Improving Heating Uniformity of Microwave Oven Using Diffusing Metasurfaces

This paper presents a method to improve the heating uniformity of a microwave oven by using diffusing metasurfaces. In this study, a 1 bit phase gradient metasurface operating near 2.45 GHz is designed and leant against the side wall of a microwave oven. Specifically, we investigate three cases when the metasurface is leant against the left, right and back walls of the microwave oven, respectively. Five cups of water are placed at the four corners and center of the tray for heating experiments. The experimental results show that the heating uniformity of the microwave oven can reach up to 88.5% when placing a diffusing metasurface leaning against the back wall, 17.8 percentage points higher than that without any metasurfaces in the microwave oven. Our study demonstrates that by loading a diffusing metasurface can effectively improve the heating uniformity of the microwave oven.