An Tropical Fish Shaped End-Fire Circularly Polarized RFID Reader Antenna
In this paper,an end-fire circularly polarized antenna for RFID readers is proposed.The antenna is combined by a rectangular waveguide structure(equivalent to a magnetic dipole)and a pair of tropical fish shaped dipole structure(equivalent to an electric dipole).At the same time,a quarter-wavelength microstrip line structure and U-shaped microstrip line are used to adjust the im-pedance matching and phase shift.Finally,a UHF end-fire right-handed circularly polarized an-tenna is designed and realized.The simulation results show that the S11 of the antenna at resonance frequency point is-29.5 dB,the gain is 4.49 dBi,and the impedance bandwidth is 90 MHz(880 MHz-970 MHz).and the 3 dB axial-ratio(AR)bandwidth is 150MHz(850MHz-1000MHz),which can be widely used in UHF RFID readers.
RFID readerhigh gainUHFend-fire circularly polarized antennas
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