LTCC/PZT accelerometer in SMD package

Abstract

Purpose – The purpose of this paper is to develop the device made of low temperature co-fired ceramics (LTCC) and lead zirconate titanate (PZT) by co-firing both materials. In the paper, the technology and properties of a miniature uniaxial ceramic accelerometer are presented. Design/methodology/approach – Finite element method (FEM) is applied to predict properties of the sensor vs main dimensions of the sensor. The LTCC process is applied during manufacturing of the device. All the advantages of the technology are taken into account during designing three-dimensional structure of the sensor. The sensitivity and resonant frequency of the accelerometer are measured. Real material parameters of PZT are estimated according to measurement results and FEM simulations. Findings – The ceramic sensor integrated with SMD package with outer dimensions of 5 × 5 × 5 mm3 is manufactured. The accelerometer exhibits sensitivity of 0.75 pC/g measured at 100 Hz. The resonant frequency is equal to about 2 kHz. Useful frequency range is limited by 3 dB sensitivity change at about 1 kHz. Research limitations/implications – Sensitivity of the device is limited by interaction between LTCC and PZT materials during co-firing process. The estimated d parameters are ten times worse comparing to bulk Pz27 material. Further research on materials compatibility should be carried out. Practical implications – The sensor can be easily integrated into various devices made of standard electronic printed circuit boards (PCBs). Applied method of direct integration of piezoelectric transducers with LTCC material enables manufacturing of complex ceramic systems with built-in accelerometer in the substrate. Originality/value – The accelerometer is a sensor and a package simultaneously. The miniature ceramic device is compatible with surface mounting technology; hence, it can be used directly on PCBs for vibration monitoring inside electronic devices and systems.