Uniform and highly efficient microwave heating based on dual‐port phase‐difference‐shifting method

A novel microwave heating method by which the uniformity and efficiency are effectively enhanced through dual-port phase-difference-shifting feed is proposed. The microwave power is fed into a waveguide from both ports with adjustable phase. Therefore, the phase difference between the dual feed ports can be either fixed or changing during the heating process, resulting in different temperature distribution inside the heated object. A simulation model of such a microwave heating system is built, and the temperature distributions with respect to phase difference are calculated using commercial software COMSOL Multiphysics. A quantitative validation of simulation results has been performed with physical experiments. Both measured and simulated results demonstrate the superiority of phase-difference-shifting heating in uniformity and efficiency, compared to the phase-difference-fixed heating. The uniformity is improved by 39.1% at the same average temperature rise (∆Tav), and the efficiency is increased about 97.8% from the same uniformity point of view.