Study on surface acoustic wave rotary motors

On the surface of 128° yx-LiNbO3 substrate, two pairs of Inter-Digital Transducers （IDTs） are parallelly arranged in the propagation direction, which is a stator of surface acoustic wave （SAW） rotary motors. A plastic disk with small balls distributed around the circumference is a rotor. When a high frequency voltage is inputted to two IDTs, two Rayleigh wave beams are generated and are propagating on the substrate in opposite directions with each other. The resulting local relative motion between the particles of the stator and the balls produces two inverse frictional forces to form a moment to drive the rotor. The experimental results and theoretical analysis and calculation for two operating frequencies are accomplished and discussed.