Abstract
In near-field levitation, an object can be levitated vertically upward above vibrating surface of an ultrasonic transducer. On the other hand, it is reported that an object can be suspended vertically downward under the vibrating surface in the air. This phenomenon called the acoustic downward suspension. When an object is suspended, there is restoring force, which attracts the object to the center of the vibrating surface. The force characteristics were investigated experimentally. A servo type measuring mechanism was composed which can measure vertical and horizontal direction force simultaneously. This paper reports the relationship between acting force and center distance between the vibrating surface and suspended object.
