Autonomous Wireless Sensors and RFID's: Energy harvesting Material and Circuit Challenges

Transcription

1 Autonomous Wireless Sensors and RFID's: Energy harvesting Material and Circuit Challenges Apostolos Georgiadis Centre Tecnologic de Telecomunicacions de Catalunya (CTTC) Barcelona - Spain Nov. 9, 2012

2 2 CTTC, Castelldefels Barcelona Foundedin 2001 Permanentresearchstaff: 34 Ph.D., 24 M.Sc. 7 Assoc. Researchers 3500-m 2 building 7 ResearchAreas: Hardware eng., Radio, Access, Communications Subsystems, IP, Optical networking, IQe 2

3 3 CTTC, Castelldefels Barcelona, SPAIN Active microwave circuit design Energy Harvesting and RFID Oscillator design including integrated CMOS oscillators (Fig. 1) Active antennas, phased arrays (Fig. 2), retro-directive arrays (Fig. 3) Substrate Integrated Waveguide (SIW) (Fig. 4) Efficient Power Amplifier Fig. 1. CMOS VCO for UWB-FM Fig. 2. C-band Coupled Oscillator Reflectrarray prototype Fig. 4. SIW circuits. Fig. 3. S-band retro-directive array. 3

4 4 Outline Introduction / Motivation Energy harvesting solutions and challenges Solar, Mechanical, Thermal, Electromagnetic Flexible Materials Integration of Harvesting Modules Summary 4

5 5 Introduction Ubiquitous sensor networks Monitoring (environment, wild-life), security, health Conformal and low profile circuit topologies Low cost (manufacturing, material and maintenance) Autonomous operation Operating with high efficiency Minimize dissipated power / maximize harvested power Green networks Environmental friendly materials and fabrication (Spent batteries pose a significant waste management concern) 5

6 6 Energy Harvesting Choice of harvesting module(s) is application dependent Hybrid harvesting modules required to guarantee sensor autonomy Transducer efficiency depends on available power density Storage modules must also be considered 6

7 7 Energy Harvesting EnergySources Harvested power Conditions examples Light/Solar 60mW 6.3 cm x 3.8 cm Flexible solar cell AM1.5G Sunlight (100 mwcm -2 )[1] Kinetic Mechanical 20mW PMG-FSH Electromagnetic transducer[2] Thermal 0.52 mw Thermoelectric Generator TEG [3] Electromagnetic mW Ambient power density 0.15 uwcm -2 [4] [1] Silicon Solar Inc., Flexible Solar Panels 3V, [2] Perpetuum, [3] MicroPelt Inc., TEG MPG-D [4] A. Georgiadis, G. Andia, and A. Collado, "Rectenna Design and Optimization Using Reciprocity Theory and Harmonic Balance Analysis for Electromagnetic (EM) Energy Harvesting, " IEEE Antennas and Wireless Propagation Letters, Vol. 9, pp , July

8 8 Energy Harvesting Human Body Sources Bodyheat Total available power from body 2.8W -4.8 W Available power for harvesting W (neck brace) Breathing band 0.83 W 0.42 W Walking 67 W W Thad Starner, 'Human powered wearable computing', IBM systems journal, vol. 35, no. 3-4,

9 9 Solar Energy Harvesting Photovoltaic Effect (Observed by Becquerel 1839) American Society for Testing and Materials (ASTM) Reference Solar Spectra ETR Spectral Irradiance Distributionismodeledas black-body radiation witht= 5800 K Atmosphere Absorption bandsvisible Principles of thermodynamics and black-body radiation allow9to estimate performance limits of solar cells (Shockley-Queisser Limit 1961)

10 10 Solar Energy Harvesting waferbasedsolar cells(150 $/m2 efficiency20%) thinfilm solar cells (30 $/m2 efficiency 5-10%) third generation solar cells (high efficiency, low cost) Challenges High efficiency and low cost Integration with other circuitry Indoor conditions? Cost ($/m 2 ) M. Green, Third Generation Photovoltaics, Advanced Solar Energy Conversion, Berlin Heidelberg: Springer-Verlag,

11 11 Solar Energy Harvesting Solar cellefficiency, measuredunderam1.5g at T = 25 C Classification Efficiency(%) V oc (V) J s (macm -2 ) FF(%) Description c-si UNSW PERL mc-si FhG-ISE GaAs(thin film) Alta Devices CIGS NREL CdTe NREL a-si Oerlikon Solar Lab Dye Sensitised Sharp Organic polymer Konarka M.A. Green, K. Emery, Y. Hishikawaand W. Warta, Solar cell efficiency tables (version 38), Progress in Photovoltaics: Research and Applications, vol. 19, pp , May

12 12 Kinetic/Vibration Energy Harvesting Conversion of mechanical movements to electrical energy Sources Vibrations Displacements Forces or pressures Traffic Human movement Heating, Ventilating and AC (HVAC) Air currents Water movement 12

13 13 Kinetic/Vibration Energy Harvesting Transducer types: Electromagnetic(inductive) - Faraday s law Electrostatic(capacitive) -Vary thecapacitanceorchargeof a variable capacitor Piezoelectric - Piezoelectric strain d tensor relating MechanicalStress TtoElectric Displacement D 13

14 14 Kinetic/Vibration Energy Harvesting Vibration transducers modeled by massm, attachedtoa frameusinga springk [*]. Mechanical to electric conversion lossesincludedin d. y(t) = Y o sin(wt) A = w 2 Y o P emax = m 2 A 2 /(8d) [*] C.B. Williams and R.B. Yates, Analysis of a Micro-Electric Generator for Microsystems, in Proc. 8 th International Conference on Solid-state Sensors and Actuators and EurosensorsIX, Stockholm, Sweden, pp , June 25-29,

15 15 Kinetic/Vibration Energy Harvesting Require low frequency high-q resonators Application dependent Application / Vibration source Vibration frequency (Hz) Acceleration amplitude (ms -2 ) Door Frame(after door closes) Clothes Dryer Washing Machine HVAC vents in office building Refrigerator Small microwave over External windows next to busy street S. Roundy, "On the Effectiveness of Vibration-based Energy Harvesting, Journal of Intelligent Material Systems and Structures, vol. 16 no. 10, pp , Oct

16 16 Kinetic/Vibration Energy Harvesting Challenges: Self-tuning / Adaptive tuning, Wideband / Multiband Description Frequency (Hz) Power (mw) REF MEMS AlN Piezoelectric [*] JouleThief Piezoelectric 50, 60, 100, [**] PMG-FSH Electromagnetic 50, 60, 100, [***] [*] R. Elfrink, et al., "First autonomous wireless sensor node powered by a vacuum-packaged piezoelectric MEMS energy harvester," in Proc. IEEE International Electron Devices Meeting (IEDM), pp.1-4, 7-9 Dec [**] JouleThief, AdaptivEnergy. [***] PMG FSH, Perpetuum. 16

17 17 Thermal Energy Harvesting Conversion of temperature differences to electrical energy. Sources Waste heat from industrial plants Heating systems Automobiles, other vehicles Human body Three thermoelectric phenomena. Seebeck Peltier Thomson 17

18 18 Thermal Energy Harvesting The Seebeckcoefficient is much higher for semiconductor materials rather than metals and metal alloys, where it can reach magnitudes of 1mV/K. Thermoelectricgenerators(TEGs) are formedbypairsof coupledof N-dopedand P-dopedsemiconductor pellets connected electrically in series and placed between two thermally conductive plates. 18

19 19 Thermal Energy Harvesting Gulielmo Marconi ~ 1895 Villa Griffone, Bologna, Italy 19

20 20 Thermal Energy Harvesting Thermoelectric Figure Of Merit: ZT α σt λ High Seebeck Coefficient(α) High Electrical Conductivity(σ) Low Thermal Conductivity(λ) S. Beeby and N. White, Energy Harvesting for Autonomous Sensors, Artech House

21 21 Thermal Energy Harvesting Wrist watch: SEIKO thermic ~ uw required to power a quartz digital wrist-watch S. Beebyand N. White, Energy Harvesting for Autonomous Systems, Norwood: Artech House, S. Kotanagi, et al., Watch Provided with Thermoelectric Generation Unit, Patent No. WO/1999/

22 22 Thermal Energy Harvesting Challenge: Increase conversion efficiency and maintain temperature gradient Conversion Efficiency limited by Carnot Efficiency n < ( T HOT T COLD )/ T HOT Example: T COLD = 293 K (20 C) and T HOT = 303 K (30 C) => n < 3,3 % T COLD = 233 K (-40 C) and T HOT = 293 K (20 C) => n < 20,48 % 22

23 23 Thermal Energy Harvesting from Power Amplifiers Conversion efficiency φ n 2 0.5n 4/ZT 23

24 24 Electromagnetic Energy Harvesting Conversion of ambient low power electromagnetic sources to electrical power AnElectric fieldof 1V/m in air correspondstoanem power densityof 0.26 uw/cm 2 Key element: Rectenna (Brown US , 1969). Application dependent. Conversion efficiency for available input power of ~ -20 dbmis 10% -20%. 24

25 25 Electromagnetic Energy Harvesting Challenges: Compact antenna elements, arbitrary polarization, broadband, multi-band designs EM simulation to model radiating element. Nonlinear optimization to model rectennacircuit and optimize rectifier taking into account the antenna properties. Antenna in receiving mode (Norton, Thevenin equivalent, Reciprocity) Measurement campaigns necessary 25

26 26 Electromagnetic Energy Harvesting Rectenna design example 2.40GHz -2.48GHz ISM band Aperture coupled patch topology: Circuit and radiator layers are made of ArlonA25N 20mil thick Separated by a Rohacell51 layer of 6mm in order to achieve the desired bandwidth. 26

27 27 Electromagnetic Energy Harvesting Circularly polarized rectenna O. A. Campana Escala, G. A. Sotelo Bazan, Apostolos Georgiadis, and Ana Collado, "A 2.45 GHz Rectenna with Optimized RF-to-DC Conversion Efficiency," PIERS, Marrakesh, Morocco, March 20-23,

28 28 Electromagnetic Energy Harvesting Joint antenna and rectifier optimization using Theveninequivalent of antenna in receive mode. A.Georgiadis, G. Andia-Vera, A. Collado Rectennadesign and optimization using reciprocity theory and harmonic balance analysis for electromagnetic (EM) energy harvesting, IEEE Antennas and Wireless Propagation Letters, vol. 9, pp ,

29 29 Power Harvesting: Electromagnetic Energy Open circuit voltage maybe calculated using reciprocity theory One may optimize in harmonic balance the efficiency at a desired direction of arrival. A.Georgiadis, G. Andia-Vera, A. Collado Rectenna design and optimization using reciprocity theory and harmonic balance analysis for electromagnetic (EM) energy harvesting, IEEE Antennas and Wireless 29 Propagation Letters, vol. 9, pp , Slide 29

30 30 Power Harvesting: Electromagnetic Energy Circuit topology important in low available power conditions Trade-off between efficiency and output voltage 30 Slide 30

31 31 Electromagnetic Energy Harvesting Challenge: determine available power 31

32 32 Flexible Substrates Flexible substrates Paper Liquid crystalline polymer (LCP) Textile Metal coated PET (polyethylene terephthalate) 32

