High and low frequency GaPO4 resonators

High frequency fundamental inverted mesa resonators with large pulling range have been produced in crystalline GaPO₄. Motional capacitances at least 3 times larger than those of equivalent quartz resonators have been achieved for resonators with a fundamental frequency up to 155 MHz. High frequency resonators behave as a function of temperature as expected. Low frequency miniature tuning fork resonators have been produced as well. Their electrical and thermal parameters are similar to those of standard quartz crystal tuning forks, however the thermal compensation is not as good as expected from theory.