Apostolos Georgiadis

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Contact Info

Senior Research Associate
CTTC
Parc Mediterrani de la Tecnologia (PMT)
Av. Carl Friedrich Gauss 7
08860 - Castelldefels
Barcelona (Spain)
Tel: +34 93 645 2900 Ext. 2180
Fax: +34 93 645 2901
Email: ageorgiadis@cttc.es
Web: CTTC, Communications Subsystems, Apostolos Georgiadis

News

  1. Ronald J. Pogorzelski and Apostolos Georgiadis, Coupled-Oscillator Based Active-Array Antennas, Deep Space Communications and Navigation Series (DESCANSO), vol. 11, Jet Propulsion Laboratory, California Institute of Technology, 2012, published by John Wiley & Sons.


Resume

Apostolos Georgiadis (S'94–M'03-SM'08) was born in Thessaloniki, Greece. He received the B.S. degree in physics and the M.S. degree in telecommunications from the Aristotle University of Thessaloniki, Greece, in 1993 and 1996, respectively. He received the Ph.D. degree in electrical engineering from the University of Massachusetts, Amherst, in 2002.

In 1995, he spent a semester with Radio Antenna Communications (R.A.C.), Milan Italy, working on Yagi antennas for U.H.F. applications. In 2000, he spent three months with Telaxis Communications, South Deerfield MA USA, assisting in the design and testing of a pillbox antenna for LMDS applications. In 2002 he joined Global Communications Devices (GCD), North Andover MA USA, as a Systems Engineer and worked on CMOS transceivers for wireless network applications. In June 2003, he joined Bermai, Inc., Minnetonka MN USA, as an RF/Analog Systems Architect. In 2005 he joined the University of Cantabria, Spain, as a Juan de la Cierva Fellow researcher. In 2006 he was a consultant for Bitwave Semiconductor, Lowell MA, US. In addition he collaborated with ACORDE S.A., Santander, Spain, in the design of integrated CMOS VCOs for ultra wideband (UWB) applications. In March 2007 he joined CTTC as a senior research associate in the area of Communications Subsystems.

In 1996, Dr. Georgiadis received a Fulbright Scholarship for graduate studies at the University of Massachusetts, Amherst. He received the Outstanding Teaching Assistant Award from the University of Massachusetts, Amherst, in 1997 and 1998. He also was the recipient of the Eugene M. Isenberg Award from the Isenberg School of Management, University of Massachusetts, Amherst, in 1999 and 2000. He is the Chairman of COST Action IC0803 RF/Microwave communication subsystems for emerging wireless technologies (RFCSET). He is the Coordinator of Marie Curie Industry-Academia Pathways and Partnerships (IAPP) project Symbiotic Wireless Autonomous Powered system (SWAP). He serves at the Editorial board of the Radioengineering Journal.

Research Interests

Research work is related to RF/microwave circuits and sytems. A lot of recent work is about oscillators and coupled oscillator arrays, but work is also done in phased array antennas, retro-directive antennas and rectifying antennas. We are interested in low power sensor design and energy harvesting techniques, as well as wideband oscillators for software radio and other ultra-wideband applications. Did I mention coupled oscillator arrays? a little bit of that too!

Energy harvesting and solar-antennas

Multi-band flexiible solar rectenna on PET substrate

Dual polarized 2.45GHz patch rectenna (front)

Dual polarized 2.45GHz patch rectenna (back)

RFID pasive solar TAG

Flexible PET 920 MHz active beacon oscillator antenna

Flexible, low cost, solar-rectenna designed on PET substrate using an a-Si:H solar cell (work together with Ana Collado).

A 2.45 GHz rectenna designed by Gianfranco Andia, used for recycling ambient electromagnetic energy from existing WiFi networks. A dual linearly polarized aperture coupled patch antenna is implemented, with a rectifying circuit optimized for low input power densities.

A solar passive RFID tag antenna with extended operating range and a flexible (PET) active oscillator antenna beacon signal generator.

Sample videos of electromagnetic (EM) harvesting demo experiments using an UWB monopole antenna and a broadband rectifier in CTTC, a) mobile phone, b) microwave oven. The maximum harvested power was about 25uW.


