A novel crossed dipole tag antenna with excellent
circular polarization has been designed and implemented.
The broad circularly polarized bandwidth (from 903 to 934
MHz) obtained in this paper is determined by unequal slots
embed to the dipoles. The complex impedance matching of
the proposed tag antenna can be achieved by properly
selecting the dimensions of the feeding loop. The measured
results verified a good CP radiation. The overall antenna size
is 00 0 0.21 0.21 0.003 λλ λ × × at 915 MHz. With smaller size,
lower weight, and lower cost, the proposed tag antenna is a
good candidate for RFID applications in the UHF band.