Anisotropy of the acoustic plate modes in ST-Quartz and 128°Y-LiNbo3

Orientation dependences of the phase velocity v_n, coupling coefficient K_n², and power flow angle Ψ_n for zero-order and high-order acoustic modes are calculated numerically in ST-quartz and 128°Y-LiNbO₃ plates with normalized thickness h/λ = 0.1, 0.25, 0.5, 1.0, 1.25, 1.5, and 1.67 (n is the mode order, θ is the angle between propagation direction and the x-axis, h is the thickness, and λ is the wavelength). Results of the calculations are experimentally verified using 128°Y-LiNbO₃ plates with h/λ = 1.0, 1.67 and θ = 0°, 30°, 60°, 90° as examples.