Efficient Transient Electro-Thermal Strongly Coupled Multiphysics Simulation via Equivalent Heat Source Based on the FDTD Method

This paper presents a multiphysics simulation algorithm for electromagnetic-thermal strong coupling (ETSC) based on the finite-difference time-domain (FDTD) method. The proposed transient strong coupling multiphysics framework takes into account the effect of temperature on temperature-dependent parameters in both electrical and thermal properties, with synchronous iterations of the electromagnetic and temperature fields. For antennas operating in the RF frequency band, the thermal coupling considers not only Joule loss but also dielectric loss, investigating the impact of introducing dielectric loss. To address the multiscale time-domain issue in the multiphysics iterative process, a fast equivalent heat source algorithm is proposed, which significantly enhances computational efficiency while maintaining engineering-acceptable accuracy. To validate the accuracy of the method, numerical simulations were performed using a printed F antenna. The algorithm results showed a high degree of consistency with COMSOL software simulations. The rapid and accurate nature of the algorithm makes it an excellent simulation tool with significant applications in the fields of microwave circuits and radio frequency technology.