0.5kWatt 2.45 GHz GaN‐based microwave heating system design with active phase control

Abstract

In this article, to improve the temperature uniformity of the microwave (MW) heating system, a 0.5-kW 2.45 GHz GaN (gallium nitride)-based MW heating system with active phase control is presented. The proposed system consists of two 2.45 GHz signal generators, two electrically controlled phase shifters, two 250 W GaN amplifiers, two metal patch antennas, and the MW applicator with a heating material. The controlled signal is radiated into the MW applicator through the antenna, and the radiation direction can be steered according to the input phase difference of the antenna. The electric field distribution and temperature uniformity at the different input phases were analyzed. Using four operating modes with a 90°phase difference between adjacent operating modes, the proposed heating system achieves a uniform temperature distribution. In comparison to the conventional heating system, the temperature uniformity was improved up to approximately 70.7%, and the system efficiency was approximately 56.7%.