pre-printImplantable antennas have been used for communication with medical implants for decades. This paper traces their roots from early transcutaneous inductively coupled devices to the microstrip and wire antennas in use today. A suggestion for where this technology may go in the future as medical devices shrink is also given

Chrysler, Andrew

Furse, Cynthia M.

English

The University of Utah: J. Willard Marriott Digital Library

A History & Future of Implantable Antennas  Cynthia M. Furse, Andrew Chrysler Electrical and Computer Engineering University of Utah Salt Lake City, Utah USA cfurse@ece.utah.edu   Abstract—Implantable antennas have been used for communication with medical implants for decades. This paper traces their roots from early transcutaneous inductively coupled devices to the microstrip and wire antennas in use today.  A suggestion for where this technology may go in the future as medical devices shrink is also given.   I. INTRODUCTION  Implantable antennas have been used for communication with medical implants for decades. Since then, wireless medical telemetry systems and their associated implantable antennas have expanded rapidly.  Implantable medical devices now touch virtually every major function in the human body. Cardiac pacemakers and defibrillators [1], neural recording and stimulation devices,[2]  cochlear [3] and retinal [4] implants are just a few of the many implantable medical devices available today.  Wireless telemetry for these devices is necessary to monitor battery level and device health, upload reprogramming for device function, and download data for patient monitoring.   Emerging medical telemetry devices have led to recent advances in the design of small, biocompatible antennas that can be implanted in the human body.  This paper will track the types of antennas seen in the past, the technologies that enabled these changes, and prospects for future implantable antennas for medical applications.  II. IMPLANTABLE ANTENNA DESIGN CHALLENGES Antennas are critical elements in all communication systems.  They are typically one of the largest system components, causing real estate challenges for any miniaturized communication and power transfer system.  Antennas are inevitably one of the largest if not the largest component of the telemetry communication system and are generally mounted on or in the implanted battery pack, usually in a body cavity.  This limited real estate significantly constrains the performance of implantable antennas. Typical battery packs today for cardiac devices are under 4cm long [5] and new devices for neural recording and stimulation are under 4mm in size. [2]  Half wave antennas in the MedRadio band (402-405MHz) [5]-[8] are 36 cm in air and 6cm plus in the body.  In addition, implantation in the body cavity means the antennas have to transmit several cm through multiple layers of body tissues, where significant power is lost.  Lost power means lost distance and lost battery life. Designing antennas for medical implants is particularly challenging because (1) Significant power is lost (deposited) in body tissues.  This reduces antenna efficiency, plus power deposition is limited by RF safety regulations [8]-[12] (2) The antenna size is constrained by the size of the battery pack, which is shrinking.[5][13]  For example, the Utah Electrode Array, is used for cochlear and optical implants, treatment of depression and Parkinson’s disease, and eventually perhaps to repair the spinal cord and other neural injuries.   Current designs use inductive coupling, but longer ranges and higher data rates are desired.; (3) Implantable antennas are easily de-tuned by variation in body size, shape, composition, electrical properties, placement, etc. [14] [15] III. IMPLANTABLE ANTENNA DESIGNS Today’s implantable antennas include various shapes of microstrip patch antennas  [4], [16]-[21],[30] dipoles or monopoles [22]-[23], inductive coils[24]-[29], and genetic algorithm (GA) designs [19].The battery pack serves as the ground plane for many designs. For smaller implants, a microstrip patch antenna has been successfully used for a retinal prosthesis [35], and a small dipole has been designed for communication with a brain implant.  [33] An insulated wire antenna has also been used, and this wire may be used as the lead between the heart and the battery pack/controls of the pacemaker.  [31]  The antenna can be treated as a waveguide, where the lossy body acts as the outer conductor of the waveguide. The insulated antenna in matter may be matched with a load resistor connected to the conducting medium in order to reduce or eliminate the reflection. Another type of antenna used for communication with cardiac devices is the circumference antenna, which is a monopole antenna that is mounted around the edge of the pacemaker case.   [32]     REFERENCES  [1] A. J. Johansson, “Simulation and verification of pacemaker antennas,” Proceedings 25th Annual Int’l Conf. IEEE EMBS, Cancun, Mexico, Sept 17-21, 2003 [2] K. Guillory and R. A. Normann, “A 100-channel system for real time detection and storage of extracellular spike waveforms,” J. Neurosci. Methods, Vol. 91, 1999, pp. 21-29 [3] T. Buchegger, et al., “An ultra-low power transcutaneous impulse radio link for cochlea implants,” Joint Ultra Wideband Systems and Technologies (UWBST) and International Workshop on UWBS 2004 (IEEE Cat. No. 04EX812) 2004, pp. 356-360 527978-1-4799-3540-6/14/$31.00 ©2014 IEEE AP-S 2014[4] K. Gosalia, G. Lazzi, M. Humayun, “Investigation of microwave data telemetry link for a retinal prosthesis,” IEEE Trans. MTT, Vol. 52, No. 8, Aug. 2004, pp. 1925-1932 [5] Trends in Cardiac Pacemaker Batteries (Oct. 2004). Available: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1502062  Sept 6, 2012. [6] Medical Implant Communications Service (MICS) Federal Register, “Rules and Regulations,” vol. 64, no. 240, pp. 69926-69934, Dec. 1999. [7] International Telecommunication Union, Recommendation ITU-R SA.1346, 1998. “Planning for  medical implant  communications systems (MICS) and related devices,” Proposals Paper SPP  6/03,  Australian Communications  Authority.  [8]  M.H. Repacholi, “Radiofrequency Field Exposure Standards:  Current Limits and Relevant  Bioeffects,” Chapter 2  in Biological Effects and Medical Applications of Electromagnetic Energy, O.P. Gandhi, editor, Prentice-Hall, 1990. [9] The United States of America. Federal Communications Commission, Electronic Code of Federal Regulation: Title 47, vol. 1, no. 95.627. [Online.] Available: http://ecfr.gpoaccess.gov. [Accessed: Aug 2012]. [10] "IEEE Standard for Safety Levels With Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz," IEEE Std C95.1-2005, vol., no., pp.1-238, 2006. [11] "IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz - Amendment 1: Specifies Ceiling Limits for Induced and Contact Current, Clarifies Distinctions between Localized Exposure and Spatial Peak Power Density," IEEE Std C95.1a-2010 (Amendment to IEEE Std C95.1-2005) , vol., no., pp.C1-9, March 16 2010. [12]  ICNIRP, “Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300 GHz),” Health Phys., vol. 74, pp. 494–522, 1998 [13] A. Skrivervik, J.-F. Zurcher, O. Staub,J.R. Mosig, “PCS Antenna Design: The challenge of miniaturization,” IEEE AP Magazine, 43(4), Aug 2001 [14] (Invited paper) J. Johnson, C. Furse, “Statistical Analysis of Detuning Effects for Implantable Microstrip Antennas,” North American Radio Science Conference URSI-CNC/USNC. July  22-26, 2007, Ottawa, Canada [15] A. Peyman, C. Gabriel, E. Grant, G. Vermeeren, L. Martens, ‘Variation of the dielectric properties of tissues with age: the effect on the values of SAR in children when exposed to walkie talkie devices,’ Phys. Med. Biol., Vol. 54, pp. 227-241, 2009 [16] C. Furse, H.K. Lai, C. Estes, A. Mahadik, A. Duncan, "An