The thermal sensitivity of acoustic-wave-based devices still is an optimization key-point for various applications (filters, sources, sensors). As the architecture of such devices becomes more and more complex to fit the RF manufacturer requirements. simple analytical models usually exploited to optimize their frequency thermal drift are found obsolete. The optimization of these complex periodic wave-guide thermal sensitivities require the development of simulation tools capable to address the problem. This paper describes a Finite Element Analysis-Boundary Element Method (FEA/BEM) model allowing for the simulation any 2D and 3D periodic wave-guide thermal sensitivity. and more specifically the extraction of the corresponding Temperature Coefficient of Frequency (TCF). Validation of the computation approach first is reported. Its capabilities then are illustrated by computing the TCF of Love wave resonator on quartz.