Design and Implementation of a Cordless Power Supply System for Pervasive Medical Devices

Pervasive medical devices are able to provide diagnostic information inside intangible in vivo organs. For better inspection, additional power besides cell batteries is required by doctors to enable locomotion and active control of devices such as capsule endoscope. We present the design and implementation of a cordless power supply system based on 900MHz RF signals. It consists of an antenna, an impedance matching network circuit, a rectifier circuit cum voltage multiplier, and a LDO (low drop out voltage regulator). After matching analytical results and simulation ones, we further implement the power supply system in a PCB and measure it with Agilent spectrum analyzer and Tektronix oscilloscope. It is also interesting that wireless signals from any 900M GSM mobile phone talking nearby can be absorbed and converted into enough power by the system. It is believed to enable the external control and the locomotion of active endoscopes as well as other power hunger pervasive medical devices.