Resonance Frequency Dependence Of A1 Lamb Mode On The Pitch Of The Electrode Structure

Dispersion of A1 Lamb mode near onset frequency is discussed. This mode is close to that used in XBAR devices. The typically used approximation is based on elliptic form of slowness curve and ignoring mode interaction is not valid for widely used materials, such as ZY-LiNbO
3
. Alternative phenomenological dispersion formula is proposed.