Decoupling effect of stepped mesa structures on spurious vibrations of AT-cut quartz plates

This paper describes the theoretical analysis and experimental results of the stepped bi-mesa structures effect on the coupling of vibrations in AT-cut quartz plates. Since strong couplings of thickness-flexure modes are of interest, straight-crested waves propagating along the X-axis are treated. Results estimated from the mode chart of the stepped bi-mesa structure indicate that the coupling strength should decrease to about one-third that of a bi-mesa resonator. Experimental results agreed well with calculated results. Therefore it should be possible to further improve the characteristics of bi-mesa structures by using a stepped bi-mesa structure. Stepped plano-mesa structures are also discussed.