On selecting the frequency for wireless implant communications

Body implanted devices are used to measure the level of different biological factors. Wireless technology is used to transfer this information to outside body. Some applications require long term continuous monitoring of the data. Therefore long term power supply source is needed that cannot be achieved easily. Ultra-low power technology and efficient design of the communication link can reduced the power consumption of the implant device. In this paper we investigate the frequency band of 200-3000 MHz for wireless bio implants. The RF path loss, related to the tissues, for different depths and frequencies is obtained through simulations. The optimum frequency range for two different tissues for abdominal and muscular parts is defined based on the minimum loss characteristics. By including a small antenna as the main part of the implant communication channel, simultaneous effects of tissue losses and antenna efficiency are considered. It is shown that the minimum loss for an implant communications can be achieved by defining an optimum frequency for each depth implementation.