Wireless Without Batteries:

Transcription

1 Wireless Without Batteries: Long-Range Data Transmission with Virtually no Power by Prof. Gregory D. Durgin IEEE APS-MTT Chapter Meeting 31 July 2012, Tuesday, TSRB

2 Acknowledgements Georgia Tech Foundation Center for Organic Photonics and Electronics Georgia Research Alliance NSF CAREER Grant ECS NSF CMDITR Grant Luna Innovations Southern States LLC Applied Physics Lab Thingamagigawerks LLC Space Solar Power Institute Center for Pediatric Health Technology & Innovation

3 Greg Durgin: Professor tenure 2009 Chris Valenta: 5.8 GHz RF tags/sensors PhD 2012 Marcin Morys: 5.8 GHz RF tags/antennas PhD 2014 M. Bashir Akbar: 5.8 GHz RF tags/sensors PhD 2014 Josh Griffin: object penalty; fading; - multi antenna system PhD 2009 Matt Trotter: Charge Pumps and Passives PhD 2011 Blake Marshall: 5.8 GHz array harvestor PhD 2014 Raj : Bhattacharjea Down-conversion - Modifications PhD 2012 Anil Rohatgi: Anti - collision MS 2006 Gregory Koo: Backscatter Antennas MS 2011 Albert Lu: RFID receivers BS 2005 Lab Engineer Azhar Hasan: REMS sensors for RFID PhD 2012 Joel Prothro: On metal tag degradations MS 2007 Cody Lamb: printed antennas and RCS MS 2007 Ryan Pirkl: RF hardware for RFID PhD 2010 Patrick Graf: Multiple - Access systems MS 2010 Rikai Huang: PIN modulator designs MS 2008 Alex Trzecieski: FET Modulator Designs MS 2008 John Livingston: magnetic material for RFID MS 2007

4 IEEE GLOBECOM 2013, Atlanta 9-13 December /21/2012 rev 2 4

5 Introduction 5 Copyright

6 Main Goals of this Talk Circuits can now communicate over surprising distances with little or no power supply Microwave backscatter sensors enable some interesting applications

7 Modulated Backscatter Systems 7 Copyright

8 Gains for Passive Communications P. Nikitin, KVS Rao, S. Lam, UHF RFID Tag Characterization: Overview And State-of-the-Art. AMTA Conference, Seattle, Oct Copyright

9 5.8 GHz Backscatter Research at GT

10 5.8 GHz Software Radio Platform Full 5.8 GHz Backscatter Transceiver System Sensor Signal RF Sensor Tag Board 5.8 GHz Backscatter Down-converter Box GHz Signal Generator Board RF Power Amplifier Board TX Antenna Board RX Antenna Board 1 RF Down-conversion Board Baseband Amplification Stage Demodulation Board 9 Sensor Signal 1 10 Copyright

11 Case Study: Power Line Sensor 11 Copyright

12 Why Use Microwave Backscatter? Low-cost sensor/id nodes Application prohibits batteries Unique physical, channel attributes Flexible protocol development Location and fine-scale tracking Unique remote sensing attributes Novel approach to circumvent IP Security (no active transmission) 12 Copyright

13 Traditional High-Voltage Sensing Current Transformers Used in current monitoring Oil used for insulation Advantages Reliable communication link Widely tested, well understood Disadvantages Costly Bulky Limited location Courtesy 13

14 Monitor Current on High Voltage Wind farm with capacitor bank Fire danger! 14 Copyright

15 Wireless High-Voltage Sensing Wireless Sensing Air gap insulation Advantages Inexpensive Small Versatile Disadvantages Complex communication channel Need to power sensor 15

16 5.8 GHz Sensor for High Voltage Lines max 3m TR separation 1000 packets/sec 3-6 channels of sensors 63-chip spread spectrum FCC-compliant freq hopping < 5mW sensor draw two 12-bit words per sample Picture of Southern States LLC Current Measurement Device II

