In this thesis, we design novel implantable antennas for medical implant communication systems and it could operate with the metamaterial which is the artificial electromagnetic (EM) cover layer. The metamaterial based matching layer placed on the surface of the body can improve the performance of the implantable antenna. First, we propose two layers and three layers antenna design. The three layers antenna features high tolerance, high gain, low-profile and miniaturization. The antenna achieves gain −21.7 dBi and efficiency 0.2%. Compared with other literatures of implanted antenna design, the proposed three layers antenna reveals the best gain with similar dimensions. Furthermore, its frequency response is insensitive to the change of the implanted environment. The conception of impedance matching is applied to further improve the gain of the proposed antenna. The matching layers are realized by utilizing the metamaterial and it is placed between the body and the air. In this case, the gain of the three¡Vlayer antenna can be enhanced by 1.23¡V5.2 dB. Furthermore, we propose a size reduction technique to reduce the thickness of the matching layer. The miniature matching layers can increase the gain of the three¡Vlayer antenna by 1.64 dB and 2.63 dB with the dimension of 40¡Ñ40¡Ñ4mm³ and 60¡Ñ60¡Ñ4mm³ respectively. Finally, we propose a co¡Vdesign method of the antenna and metamaterial. The antenna will resonate after placing metamaterial on the surface of the body. So that we can control the antenna whether to transmit power or not by the circuit design in the biomedical device to detect the return loss of the antenna.

Thesis (Ph. D.)--University of Technology, Sydney, 2001. / Bibliographic references: leaves [304]-318.

No description available.

Thesis (Ph. D.)--State University of New York at Binghamton, Decker School of Nursing, 2005. / Includes bibliographical references.

Les personnes qui se sont vues amputées d'un membre peuvent retrouver une partie de leur autonomie et de leur qualité de vie grâce à l'utilisation d'une prothèse adaptée à leurs besoins.Les récentes avancées technologiques dans le domaine de la prothétique laissent entrevoir qu'il sera bientôt possible de commander les mouvements d'une prothèse motorisée à partir de l'interprétation des influx nerveux qui auraient été destinés aux muscles du membre maintenant amputé. Pour ce faire, les impulsions nerveuses seront mesurées par un dispositif totalement implantable et celui-ci devra transmettre en temps réel les données recueillies vers la prothèse à l'aide d'un système de biotélémétrie. Si cette transmission de données requiert une bande passante élevée et une grande qualité du lien de communication, cela se traduira par une consommation énergétique plus élevée. Or, les circuits électroniques du dispositif implanté étant alimentés par une pile, cette consommation énergétique devra être minimisée. Les systèmes actuels de biotélémétrie utilisent le couplage inductif ou les ondes radio afin de transmettre les données, mais ces systèmes ne peuvent rencontrer à la fois les contraintes de faible consommation énergétique et de capacité élevée de transmission qu'impose une prothèse à commande neuronale. Afin d'y parvenir, un système de télémétrie optique transcutané qui utilise les propriétés optiques des tissus cutanés est proposé. Il a été conçu dans le but de transmettre des données à un débit de 16 Mb/s et à un taux de bits erronés de 1E-9 en consommant une puissance de 10 mW. Ce mémoire présente l'impact du taux de transmission des données sur la consommation énergétique du transmetteur, de même qu'une mesure de la puissance requise pour assurer une transmission à travers des tissus cutanés d'épaisseurs variées. La sensibilité du système à un désalignement entre l'émetteur et le récepteur a également été étudiée.

No description available.

The implantable cardioverter defibrillator (ICD) is a reliable, cost-effective implanted device designed to terminate life-threatening cardiac arrhythmias and prevent sudden death. The recent exponential increase in implantation rates emphasises the need for nurses, doctors and other clinicians to understand the experience of living with an ICD for patients and partners. Current knowledge of patient experiences is mostly derived from overseas studies of specific variables, including physical problems, psychosocial outcomes, ICD shocks and quality of life issues. Studies of partner experiences focus on psychosocial concerns. Using van Manen's (1990) hermeneutic phenomenological approach, this study describes the experience of living with an ICD for seven Australian patients and six partners. Experiential descriptions, obtained in tape-recorded conversational interviews, were subjected to three levels of analysis. The first descriptive analysis summarised individual experiences of living with an ICD. The second, thematic analysis phenomenologically described the collective lived experience of being a patient, and of being a partner. Each description identified a challenging and changing experience through the themes of Being Disrupted and Distressed, Reconstructing Life, Appreciating and Celebrating Life, and Accommodating the ICD. For the patient, various everyday interactions, events and activities meant either being able to trust the ICD as a reassuring protection or experiencing it as an inescapable intrusive object. For the partner, a trusting reliance on the ICD's protective security eased the vulnerability and onerous perceived responsibility for the patient's survival and well-being. Threats to the partner's restored sense of normality, security and hope occurred when the patient wanted the ICD removed or discontinued. The third hermeneutic analysis specifically explored how the ICD, as an implanted biomedical device, was perceived, embodied and comprehended by patients. This analysis disclosed the varied, ambiguous existential meanings derived from and accorded to the ICD's presence, power and potential. The interpretation concluded that the ICD was either embodied as a trusted and reassuring friend, or existentially rejected as an intruder that thwarted meaningful possibilities. Theoretical and practical implications of this understanding of living with an ICD included several recommendations for improving staff education, as well as practical interventions for informing and supporting patients and partners. A proposal for implementing these recommendations concluded with suggestions for future inquiries that would extend understanding of this increasingly common human phenomenon.

No description available.

This thesis proposes a multi-parameter implantable micro-stimulator system. By using wireless communication and the muli-parameter control, the infection caused by the wound could be avoided and various stimulation waveforms could be generated for different bio-medical applications. Besides, a graphic user interface (GUI) is implemented for the proposed micro-stimulator for the convenience of usage. Moreover, the in vitro experiments are carried out, where the neurons could be stimulated successfully. To reduce the system area caused by external capacitors required by traditional ASK demodulators, a C-less ASK demodulator is proposed in this thesis. A bias-based envelope detector and a Schmitt trigger are used for demodulation. Moreover, by enlarging the noise margin of the envelope detector, an all-MOS ASK demodulator is carried out such that no passive element is needed and the system area could be further reduced. Besides, two high sensitivity voltage-to-frequency (VFC) are proposed for the full duplex transmission. By using a voltage-to-current converter, a charge and discharge circuit, and an all-MOS voltage window comparator 1 (VWC1), a high sensitivity VFC1 is accomplished. Moreover, a linear VFC2 is also proposed by including a fast all-MOS voltage window comparator, VWC2. Finally, a wide range I/O buffer is proposed for the interface of the implantable micro-stimulator system. With the stacked PMOS and NMOS output stage and the dynamic gate bias generator, high voltage and low voltage signals (VDDH and VDDL) could be transmitted and received without any gate-oxide overstress and leakage currents.

Thesis (Ph.D.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 123-161). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR39008