Cut the Cord: Low-Power Far-Field Wireless Powering

摘要

Although the idea of eliminating cords seemsr attractive, the efficiency will always be betterr when a wire or cable is used to deliverr power. So, what are the applications thatr warrant wireless powering, and especiallyr wireless powering at longer ranges? It might ber appropriate to remember a quote by Rudyard Kiplingr in this introduction:r I keep six honest serving menr (they taught me all I knew)r Their names are What and Why and Whenr And How and Where and Whor Let us start by answering the main questions relatedr to wireless powering. There are essentially three types,r Figure 1(a) inductive, capacitive or resonant reactiver near-field coupling; (b) far-field directive power beaming;r and (c) far-field nondirective power transfer.