Design of a broadband UHF near-field RFID reader antenna
A wideband UHF RFID reader antenna with Wilkinson power divider and the composite left and right hand (CRLH) transmission lines is proposed. The antenna is composed of a Wilkinson power divider, CRLH transmission lines, and two open-ended microstrip meander lines. The traditional Wilkinson power divider has a 1/4 wavelength band microstrip transmission line, as transmission line is a narrow band, it is not a broadband device. The Wilkinson power divider and the CRLH transmission lines are used to expand the bandwidth of the antenna and to make a 180 degree phase shift. The proposed antenna works from 860 MHz to 960 MHz with S11 less than -27 dB, including the entire UHF RFID band. Due to the wide band characteristic of the antenna, it can be widely used in the different countries.