volume | PIER Journals

Abstract

Retinal prosthesis system is currently being developed in various places around the world. This system involved data transfer between an implanted antenna inside an eyeball and an external camera that is located just in front of the eyeball. While there are plenty of publications about the stimulating electrodes or the processing unit of the system itself, very limited amount has been published regarding the wireless communication link between the two antennas despite the fact that the electromagnetic wave will propagate through a complex medium in the form of Vitreous Humor. This paper will discuss about the constraints associated with implanting an antenna into an eyeball. An antenna design and simulation was performed with the aid of High Frequency Structure Simulator (HFSS) and its Finite Element Method (FEM) mathematical solver in the operating frequency of 402-405 MHz. The antenna, which was a 4 layer microstrip antenna, was positioned at the centre of a spherical model filled with homogeneous Vitreous Humor material. Antenna performances that include return loss, bandwidth, gain, radiation pattern, and SAR value are analysed and compared against those of other implantable antennas operating in Medical Implant Communication Service (MICS) band. Free space and simulating fluid measurements were also conducted on the fabricated antenna to validate the simulation results. It was concluded that the fabricated antenna was able to produce the similar performance to the simulation results and hence at the same level as the other antennas operating in material with lower dielectric constants and conductivities.

1. Friedman, D. S., B. J. O'Colmain, B. Munoz, S. C. Tomany, C. McCarty, P. T. V. M. De Jong, et al. "Prevalence of age-related macular degeneration in the United States ," Archives of Ophthalmology, Vol. 122, No. 4, 564-572, 2004.
doi:10.1001/archopht.122.4.564

2. Margalit, E. and S. R. Sadda, "Retinal and optic nerve diseases," Artificial Organs, Vol. 27, No. 11, 963-974, 2003.
doi:10.1046/j.1525-1594.2003.07304.x

3. Rein, D. B., J. S. Wittenborn, X. Zhang, A. A. Honeycutt, S. B. Lesesne, and J. Saaddine, "Forecasting age-related macular degeneration through the year 2050: The potential impact of new treatments," Archives of Ophthalmology, Vol. 127, No. 4, 533-540, 2009.
doi:10.1001/archophthalmol.2009.58

4. Margalit, E., M. Maia, J. D.Weiland, R. J. Greenberg, G. Y. Fujii, G. Torres, et al. "Retinal prosthesis for the blind," Survey of Ophthalmology, Vol. 47, No. 4, 335-356, 2002.
doi:10.1016/S0039-6257(02)00311-9

5. Weiland, J. D., W. Liu, and M. S. Humayun, "Retinal prosthesis," Annual Review of Biomedical Engineering, Vol. 7, No. 1, 361-401, 2005, doi: 10.1146/annurev.bioeng.7.060804.100435.
doi:10.1146/annurev.bioeng.7.060804.100435

6. Rogers, K., "The Eye: The Physiology of Human Perception," Britannica Educational Publishing, Chicago, 2010, Available from: http://RMIT.eblib.com.au/patron/FullRecord.aspx?p=514090.

7. 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," Physics in Medicine and Biology, Vol. 41, No. 11, 2251-2269, 1996.
doi:10.1088/0031-9155/41/11/002

8. Lin, J. C., "A new IEEE standard for safety levels with respect to human exposure to radio-frequency radiation," IEEE Antennas and Propagation Magazine, Vol. 48, No. 1, 157-159, 2006.
doi:10.1109/MAP.2006.1645601

9. Kwak, S. I., K. Chang, and Y. J. Yoon, "Small spiral antenna for wideband capsule endoscope system," Electronics Letters, Vol. 42, No. 23, 1328-1329, 2006.
doi:10.1049/el:20062074

10. Karacolak, T., R. Cooper, and E. Topsakal, "Electrical properties of rat skin and design of implantable antennas for medical wireless telemetry," IEEE Transactions on Antennas and Propagation, Vol. 57, No. 9, 2806-2812, 2009.
doi:10.1109/TAP.2009.2027197

11. Soora, S., K. Gosalia, M. S. Humayun, and G. Lazzi, "A comparison of two and three dimensional dipole antennas for an implantable retinal prosthesis," IEEE Transactions on Antennas and Propagation, Vol. 56, No. 3, 622-629, 2008.
doi:10.1109/TAP.2008.916889

12. Liu, W. C., S. H. Chen, and C. M. Wu, "Bandwidth enhancement and size reduction of an implantable PIFA antenna for biotelemetry devices," Microwave and Optical Technology Letters, Vol. 51, No. 3, 755-757, 2009.
doi:10.1002/mop.24142

13. Kim, J. and Y. Rahmat-Samii, "Implanted antennas inside a human body: Simulations, designs, and characterizations," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 8, 1934-1943, 2004.
doi:10.1109/TMTT.2004.832018

14. Karacolak, T., A. Z. Hood, and E. Topsakal, "Design of a dual-band implantable antenna and development of skin mimicking gels for continuous glucose monitoring," IEEE Transactions on Microwave Theory and Techniques, Vol. 56, No. 4, 1001-1008, 2008.
doi:10.1109/TMTT.2008.919373

15. Lee, C. M., T. C. Yo, F. J. Huang, and C. H. Luo, "Bandwidth enhancement of planar inverted-F antenna for implantable biotelemetry," Microwave and Optical Technology Letters, Vol. 51, No. 1, 749-752, 2009.
doi:10.1002/mop.24189

16. Huang, F. J., C. M. Lee, C. L. Chang, L. K. Chen, T. C. Yo, and C. H. Luo, "Rectenna application of miniaturized implantable antenna design for triple-band biotelemetry communication," IEEE Transactions on Antennas and Propagation, Vol. 59, No. 7, 2646-2653, 2011.
doi:10.1109/TAP.2011.2152317

17. Karacolak, T., R. Cooper, J. Butler, S. Fisher, and E. Topsakal, "In vivo verification of implantable antennas using rats as model animals," IEEE Antennas and Wireless Propagation Letters, Vol. 9, 334-337, 2010.
doi:10.1109/LAWP.2010.2048693

18. Liu, W. C., F. M. Yeh, and M. Ghavami, "Miniaturized implantable broadband antenna for biotelemetry communication," Microwave and Optical Technology Letters, Vol. 50, No. 9, 2407-2409, 2008.
doi:10.1002/mop.23649

19. Soontornpipit, P., C. M. Furse, and Y. C. Chung, "Design of implantable microstrip antenna for communication with medical implants," IEEE Transactions on Microwave Theory and Techniques, Vol. 52, No. 8, 1944-1951, 2004.
doi:10.1109/TMTT.2004.831976

20. Balanis, C. A., Antenna Theory, 3rd Ed., John Wiley & Sons, Inc., New Jersey, 2005.

21. Ulaby, F. T., Fundamentals of Applied Electromagnetics, 5th Ed., 464, Pearson Education, Inc., Upper Saddle River, 2007.

22. Lee, C. M., T. C. Yo, C. H. Luo, C. H. Tu, and Y. Z. Juang, "Compact broadband stacked implantable antenna for biotelemetry with medical devices," Electronics Letters, Vol. 43, No. 12, 660-662, 2007.
doi:10.1049/el:20070463

23. Waterhouse, R. B., Microstrip Patch Antennas: A Designer's Guide, Kluwer Academic Publishers, Boston, 2003.

24. Blake, L. V. and M. W. Long, "Antennas --- Fundamentals, Design, Measurement," SciTech Publishing, 2009, 371-421.

25. Johnson, R. C., Antenna Engineering Handbook, 3rd Ed., McGraw-Hill, Inc., New York, 1993.

26. IEEE "IEEE Standard Test Procedures for Antennas," Wiley-Interscience, 1979.

Dr. Hans Permana

Dr. Qiang Fang

Prof. Wayne Rowe