PIEZOELECTRIC THIN-FILM RESONATOR, FILTER CIRCUIT, AND COMMUNICATION EQUIPMENT USING THE SAME

摘要

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric thin-film resonator which uses a lateral vibration mode available for radio communication. Ž<P>SOLUTION: The piezoelectric thin-film resonator comprises a circular piezoelectric thin film 102, circular electrodes formed on an upper surface and a lower surface of the circular piezoelectric thin film and in the vicinity of the center of the disk-like piezoelectric thin film, and a plurality of annular electrodes 101u and 101d formed on the upper surface and lower surface of the circular piezoelectric thin film concentrically around the circular electrodes. The circular electrodes and the plurality of annular electrodes are formed to reduce electrode width toward end surfaces of the respective disks, and the piezoelectric thin-film resonator has the electrodes arranged and supported such that a higher vibration mode of spread vibrations is forcibly excited. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž