RFID Chipless Tag Based On Multiple Phase Shifters

Transcription

1 RFID Chipless Tag Based On Multiple Phase Shifters A. Vena, E. Perret, S.Tedjini Grenoble-inp/LCIS O R S Y S

2 Introduction Outline Chipless RFID vs. RFID Chipless Tag Classification Tag Design Coding Methods Set-up for Frequency Measurements Measurement Results Performances Considerations Practical Implementation Conclusion Slide 2

3 Introduction Principle of communication by reflected power (H. Stockman) IFF application Commercial tag : EAS Numerous applications in various area : traceability, access control Identification/Authentication Coupling RFID to other Technologies Slide 3

4 Hardware Chipless Tags vs RFID RFID Tags Signal&Software Power Com. Range Data Proc. Program. Protocol Passive Long range IC based Read Tag Driven Semi passive Active Short range NFC Chipless Printed SAW Based WORM R/W Reader Driven RF Circuits THZ/volume Slide 4

5 1. Introduction Chipless Tags vs RFID (cont) Barecode Chipless RFID RFID 5

6 Chipless Tag Classification Temporal approach Reader Interrogation pulse Chipless RFID tag Reflected waves Waves Reflectors Reader RCS Frequency approach RCS Frequency Frequency copper dielectric Slide 6

7 Chipless Tag Classification (cont) Slide 7

8 Tag Design Chosen Basic resonator : C cell - In Magnitude : Gives a peek and a dip - In phase : exhibits a phase shifter behavior wi FR4 Copper 40mm gi E li H Basic Scatterer 20mm View of 3 realized tags Slide 8

9 Tag Design (cont) Simulated Magnitude and Phase Response for various length l w=1mm, g=0.5mm RCS, dbsm L=16.5mm Phase, rad -80 L=17.5mm L=18.5mm Frequency, GHz L=16.5mm L=17.5mm L=18.5mm Frequency, GHz Slide 9

10 Tag Design (cont) Simulated Magnitude and Phase Response for various gap g E-field, dbv g=0.5mm g=1.5mm g=2.5mm g=3.5mm Frequency, GHz Phase, rad w=1mm, l=18.5mm g=0.5mm g=1.5mm g=2.5mm g=3.5mm Frequency, GHz Slide 10

11 Tag Design (cont) Transfer Function Model E-field, dbv Phase, rad Frequency, GHz g=0.5mm Model g=0.5mm g=0.5mm Model g=0.5mm IMS Baltimore TU1C-1 Frequency, GHz 2mzjω 1+ + ωz T ( ω ) = G 2mpjω 1+ + ω p mp=0.002 fp=2.53 GHz mz=0.005 fz=2.58 GHz G= nd order Zero jω ωz jω ωp nd order Pole Slide 11

12 RCS Coding Methods Traditional Coding Way : OOK - Low coding efficiency - reliable λ/2 RCS Frequency λ/2 Frequency Shorted dipoles introduced by Jalaly e al. (2005) Slide 12

13 Coding Methods (cont) A New Encoding Way : Phase deviation encoding Code = (01) 2 Code = (10) 2 Phase f1 f2 Frequency deviation f1 f2 Binary Code 0 1 Coding due to phase deviation for fr1 fr1 fr2 Frequency Example : a tag with 2 bits of capacity Slide 13

14 Coding Methods (cont) Use of Hybrid technique to Increase the Coding Efficiency - Frequency Position - Phase deviation Presence/absence ON Coding efficiency enhancement Frequency shift OFF Constellation in frequency domain for OOK case Constellation in frequency domain for the new coding technique Phase deviation 1 resonator 1bit 1 resonator N bits Slide 14

15 Setup for Frequency Measurement Complex RCS measurement (Radar Cross Section) Vector Network Analyser 20GHz Anechoic chamber 65cm 60cm 65cm Horn antenna 12dBi 50cm 50cm Tag Calibration Isolation measurement (to remove reflection from surrounding object) Metallic plane measurement (to remove antennas and cables effects) Slide 15

16 Measurement Results RCS Magnitude Response for various configurations g=2.5mm g=3.5mm g1=3.5mm g2=2.5mm g3=1.5mm g4=g5=0.5mm S21 (db) g=0.5mm g=3.5mm g1=3.5mm g2=2.5mm g3=1.5mm g4=g5=0.5mm Frequency(GHz) Slide 16