33 33 Flexible Substrates Paper Dielectric constant (*): GHz) Loss tangent (*): GHz) Can be made hydrophobic Inkjet printing Cost : very low Multilayer capability Li Yang, et. al, RFID Tag and RF Structures on a Paper Substrate Using Inkjet-printing Technology, IEEE Transactions on Microwave Theory and Techniques, vol. 55, no. 12, pp , Dec,

34 34 Flexible Substrates PET (Polyethylene Terephthalate) Dielectric constant: GHz) Loss tangent: GHz) Thickness: 50 um 100 um 34

35 35 Flexible Substrates Liquid crystalline polymer (LCP) Dielectric constant: GHz) Loss tangent: GHz) Water absorption < 0.04% Lamination < 282º C Multilayer capability Laser drilling (YAG, CO2) Low cost 35

36 36 Flexible Substrates Textile materials Substrates: natural or man-made fibers, Synthetic fibers: Textile Aramid Fleece Upholstery fabric Vellux Cordura Properties Dielectric constant Strong Heat resistant Dries rapidly 1,85 1,25 Mixture of polyester and polyacryl Synthetic fibre covered by thin layers of foam Polyamide fiber Loss tangent 0,015 0,019 P. Salonen, et. al, Effect of Textile Materials on Wearable Antenna Performance: A Case Study of GPS Antennas, IEEE AP-S, pp , C. Hertleeret. al. Aperture-Coupled Patch Antenna for Integration Into Wearable Textile Systems, IEEE AWPL vol. 6, p , F. Declercq, et al. Permittivity and Loss Tangent Characterization for Garment Antennas Based on a New Matrix Pencil Two-Line Method, IEEE T-AP vol. 56, no. 8, pp , Aug

37 37 Flexible Substrates Conductive Textiles FlecTron, Zelt, ShiedIt, Global EMC ShieldIt has adhesive backing (can be glued, stitched, sewn, ironed to substrate) Surface Resistivity ( Ohm/sq) 37

38 38 Integration Possibilities Smart textiles MEMS (sensors) Hybrid harvesting modules Organic electronics Challenges Washability, Strechability, User comfort, Conformal shape 38

39 39 Integration Solar / Electromagnetic harvester 1.9GHz/-1.5 dbm Transmitter 2.4x3.9 cm 2 Shad Roundy, Brian P. Otis, Yuen-HuiChee, Jan M. Rabaey, Paul Wright, A 1.9GHz RF Transmit Beacon using EnvironmentallyScavengedEnergyIEEE Int. Symposium on Low Power Elec. and Devices, 2003, Seoul, Korea. M. Tanaka, R. Suzuki, Y. Suzuki, K. Araki, "Microstripantennawithsolar cellsformicrosatellites," IEEE International SymposiumonAntennasand Propagation(AP-S), vol. 2, pp , June S. Vaccaro, J.R. Mosig, P. de Maagt, Two Advanced Solar Antenna SOLANT Designs forsatelliteand TerrestrialCommunications, IEEE Transactions on Antennas and Propagation, vol. 51, no. 8, Aug. 2003, p

40 40 Integration Textile /flexible foam passive and active circuit integration. Wearable smart fabric with sensing and communication (transmission) capabilities. F.Declercq, A. Georgiadis and H. Rogier, Wearable Aperture-Coupled Shorted Solar Patch Antenna for Remote Tracking Applications, EuCAP, Rome, April

41 41 Integration Solar / Electromagnetic harvester Ultra-widebandrectenna/ solar harvester Reconfigurable bands, Multiband design Measurements under bended conditions Propagation environments A. Georgiadis, A. Collado, S. Via and C. Meneses, "Flexible Hybrid Solar/EM Energy Harvester for Autonomous Sensors", in Proc IEEE MTT-S Intl. Microwave Symposium (IMS), Baltimore, US, June 5-10,

