Deathmagus;22428 wrote:

Alright, I'll bite. I've thought about wireless energy several times, and I've always run into a few problems.

1. The inverse square law makes it exceedingly difficult to propagate a field to usable proportions without expending a massive amount of energy. Induction works well in transformers because everything is relatively close together. In an open environment, however, a great deal of energy must be used to generate a field powerful enough to induce meaningful current any useful distance away. How do you propose we overcome this difficulty?

2. If I recall correctly, it is fluctuations in magnetic fields relative to the wires that produces the current. Thus, either the wires themselves must be moving, the electro-magnet, or the field itself must be oscillating. Which of these techniques do you suggest we utilize, and why?

3. Induction through a single strand of wire is negligible. We obtain useful amounts of current through coiling the wires, allowing the combined effect of individual inductions to create usable power. Referencing back to point number one, it would seem the number of coils would have to be considerable to obtain useful power from a field originating at an arbitrary distance. At some point, the weight and volume of said coils negates the advantage of wireless power in the first place. How do you propose we alleviate that difficulty?

If I've made a fundamental error in my understanding of the situation, please feel free to let me know. My area of concentration is limited to electromagnetic induction in microphones, so I haven't taken a formal class on this stuff in years.

I'll deal with number two first since that's the easiest. We'd be using AC. Numbers one and two I'll deal with together because both are overcome by the same solution. You are quite right when you mention the inverse square law and the size of coils. The amount of power needed to overcome distance issues makes induction unusable and with coils that are too large it becomes impractical to use them. How we get around these problems is with evanescent wave coupling. By resonating the evanescent waves it creates an effect that is mathematically similar to quantum tunneling and allows for smaller coils and less power for the same amount of induction at greater distances.