Research On The Broadband Circularly Polarized Microstrip Antenna And Miniaturized Circularly Polarized Missile-borne Antenna

According to the scientific projects,the broadband circularly polarized microstrip antenna and the miniaturized circularly polarized missile-borne antenna are designed in this thesis.The research content of the thesis can be summarized as follow.Firstly,the related concepts used in the thesis are explained,the research status and existing problems are discussed,and the background and significance of the research on wideband circularly polarized microstrip antennas and missile-borne miniaturized circularly polarized antennas are discussed.Relevant basic theories and methods used are introduced.Secondly,the research on the broadband circularly polarized microstrip antenna and the missile-borne miniaturized circularly polarized antenna is carried out.The research work can be summarized as follow.1.Design of the wideband circularly polarized microstrip antenna?1?According to the requirements of wideband circularly polarized microstrip antennas,the technical difficulties of the realization of broadband and circular polarization are analyzed.And the technical approaches to solve the above two technical difficulties are proposed.The design scheme of the wideband circularly polarized microstrip antenna is introduced.?2?According to the design scheme,the wideband circularly polarized microstrip antenna is simulated by Ansys HFSS simulation software.The simulation results show that the antenna can achieve a broad VSWR<2 impedance bandwidth of 20.3%,a 3dB axial ratio bandwidth of 14.6%and a 6dB axial ratio bandwidth of 20.0%.The main polarization peak gain of the antenna is 7.5dBic,and the gain drop in the band is 1.5dB.The simulation results show that the electrical parameters of the antenna fully meet the requirements of the design,indicating the reasonable feasibility of the design scheme.?3?Under the condition that the simulation design meets the requirements of the design,a prototype of a wideband circularly polarized microstrip antenna is developed.The test results of the prototype are in good agreement with the design results,which verifies the effectiveness of the design method and also shows that the prototype developed meets the requirements of the engineering application.?4?The design scheme of the slot-loaded wideband circularly polarized antenna is determined after the further research on the wideband circularly polarized microstrip antenna.The simulation results show that the slot-loaded broadband circularly polarized antenna can achieve a broad VSWR<2 impedance bandwidth of 75.2%,a 3dB axial ratio bandwidth of23.1%,a 6dB axial ratio bandwidth of 60.1%and 2.7dBic main polarization peak gain.The simulation results show that the slot-loaded wide-band circularly polarized antenna achieves a larger impedance bandwidth and axial ratio bandwidth than the wide-band circularly-polarized microstrip antenna mentioned aboved,and the antenna's electrical size is also reduced by 42%.2.Development of the miniaturized circular polarized missile-borne antenna?1?According to the requirements of the miniaturized circularly polarized missile-borne antenna,the technical difficulties of the realization of miniaturization and circular polarization are analyzed.And the technical approaches to solve the above two technical difficulties are proposed.The design scheme of the miniaturized circularly polarized missile-borne antenna is introduced.?2?According to the design scheme,the miniaturized circularly polarized antenna is simulated by Ansys HFSS simulation software.The antenna achieves a size of0.098?₀×0.063?₀×0.036?₀.The simulation results show that the miniaturized antenna can achieve an absolute bandwidth of 20MHz in L-band and a main polarization peak gain of-3.8dBic.The simulation results show that the electrical parameters of the antenna meet the requirements of the design,indicating the reasonable feasibility of the design.?3?Under the condition that the simulation design meets the requirements of the design,a prototype of the projectile miniaturized circularly polarized missile-borne antenna is developed.Except that the main polarization gain test result is 2.0dB smaller than the simulation result,the prototype test results are in good agreement with the design results,and the prototype test results basically meet the design index requirements,indicating that the developed engineering prototype meets the requirements of the engineering application.Finally,the thesis points out the research work which needs to be further researched.