Investigation of Electromechanical Coupling and Quality Factor of X-Cut Lithium Niobate Laterally Vibrating Resonators Operating Around 400 MHz

Abstract

In this paper we present laterally vibrating resonators (LVRs) based on X-cut lithium niobate (LN) exhibiting a maximum quality factor (Q) around 1200 and an electromechanical coupling (k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) of 30%. This paper shows how the highest k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ever attained in X-cut LN resonators can be combined with very high Q to achieve a resonator figure of merit (FoM = k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> · Q) of 360. In this paper, we validate the theoretical prediction of k <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> versus the resonator orientation in the YZ plane and investigate what geometrical parameters mostly impact the Q of these devices.