MicroSurf: Guiding Energy Distribution inside Microwave Oven with Metasurfaces

Microwave ovens have become an essential cooking appliance owing to their convenience and efficiency. However, microwave ovens suffer from uneven distribution of energy, which causes prolonged delays, unpleasant cooking experiences, and even safety concerns. Despite significant research efforts, current solutions remain inadequate. In this paper, we first conduct measurement studies to understand the energy distribution for 10 microwave ovens and show their energy distribution in both 2D and 3D is very skewed, with notably lower energy levels at the center of the microwave cavity, where food is commonly placed. To tackle this challenge, we propose a novel methodology to enhance the performance of microwave ovens. Our approach begins with the development of a measurement driven model of a microwave oven. We construct a detailed 3D model in the High Frequency Structure Simulator (HFSS) and use real temperature measurements from a microwave to derive critical parameters relevant to the appliance's functionality (e.g., operating frequency, waveguide specifications). We then develop a novel approach that optimizes the design and placement of a low-cost passive metasurface for a given heating objective. Using extensive experiments, we demonstrate the efficacy of our approach across diverse food, optimization objectives, and microwave ovens.