17 Checklist for High Voltage Sensing Low-cost sensor/id nodes Application prohibits batteries Unique physical, channel attributes Flexible protocol development Location and fine-scale tracking Unique remote sensing attributes Novel approach to circumvent IP Security (no active transmission) 17 Copyright

18 Corona Noise Corona process involves avalanche of electrons Moving charges electromagnetic radiation Xiaofeng, et.al measured noise spectrum [1] Radiated energy measured up to 650 MHz Energy proportional to line voltage [2] Design RFID/sensor system to operate well above expected noise frequency bands 2.4GHz, 5.8GHz 18

19 Corona Measurement Setup We want to measure: Corona noise Corona shielding Additional losses Test Setup Durgin, et. al. 5.8 GHz Backscatter Sensor Measurement Across High Voltage Insulation Gaps, PG-TR CRV, 21 April Copyright 2006-present

20 Corona Shielding Direction connection to corona wire Fails past 100 kv Electronics still working Invisible Faraday cage Cutoff frequency: 20 Copyright 2006-present

21 Analysis of Antennas in Corona 21 Copyright

22 Propagation Through Corona Layer E m = electron mass x = electron displacement e = electron charge E = wave electric field strength v = collision frequency 22

23 Propagation Through Corona Layer Applying Maxwell s equations, obtain the attenuation and propagation constants [3] At atmospheric pressure, electron collision frequency much higher than wave frequency [4] Complex permittivity given by m = electron mass e = electron charge n = electron density v = collision frequency 23

24 Attenuation (db/cm) Wave Attenuation By Corona Frequency (GHz) 24

25 Simulation Plasma Modeling Plasma can be modeled with separate electron density slabs [5] Corona layer electron density distribution based on corona simulations of Argon at atmospheric pressure [6] 10 layers of 0.1mm thickness 25

26 Simulation Model, No Plasma Dimension Size (mm) Antenna x Antenna y 19.3 Antenna-ground plane height 0.24 Board height 1.5 Board length 30 26

27 S11 db Antenna Impedance Change 27 Frequency (GHz)

28 Simulation Input Impedance 28

29 Gain and Radiation 5.8 GHz Electron density (m^-3) Radiation efficiency Peak Gain (db) No Plasma 55% 4.46 n_max = 1e18 50% 4.15 n_max = 1e19 39% 3.02 n_max = 1e20 23%

30 Conclusions Strategies for both analysis and design of antennas for the high-voltage environment Successful tech transfer of microwave backscatter system Other case studies Motion capture systems ATM skimmer detection Wireless diapers 30 Copyright

31 Bibliography [1] H. Xiaofeng, L. Shanghe, W. Ming, and W. Lei, Measurement and analysis of Electromagnetic Fields Radiated by Corona Discharge, in International Symposium on Electromagnetic Compatibility [2] P. Sporn and A. C. Monteith, Progress Report on Tidd 500-kV Test Project of the American Gas and Electric Company Corona, Radio Influence, and Other Factors, AIEE Summer and Pacific General Meeting, Vol. 69, pp , June [3] M. A. Heald and C. B. Wharton, Plasma Diagnositics With Microwaves. New York: Wiely, [4] M. Laroussi and W. T. Anderson, Attenuation of electromagnetic waves by a plasma layer at atmospheric pressure, International Journal of Infrared and Millimeter Waves, vol. 19, no. 3, 1998, pp [5] Li Wei, Qiu Jinghui, and Deng Weibo, Radiation characteristics of planar reflector antenna covered by a plasma sheath, in The 19th International Zurich Symposium on Electromagnetic Compatibility, Zurich, 2008, pp [6] T. Farouk, B. Farouk, D. Staack, A. Gutsol, and A. Fridman, Simulation of dc atmospheric pressure argon micro glow-discharge, Plasma Sources Science and Technology, vol. 15, p. 676,

32 [Questions]