from New Scientist:
The last few years have seen promising demonstrations of cellphones, laptops and TVs being powered wirelessly. Are we on our way to waving goodbye to wires once and for all?
[...] Enter Karalis and his colleagues. It has long been known that such mechanical energy transfer is improved enormously if two objects resonate at the same frequency – it’s how an opera singer can smash a glass if she hits the right pitch. Karalis wondered whether the same idea could improve the efficiency of magnetic induction at greater distances.