Four-kilowatt homogeneous microwave heating system using a power-controlled phase-shifting mode for improved heating uniformity

Abstract

For homogeneous microwave heating in a microwave cavity with multiple 2.45 GHz microwave generators, power-controlled phase-shifting mode is proposed in this Letter. The proposed microwave heating system consists of a multimode microwave cavity in which dielectric materials are placed to be heated, four phase-shifting WR-340 waveguides for different phase excitation, four 1 kW magnetrons that produce microwave power at 2.45 GHz, and a power supply with a system controller for the magnetron output power controls. Using the proposed power-controlled phase-shifting mode, uniform heating distribution is achieved by reducing the hot and cold spots in the microwave cavity. The proposed experiments demonstrated that in comparison to a conventional mode with simultaneous multiple inputs, the proposed mode can achieve an improved heating uniformity of 64.4%. ? The Institution of Engineering and Technology 2019