A Master of Science Thesis in Electrical Engineering submitted by Mai Ali entitled, "Low Power Wireless Subcutaneous Transmitter," submitted in December 2010. Available are both soft and hard copies of the thesis.
Low power wireless transmitters are finding applications in diverse fields. A field that is expressing a noticeable growth is biomedical telemetry, where a wireless transmitter accompanied with sensors is used to measure different physiological parameters. The design of low power transmitters, especially when intended for biomedical applications, is limited by a set of constraints ranging from signal interaction with biological tissues, ensuring biocompatibility of design materials, design complexity to power supply methodology. The objective of this thesis is to design a low power wireless subcutaneous transmitter that can be used for biotelemetry applications. The novelty of this work resides in using low power system and circuit techniques to achieve the objective of low power consumption. The RF signal interaction with biological tissue under investigation i.e. subcutaneous tissue is characterized. The loss in signal power due to propagation through the skin is determined as well as maximum energy absorption that complies with the defined safety limits. In order to compensate for the signal power loss, an efficient class E power amplifier (PA) is designed. A direct modulation transmitter architecture is proposed that incorporates the carrier generation and data modulation into a single unit which not only decreases the system power consumption but also reduces its complexity to achieve the goal of miniaturization. An inductive link is proposed for power supplying the implantable transmitter for which another class E PA was designed to from a class E power transmitter.