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RFMTC11 GÄVLE OCTOBER 4–5th 2011 Impact of Moisture Content on RFID Antenna Performance for Wood-Log Monitoring Sohil Shahabi Ghahfarokhi, Sathyaveer Prasad,

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Presentation on theme: "RFMTC11 GÄVLE OCTOBER 4–5th 2011 Impact of Moisture Content on RFID Antenna Performance for Wood-Log Monitoring Sohil Shahabi Ghahfarokhi, Sathyaveer Prasad,"— Presentation transcript:

1 RFMTC11 GÄVLE OCTOBER 4–5th 2011 Impact of Moisture Content on RFID Antenna Performance for Wood-Log Monitoring Sohil Shahabi Ghahfarokhi, Sathyaveer Prasad, Danial Tayari University of Gävle October 4, 2011

2 RFMTC11 Presentation outline Traditional wood supply chain RFID in wood supply chain Challenges of using RFID in wood supply chain Effect of moisture content on the dielectric constant of wood Parameters for RFID tag performance evaluation Antenna design Simulation results Reader range calculations Summary Questions

3 RFMTC11 Traditional Wood Supply Chain Designated Area Cutter Logged Area Collectors Piles/Stacks of log Transport Factory Stamping

4 RFMTC11 RFID in Wood Supply Chain Designated Area Cutter Logged Area Collectors Piles/Stacks of log Transport Factory RFID

5 RFMTC11 Challenges of using RFID in wood supply chain The whole process should be completed 3-5 weeks. Processing time can go up to 15 weeks during winter. During these 15 weeks, moisture content may vary due to environmental factors like sun, rain, snow, etc., Hence, it influences the RFID tag and reader performance

6 RFMTC11 Effect of Moisture Content on the Dielectric Constant of Wood Moisture content of wood : the weight of water expressed as a fraction,usually a percentage, of the weight of oven dry wood. Dielectric constant Loss tangent Ref: G.I. Torgovnikov, Dielectric properties of wood and wood based material., Springer series in wood science, Berlin Springer-Vlg cop, Moisture contentDielectric constantLoss tangent 5% % % % % % %

7 RFMTC11 Ref: Choo, J.; Ryoo, J.; Hong, J.;, "Novel RFID tag antenna with stability to material," Antennas and Propagation Society International Symposium, AP-S IEEE, vol., no., pp.1-4, 5-11 July Parameters for RFID tag performance evaluation RFID Antenna Parameters – Return Loss – Directivity – Radiation Efficiency RFID performance is evaluated by computing the maximum reader range 7 Max. reading range [Ref] defined using Friis transmission formula:

8 RFMTC11 Antenna Design Designed in HFSS Folded Dipole Polyamide Casing Operating Frequency: 867 MHZ Dielectric Constant of wood:

9 RFMTC11 Simulation Results 9 Return loss of designed antenna at different dielectric constants

10 RFMTC11 10 Simulation Results Radiation efficiency vs. Directivity at different dielectric constants

11 RFMTC11 Reader Range Calculation Reader Parameters (XCODEEIU9050) Antenna Parameters (From Simulation Results) Return Loss (η reader )= -10 dB Radiation efficiency(Eff reader )= 0.8 Directivity (D reader ) = 0 dBi Transmitted Power (P t )=29.5dBm Polarization efficiency = 1 Return Loss (η tag ) Radiation Efficiency (Eff tag ) Directivity (D tag ) Max. reading range defined using Friis transmission formula:

12 RFMTC11 Reader Range Calculations εrεr Loss tangent Moisture Content η tag (dB) D tag Eff tag Max. Range (m) % change % %1.810% % % % %1.7811% % %1.7612% % %1.6120% A= Reader range for desired dielectric constant B= Reader range for ε r =3.2

13 RFMTC11 Summary Increase of moisture content decreases the resonating frequency and increases the return loss of the RFID antenna. Hence the maximum reader range decreases up to 20%. Variation of maximum reader range may increase the overall cost of the wood supply chain and also reduces the reliability

14 RFMTC11 Questions


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