Highly directional liquid surface wave source based on resonant cavity

By placing a point source inside a resonant cavity structure, we present a method to realize a highly directional liquid surface wave source. The resonant cavity is surrounded by two slabs of different thickness, with each slab consisting of a finite square array of rigid cylinders standing vertically in the liquid. It is shown that more than 68% of the total energy is emitted out along the normal directions of the cavity within a very narrow angular range. At the resonant frequency, narrow emission pattern with half-power angular width of only several degrees is obtained.