Study on Techniques of Outside Energy Supply for the Wireless Capsule Endoscope

The wireless capsule endoscopic MEMS for diagnosing human gastrointestinal tract is a great break-through. The system overcomes some disadvantages of the traditional push endoscope and causes less comfortlessness for patients. Some kinds of capsule endoscopes have been successfully put into practical use as a diagnostic tool for the digestive system, especially in small intestine. It is found that some problems, such as the supplying power by the battery is limited and the security is not reliable enough. In the present paper, a detailed analysis of the techniques for outside power supply of the endoscope is presented. One wireless power transmission method is based on electromagnetic coupling principles, combining with electric power and electron technology. Firstly, the concepts and the basic principles of a loosely inductively coupled power system are introduced. Different from a traditional transformer, an equivalent electronic circuit is set up with the mutual inductive model on electromagnetic coupling, and then a wireless inductive power transmission mathematical model can be established. With numerical calculation and simulation of the system, the influences of electromagnetic coupling geometrical and electrical parameters on the performance of the wireless power transmission system are discussed. With analysis of possibility for the wireless power transmission of the capsule endoscope, the transmission sketch is proposed.