Planar Broadband Circularly Polarized Antenna With Square Slot for UHF RFID Reader

Novel circular polarization (CP) design of planar broadband antenna with square slot for UHF RFID system is proposed and experimentally studied. By insetting the arc-shaped strip into the square slot, the proposed CP design can easily be achieved with the impedance bandwidth ( RL ≥ 10 dB) of about 142 MHz (15.3% @ 931 MHz) and the 3 dB axial-ratio (AR) bandwidth of about 166 MHz (17.7 % @ 940 MHz) for UHF RFID applications. The measured peak gain and radiation efficiency are about 6.8 dBic and 98% across the operating band, respectively, with nearly bidirectional pattern in the XZ- and YZ-plane.

[1]  Xianming Qing,et al.  Asymmetric-Circular Shaped Slotted Microstrip Antennas for Circular Polarization and RFID Applications , 2010, IEEE Transactions on Antennas and Propagation.

[3]  Xianming Qing,et al.  Ultra-wideband Circularly Polarized Wide-slot Antenna Fed by Three-stub Hybrid Coupler , 2007, 2007 IEEE International Conference on Ultra-Wideband.

[4]  Zhongbao Wang,et al.  Single-Fed Broadband Circularly Polarized Stacked Patch Antenna With Horizontally Meandered Strip for Universal UHF RFID Applications , 2011, IEEE Transactions on Microwave Theory and Techniques.

[5]  Hua-Ming Chen,et al.  Bidirectional radiated circularly polarised square-ring antenna for portable RFID reader , 2008 .

[6]  Jeongpyo Kim,et al.  Aperture‐coupled UHF RFID reader antenna for a handheld application , 2008 .

[7]  Vincent F. Fusco,et al.  Understanding and measuring circular polarization , 2003, IEEE Trans. Educ..

[8]  J. Nourinia,et al.  Broadband CPW-Fed Circularly Polarized Square Slot Antenna With Inverted-L Strips for UWB Applications , 2011, IEEE Antennas and Wireless Propagation Letters.

[9]  Christopher L. Holloway,et al.  Coplanar waveguide fed wideband slot antenna , 2000 .

[10]  H.A. Ghali,et al.  Broad-band and circularly polarized space-filling-based slot antennas , 2005, IEEE Transactions on Microwave Theory and Techniques.

[11]  Zhongxiang Shen,et al.  A CPW‐FED circularly polarized antenna for lower ultra‐wideband applications , 2009 .

[12]  R. Joseph,et al.  Broadband circularly polarized antenna with circular sot and separated L-probes , 2010, 2010 IEEE Antennas and Propagation Society International Symposium.

[13]  Chien-Jen Wang,et al.  CPW-Fed Stair-Shaped Slot Antennas With Circular Polarization , 2009, IEEE Transactions on Antennas and Propagation.

[14]  Horng-Dean Chen,et al.  Broadband CPW-fed square slot antennas with a widened tuning stub , 2003 .

[15]  Xianming Qing,et al.  A Universal UHF RFID Reader Antenna , 2009, IEEE Transactions on Microwave Theory and Techniques.

[16]  Kai-Fong Lee,et al.  Wideband Circularly Polarized Antenna With L-Shaped Slot , 2008, IEEE Transactions on Antennas and Propagation.

[17]  Hua‐Ming Chen,et al.  Slotline-fed circularly polarized annular-ring slot antenna for RFID reader , 2009, 2009 Asia Pacific Microwave Conference.

[18]  Kin‐Lu Wong,et al.  Bandwidth enhancement of a microstrip-line-fed printed wide-slot antenna , 2001 .

[19]  C. H. Cheng,et al.  Broadband circularly polarized wide‐slot antenna , 2007 .

[20]  Jeen-Sheen Row,et al.  Circularly-Polarized Wide Slot Antenna Loaded With a Parasitic Patch , 2008, IEEE Transactions on Antennas and Propagation.

[21]  The Nan Chang,et al.  A Novel Circularly Polarized Patch Antenna With a Serial Multislot Type of Loading , 2007, IEEE Transactions on Antennas and Propagation.

[22]  Lotfollah Shafai,et al.  Circularly polarized broadband antenna with L-shaped probe and wide slot , 2006, 2006 12th International Symposium on Antenna Technology and Applied Electromagnetics and Canadian Radio Sciences Conference.