Radio frequency controlled microvalve for biomedical applications

Abstract

In this paper we propose the use of a RF controlled microvalve for implementation on a PZT substrate for biomedical applications. Such device has a huge range of applications such as parallel mixing of photo-lithographically defined nanolitre volumes, flow control in pneumatically driven microfluidic systems and lab-on-chip applications. The microvalve makes use of direct actuation mechanisms at the microscale level to allow its use in vivo applications. A number of acoustic propagation modes are investigated and their suitability for biomedical applications, in terms of the required displacement, device size and operation frequency. A theoretical model of the Surface Acoustic Wave (SAW) device is presented and its use in micro-valve application was evaluated using ANSYS tools. Furthermore, the wireless aspect of the device is considered through combining the RF antenna with the microvalve simulation by assuming a high carrier frequency with a small peak-to-peak signal. A new microvalve structure which uses a parallel type piezoelectric bimorph actuator was designed and simulated using ANSYS tools. Then, further optimization of the device was carried out to achieve a better coupling between electrical signal and mechanical actuation within the SAW device.