Actuators to be integrated in low temperature cofired ceramics (LTCC) microfluidic systems

LTCC technology has recently been used for microfluidic elements, e.g. channels, cavities and other passive fluidic components. However, microfluidic systems having enhanced functionality, e.g. differential pressure sensors, dosing devices and pumps, require active components that include electrically driven actuators. Up to now, only piezo-cantilevers, electromagnetic and thermo-pneumatic actuators have been engineered for the LTCC integration [1-4]. Due to their specific properties, they are not suitable for all applications that require an actuator. Therefore, a review on actuators capable of being integrated in LTCC is given. On the one hand, the actuators are compared according to their functional properties, e.g. stroke and switching energy, so that actuators can be figured out that fulfil the requirements of a microfluidic system to be designed. On the other hand, the technological challenges to be coped with in the integration of the actuators are listed. Both the functional properties of an actuator and the possibility to integrate it decide on the suitability for a specific application. Using our evaluation method, we introduced actuators for two different microfluidic applications, a piezo-electrically controlled throttle for a DMFC (direct methanol fuel cell) application and an electrostatic valve for a differential pressure sensor.