Compact RFID Tag Antenna With Circular Polarization and Embedded Feed Network for Metallic Objects

A low-profile radio frequency identification (RFID) tag antenna is proposed with a compact size of 45 ×45 mm2 and circular polarization (CP) for metallic surfaces. A star-shaped slot is etched onto the antenna for the CP and antenna size reduction. A terminal-grounded L-shaped feedline is embedded in the etched slot to efficiently excite the wideband CP mode, complexly match the tag-antenna impedance, and further reduce the antenna size. The embedded feed structure also helps achieve a relatively higher gain, resulting in a longer reading range. The proposed antenna can cover the impedance bandwidth of 60 MHz (from 880 to 940 MHz) as well as the 3-dB CP bandwidth of 12 MHz (from 905 to 917 MHz). Further results demonstrate that the proposed tag antenna provides a stable reading range when mounted on metal plates of various sizes.

[1]  Hosung Choo,et al.  Design of a Circularly Polarized Tag Antenna for Increased Reading Range , 2009, IEEE Transactions on Antennas and Propagation.

[2]  Horng-Dean Chen,et al.  Coupling-Feed Circularly Polarized RFID Tag Antenna Mountable on Metallic Surface , 2012, IEEE Transactions on Antennas and Propagation.

[3]  C. Pyo,et al.  Design of RFID tag antennas using an inductively coupled feed , 2005 .

[4]  G. Marrocco,et al.  The art of UHF RFID antenna design: impedance-matching and size-reduction techniques , 2008, IEEE Antennas and Propagation Magazine.

[5]  Xianming Qing,et al.  Impedance Characterization of RFID Tag Antennas and Application in Tag Co-Design , 2009, IEEE Transactions on Microwave Theory and Techniques.

[6]  Hua‐Ming Chen,et al.  Proximity-Fed Circularly Polarized Slotted Patch Antenna for RFID Handheld Reader , 2013, IEEE Transactions on Antennas and Propagation.

[7]  Horng-Dean Chen,et al.  Compact Broadband Dual Coupling-Feed Circularly Polarized RFID Microstrip Tag Antenna Mountable on Metallic Surface , 2012, IEEE Transactions on Antennas and Propagation.

[8]  S.F. Lam,et al.  Power reflection coefficient analysis for complex impedances in RFID tag design , 2005, IEEE Transactions on Microwave Theory and Techniques.

[9]  Daniel D. Deavours,et al.  A circularly polarized planar antenna modified for passive UHF RFID , 2009, 2009 IEEE International Conference on RFID.

[10]  Horng-Dean Chen,et al.  Design of compact circularly polarized radio frequency identification tag antenna for metallic object application , 2013 .

[11]  Harish Rajagopalan,et al.  A thin multi-slotted dual patch UHF-band metal-mountable RFID tag antenna , 2011 .

[12]  Lauri Sydanheimo,et al.  Compact Metal Mountable UHF RFID Tag on a Barium Titanate Based Substrate , 2012 .