Experiments showed that microwave heating could raise the internal temperature of many foods far more rapidly than a conventional oven1.
The first Raytheon commercial microwave oven was the 1161 Radarange, which was marketed in 1954. Rated at 1600 watts, it was so large and expensive that it was practical only for restaurant and institutional use.
In 1967, Amana, a division of Raytheon, introduced its domestic Radarange microwave oven, marking the beginning of the use of microwave ovens in home kitchens. Although sales were slow during the first few years, partially due to the oven's relatively expensive price tag, the concept of quick microwave cooking had arrived. In succeeding years, Litton and a number of other companies joined the countertop microwave oven market. By the end of 1971, the price of countertop units began to decrease and their capabilities were expanded2.
All electromagnetic energy can be characterized as waves with a specific wavelength and frequency distributed over a continuous range known as the electromagnetic spectrum. For example, some radio waves have a wavelength of 6 feet (2 meters) and a frequency of 50 million hertz (Hz-cycles per second). ...