  This paper investigates an acoustic prism for continuous acoustic beam
steering by a simple frequency sweep. This idea takes advantages of acoustic
wave velocity shifting in metamaterials in the vicinity of local resonance. We
apply this concept into the piezoelectric metamaterial consisting of host
medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are
carried out. It is shown that the phase velocity of acoustic wave changes
dramatically in the vicinity of local resonance. The directions of acoustic
wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of
the excitation frequency. Such an electro-mechanical coupling system has a
feature of adjusting local resonance without altering the mechanical part of
the system.
