Electromagnetic energy harvesting holds a promising future for energizing low power electronic devices in wireless communication circuits. This article presents an RF energy harvesting system that can harvest energy from the ambient surroundings at the downlink radio frequency range of GSM-900 band. The harvesting system is aimed to provide an alternative source of energy for energizing low power devices. The system design consists of three modules: a single wideband 377 Ω E-shaped patch antenna, a pi matching network and a 7-stage voltage doubler circuit. These three modules were fabricated on a single printed circuit board. The antenna and Pi matching network have been optimized through electromagnetic simulation software, Agilent ADS 2009 environment. The uniqueness of the system lies in the partial ground plane and the alignment of induced electric field for maximum current flow in the antenna that maximizes the captured RF energy. The design and simulation of the voltage doubler circuit were performed using Multisim software. All the three modules were integrated and fabricated on a double sided FR 4 printed circuit board. The DC voltage obtained from the harvester system in the field test at an approximate distance of 50 m from GSM cell tower was 2.9 V. This voltage was enough to power the STLM20 temperature sensor.
2. Roundy, S., B. Otis, Y. H. Chee, J. Rabaey, and P. Wright, "A 1.9 GHz RF transmit beacon using environmentally scavenged energy," ACM International Symposium on Low Power Electronics and Design , 2003.
3. Le, T., K. Mayaram, and T. S. Fiez, Efficient far-field radio frequency power conversion system for passively powered sensor networks, IEEE Custom Integrated Circuits Conference (CICC), 293-296, Sep. 2006.
4. Sudou, M., H. Takao, K. Sawada, and M. Ishida, A novel RF induced DC power supply system for integrated ubiquitous micro sensor devices, International Solid-State Sensors, Actuators and Microsystems Conference, 907-910, Jun. 2007.
5. Ungan, T. and L. M. Reindl, "Concept for harvesting low ambient RF-sources for microsystems," http://www.imtek.de/content/pdf/public/2007/powermems 2007paper ungan.pdf, Accessed on April 9, 2009.
6. Ungan, T. and L. M. Reindl, "Harvesting low ambient RF-sources for autonomous measurement systems," IEEE Instrumentation and Measurement Technology Conference proceedings, 62-65, May 2008.
7. Le, T. T., E±cient power conversion interface circuits for energy harvesting applications, PhD Thesis, Oregon State University, USA, Jun. 2008.
8. Visser, H. J., A. C. F. Reniers, and J. A. C. Theeuwes, Ambient RF energy scavenging: GSM and WLAN power density measurements, Proceedings of the 38th European Microwave Conference, 721-724, Netherlands, Oct. 2008.
9. Asefi, M., S. H. Nasab, L. Albasha, and N. Qaddoumi, "Energizing low power circuits by using an RF signal harvester," 16th Telecommunications Forum TELFOR, Nov. 2008.
10. Hart, H., K. Lanham, and M. Sass, S-band radio frequency energy harvesting, Science Applications International Corporation, May 2009.
11. Jabbar, H., Y. S. Song, and T. T. Jeong, "RF energy harvesting system and circuits for charging of mobile devices consumer electrons," IEEE Transcations on Consumer Electronics, Vol. 56, No. 1, 247-253, Feb. 2010.
12. Arrawatia, M., M. S. Baghini, and G. Kumar, RF energy harvesting system at 2.67 and 5.8 GHz, Proceedings of Asia-Pacific Microwave Conference, 900-903, 2010.
13. Arrawatia, M., M. S. Baghini, and G. Kumar, RF energy harvesting system from cell towers in 900MHz band, National Conference on Communications, (NCC) 2011, 1-5, Jan. 28-30, 2011.
14. http://www.rfwirelesssensors.com/2009/01/intel-ambient-rf-energy-harvesting-demonstration/, Accessed on May 5, 2009.
15. http://www.powercastco.com/PDF/P2110-datasheet.pdf, Accessed on Jun. 14, 2010.
16. Chiam, T. M., L. C. Ong, M. F. Karim, and Y. X. Guo, 5.8 GHz circularly polarized rectennas using schottky diode and LTC5535 rectifier for RF energy harvesting, 2009 Asia-Pacific Microwave Conference (APMC 2009), 32-35, 2009.
17. Farinholt, K. M., G. Park, and C. R. Farra, "RF energy transmission for a low-power wireless impedance sensor node," IEEE Sensors Journal, Vol. 9, No. 7, 793-800, Jul. 2009.
18. Devi, K. K. A., S. Sadasivam, N. M. Din, C. K. Chakrabarthy, and S. K. Rajib, "Design of a wideband 377 E-shaped patch antenna for RF energy harvesting ," Microwave and Optical Technology Letters, Vol. 54, No. 3, 569-573, Mar. 2012.
19. Balanis, C. A., Antenna Theory, 3rd Ed., John Wiley & Sons, New York, 2005.
20. Stutzman, W. and G. Thiele, Antenna Theory and Design, 2nd Ed., ISBN 0-471-02590-9, Wiley, 1997.
21. Devi, K. K. A., N. M. Din, and C. K. Chakrabarthy, "Optimization of the voltage doubler stages in an RF-DC convertor module for energy harvesting," Circuits and Systems, Vol. 3, No. 3, Jul. 2012.
22. Harris, D. W. Wireless battery charging system using radio frequency energy harvesting, Thesis, BS, University of Pittsburgh, Jul. 13-15, 2004.
23. Wong, K. L. and Y. F. Lin, "Small broadband rectangular microstrip antenna with chip-resistor loading," Electron. Lett., Vol. 39, 1593-1594, 1997.
24. STMicroelectronics STLM20 application note, http://www.st.com/internet/com/Technical resources/technicalliterature/application note /CD00174666.pdf, Accessed on Nov. 12, 20.
25. STMicroelectronics, "STLM20 ultra-low current precision analog temperature sensor," http://www.st.com/, Accessed on Nov. 12, 2010.