Murata Manufacturing Co., Ltd.

Yoshihiko Gotoh

Masaki Takeuchi

Tadashi Nomura

Hajime Yamada

Yukio Yoshino

Daisuke Nakamura

Hideki Kawamura

Masato Kobayashi

Katsuhiko Tanaka

Seiichi Arai

Hiroyuki Fujino

Ken-ichi Uesaka

A piezoelectric thin-film resonator includes a supporting substrate. A piezoelectric thin-film is formed on the supporting substrate. A lower electrode and an upper electrode are formed with the piezoelectric thin-film therebetween. The stiffness of at least one of the lower and upper electrodes is higher than that of the piezoelectric thin-film.

Piezoelectric thin-film resonator, piezoelectric filter, and electronic component including the piezoelectric filter

A piezoelectric filter and other electronic components are constructed such that the accuracy of frequency adjustment can be increased and an improvement in efficiency of the adjustment operation can be achieved. The piezoelectric filter includes a plurality of piezoelectric resonators including a substrate and a vibration portion provided on the substrate, the vibration portion having a structure in which the top and bottom surfaces of a thin film portion including at least one piezoelectric thin film are sandwiched between at least a pair of an upper electrode and a lower electrode facing each other, wherein the upper electrode of a predetermined piezoelectric resonator is made of a material having susceptibility to etching that is different from that of the upper electrode of the other piezoelectric resonator.

Piezoelectric filter, duplexer, composite piezoelectric resonator, communication device and method for adjusting frequency of piezoelectric filter

A piezoelectric resonator includes a substrate and a vibrator. The vibrator includes a thin-film portion having at least one piezoelectric thin-film layer disposed on the substrate and at least one pair of upper and lower electrodes disposed on the substrate. The vibrator has a structure in which the thin-film portion is sandwiched from the upper and lower surfaces thereof by the upper and lower electrodes, which oppose each other in the depth direction, and the overlapping portion of the vibrator defined by the opposing upper and lower electrodes has a tetragonal shape, when viewed in the depth direction, other than a rectangle and a square, the tetragonal shape having substantially parallel sides having a longitudinal length equal to or smaller than about 10 times the oscillatory wavelength and also having at least one portion in which the distance between opposing electrode edges varies.

Piezoelectric resonator, and piezoelectric filter, duplexer, and communication apparatus, all including same

A duplexer includes a transmission band filter and a reception band filter connected in parallel to each other and connected to an antenna terminal. The transmission band filter and the reception band filter are accommodated in a package covered with an electroconductive lid. The package is mounted on a mounting substrate having the antenna terminal and covered with an electroconductive shield mounted on the mounting substrate. At least one of the transmission band filter and the reception band filter has a ground terminal connected to the lid. The lid is electrically connected to the shield.

Duplexer and composite module having a package with an electroconductive lid electrically connected to a shield

A thin-film multilayered electrode has a dielectric substrate; a ground conductor provided on a back surface of the dielectric substrate; and a plurality of thin-film conductive layers and dielectric layers alternately stacked on a front surface of the dielectric substrate. In one example, the ground conductor, one of the thin-film conductive layers in contact with the dielectric substrate and the dielectric substrate interposed therebetween form a TEM mode principal transmission line, and each thin-film dielectric layer and a pair of thin-film conductive layers sandwiching the thin-film dielectric layer form a TEM mode sub-transmission line. A thickness and a dielectric constant of each thin-film dielectric layer is set such that phase velocities of TEM waves which propagate through the TEM mode principal transmission line and the TEM mode sub-transmission lines are substantially identical with each other. A thickness of each thin-film conductive layer is set at a predetermined value which is smaller than a skin depth at a predetermined operating frequency such that electromagnetic fields between the TEM mode principal transmission line and its adjacent TEM mode sub-transmission line, and between each adjacent pair of TEM mode sub-transmission lines, are coupled with each other. At least one of the thin-film dielectric layers which is closest to the dielectric substrate has a thickness greater than that of the other thin-film dielectric layers.

Growing community of inventors

Shiga-ken, Japan

Yoshihiko Gotoh