Electrical reflection coefficient and velocity shift for groove gratings

All previous calculations for the electrical reflection coefficient and velocity shift for grooves have used formulas valid for the reflection of a SAW (surface acoustic wave) from an array of conducting strips. However, the discontinuity in electrical boundary conditions leading to these formulas does not exist in groove gratings. A new expression for the electrical reflection coefficient and velocity shift for the same material overlays is derived from the variational principle and from perturbation theory. The results for various substrates are compared to show the agreement between the two approaches. The implications of this new formulation for the design of grooved arrays on various materials is discussed