Antenna structure design and heating efficiency in high-speed microwave ovens

Abstract In order to enhance the heating efficiency of commercial high-speed microwave ovens, the microwave antenna composed of the inner conductor and the guide plate was designed based on the prototype using numerical simulation method. The heating efficiency, heating uniformity, and heating performance on foods (croissants, pizza, panini, donuts, and beef patty) between the optimized machine and the prototype were compared and analyzed. The results showed that the average electric field intensity in the effective heating area of the optimized scheme increased by 78.78 %. Using water as the test object, the temperature rise elevated by 17.97 %, and the microwave absorption efficiency increased by 6.1 %. In the combined microwave-hot air heating of bread, pizza (dough), panini, doughnuts, and beef patty, both the internal and surface temperature rises of the foods under the optimized scheme were higher than those of the prototype. The average temperature rise increased by 13.53 % and 12.97 %, respectively. The designed optimized scheme can further reduce the heating time of the high-speed microwave oven, thus meeting the requirements of rapid food heating.