Design Of Microwave-heated System And Research On Electromagnetic Field In Resonant Cavity

Microwave can penetrateintomaterial andcause volumeheating,whichis characterized in low cost, short processing time and easily controlling,especially for solid materials. Temperature measurement and control inhigh-power electromagnetic environment is a difficult technical problem.The temperature field uniformity is the key problem in microwaveapplicationforalongtime.Design of hardware and software in Microwave heating control systemhas been achieved, which is controlled by SPCE061A as CPU core. Theclosed-looptemperature control has beenimplementedbydigital PID,whichcould ensure adjustability of the microwave power and the system workinginthereferencetemperature.An improved thermocouple, which is less affected by electromagneticinterference, is applied in the temperature measurement.In order tostabilizevariable power production of microwave source, improve control precisionand reduce pollution to the common power net, an AC power regulator offullcycle-switch isdesigned.The temperature field uniformity is decided by the electric fielduniformity.Anumerical modelis developed tosimulatethe electricfieldin a rectangular single mode resonant cavity by Ansys, finite element software.The effect of microwave resonant modeand material dielectric properties onthe electric field inside the cavity is studied. The results show theTE101model can achieve a more uniform electric field than TE103. Thenonuniformity of electric field inside sample increase with sample'sconductivity has been found. The Rectangular resonant cavity is moresuitable for this system than cylindrical or spherical resonant cavity. Designof Microwave resonant cavityhas been completed on the basis of theoreticalanalysis.