Development of a Novel Sensor-Actuator-Module with Ceramic Multilayer Technology

There is a need for low-profile piezoelectric modules directly integrated into structural components like lightweight metals to control the vibration and noise of thin-walled structures and components. This paper reports on a new module design based on LTCC/PZT multilayers. The newly developed packaging technology entails the lamination of sintered PZT ceramic plates with LTCC green layers and subsequent sintering. This module design has the advantage of complete encasement of the PZT by the insulating carrier material. The approach combines LTCC microsystems technology and piezo technology and allows for tremendous consolidation of functional integration, e.g. sensing, actuation and electronic control. Ferroelectric hysteresis loops and deflection of LTCC/PZT modules glued onto steel plates were measured and compared with reference steel plates based on PZT plates. LTCC/PZT modules showed a maximum deflection of around 130 pm in the static mode and above 550 pm in the dynamic mode with a resonance frequency of 19.7 Hz. Single LTCC/PZT modules with optimum design were integrated into an aluminium matrix prepared by metal die casting in cooperation with the University of Erlangen-Nuremberg. X-ray analysis was performed to show that the LTCC/PZT modules survived this manufacturing step without cracks, confirming the vision of adaptive metal structures in the automotive and machine engineering industries.