ENERGY TRAPPING EFFECT OF STEPPED ELECTRODE IN MINIATURE AT-CUT QUARTZ RESONATOR

Abstract

As the size of quartz resonator continues to shrink, beveling of the plano-plano quartz crystal is needed to reduce mounting loss and to sustain energy trapping so to have low motional resistance for oscillation. The beveling process though is time consuming and difficult to control for small size and low frequency quartz crystals. In recent years, studies on stepped electrode (a.k.a bi-mesa electrode) began to appear. It's believed that stepped electrode on plano-plano crystal would do part of the job in energy trapping like beveled crystals. In this paper, we report our own study of stepped electrode with the following configurations- single layer electrode on plano-plano crystal, stepped electrode on plano-plano crystal, single layer electrode on beveled crystal, and stepped electrode on beveled crystal. The vehicle for this study was a 15 MHz 3.2mmx2.5mm crystal. Preliminary results show that stepped electrode can provide to some degree of energy trapping as bevel crystals.