High Velocity Acoustical Head Wave on Surface of ST Quartz

According to surface transient excitation theory of elastic wave for piezoelectric crystal,in the surface of a piezoelectric crystal can exist acoustical high velocity head wave except the general surface acoustic wave(SAW).Such a mode is to propagate with the group velocity of the longitudinal bulk wave along the crystal surface.For ST quartz its value is 5.744×10^(3)m/s,which agrees with our experiments.The fact that the longitudinal head wave mode has a high propagation velocity offerspotential applications for high frequency SAW devices.