Σχεδίαση Και Μελέτη Εξωτερικών Κεραιών Για Τηλεμετρία Με Εμφυτεύσιμες Ιατρικές Διατάξεις.

Abstract

Recent advances in telecommunications technology and electronics have given a considerable boost to the development of implantable medical devices, which record and post-process crucial physiological signals of the human beings, and are capable of wirelessly communicating (telemetering) with exterior devices. The overall telemetry system consists of the implantable medical device and an external control device, which exchange data in real-time, thus contributing in the rapid diagnosis and treatment of several diseases. The band of 402-405 MHz, which is also known as the "Medical Implant Communications Service Band", has been allocated exclusively for the communication of these devices. The aim of this thesis is to design and study the performance of three exterior antennas (half-wavelength dipole, simple patch, miniaturized patch), which will be integrated on exterior control devices of medical telemetry systems for implantable devices operating at 402-405 MHz. Initially, the antennas are designed in free-space, and their resonance and radiation performance is evaluated in the same environment. Three-layer canonical models of the human head, arm and trunk are subsequently considered, and their effect on antenna performance is investigated, as a function of distance. A miniature implantable antenna, which has already been proposed in the literature, is further studied, and optimized for operation inside the skin-tissue of the three-layer head model (e.g. intra-cranial pressure monitoring). Finally, the performance of the telemetry link which is formed between the implantable antenna and the proposed exterior dipole antenna is evaluated. Patient safety issues and conformance with international safety guidelines are taken into account throughout this study. Numerical investigations are carried out using the Finite Element Method.