Electro-thermal Modeling of TCSAW Filter

In this paper, an electro-thermal model of a surface acoustic wave (SAW) filter is presented. The thermal behavior is modeled in a finite element method (FEM) simulation. The thermal ports are defined to represent the resonators and busbars of the layout. The electro-thermal model is realized in an RF circuit simulator in which acoustic resonator models and busbar models are combined with the thermal behavior of the layout. Electro-thermal ports are implemented to simulate the temperature increase of the resonators. In an experiment, a resistive temperature sensor is utilized to detect the temperature increase at a series resonator within the filter topology. The result due to a fixed input power of 29 dBm is compared to the simulation and a frequency sweep of the applied load tone is performed. The impact of the resonator's self heating and the mutual heating of the surrounding heat sources are separated in the simulation. Furthermore, the dissipated powers at the electrothermal ports are used to simulate the temperature distribution in the filter.