Design And Research Of Circularly Polarized And Variable Polarization Antenna With Coplanar Waveguide Fed

Antenna is an important part of the communication system and a bridge of information transmission.Its performance has great influence of the communication ability of the whole system.As one of the widely used printed antennas,coplanar waveguide fed antenna has its unique advantages:simple fabrication process,low cost,smaller antenna size,higher integration degree,lower grounding inductance,etc.relative to metal holes.With the development of microstrip antenna,the design of antenna has made great progress.A single linear polarization antenna cannot meet the demand of the communication system to the antenna.The appearance of circular polarized antenna and variable polarization antenna greatly impoves the capacity of the system,improves the flexibility and freedom of the system,and reduces the formation of wireless communication.Ben.Several coplanar waveguide fed printed antennas have been designed to realize circular polarization and variable polarization respectively,In particular,the main work has the following points:Firstly,a universal UHF RFID reader antenna is designed,which shows the characteristics of circular polarization,At present,the frequency bands of the UHF RFID reader antenna in different regions ane different,so it is necessary to design a UHF RFID reader antenna for a general frequency band,which covers the bandwidth of 840-960MHz,that is,all UHF RFID bands.The coplanar waveguide feeder is tortuous and designed to improve the impedance bandwidth of the antenna,and then its procssing is testes and the result is good.Secondly,a variable polarization antenna with wide axis ratio bandwidth is designed to realize the conversion between the left circular polarization state and the right circular polarization state.The antenna works at tht WLAN 2.4GHz band.Through the design of the coplanar waveguide feeder,the impedance bandwidth is improved,and the angle of the patch is cut,the axial ratio of the antenna is broadened to achieve the wide-band characteristics of the antenna.Thirdly,a miniaturized and wide bandwidth variable polarization antenna is designed to realize the conversion between the left circular polarization state and the right circular polarization state.The antenna works at the WLAN 5GHz band.Combining the demand of WLAN 5GHz band antenna in practical application,the antenna is optimized to make its working band in the open WLAN SGHz band of our country and meet the broadband characteristics.