5 - Dielectric Heating: Microwave, Radio Frequency Processes

Abstract

Dielectric heating includes microwave and radio frequency (RF) heating, and is a process in which nonmetallic materials are heated by absorbing high-frequency electromagnetic radiation. Heat is generated from within the object being heated. This method of heating contrasts the more conventional method of using convection and/or radiation to heat the surface of the object and then relying on conduction to transfer the heat into the object. RF heating uses lower frequency radiation than microwave heating, which allows it to penetrate deeper into the heated object and is generally used for thicker materials. Because microwave heating uses higher frequencies than RF heating, its heating intensity is greater and heating rates are faster. Dielectric heating is appropriate for heating electrically non-conducting materials that contain polar molecules, such as water.