Implantable 400MHz PIFA for bio-telemetry system

A miniaturized implantable antenna, to be implanted in small animal, designed for Medical Implantable Communications Services (MICS), is presented in this paper. The proximity couple-fed technique is applied to enhance the bandwidth of the antenna to overcome the out-of-band probability of the antenna due to frequency detuning by the surrounding tissue and encapsulation. The aim of this research is to transmit the extracted physiological signals from the body of a small animal wirelessly to an external RFID reader (400MHz) connected to a computer via USB cable. The overall dimensions of the antenna are 32mm×22mm×4mm and the ground plane of RFID tag is utilized to improve the performance of the antenna. Animal tissue model has been developed and the antenna is encapsulated by a bio-compatible material before putting it in this model. Effect of encapsulation material is explored in this paper which may be utilized to retune the antenna if needed. The predicted bandwidth of the proposed implanted antenna is found as approximately 8%.