The Design Of Implantable Wireless Telemetry System

Implantable wireless telemetry system is a kind of electronic equipment which buried in the body of animal or humans. It is mainly used to measure changes in biochemical and physiological parameters for long term and then diagnoses, treats certain diseases. Implantable wireless telemetry system can get physiological data in unrestrained status which makes it suitable for long-term monitoring.The volume, weight and power consumption are key parameters of implantable system. Digital wireless communication consumes excessive power, FM/AM analog communication needs continuous carrier launching and therefore consumes large power. There is no general electronic circuit solution in this field.An implantable wireless telemetry system used for physiological parameter monitoring of rat is designed in this paper. Multiple pulse position modulation (MPPM) is adopted in the implantable circuit to realize real-time continuous monitoring for multichannel signals with restricts of volume and power consumption. The launching energy is enhanced through the L-C resonance antenna design.The main work in this paper is as follow:1. Get the best circuit parameters through simulation analysis, debugging and optimization. The power consumption is only 32uA for two channels monitoring system (one channel ECG, one channel temperature).2. Design all kinds of segmentation methods and packaging forms (cylindrical, cuboids) of the implantable module, the size (two channel) is only 1.8cm3.3. Design the receiving circuit and analysis software in PC. Got system performance parameters through system debugging.The experiments on eight SD male rats show that the system can get ECG and temperature signals and has better performance than the same product at high frequency. The monitoring time is up to 78 days (powered by two RENATA395), which meets the requirements of implantable system.