Design of a Circularly-polarized Microstrip Antenna with Broad Band and Wide Beamwidth
In this paper,a broadband circularly-polarized microstrip antenna is designed.The antenna adopts a stacked double-lay-er circular patch structure,combined with a four-point sequential-rotation feed,to achieve broadband circularly polarized radiation per-formance.A ring array of vertically grounded metal columns is loaded around the laminated circular patch,which introduces the beam steering effect and equivalent zero mode resonance characteristics to effectively broaden the half-power beam width(HPBW)over a broadband and ensure the circular polarization radiation performance within the broadband and broad beam volume.A prototype antenna is fabricated and measured.Measured results show that the impedance bandwidth(4.54 GHz～11.50 GHz)of S11 less than-10 dB is 87%,covering the expected application working frequency band of 6 GHz～10 GHz.The bandwidth with axial ratio less than 3 dB rea-ches 33.1%(6.71 GHz～9.36 GHz).HPBW approaches 100° in the range of 6 GHz～8 GHz,and more than 75° in the whole bandwidth.Except for the frequency band above 9.5 GHz,the 6 dB axial ratio beamwidth coverage in the working frequency band is close to 200°,indicating that the antenna has good circular polarization performance during a broad band and wide beamwidth.
万方数据
维普
