Active wave-guiding of piezoelectric phononic crystals

By numerical simulations, we show that active wave-guiding can be realized in a stop band frequency range of a phononic crystal (PC) if piezoelectric inclusions in the PC are electrically controlled. The advantages of the wave-guiding are that no permanent geometry or material change is needed and that somewhat arbitrarily shaped waveguides can be formed actively in PC structures. The analysis with supercells consisting of piezoelectrically coupled and decoupled inclusions shows that symmetric wave modes confined within the waveguide formed by decoupled inclusions are most responsible for wave transmission.