficient decreases with the increase of the relative bandwidth.Secondly,the circular polarization technique of microstrip antenna and the method of widening the 3dB axial bandwidth of the circular polarization microstrip antenna are studied,and the antenna unit with broadband circular polarization characteristics was designed.Then the impedance matching principle and antenna array technology are studied and the corresponding feed network and microstrip antenna array with circular polarization are designed.Then,the method to improve the gain of Fabry-Perot cavity antenna was studied,and the microstrip antenna unit and microstrip antenna array were used as the feed sources of Fabry-Perot cavity antenna,respectively.The influence of Partially Reflective Surface on the radiation characteristics of two feeders is analyzed by simulation.Based on the results of the two analyses,it is found that the antenna gain can be improved effectively by loading the Partially Reflective Surface designed in this paper,and the gain can be kept stable and high in a wide range of frequency bands.Finally,the simulation results were compared with the simulation results of the Partially Reflective Surface without loading and the traditional Partially Reflective Surface with loading.It was found that the gain bandwidth of loading the Partially Reflective Surface with the antenna unit as the feed was only 6%,while the gain bandwidth of loading the Partially Reflective Surface designed in this paper was over 13%.With the antenna array as the feed,the gain bandwidth of loading the conventional Partially Reflective Surface is only 6%,while the gain bandwidth of loading the Partially Reflective Surface designed in this paper is 10.9%.Then,physical processing and testing are carried out to further demonstrate the effectiveness of the design in this paper.The Fabry-Perot cavity antenna designed in this paper has a size of 210mm?210mm and a profile height of 13.6mm.It can achieve a stable gain of more than 28 dB in the range of 11.5GHz-12.5GHz frequency band.The maximum gain reaches 28.4dB,and it has a wide impedance bandwidth and axial bandwidth.It can be loaded onto the vehicle,ship and other carriers as the satellite receiving antenna of the 11.7 GHz-12.2GHz frequency band. |
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