Research About Simulation Design Match Of Elecromagnetic Field In Microwave Oven

It is one of important factors decide the fit or unfit microwave oven qualitywhether impedance matching of microwave is good, need to know the distribution ofelectromagnetic field in the cavity. If improper matching, microwave energy inmicrowave oven may gather lead to strike fire, have local thermal alteration or otherquality problems when test with light load, or reduce the microwave heating power andefficiency, seriously sacrifice the quality of the microwave oven. It is usual in actualmanufactures production the local thermal alteration, striking fire, etc. Proper matchingis main decided by the cavity structure and size, waveguide size and location as well asthe structure of coupling window, etc. So analyze the inference structure of waveguideand coupling window, cavity to impedance matching, then confirm a suitable size, sothat to improve the microwave matching, decrease probability of quality problems andunnecessary waste of manpower or material resources, improve research anddevelopment, production efficiency. Usually practical research and production aboutmicrowave oven is constantly "design-manufacture-correction", as we all know this is along R&D time and more money way, so many microwave oven manufacturers and ourresearchers are looking for a shorter development cycle and lower cost design method.For some microwave ovens have frequent problems such as Striking fire, fusingshaft in quality measurement, failed to meet requires target. To solve these problems,improve matching performance of the microwave oven, need exact data basis andtheoretical guidance. As structure of microwave oven cavity is complex, only by theoryto analyze the electromagnetic field distribution is difficult, and get an accuratenumerical value is scarcely possible, need the help of simulation software onthree-dimensional electromagnetic field to draw a distribution of electromagnetic fieldin the cavity and reflection coefficient of microwave. This article main work as follows:(1) It used Ansoft HFSS software to carry on air and solid modeling of themicrowave oven, and electric field of glass plate, S11parameter curve in polar plot,areas where electric field or energy concentrated from simulation were respectivelyconsistent with the actual temperature distribution of glass plate, network analyzer S11 parameter curve, location where striking fire or thermal alteration happened, verified theaccuracy of microwave oven modeling and the electrical characteristics parametersetting on dielectric material.(2) On basis of ensuring the microwave oven model accuracy, it respectivelysimulated and optimized several parameters such as coupling window, waveguide, thebackboard and roof of cavity, glass plate, swivel wheels and combined the experimentaltest to analyze influence law of the change on microwave matching, and then usedsimulation to find method of improve matching so that to solve the problem that affectmicrowave oven matching, thus put forward the final optimization scheme.(3) The article finally described the optimized scheme and applied it to practicalmicrowave ovens, had the energy efficiency and cooking test, then found the problemsof the microwave oven really solved, and increased the output power and efficiency,cooking test score was81.4, reached the requires target.