In this paper, a methodology to design non-50 Ω antennas for energy harvesting is presented. Two prototypes are simulated and realized on an epoxy substrate: one operating at 433 MHz and 900 MHz, the other at 900 MHz and 2.4 GHz. These antennas are designed to match the input impedances of an integrated radio-frequency harvester for an output voltage of 1 V, value chosen considering the voltage needed to power the new generation of micro-controllers and electronic circuits for the Internet of Things. The measurement results indicate a reflection coefficient below -10 dB at the frequencies of interest, validating the methodology.
2. Pinuela, M., P. D. Mitcheson, and S. Lucyszyn, "Ambient RF energy harvesting in urban and semiurban environments," IEEE Transactions on Microwave Theory and Techniques, Vol. 61, No. 7, 2715-2726, July 2013.
3. Li, B., S. Xi, N. Shahshahan, N. Goldsman, T. Salter, and G. M. Metze, "An antenna co-design dual band RF energy harvester," IEEE Transactions on Circuits and Systems I: Regular Papers, Vol. 60, No. 12, 3256-3266, December 2013.
4. Niotaki, K., S. Kim, S. Jeong, A. Collado, A. Georgiadis, and M. Tentzeris, "A compact dualband rectenna using slot-loaded dual band folded dipole antenna," IEEE Antennas and Wireless Propagation Letters, Vol. 12, 1634-1637, 2013.
5. Kuhn, V., C. Lahuec, F. Seguin, and C. Person, "A multi-band stacked RF energy harvester with RF-to-DC efficiency up to 84%," IEEE Transactions on Microwave Theory and Techniques, Vol. 63, No. 5, 1768-1778, May 2015.
6. Parks, A. N. and J. R. Smith, "Sifting through the airwaves: Efficient and scalable multiband RF harvesting," Proc. of IEEE International Conference on RFID, 7481, April 2014.
7. Parks, A. N. and J. R. Smith, "Active power summation for efficient multiband RF energy harvesting," Proc. of International Microwave Symposium, 2015.
8. HFSS by Ansys, http://ansys.com/en-GB/Products/Electronics/ANSYS-HFSS,.
9. Balanis, C. A., Antenna Theory: Analysis and Design, 3rd Ed., Wiley-Interscience, Hoboken, New Jersey, 2005.
10. Brown, G. H. and O. M. Woodward, "Experimentally determined radiation characteristics of conical and triangular antennas," RCA Review, Vol. 13, No. 4, 425-452, December 1952.
11. Booker, H. G., "Slot aerials and their relation to complementary wire aerials (Babinet’s principle)," Journal of the Institution of Electrical Engineers --- Part IIIA: Radiolocation, Vol. 93, No. 4, 620-626, 1946.
12. Bergeret, E., J. Gaubert, P. Pannier, and P. Rizzo, "Power generation system for UHF passive RFID," Electronics Letters, Vol. 42, No. 25, 1452-1454, December 2006.
13. Rizzo, P., E. Bergeret, J. Gaubert, and P. Pannier, Contactless integrated circuit with highefficiency electrical power supply circuit, patent US7580694 B2, August 2009.
14. Qing, X., C. K. Goh, and Z. N. Chen, "Impedance characterization of RFID tag antennas and application in tag co-design," IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 5, 1268-1274, May 2009.