1. Microwaves

Microwave radiation [1] is an electromagnetic wave propagating in a vacuum at the speed of light. They have a frequency of between 300 MHz and 30 GHz, i.e. a wavelength of between 1 m and 1 cm. In the electromagnetic spectrum, they lie between radiofrequencies and infrared.

The frequencies usable by industrial microwave applications are regulated to avoid the risk of interference with radiocommunication and radar, which are the main uses of microwaves. The frequency of 2450 MHz ( λ = 12.2 cm) is generally used. In France, the frequency 915 MHz ( λ = 32.8 cm) is used for tempering and defrosting applications in the food industry. Use of this frequency requires an exemption granted by prefectoral decree.