42 42 RF to DC conversion efficiency optimization: Dual-Band Case 42

43 43 RF to DC conversion efficiency optimization: Broadband Case 43

44 44 Integration Solar powered Active oscillator antenna Beacon signal generator Coplanarfoldedslot antenna Dissipates9 mw Multiband design Solar cell capable to provide up to60 mw 927 MHz operation Francesco Giuppi, ApostolosGeorgiadis, Selva Via, Ana Collado, RushiVyas, Manos M. Tentzerisand Maurizio Bozzi, A 927 MHz Solar Powered Active Antenna Oscillator Beacon Signal Generator, RWW 2012, Santa Clara. 44

45 45 Solar Beacon Signal Generator 927 MHz beacon signal Active antenna oscillator Solar powered 45

46 46 Solar Beacon Signal Generator 920 MHz beacon signal Active antenna oscillator PET substrate Solar powered A. Georgiadis, A. Collado, S. Kim, H. Lee, M. M. Tentzeris, UHF Solar Powered Active Oscillator Antenna on Low Cost Flexible Substrates for Wireless Identification Applications, to appear at MTT-S IMS

47 47 Solar Beacon Signal Generator Frequency (MHz) 47

48 48 Solar Passive RFID Tag A. Georgiadis and A. Collado, Improving Range of Passive RFID Tags Utilizing Energy Harvesting and High Efficiency Class-E Oscillators, to appear at EuCAP

49 49 Performance Evaluation Proofof concept: RFID tagand wireless power transmission Using Impinj reader and RF signal generator Read rate improvement Saturation Read rate (%) Read rate (%) Freq (MHz) 49

50 50 Performance Evaluation Using Impinj reader and oscillator Measured3 dbmless reader power for maximum read rate 50

51 51 Signal Waveform Design for Improved Efficiency Improved RF to DC conversion efficiency when using chaotic signals. Output power (dbm) 433 MHz chaotic generator 51 A. Collado, A. Georgiadis, "Improving Wireless Power Transmission Efficiency Using Chaotic Waveforms," to appear at IEEE MTT-S IMS 2012, Montreal, June 2012.

52 52 Signal Waveform Design for Improved Efficiency Total power of 1-tone signal selected to be equal to the chaotic signal total power in the bandwidth of the rectifier rectifier circuit with optimized efficiency at 433 MHz Output power (dbm) 52 A. Collado, A. Georgiadis, "Improving Wireless Power Transmission Efficiency Using Chaotic Waveforms," to appear at IEEE MTT-S IMS 2012, Montreal, June 2012.

53 53 Signal Waveform Design for Improved Efficiency Input power = -6.5 dbm DC voltage for the 1-tone signal is 0.76V (46% RF to DC conversion efficiency) DC voltage for chaotic signal is 0.91 V (66% RF to DC conversion efficiency) 53 A. Collado, A. Georgiadis, "Improving Wireless Power Transmission Efficiency Using Chaotic Waveforms," to appear at IEEE MTT-S IMS 2012, Montreal, June 2012.

54 54 Energy Harvesting - Example Harvester output: 2.5V, 0.5mA (1.25mW) Required TX Pulsed transmission: 2.5 V, 20mA (50mW), with a pulse duration of T = 10 ms. Maximum duty cycle: DC = 100*1.25/50 = 2.5% Burst rate: T/DC = 0.01/0.025 = 0.4sec or2.5hz If harvester output is 10 uw => Burst rate 50 sec 54

55 55 Power Management Voltage Regulators Storage Units 55

56 56 Summary Energy Harvesting Technologies Low cost, flexible materials and fabrication techniques Hybrid harvesting systems and integration 56

57 57 ACKNOWLEDGEMENT: Work supported by EU COST Action IC0803 RFCSET EU Marie Curie project SWAP, FP

58 58 Upcoming events: IEEE MTT-S IMS2013, Seattle, June 2-7, 2013 Technical Area 32: RFID Technologies Deadline for paper submission: 10 Dec IEEE MTT-S Wireless Power Transfer Conference(WPTC ) Perugia, May 2013 Deadline for paper submission: 12 Jan Questions? 58