Chipless Tags for RF and THz Identification

Transcription

1 Chipless Tags for RF and THz Identification S. Tedjini*, *, V. Deepu*, M. Bernier*, F. Garet +, L. Duvillaret + * Grenoble-INP/LCIS, 50, rue de Laffemas, BP 54, Valence, France + Grenoble-INP/IMEP-LAHC, 3, parvis Louis Néel, Grenoble Cedex 01, France etienne.perret@lcis.grenoble-inp.fr

2 Outline 1. Introduction 2. Chipless RFID 3. Towards Chipless THz ID 4. Concluding remarks 2

3 Outline 1. Introduction 2. Chipless RFID 3. Towards Chipless THz ID 4. Concluding remarks 3

4 Introduction The RFID is one of the major technologies in the field of identification. Its field of application is expanding rapidly. More than 3000 application cases are known (Logitics, Item, Pallet, Animal, ID paper, Toll road, pharmacy ) Variety of applications lot of constraints : Size, Cost, Reliability (vibration, temperature ), Data security Different classes of tags for different applications. 4

5 1. Introduction Tentative of classification for RFID tags Hardware 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 WORM R/W Reader Driven 5 5

6 1. Introduction Tentative of classification for RFID tags Hardware 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 EEPROM WORM R/W Reader Driven µprocessor ASIC 6 6

7 1. Introduction Tentative of classification for RFID tags Hardware 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 7 THz 7

8 Outline 1. Introduction 2. Chipless RFID 3. Towards Chipless THz ID 4. Concluding remarks 8

9 2. Chipless RFID Chipless RFID Barecode RFID Chipless RFID 9 Easy to use Universal Low cost Personal software, printer to generate printable barcode labels Short range, direct line of sight RF communication Flexibility for placement, orientation, direct line of sight is not necessary, Extensive read ranges, multi-read. More complex solution Not universal, lack of security, Cost, With a chip, more or less robust.

10 2. Chipless RFID Chipless RFID Barecode Chipless RFID RFID Low Storage capacity 10

11 2. Chipless RFID Principle of operation 11

12 Temporal approach 2. Chipless RFID Reader Data encoding Interrogation pulse Chipless RFID tag Reflected waves Waves Reflectors Example of different ways to encode data using: (a) the presence or absence of a specific reflector (b) the position between reflectors. In both case, the data encoded corresponds to the same ID On-Off Keying (OOK) approach Pulse position modulation (PPM) approach 12

13 2. Chipless RFID 1. Introduction Frequency approach Example of Chipless RFID: RF Circuits Frequency response 15 mm 17.5 mm Without ground plane Very compact solution 13

14 2. Chipless RFID Modified current paths Example of Chipless RFID: RF Circuits 14

15 2. Chipless RFID Example of Chipless RFID: RF Circuits Highest frequency variation 15

16 2. Chipless RFID Example of Chipless RFID: RF Circuits Middle frequency variation 16

17 2. Chipless RFID Example of Chipless RFID: RF Circuits Lowest frequency variation 17

18 2. Chipless RFID Example of Chipless RFID: RF Circuits How data is coded??? N 1 Frequency (GHz) Code for N 1 short positions Frequency (GHz) Code for N 2 short positions 15 mm N 3 N Frequency (GHz) Code for N 3 short positions 17.5 mm To code produce resonances at 2.55, 4.4 and 2.2 GHz Nb of bits = = 6 Bits/cm² = 6/1.5*1.75 = 2.3

19 Outline 1. Introduction 2. Chipless RFID 3. Towards Chipless THz ID 4. Concluding remarks 19

20 3. Towards Chipless THz ID Novel chipless RFID tag in THz domain Objectives : Increased the tag capacity by encoding information in volume 20

21 3. Towards Chipless THz ID transmission Principle : 1-D photonic crystal Bragg mirror Periodical stack of layers THz PBG a = 475 µm Defect in the multilayer structure fréquence (THz) simulation measurements Fabry-Pérot cavity GHz = 548 µm 586 GHz 21 0,0 0,2 0,4 0,6 0,8 1,0 fréquence (THz)

22 3. Towards Chipless THz ID The storage capacity The storage capacity Encoding principle The defect layer thickness controls the number and the position of the transmission peaks within a given PBG. The simplest method consists in coding the information by the position of defect modes within the considered PBG. Number of coding channels : N How many discernable codes can be coded with N channels? P N N f f 22

23 3. Towards Chipless THz ID Simulations and results The optical bench Classical THz-TDS setup : LT-GaAs photoswiches illuminated by 800 nm wavelength fs laser pulses (60 fs) The realized multilayer structure δ=225 μm δ=450 μm δ=120 μm δ=950 μm 23 A 75µm thick 2-inches high resistivity silicon wafers. B 300µm thick air layers. Measured (doted line) and simulated transmission coefficient.

24 3. Towards Chipless THz ID Simulations and results A 75µm thick 2-inches high resistivity silicon wafers. B 300µm thick air layers. Δf =150 GHz The number of available coding channels N 50 Storage capacity 10 bits. Spectral resolution = 3 GHz The realized tags present total thicknesses ranging from 2 to 2.6 mm. 24 Since the information is coded in volume, the surface of such tags can be as small as the size of the THz reader beam (beam diameter ~ 10 mm).

25 Outline 1. Introduction 2. Chipless RFID 3. Towards Chipless THz ID 4. Concluding remarks 25

26 Concluding remarks Chipless RFID tags Well adapted for low cost and data security purposes. Prospective studies show that Chipless tags will reach 60% of the tags market within this decade. A new family of chipless tag in order to enlarge the memory capacity By combining the coding of both the surface and the volume of the structure. The information on the surface is obtained via metallic electrodes and RF signals are used to read the coded information. A multilayer structure is used for the information coded in the volume and THz signals are used for reading. 26