Active and passive SIW circuits

C-band flexible SIW slot array on PET substrate

C-band flexible SIW filter on PET substrate

X-band compact active antenna oscillator

X-band compact active oscillator array (top-active circuit)

X-band compact active oscillator array (bottom-antenna)

X-band Cavity backed patch antenna

X-band Cavity backed slot antenna

2x1 Slot Antenna Array

X-band Oscillator

29 GHz Push-push Oscillator


24 GHz SIW array, courtesy of Tomas Mikulasek, visiting from Brno University of Technology, CZ

24 GHz SIW array (top side - slot coupled patch array)

24 GHz SIW array (anechoic chamber)


Recent work includes oscillators and active oscillator antennas using Substrate Integrated Waveguide (SIW) resonators. C-band flexible SIW passive circuits on PET substrate including a slot array and a filter, implemented together with Riccardo Moro from the University of Pavia. Recent active antenna work includes compact antenna oscillators and a three element array. X-band active oscillator antennas based on SIW cavity resonators, patch, slot and a 2x1 slot array are also shown. This work was done in collaboration with Francesco Giuppi and Maurizio Bozzi from the University of Pavia. Furthermore the measurement setup of a 9.17 GHz oscillator is shown, followed by a photo of a 29.5 GHz push-push oscillator. Recent collaboration with Tomas Mikulasek from Brno University of Technology has led to the design of 24 GHz SIW antennas and arrays.

Oscillators and arrays

Triple push oscillator with 2 GHz fundamental frequency

UWB CMOS VCO

4x4 6GHz active antenna coupled oscillator array

X-band 2nd harmonic coupled oscillator array antenna

S-band self-oscillating mixer (SOM) retrodirective array

Left to right: A photo of a triple push oscillator, with fundamental frequency at 2 GHz. Nonlinear analysis is used to predict the various operating modes due to the symmetry of the topology and eliminate the unwanted ones. The work was done together with Ana Collado and Selva Via.

A low power, UWB CMOS VCO was designed for ACORDE, Santander, -10 dBm output power, 0.5 GHz - 5 GHz tuning range are some of the specifications. This is a photo of the PCB test board of one of the samples.

This is a 2D, 16 element, C-band coupled oscillator array designed using off-the-shelf components. The nonlinear properties of the coupled oscillator system are used to generate phase shift distributions among the array elements and introduce reconfigurable beam properties in the array. The design work was done together with Ana Collado.

A 2nd harmonic, three element, X-band active antenna array based on coupled oscillators, and a 2.9 GHz retro-directive, two element array, heterodyne architecture, using coupled self-oscillating mixers.


...and finally, some pictures from my Ph.D. work at UMass (long ago!)...

2.4 GHz tranceiver using off-the-shelf components

Receiver early prototype photo

Receiver photo

Measured QPSK eye pattern at 10MBPS

Outdoor BER measurements

Two versions of the receiver board are shown followed by an eye pattern taken using 5 MSPS QPSK modulation. A corresponding transmitter board was designed and the system was used as a bit error rate test-bed. One of many outdoor measurements is shown taken at the UMASS Amherst campus, outside Marcus Hall, back in 2001 !

Grants / Awards

  • 2012 IEEE Topical Meeting on Wireless Sensors and Wireless Sensors Networks (WiSNet), Radio Wireless Week, Santa Clara Jan. 15-18, 2012, (advisor) Student Contest Finalist
  • 2011 IEEE RFID-TA Conference, Sitges Sep. 15-16, 2011, 3rd Best Paper Award
  • 2010 Acreditation Profesor Agregado AQU Catalunya
  • 2010 5th COST IC0803 Workshop, Nov. 8-9,2010 EPFL, Lausanne, Switzerland (advisor) Best Student Paper Award
  • 2010 Applied Computational Electromagnetics (ACES) Symposium (advisor) 2nd Best Student Paper Award
  • 2010 European Antennas and Propagation (EuCAP) Symposium (advisor) Best Student Paper Award
  • 2007 Torres Quevedo Grant, Ministry of Science and Innovation, Spain
  • 2004 Juan de la Cierva Grant, Ministry of Science and Innovation, Spain
  • 2000 Eugene M. Isenberg Award, University of Massachusetts, Amherst
  • 1999 Eugene M. Isenberg Award, University of Massachusetts, Amherst
  • 1998 Outstanding Teaching Assistant Award, University of Massachusetts, Amherst
  • 1997 Outstanding Teaching Assistant Award, University of Massachusetts, Amherst
  • 1996 Fulbright-Hayes Fellowship, Fulbright Foundation, Greece

Activities / Event Organization

Visitors / Students

  1. Kyriaki Niotaki, Ph.D. student.
  2. Alessandro Acampora, Ph.D. student, Design of Novel Frequency Generation Circuits with Application to Ultrawideband Distributed Oscillators.