17 1.5 Measurement Results (cont) RCS Phase Response for various configurations 1 131MHz g=0.5mm g=3.5mm g1=3.5mm g2=2.5mm g3=1.5mm g4=g5=0.5mm g=2.5mm g=3.5mm g1=3.5mm g2=2.5mm g3=1.5mm g4=g5=0.5mm Phase S21(rad) Half deviation Deviation = 2.5 rad Frequency(GHz) Slide 17

18 Measurement Results (cont) Realized Tags dimensions in mm g1 g2 g3 g4 g5 L1 L2 L3 L4 L5 Tag wi Tag 2 Tag 3 Tag gi li E H Tag Half Deviation Phase Bandwidth for each Realized Tag Tag name Tag 1 Tag 2 Tag 3 Tag 4 Tag 5 Bandwidth for each resonant mode (in MHz) 2.5GHz 3.5GHz 4.5GHz 5.5GHz 6.5GHz Code Slide 18

19 Performances Considerations Coding Capacity Calculation For this Design - N=4 states for each resonator - Ntot = 4^5=1024 (i.e. 10bits) for the 5 resonators Coding Capacity Calculation For the General Case 100 Coding Capacity (bits) N tot = k i= 1 BW fi i + 1 C= log 2 ( Ntot) BP=3-9GHz BP=4-12GHz Δf=50MHz K resonators Slide 19

20 Performances Considerations (cont) Frequency Constellation For Hybrid Coding technique Frequency shift Unreachable states due to overlapping between the modes Reachable states N=10 states for each resonator Phase deviation Actually tested configurations N=4 states for each resonator Coding Capacity Calculation For this Design with Hybrid Technique - N= 10 states for each resonator - Ntot = 10^5= (i.e. 16.6bits) for the 5 resonators Slide 20

21 Practical Implementation State of Art : Preradovic et al. Frequency domain approach Simple solution that works from 5 to 11GHz Not compliant to FCC and ECC rules

22 Practical Implementation (cont) FCC and ECC Mask for UWB communications Power Mask -40 PSD (dbm) FCC Mask indoor FCC Mask handheld ECC Mask ISM Band Frequency (GHz) Needed bandwidth UWB Low Duty Cycle signals

23 Pulse generator Practical Implementation (cont) Future work Impulse Radio based Reading system PA µp DSP ADC LNA FCC UWB bandwidth : 3.1GHz to 10.6GHz -41.3dBm/MHz => -2.5dBm mean power Pulse Repetition Frequency min 1MHz Instantaneous peak power as high as 5W for a 100ps pulse duration

24 Practical Implementation (cont) Behavior of 100ps Gaussian Pulse (Pulse Repetition Frequency = 1MHz) pulse UWB (normalisé (50Ω)) -40 Power Mask Amplitude (V/ (Ω)) temps (ns) PSD (dbm) Not compliant Tx Pulse PSD FCC Mask indoor FCC Mask handheld ECC Mask ISM Band Frequency (GHz) Solution : modifying the pulse shape

25 Practical Implementation (cont) Pulse shaping to fit the FCC mask pulse UWB (normalisé (50Ω)) -40 Power Mask Amplitude (V/ (Ω)) temps (ns) ECC not compliant Tx Pulse PSD FCC Mask indoor FCC Mask handheld ECC Mask ISM Band Frequency (GHz) ECC rules are more stringent than FCC rules for UWB ECC solution : Sending two pulses

26 Practical Implementation (cont) Double pulse solution for the ECC mask pulse UWB (normalisé (50Ω)) Power Mask Amplitude (V/ (Ω)) Amplitude (V/ (Ω)) temps (ns) pulse UWB (normalisé (50Ω)) temps (ns) PSD (dbm) PSD (dbm) Tx Pulse PSD -80 FCC Mask indoor FCC Mask handheld -85 ECC Mask ISM Band Frequency (GHz) -40 Tx Pulse PSD -45 FCC Mask indoor FCC Mask handheld -50 ECC Mask ISM Band

27 Conclusion New miniaturized chipless tag design New coding technique based Phase deviation Concept of Hybrid Coding is introduced Capacity = 10 bits into 4x2cm² ( GHz) Capacity = 16.6 bits into 4x2cm² is possible with hybrid coding technique Future work : design of a reading system Slide 27