Implantable loop antenna

Building a communication link with implanted devices increases capability of diagnosis and treatment and reduces the need for invasive surgical operations. The technology can also be used in tracking animals and gathering their biological information. In this dissertation a loop antenna is proposed for an implanted tag which is to be used under the skin of Steller sea lions for tracking purposes. The impedance of the antenna has been measured inside a tissue simulating liquid. Two types of housings (alumina and ABS) have been used. It has been shown that both housings reduce the effect of surrounding changes on the antenna impedance. Also the impedance of the antenna is not influenced by the changes in the skin tissue thickness. Using the power loss measurements, the range of the antenna is calculated to decrease 40 % when implanted. Finally a matching method is proposed to increase the efficiency of the transmission.