Abstract :
The propagation characteristics of leaky surface waves on Li2 B4O7 substrate are theoretically calculated for all cuts and propagation directions by changing Euler´s angle. The theoretical contour maps for phase velocity, electromechanical coupling constant (K2), temperature coefficient of delay (TCD), propagation loss, and power-flow angle (PFA) are displayed. From these results, the following features of leaky surface waves are obtained. Phase velocity varies from 3570 to 5242 m/s. The maximum value of K2 is about 6.4%, which is much larger than 1.6% for the Rayleigh wave. At 45°, 90°, and 70°, the values of phase velocity, TCD, K2, propagation loss, and PFA are about 3780 m/s, 0.15 p.p.m./°C, 3.6%, 0.87 dB/λ, and 27.4°, respectively. The effects of a thin aluminum plate on the TCD are also investigated
Keywords :
lithium compounds; losses; substrates; surface acoustic waves; ultrasonic propagation; ultrasonic velocity; Euler´s angle; Li2B4O7 substrate; PFA; Rayleigh wave; SAW; TCD; electromechanical coupling constant; leaky surface wave propagation characteristics; phase velocity; power-flow angle; propagation directions; propagation loss; surface acoustic wave; temperature coefficient of delay; theoretical contour maps; thin Al plate; Acoustic devices; Aluminum; Delay; Frequency; Load flow; Piezoelectric materials; Propagation losses; Surface acoustic wave devices; Surface waves; Temperature;