Alumni

  1. Tomas Mikulasek, Ph.D. student, Short Term Scientific Mission, COST IC0803, 1 Feb - 23 Mar 2012, visiting from Brno University of Technolgy, Czech Republic.
  2. Kyriaki Niotaki, M.Sc. student, Ambient Energy Harvesting Measurements, July 1, 2011 - Sep. 30, 2011, visiting from Aristotle Univ. of Thessaloniki, Greece with Erasmus Student Mobility Program.
  3. Ludimar Guenda, M.Sc., Short Term Scientific Mission, COST IC0803, June 13-25 2011, visiting from University of Aveiro, Portugal.
  4. Francesco Giuppi, Ph.D. student, Sep. 2010 - Feb. 2011, visiting from the University of Pavia, Italy.
  5. Gustavo Adolfo Sotelo Bazán, M.Sc., December 2010, Design of a circularly polarized patch antenna for satelite mobile communications in L-band.
  6. Chomora Mikeka, Ph.D. student, Nov. 2010 - Dec. 2010, visiting from Yokohama National University, Japan.
  7. Cesar Meneses Ghiglino, M.Sc., October 2010, Ultra-Wideband (UWB) rectenna design for Electromagnetic Energy Harvesting.
  8. Omar André Campana Escala, M.Sc., October 2010, Study of the efficiency of EM harvesting rectifying antenna systems.
  9. Renzo Diaz, M.Sc., October 2010, X-band Substrate Integrated Waveguide Cavity-backed Patch Antenna Self-Oscillating Mixer.
  10. Frederick Declercq, Ph.D. student, Short Term Scientific Mission, COST IC0803, May 3-15 2010, visiting from Ghent University, Belgium.
  11. Francesco Giuppi, Ph.D. student, Short Term Scientific Mission, COST IC0803, Sep. 2009 - Oct. 2009, visiting from the University of Pavia, Italy.
  12. Gianfranco Andia, M.Sc., June 2009, Efficient Rectenna Design for Ambient Microwave Energy Recycling.

Publications

For a detailed list of publications please visit CTTC, and for a list of citations take a look at google scholar citation.

Recent Book

  1. Ronald J. Pogorzelski and Apostolos Georgiadis, Coupled-Oscillator Based Active-Array Antennas, Deep Space Communications and Navigation Series (DESCANSO), vol. 11, Jet Propulsion Laboratory, California Institute of Technology, 2012, published by John Wiley & Sons. (New)



Recent Journal Publications

  1. F. Giuppi, A. Georgiadis, A. Collado and M. Bozzi, "A Compact, Single-Layer Substrate Integrated Waveguide (SIW) Cavity-Backed Active Antenna Oscillator," IEEE Antennas and Wireless Propagation Letters, vol. 11, 2012. (New)
  2. A. Georgiadis and M. Bozzi, "Editorial: RF/Microwave Communication Subsystems for Emerging Wireless Technologies," IET Microwaves, Antennas and Propagation, vol. 5, no. 8, pp. 861–863, June 2011.
  3. M. Bozzi, A. Georgiadis, and K. Wu, "Review of Substrate Integrated Waveguide (SIW) Circuits and Antennas," IET Microwaves, Antennas and Propagation, vol. 5, no. 8, p.909–920, June 2011.
  4. F. Mira, M. Bozzi, F. Giuppi, L. Perregrini, and A. Georgiadis, "Efficient Design of SIW Filters by Using Equivalent Circuit Models and Calibrated Space-Mapping Optimization," International Journal of RF and Microwave Computer–Aided Engineering, Vol. 20, No. 6, pp. 689–698, November 2010.
  5. A. Collado and A. Georgiadis, “Performance of Coupled Oscillator Arrays with Angle-Modulated Injection Signals,” IEEE Transactions on Circuits and Systems I, vol. 57, no.9, pp. 2343 - 2352, Sep. 2010.
  6. F. Giuppi, A. Georgiadis, M. Bozzi, S. Via, A. Collado, and L. Perregrini, "Hybrid Electromagnetic and Non-linear Modeling and Design of SIW Cavity-Backed Active Antennas," ACES Journal, Vol. 25, No. 8, pp. 682-689, Aug. 2010.
  7. F. Giuppi, A. Georgiadis, A. Collado, M. Bozzi, and L. Perregrini, "Tunable SIW Cavity Backed Active Antenna Oscillator," IET Electronics Letters, vol. 46, no. 5, p.1053-1055, July 2010.
  8. 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 Propagation Letters, vol. 9, pp. 444-446, 2010.

