Ultrasonic Propeller with Electrically Controllable Propulsion Direction

This paper introduces a novel ultrasonic propeller with electrically controllability over its propulsion direction. Built on a 1.02 mm thick nickel-coated lead zirconate titanate (PZT) substrate, the propeller consists of 18 sectors of individually accessible Fresnel lens that are composed of Parylene air-cavity-reflectors on top of the front-side nickel electrode. A backside air-reflector is added to prevent any propulsion from the backside that may cancel the propulsion from the front side. A fabricated propeller weighing 4.9 grams is measured to have (1) a maximum perpendicular thrust of 13.8mN in water when driven by 80V
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applied to all the sectors and (2) a maximum lateral thrust of 2.1mN under 80V
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applied to a single sector.