| abstract |
SUMMARY A tunable filter arrangement having a plurality of resonators connected to one another, at least one of which has a piezoelectric element formed of a ferroelectric material, and is connected to a DC power supply, is disclosed. Application of a DC voltage to the resonator changes its electrical properties and changes the overall filter properties. Further, a transmitter, a receiver and a mobile telephone device having such a filter configuration are disclosed together with a tunable bulk acoustic wave resonator. |