Cryogenic Q enhancement in 50 GHz piezoelectric resonators

Abstract

Piezoelectric resonators are a critical component of many systems. Recent advances have increased the operation frequency of these resonators into the tens to hundreds of GHz; however, the performance is still limited to moderate quality factors in the low hundreds. When viewed through the lens of the frequency-quality factor product, which can illustrate frequency-scaled loss mechanisms, a perceived limit becomes apparent. To probe this limit, we characterize solidly mounted piezoelectric resonators at cryogenic temperatures (7 K). The resonators provide mechanical robustness, as well as high-frequency shear modes around 50 GHz. Both the loaded and unloaded quality factors of these modes see enhancement with the temperature reduction, suggesting the impact of temperature-dependent fundamental loss mechanisms. This provides a launching pad for further dedicated studies to examine how energy dissipation occurs in these emerging high-frequency resonators.