Radio frequency (RF) drying is a type of dielectric heating. Instead of depending only on hot air or a hot surface to transfer heat into a material, RF energy creates an alternating electromagnetic field through the material. Materials containing polar molecules, especially water, respond to this alternating field. Molecular movement and dielectric losses convert electromagnetic energy into heat inside the material. This is why RF is often called volumetric heating. Energy can be absorbed inside the material instead of being transferred only from the outer surface. With conventional hot-air drying, heat generally moves from the surface towards the inside, while moisture moves outward. With RF drying, electromagnetic energy can be absorbed within the material and generate heat internally, which can help remove moisture. This does not mean every point of a product is heated completely and equally. Actual heating depends on the material, geometry, moisture distribution, RF field and equip...