There is provided a piezoelectric thin-film resonator including a substrate, a lower electrode disposed on the substrate, a piezoelectric film disposed on the lower electrode, an upper electrode disposed on the piezoelectric film in such a manner that a portion of the upper electrode is opposed to the...http://www.google.com/patents/US7952257?utm_source=gb-gplus-sharePatent US7952257 - Piezoelectric thin-film resonator