Implantable Antenna for Communication with Implantable Medical Devices," 1999 IEEE Antennas and Propagation/ URSI International Symposium, Orlando, FL, July 1999 [17] JJ. Kim and Y. Rahmat-Samii, “Implanted antennas inside a human body: simulations, designs, and characterizations,” IEEE Trans. Microwave Theory Tech., vol. 52, no. 8, Aug. 2004, pp. 1934-1943. [18] P. Soontornpipit, C.M. Furse, and Y.C. Chung , “Design of Implantable Microstrip Antenna for Communication with Medical Implants,” Special Issue of IEEE Transactions on Microwave Theory and Techniques on Medical Applications and Biological Effects of RF/Microwaves , Vol. 52, No. 8 Part 2, Sept. 2004, pp. 1944‐1951 [19] Pichitpong Soontornpipit, Cynthia M. Furse and You Chung Chung, “Miniaturized Biocompatible Microstrip Antenna using Genetic Algorithm,” IEEE Trans. Antennas and Propagation, Vol. 53, No. 6, June 2005, pp. 1939-1945 [20] IA. J. Bahl, P. Bhartia, and S. S Stuchly, "Design of microstrip antennas covered with a dielectric layer," IEEE Trans. Antennas Propagat., vol. AP-30, no. 2, pp. 314-318, March 1982. [21] T. Karacolak, R. Cooper, E. Topsakal, “Electrical properties of rat skin and design of implantable antennas for medical wireless telemetry,” IEEE Trans. AP 57(9), Sept.2009 [22] S. Soora, K.  Gosalia, M.Humayun, G. Lazzi, “A comparison of 2 and 3D dipole antennas for an implantable retinal prosthesis,” IEEE Trans.AP, 36(3), March 2008 [23] MM. D. Amundson, et al., “Circumferential antenna for an implantable medical device,” U.S. Patent 6,456,256, Sep. 24, 2002.  [24] IA. J. Bahl, S. S. Stuchly, J. Lagendijk, and M. Stuchly, "Microstrip loop applicators for medical applications," IEEE Trans. MTT, pp. 1090-1093, July 1982. [25] WW.G. Scanlon, N.E. Evans, G.C. Crumley, Z.M. McCreesh, "Low-power radio telemetry: the potential for remote patient monitoring," Journal of  Telemedicine and Telecare, Dec. 1996, (2)4, pp. 185 [26] N. de N. Donaldson and T. A. Perkins, “Analysis of resonant coupled coils in design of radio frequency transcutaneous links,” Med., Biol.Eng. Comput., vol. 21, pp. 612–626, Sept. 1983   [27]   D. C. Galbraith, S. Mani, and R. L. White, “A wide band efficient inductive transdermal power and data link with coupling insensitive gain,” IEEE Trans. Biomed. Eng., vol. BME-34, pp. 265–275, Apr. 1987.  [28] WW.G Scanlon, N.E. Evans, Z.M. McCreesh, "RF Performance of a 418 MHz radio telemeter packaged for human vaginal placement," IEEE Trans. BME, May 1997,44(5), pp. 427-430 [29] P. R. Troyk and M. A. K. Schwan, “Closed loop Class E transcutaneous power and data link for microimplants,” IEEE Trans. Biomed. Eng., vol. 39, pp. 589–598, June 1992. [30] C. Furse, “Design an antenna for pacemaker communication,” Microwaves & RF, pp. 73-76, March 2000.  [31] R. S. Mackay, Bio-Medical Telemetry. IEEE Press, 2nd ed., 1993.   [32] A. J. Johansson, Wireless Communication with Medical Implants: Antennas and Propagations, PhD Dissertation, Lund University, 2004, ISSN 1402-8662 [33] Mingui Sun, Marlin Mickle, Wei Liang, Qiang Liu, and Robert J. Sclabassi, “Data Communication Between Brain  Implants and Computer,” IEEE Trans. On Neural Systems and Rehabilitation Engineering, Vol. 11, No. 2, 2003, pp. 189-192 [34] J. Kim, and Y. Rahmat-Samii, “Implanted antennas inside a human body: simulations, designs, and characterizations”, IEEE Trans. MTT, vol. 52, issue 8, pp. 1934- 1943, Aug. 2004. [35] K. Gosalia, J. Weiland, M. Humayun, and G. Lazzi, “Thermal elevation in the human eye and head due to the operation of a retinal prosthesis,” IEEE Trans. Biomedical Engineering, vol. 51, no. 8, Aug. 2004.    528

A history & future of implantable antennas

https://collections.lib.utah.edu/dl_files/9f/57/9f570dae9cd2a351c98ec0a39e3ef2f835affe37.pdf

A history & future of implantable antennas

Abstract

Similar works

Full text

Available Versions

The University of Utah: J. Willard Marriott Digital Library