Single-sided acoustic levitation based on array of focused ultrasound transducers

Ultrasound levitation technology has been widely applied in various fields. Two main kinds of ultrasound levitation configurations are the standing-wave system and the phased array system. Depending on the principle of the phased array and the focusing transducers, we proposed and designed a levitation system consists of two pairs of focusing ultrasound transducers fitting in confocal mode. When paired transducers are excited in the reverse phases, the acoustic pressure at the geometric focus will be constant 0 Pa, which means a potential well exists here. Depending on the finite element method, we simulated the field distribution and demonstrated the designed potential well. By modulating the phase sequences of the paired transducer, we obtained three kinds of acoustic field distributions with potential well. We optimized the included angle between the axis of the paired transducer to reduce the secondary potential well and improve the accuracy of the levitation. Moreover, we carried out an experiment in water with ultrasound of 2 MHz. The quartz sand with a diameter of 0.2 mm was captured by our levitation system stably.