Antenna Design and Optimization
Numerous medical devices are
implanted in the body for medical use. These include pacemakers and
defibrillators, hormone pumps, nerve stimulators, and more. With the
advancement and miniaturization of bio-electronics it is likely that the array
of implantable medical devices will continue to expand in the years to come. Medical
implants are intended to stay in the body for many years or decades, and it is
often necessary to communicate with the device to download data about the
health of the device or its batteries or the health of the patient, or to
upload changes in settings or new procedures specified by the doctor. It is
even conceivable that the patient could control the setting of his or her
medical implant with the touch of a button from a wireless device.
The
design of antennas that can communicate with implantable devices is an
interesting and challenging problem. The antenna must be small and long-term
biocompatible, preferably able to be mounted on existing implant hardware or to
utilize part of the hardware itself. The antenna must be electrically insulated
from the body so as not to short out and be ineffective, and it must be
efficient so as not to excessively drain the batteries. It must not exceed the
safety guidelines for power deposited in the body, and should be insensitive to
external EM noise. Some applications (such as data up or down load) could use a
high-gain directional system, whereas other applications (such as monitoring
while the patient is mobile and active) would require a more isotropic system. For
some cases (such as nerve stimulators) it is possible that the implanted
antenna for communication could also be used for sensing the electrical
properties of the tissue in the surrounding region, which might be used to
provide biologically-relevant information about the health of the patient.
Some of the most successful
designs have been the spiral, serpentine, or genetic-algorithm waffle-type
designs.
Other
applications of the genetic algorithm antenna design software are multi-band
designs (such as the one shown top left), broad band designs, or antennas for
specialty applications.
Thank you to our Sponsors:
National Science
Foundation
Last revised: August 2007
For more information,
contact Dr. Cynthia Furse