Computing spiral microwave heating by transformation optics

In this paper, a spiral motion computation method based on transformation optics for computing the microwave heating processes with irregular food is presented. Firstly, the theoretical derivations of the rotating, lifting, and overlapping regions caused by rotating and lifting are conducted. Secondly, the electric field distribution computed by the proposed method is verified, and the computation accuracy and time are compared with implicit function and level set methods (IFLSM). It was found that the root-mean-square-errors (RMSEs) of the port reflection coefficients for rotating motion, lifting motion, and spiral motion are 0.021, 0.164, and 0.151, respectively, demonstrating the effectiveness of the proposed method in computing the spiral motion of irregular food shapes. Finally, the computation of spiral microwave heating of irregular-shaped bears with different materials under different motion states is studied, and the industrial application of cookies in secondary processing is analyzed.