Platform-Tolerant RFID Tag Antenna

872 views

Published on

Published in: Business, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
872
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
16
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Platform-Tolerant RFID Tag Antenna

  1. 1. Platform-Tolerant RFID Tag Antenna Y. C. Or (1) , K. W. Leung * (1) , R. Mittra (2) , and K.V.S. Rao (3) (1). Wireless Communications Research Centre and Department of Electronic Engineering, City University of Hong Kong, Kowloon Tong, Hong Kong. E-mail: 50450664@student.cityu.edu.hk E-mail: eekleung@cityu.edu.hk (2). EE Department, Pennsylvania State University, 319 Electrical Engineering East University Park, PA 16802-2705 E-mail: mittra@engr.psu.edu (3). RFID Intellitag Engineering Department, Intermec Technologies Corporation, Everett, WA 98203 USA E-mail: kvs.rao@intermec.com
  2. 2. Outline 1. Introduction 2. OR -Patch Antenna 3. RFID Tag Antenna 4 . Conclusion
  3. 3. Objectives <ul><li>Design an OR -shaped patch antenna. </li></ul><ul><li>Design a platform-tolerant RFID tag antenna with the patch antenna (902-928 MHz). </li></ul><ul><li>Measure the read range of the tag antenna. </li></ul><ul><li>Test the platform-tolerant ability. </li></ul><ul><li>Introduction </li></ul>
  4. 4. Impedance Matching <ul><li>Introduction </li></ul>Thevenin's equivalent circuit of an RFID tag Circuit Model of an RFID Tag where Ra and Rc are the input resistances of the tag antenna and of the chip, respectively, and Xa , Xc are their corresponding input reactances.
  5. 5. Maximum Power Transfer <ul><li>Introduction </li></ul>Power transfer formula where Ra and Rc are the input resistances of the tag antenna and of the chip, respectively, and Xa , Xc are their corresponding input reactances. <ul><li>Conjugate match between the chip and the antenna </li></ul><ul><li>Percentage power transferred to the tag </li></ul>
  6. 6. Inductively-Coupled Feed <ul><li>Introduction </li></ul>Inductively-coupled feed structure * * H. W. Son, C.S. Pyo “ Design of RFID tag antennas using an inductively coupled feed ”, Electronics Letters , vol 41. no. 18, Sep, 2005
  7. 7. Platform-Tolerant <ul><li>Introduction </li></ul><ul><li>Use a patch antenna as the resonating element. </li></ul><ul><li>The ground plane isolat es the t ag antenna from the surface materia l. </li></ul><ul><li>S table performance regardless of the mounting surface. </li></ul>
  8. 8. OR -Patch Antenna <ul><li>Patch Antenna </li></ul>Ground Plane: W 1 = 55 mm (0.17 λ) L 1 = 109mm(0.33λ) OR -patch: W 2 = 50 mm (0.15 λ) L 2 = 83 mm (0.26 λ) Duroid Substrate: Loss Tangent: 0.0021 Dielectric Constant: 3.38 Thickness: 1.52 mm where λ is the freespace wavelength at 915MHz Top view of the OR -patch
  9. 9. Current Distribution (IE3D) <ul><li>Patch Antenna </li></ul>At 915MHz,significant current flows around the “ O ” of the patch.
  10. 10. Return Loss <ul><li>Patch Antenna </li></ul><ul><li>Measured resonance frequency: 906MHz </li></ul><ul><li>Simulated resonance frequency: 915MHz </li></ul><ul><li>Percentage error: ~1% </li></ul>Simulated and Measured S 11 of the patch antenna
  11. 11. Simulated Radiation Pattern (IE3D) <ul><li>Patch Antenna </li></ul>E-Plane at 915MHz H-Plane at 915MHz
  12. 12. Simulated Gain (IE3D) <ul><li>Patch Antenna </li></ul>Simulated gain of the patch antenna
  13. 13. RFID Tag Antenna
  14. 14. Specifications <ul><li>RFID Tag Antenna </li></ul><ul><li>RFID Chip: Philips Electronics </li></ul><ul><li>Chip-on-board Impedance at 915MHz: 16-j380Ω </li></ul><ul><li>Chip’s Minimum Operating Power at 915MHz: -13dBm </li></ul><ul><li>Frequency Band: UHF, 902MHz- 928MHz </li></ul><ul><li>Transmitting Antenna Gain (Reader): ~ 6dBi </li></ul><ul><li>Transmitting Power (Reader): ~ 30dBm </li></ul>
  15. 15. Antenna Configuration <ul><li>RFID Tag Antenna </li></ul>Top view of the antenna Side view of the antenna Ground Plane: W 1 = 78mm (0.24 λ) L 1 = 108mm(0.33 λ) OR -patch: W 2 = 50 mm (0.15 λ) L 2 = 82mm (0.25 λ) Duroid Substrate: Loss Tangent: 0.0021 Dielectric Constant: 3.38 Thickness: 1.52mm where λ is the freespace wavelength at 915MHz
  16. 16. Antenna Configuration <ul><li>RFID Tag Antenna </li></ul>The C -loop is directly connected to the OR -patch
  17. 17. Range Measurement <ul><li>RFID Tag Antenna </li></ul><ul><li>The r ead r ange was measured in side an EMC c hamber </li></ul><ul><li>R eader a ntenna was moved inside the EMC c hamber </li></ul><ul><li>Measure the maximum readable distance that the backscatter signal can be detected . </li></ul>RFID Tag range measurement using EMC chamber
  18. 18. Platform-Tolerant Test <ul><li>RFID Tag Antenna </li></ul><ul><li>Following surfaces were used in the test : </li></ul><ul><li>Alumin i um plate (200 x 200 x 3 mm ) </li></ul><ul><li>Acrylic resin plate (200 x 200 x 3 mm) </li></ul><ul><li>Wood (200 x 200 x 3 mm) </li></ul>
  19. 19. Simulated Radiation Pattern (IE3D) <ul><li>RFID Tag Antenna </li></ul>E-Plane at 915MHz H-Plane at 915MHz
  20. 20. Measured Read Range <ul><li>RFID Tag Antenna </li></ul>Read range of the tag antenna mounted on different surfaces <ul><li>Measured from 902MHz to 928MHz, with a step frequency of 1MHz. </li></ul><ul><li>Minimum: 87 cm. </li></ul><ul><li>Maximum: 448 cm. </li></ul><ul><li>Basically independent of mouting surfaces </li></ul>
  21. 21. Current Distribution <ul><li>RFID Tag Antenna </li></ul>902MHz
  22. 22. Current Distribution <ul><li>RFID Tag Antenna </li></ul>915MHz
  23. 23. Current Distribution <ul><li>RFID Tag Antenna </li></ul>928MHz
  24. 24. Simulated Power Transfer <ul><li>RFID Tag Antenna </li></ul>Percentage power transfer to the tag More than 65% across the band.
  25. 25. Conclusion <ul><li>Conclusion </li></ul><ul><li>An OR -patch antenna has been investigated. </li></ul><ul><li>A platform-tolerant RFID Tag antenna has been designed with the OR -patch. </li></ul><ul><li>The feeding loop is connected to the OR -patch directly. </li></ul><ul><li>Tests have been carried out using different materials, e.g., metal, plastic, and wood, with little adverse effect on its performance. </li></ul><ul><li>The minimum and maximum read ranges are 87cm and 448cm, respectively, across the 902-928 MHz band. </li></ul>
  26. 26. Thank You!

×