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%.

Keywords

• power‐controlled phase‐shifting mode
• multimode microwave cavity
• phase‐shifting WR‐340 waveguides
• microwave power
• system controller
• magnetron output power controls