DbSWPT: A Novel Distance-based Switch for Efficient Wireless Power Transfer in Battery-less Wireless Capsule Endoscopy

Abstract

The restricted power supply of batteries hampered the development of capsule endoscopy. Accordingly, a distance-based switch is proposed for efficient wireless power transfer (WPT) system. It targets battery-less wireless capsule endoscopy (WCE). The proposed system consists of two separate coils with distance significant impact. To tackle problem, a distance-based switch configuration is proposed between two variable load resistances according to distance between transmitting and receiving circuits. Results proved high efficiency at short distances using potentiometer in decreasing direction which starts with high resistance values and then decreases to a certain value of resistance according to measured distance whereas the other has a high efficiency at long distances using potentiometer in increasing direction which starts with low resistance values and then increases to certain value of resistance according to measured distance. The results illustrated that the system performance using series-series (S-S) configuration is superior to using the parallel-parallel (P-P) configuration. It is found that the minimum efficiency for the proposed P-P distance-based switch is 51%, while for the proposed P-S is 83.33% . Accordingly, the proposed switch-based S-S configuration achieved minimum efficiency 90.91%. It increases the efficiency by 8.34%.