Single‐layer crossed dipole antenna with circular polarization for handheld RFID reader

A compact circularly polarized coplanar crossed dipole antenna with an unequal length of arms for RFID reader is designed and measured in this paper. It uses two unequal length dipoles connected in parallel to a coaxial cable feed and requires no matching network. The impedance bandwidth of the proposed antenna for S11 <10 dB is about 6.9% and it has a 3-dB CP bandwidth of about 1.0%. Experimental results and simulations reveal that the proposed antenna features total size of 0.15 λ0 in side of square substrate and 0.005 λ0 in height at the center frequency 924 MHz. In addition to this, the compact antenna is easily to be embedded in the holding box as transmitting antenna in handheld RFID reader. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1172–1176, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25937