Research On Wideband Circularly Polarized Millimeter Wave Antenna

With the development of information technology,the speed of data interaction becomes faster and the size of data interaction becomes larger and larger,which puts forward new requirements for wireless communication systems.This leads the communication frequency band to high frequency and band-width to wideband.The high frequency millimeter wave band is sensitive to bad weather such as rain and fog,and mobile communication has requirements for ground interference and receiving location.These new characteristics of anti-interference and mobile reception make it difficult for the traditional linear polarization antenna to meet the requirements.The circularly polarized antenna,with the charac-terristics of resisting multipath interference and adapting to various bad weather,has been attracting more and more attention.The antenna with broadband,circular polarization and working in millimeter wave band will become the key technology of future communication system.Since Clavin proposed the idea of using electric dipoles and magnetic dipoles to form complementary antennas in 1974,Kwai-Man Luk proposed and designed the first mature magneto-electric dipole antenna in 2006,magneto-electric dipole antenna has been studied as a hot research.The magneto-electric dipole antenna has characteristics like broadband,omnidirectional,stable gain and low back lobes,making it ideal for designing broadband circularly polarized antennas.Based on the previous studies,this thesis focuses on the magnetic dipole antenna working in the millimeter wave band,and studies wideband and circular polarization.Two broadband circularly polarized magneto-electric dipole antennas are designed and processed.The innovations are as follows:A 1x2 wideband circularly polarized magneto-electric dipole antenna array is designed.The unit of antenna array is designed as a magneto-electric dipole antenna consisting of a rectangular patch with perturbation and chamfering and a vertical metallized through hole.By means of rectangular perturbation,two orthogonal modes are separated to form a phase difference of 90 degrees,so as to radiate circular polarized waves.The antenna achieved 27.1%?24.29 GHz-31.9 GHz?of impedance band-width,and 9.7%?27.4-30.2 GHz?of the axial ratio bandwidth.The two antenna elements rotate in sequence,and the power split phase shift is fed through the complementary substrate integrated wave-guide,and the wider axial ratio bandwidth is realized by the multivariate method.The antenna achieved 25%?24.4 GHz to 31.4 GHz?of impedance bandwidth,24.7%?24.8 GHz to 31.7 GHz?of an axial ratio band-width,which is 2.5 times of the unit.A broadband circularly polarized magneto-electric dipole antenna based on filter power split phase shifter is designed.The antenna is composed of four centrally connected rectangular patches and vertical metallized through holes.The double-polarized magneto-electric dipole antenna is excited by a high-order modeTE₂₁₀ andTE₁₂₀ coupled with a cross gap,and the impedance bandwidth reaches 16.8%?24GHz to 28.4 GHz?.The filter power divider composed of weakly coupled line and short-circuit truncated line introduces a 90 degree phase difference,which is fed into the two ports of the double-polarized antenna respectively,so as to radiate the circularly polarized wave.The antenna achieved 19.67%?23.4GHz to 28.5 GHz?of impedance bandwidth and 10%?24.5 GHz to 27.1 GHz?of axial ratio,with filtering antenna character-istics.