Recent Conference Publications

  1. R. Moro, A. Collado, A. Georgiadis, S. Via, M. Bozzi, "Plastic-based Substrate Integrated Waveguide (SIW) Components and Antennas" to appear at EuMW 2012, Amsterdam, 28 Oct. - 2 Nov. 2012. (New)
  2. A. Collado, R. Diaz, A. Georgiadis, "X-band Substrate Integrated Waveguide (SIW) Active Antenna Self-Oscillating Mixer (SOM)," to appear at 2012 IEEE AP-S/USNC-URSI, Chicago, 8-14 July 2012. (New)
  3. A. Georgiadis, A. Collado, S. Kim, H. Lee, M.M. Tentzeris, "UHF Solar Powered Active Oscillator Antenna on Low Cost Flexible Substrate for Application in Wireless Identification," to appear at IEEE MTT-S IMS 2012, Montreal, 17-22 June 2012. (New)
  4. A. Collado, A. Georgiadis, "Improving Wireless Power Transmission Efficiency Using Chaotic Waveforms," to appear at IEEE MTT-S IMS 2012, Montreal, 17-22 June 2012. (New)
  5. F. Giuppi, A. Collado, A. Georgiadis and M. Bozzi, "Active Substrate Integrated Waveguide (SIW) Antenna with Phase-Shifterless Beam-Scanning Capabilities," to appear at IEEE MTT-S IMS 2012, Montreal, 17-22 June 2012. (New)
  6. A. Georgiadis and A. Collado, "Improving Range of Passive RFID Tags Utilizing Energy Harvesting and High Efficiency Class-E Oscillators," in Proc. EuCAP 2012, Prague, 26-30 March 2012.
  7. Francesco Giuppi, Apostolos Georgiadis, Selva Via, Ana Collado, Rushi Vyas, Manos M. Tentzeris and Maurizio Bozzi, "A 927 MHz Solar Powered Active Antenna Oscillator Beacon Signal Generator," 2012 IEEE Topical Conference on Wireless Sensors and Sensor Networks part of 2012 IEEE Radio Wireless Week (RWW 2012), Santa Clara, US, 15-18 Jan 2012. (Student Contest Finalist)
  8. Ludimar Guenda, Ana Collado, Nuno Borges Carvalho, Apostolos Georgiadis and Kyriaki Niotaki, "Electromagnetic Geo-referenced Footprints for Energy Harvesting Systems," 2012 IEEE Radio Wireless Week (RWW 2012), Santa Clara, US, 15-18 Jan 2012.
  9. N. Bui, A. Georgiadis, M. Miozzo, M. Rossi, X. Vilajosana, "SWAP Project: Beyond the State of the Art on Harvested Energy-Powered Wireless Sensors Platform Design," IEEE Workshop on Internet of Things Technology and Architectures 2011 (IoTech), Valencia, Spain, Oct. 27-21, 2011.
  10. Ch. Mikeka, H. Arai, A. Georgiadis and A. Collado, "DTV Band Micropower RF Energy-Harvesting Circuit Architecture and Performance Analysis," 2011 IEEE RFID- Technologies and Applications (RFID-TA), Sitges – Barcelona, Spain, Sep. 15-16, 2011. (3rd Best Paper Award)
  11. F. Giuppi, A. Collado, A. Georgiadis, M. Bozzi, S. Via, L. Perregrini, "A Tolerance Study on 30 GHz Planar Filters based on Substrate Integrated Waveguide Technology," 2011 IEEE MTT-S International Microwave Workshop Series (IMWS) on Millimeter Wave Integration Technologies, Sitges – Barcelona, Spain, Sep. 15-16, 2011.
  12. A. Collado, A. Georgiadis, "Flexible Dual‐Band Rectifier Circuits for Electromagnetic Energy Harvesting Solutions," 4th International Symposium on Flexible Organic Electronics (ISFOE11), Thessaloniki, Greece, 10‐13 July 2011.
  13. A. Georgiadis, A. Collado, "Flexible Solar Antenna for Autonomous Smart Sensors," 4th International Symposium on Flexible Organic Electronics (ISFOE11), Thessaloniki, Greece, 10‐13 July 2011.
  14. F. Giuppi, A. Georgiadis, A. Collado, M. Bozzi, L. Perregrini, "A study of a reflectarray topology based on coupled oscillator arrays using Substrate Integrated Waveguide technology," IEEE AP-S, Spokane WA, USA, July 3-8, 2011.
  15. A. Georgiadis, A. Collado, S. Via and C. Meneses, "Flexible Hybrid Solar/EM Energy Harvester for Autonomous Sensors", in Proc. 2011 IEEE MTT-S Intl. Microwave Symposium (IMS), Baltimore, US, June 5-10, 2011.
  16. F. Declercq, A. Georgiadis and H. Rogier, "Wearable Aperture-Coupled Shorted Solar-Patch Antenna for Remote Tracking and Monitoring Applications", in Proc. EuCAP, Rome, Italy, April 11-15, 2011.
  17. 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, 2011.
  18. A. Collado, A. Georgiadis, "Experimental Investigation of Distributed Detection Using a Sensor Network Based on Coupled Oscillator Arrays," IEEE Sensors 2010 Conference, Waikoloa HI, USA, Nov. 1-4, 2010.
  19. A. Georgiadis, A. Collado, "Active Reconfigurable Reflectarray based on Voltage-Controlled Oscillators," IEEE International Symposium on Phased Array Systems and Technology, Waltham MA, USA, Oct. 12-15, 2010.


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