This paper proposes a backscattering communication technique based on modulated frequency selective surfaces (FSS) for wearable applications. The FSS is composed of dipoles loaded with varactor diodes to modulate the backscatter response, in order to separate it from the clutter. The paper describes the effect in the transponder response according to the number of dipoles, the separation between them and the effect produced when FSS is placed on-body. An analysis based on simulations of several cases and experimental results is provided.
2. Rasyid, M. U. H. A., B. H. Lee, and A. Sudarsono, "Wireless body area network for monitoring body temperature, heart beat and oxygen in blood," 2015 International Seminar on Intelligent Technology and Its Applications (ISITIA), 95-98, 2015.
3. Movassaghi, S., M. Abolhasan, J. Lipman, D. Smith, and A. Jamalipour, "Wireless body area networks: A survey," IEEE Commun. Surv. Tutor., Vol. 16, No. 3, 1658-1686, 2014.
4. Hoang, D. C., Y. K. Tan, H. B. Chng, and S. K. Panda, "Thermal energy harvesting from human warmth for wireless body area network in medical healthcare system," 2009 International Conference on Power Electronics and Drive Systems (PEDS), 1277-1282, 2009.
5. Barroca, N., H. M. Saraiva, P. T. Gouveia, J. Tavares, L. M. Borges, F. J. Velez, C. Loss, R. Salvado, P. Pinho, R. Goncalves, N. BorgesCarvalho, R. Chave-Santiago, and I. Balasingham, "Antennas and circuits for ambient RF energy harvesting in wireless body area networks," 2013 IEEE 24th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), 532-537, 2013.
6. Marrocco, G., "Pervasive electromagnetics: Sensing paradigms by passive RFID technology," IEEE Wirel. Commun., Vol. 17, No. 6, 10-17, Dec. 2010.
7. Merilampi, S., P. Ruuskanen, T. Bjorninen, L. Ukkonen, and L. Sydanheimo, "Printed passive UHF RFID tags as wearable strain sensors," 2010 3rd International Symposium on Applied Sciences in Biomedical and Communication Technologies (ISABEL 2010), 1-5, 2010.
8. Amendola, S., R. Lodato, S. Manzari, C. Occhiuzzi, and G. Marrocco, "RFID technology for IoT-based personal healthcare in smart spaces," IEEE Internet Things J., Vol. 1, No. 2, 144-152, Apr. 2014.
9. Rais, N. H. M., P. J. Soh, F. Malek, S. Ahmad, N. B. M. Hashim, and P. S. Hall, "A review of wearable antenna," Antennas Propagation Conference, 2009, LAPC 2009, Loughborough, 225-228, 2009.
10. Grosinger, J. and M. Fischer, "Evaluating on-body RFID systems at 900 MHz and 2.45 GHz," 2012 Fourth International EURASIP Workshop on RFID Technology (EURASIP RFID), 52-58, 2012.
11. Ziai, M. A. and J. C. Batchelor, "Temporary on-skin passive UHF RFID transfer tag," IEEE Trans. Antennas Propag., Vol. 59, No. 10, 3565-3571, Oct. 2011.
12. Occhiuzzi, C., A. Ajovalasit, M. A. Sabatino, C. Dispenza, and G. Marrocco, "RFID epidermal sensor including hydrogel membranes for wound monitoring and healing," 2015 IEEE International Conference on RFID (RFID), 182-188, 2015.
13. Munk, B. A., R. G. Kouyoumjian, L. Peters, and Jr., "Reflection properties of periodic surfaces of loaded dipoles," IEEE Trans. on Antennas Propag, Vol. 19, No. 5, 612-617, 1971.
14. Che, Y., X. Hou, and Z. Gao, "A tunable miniaturized-element frequency selective surfaces without bias network," 2011 IEEE International Conference on Microwave Technology & Computational Electromagnetics (ICMTCE), 70-73, 2011.
15. Lorenzo, J., A. Lazaro, D. Girbau, and R. Villarino, "Backscatter transponder based on frequency selective surface for FMCW radar applications," Radioengineering, 2014.
16. Lazaro, A., A. Ramos, D. Girbau, and R. Villarino, "A novel UWB RFID tag using active frequency selective surface," IEEE Trans. on Antennas Propag., Vol. 61, No. 3, 1155-1165, 2013.
17. Thornton, J. and D. J. Edwards, "Range measurement using modulated retro-reflectors in FM radar system," IEEE Microw. Guid. Wave Lett., Vol. 10, No. 9, 380-382, 2000.
18. Lorenzo, J., A. Lazaro, R. Villarino, and D. Girbau, "Modulated frequency selective surfaces for wearable RFID and sensor applications," IEEE Trans. Antennas Propag., Vol. 64, No. 10, 4447-4456, Oct. 2016.
19. Collin, R. E., F. J. Zucker, and Ed., The Receiving Antenna, Antenna Theory 1, McGraw-Hill, New York, NY, USA, 1969.
20. Green, R. B., "The general theory of antenna scattering,", Rep. 1223-17, ElectroScience Laboratory, Columbus, OH, 1963.
21. Nikitin, P. V., K. S. Rao, S. F. Lam, V. Pillai, R. Martinez, and H. Heinrich, "Power reflection coefficient analysis for complex impedances in RFID tag design," IEEE Trans. Microw. Theory Tech., Vol. 53, No. 9, 2721-2725, 2005.
22. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: I. Literature survey," Phys. Med. Biol., Vol. 41, No. 223, I-2249, 1996.
23. Gabriel, S., R. W. Lau, and C. Gabriel, "The dielectric properties of biological tissues: II. Measurements in the frequency range 10 Hz to 20 GHz," Phys. Med. Biol., Vol. 41, No. 11, 2251, 1996.
24. Tsai, M.-C., C.-W. Chiu, H.-C. Wang, and T.-F. Wu, "Inductively coupled loop antenna design for UHF RFID on-body applications," Progress In Electromagnetics Research, Vol. 143, 315-330, 2013.