Design and experiment of a focused acoustic sorting chip based on TSAW separation mechanism

Based on the traveling surface acoustic wave separation mechanism, a focused acoustic sorting chip is presented in this work, which fully utilizes the focusing energy characteristics of the focused interdigital transducer (F-IDT). Firstly, the structure of the focused acoustic sorting chip and the basic parameters of F-IDT are determined by numerical analysis. Then, the related optimal operating parameters of working frequency (f), the inlet flow ratio and average velocity of main channel (Va) are determined by COMSOL simulation, namely, f = 131.83 MHz, the inlet flow ratio 10:1:1, and Va = 4 mm/s. In the lab, the prototypes of the focused acoustic sorting chip are designed and fabricated. The corresponding separation experiments are carried out using the developed acoustic sorting chip to separate the polystyrene particles with diameters of 1 μm and 10 μm, and the sorting efficiency of particles are calculated and analyzed under different power. The experimental results show that focused acoustic sorting chip can achieve particle separation and the sorting efficiency is over 99%. The proposed focused acoustic sorting chip has the advantages of simple structure, high sorting efficiency, focusing energy and contact-free particle manipulation.