The origin of radio frequency (RF) identification technology is generally traced back to the 1940s during World War II when British developed the first radar system that could actively identify friend or foe. The early efforts attempted to apply RF energy to cook various processed meat products, to heat bread and to dehydrate and blanch vegetables.
The desired energy transferred rate enhancement led to an increased frequency: the microwaves. The first patent, describing an industrial conveyor belt microwave system was issued in 1952, however it first application started 10 years later.
By the 1960s, studies on the application of RF energy in foods focused mainly on thawing frozen products, which resulted in several commercial production lines.
The next generation of commercial applications of RF energy in the food industry was postbake drying of cookies and snack foods, starting in the late 1980s.
Radio frequency heaters
