Bleustein-Gulyaev wave propagation under periodic metal gratings

Bluestein-Gulyaev (BG) piezoelectric surface wave propagation under a periodic metal strip grating on piezoelectric cubic crystals is investigated. A general theory that fits both the elastic and the electric periodic boundary conditions has been developed. Numerical examples are given for aluminum and gold shorted gratings on a GaAs substrate. It is found that the BG waves which penetrate deep into the substrate in the absence of the metal grating become trapped at the surface when the grating is present, and the depth of penetration is heavily dependent on the metal thickness. The relevant physical quantities, such as particle displacement and dispersion curves, are also computed and analyzed. The velocities of BG waves under grating structures are greater than those of surface acoustic wave modes, and thus devices that operate at higher frequencies with the same grating periods can be implemented