Acoustic wave sensing devices and their LTCC packaging

The paper presents the relevant results of manufacturing LTCC packages intended for chip assembly as well as the RF behavior of SAW and FBAR structures used as temperature and, respectively, humidity sensing devices. Packaged SAW-based temperature sensors were characterized in a cryostat set-up, while the packaged FBAR-based humidity sensors were measured in a small enclosure with controlled humidity. Linear behaviour of the frequency shift vs. temperature and, respectively, relative humidity was evidenced.