Soviet-era 'Tesla Tower' restarted with spectacular lightning bolts (VIDEO)
Brown Noses Ahead (MPT)
WPT, as a means for transferring useful energy, say to charge batteries with or operate appliances with, definitely occurred a few decades later, though still not in the “safe” form we prefer to use in today. It first appeared in the form of microwave power transfer (MPT). The enabler was the resonant-cavity magnetron, invented in 1940. The radar soon followed as a result.
Over the period 1961 to 1984 while working for Raytheon, William C. Brown (1916-99) developed his long-range version of WPT. It was in effect a powerful wireless radio-wave broadcaster. In 1963, he successfully delivered 100 Watts over a few feet, with an efficiency of 13%. By 1975 he had sent 30 kilowatts over a mile, at 54% efficiency using high-power magnetrons and special antenna. That was indeed impressive. More importantly, these events were all scientifically documented. They weren’t just flashy demonstrations using smoke and mirrors. These were therefore very likely the first real, recorded cases of useful WPT.
From a modern engineering standpoint, the key thing to emphasize here is that Brown’s proposed method used powerful beams of microwaves, the same used for communication purposes, and also in the cheap microwave oven standing there in our kitchen. We do transfer energy wirelessly in that appliance too.
Microwave Ovens and Induction Cookers
The first commercial microwave oven came from Raytheon in 1954. The use of microwaves to heat food instead of just using it for radars, was actually purely accidental, but bound to happen.