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.
National Science Foundation
Last revised: August 2007
For more information, contact Dr. Cynthia Furse