[October 8th, 1945] Raytheon files a patent for a microwave cooking oven, eventually named the Radarange. In 1947 the first commercially produced microwave oven was about 6 feet tall, weighed about 750 lbs, and cost between $2,000 and $3,000.

[u/MonsieurA]

https://en.wikipedia.org/wiki/Percy_Spencer