Study of the factors limiting the Q factors of high performance quartz resonators.

In this contribution we review the main origins of dissipation in crystal resonators. Several factors appear to be important: the intrinsic dissipations (viscous losses, the dielectric losses and the conductivity), the leakage of acoustical energy via the fixations and the energy dissipation resulting of the existence of other modes, more dissipative (electrical interactions). A calculation is made of the influence of intrinsic dissipation in energy trapping resonators.