There are two major problems with traditional methods of operating an RFID tag embedded on orthopedic implants by wireless transmission: (1) interference with metallic orthopedic implants causes significant signal attenuation around the RFID tag; (2) interference with other medical devices may lead to the failure of their functionality. The creation of a feasible solution to the above two problems is critical to the success of operation of implanted RFID devices embedded on or near metallic implants and in any other situation where wireless interference may occur. The solution proposed in this dissertation is the Ortho-tag RFID system which uses the conductivity of human tissue at radio frequencies for energy and signal transmission. With the viability experiments proving the feasibility of using volume conduction in this research, two present issues have been addressed: (1) the lack of availability of a matching technique between tissue/saline and the RFID device; (2) the lack of an efficiency study on the operation of RFID through tissue/saline with variable thickness. This fundamental work then details the development of a general solution for the above two issues, in a power and communication platform technology for implanted RFID devices. The platform is developed using equipment in the RFID Center of Excellence in which pig skin and saline are used as a medium for in vivo environment as human tissue surrogates. The selection and design of the volume conduction electrodes are discussed and optimized using ANSYS/HFSS. The system optimization focuses on matching the RFID reader and the tag to the tissue/saline based on an equivalent 2-port network model for tissue using Z parameters. Matching networks are designed and optimized so that the tag is matched to the tissue from the internal side, and the tissue is matched to the RFID reader from the external side. For high data rate considerations, two RFID frequencies are utilized for the Ortho-tag RFID system. The frequencies are HF at 13.56 MHz and UHF at 915 MHz. The system is finally prototyped and demonstrated as the proof of concept
