Abstract: A piezoelectric filter comprises a substrate and a plurality of piezoelectric resonators provided on the same substrate. Each piezoelectric resonator comprises a cavity formed in the substrate, a lower electrode formed on the substrate, covering the cavity, a piezoelectric material layer formed on the lower electrode, and an upper electrode formed on the piezoelectric material layer. At least one of the piezoelectric resonators has a cavity formed of a plurality of cells.

Abstract: A high frequency filter includes an inductor, a serial resonance circuit including an inductor and capacitors, a serial resonance circuit including an inductor and capacitors, and a varactor diode connected between a connection point between the capacitor and the capacitor and a connection point between the capacitor and the capacitor. A controller simultaneously changes two attenuation pole frequencies of the filter device by changing a capacitance of the varactor diode.

Abstract: An acoustic resonator includes a substrate, a support section provided on the substrate, a lower electrode provided on the support section, a piezoelectric body provided on the lower electrode, and an upper electrode provided on the piezoelectric body. The lower electrode, the piezoelectric body and the upper electrode form a vibration section. The support section for supporting the vibration section is shaped such that at least one portion of a vertical cross-section thereof has a curvature.

Abstract: A micromachine switch of the present invention is a micromachine switch for switching an electrical connection between signal electrodes in accordance with control signals from outside which include: a first control signal for electrically connecting the signal electrodes between which a signal is to be passed; and a second control signal for disconnecting the electrical connection between the signal electrodes.

Abstract: An acoustic thin film resonator including: a first piezoelectric thin film 101; a pair of primary electrodes 103 and 104 for applying an electric signal, which are formed on the first piezoelectric thin film; a second piezoelectric thin film 102 that is disposed so that an oscillation generated in the first piezoelectric thin film propagates to the second piezoelectric thin film; a pair of secondary electrodes 104 and 105 for outputting an electric signal, which are formed on the second piezoelectric thin film; a load 108 that is connected between the secondary electrodes; and a control portion 109 that controls a value of the load. Thereby, an acoustic thin film resonator element is formed so that an electric signal inputted from the primary electrodes is outputted from the secondary electrodes by a piezoelectric effect, and a resonant frequency and an antiresonant frequency are made variable through the control of the value of the load.

Abstract: A filter module includes a substrate and a plurality of resonators formed on the substrate and utilizing longitudinal vibration along the thickness of a piezoelectric layer. A plurality of external connection terminals are formed above or below the piezoelectric layer so as to be electrically connected to external circuits and also electrically connected to some of the plurality of resonators through a plurality of interconnects formed to the side of the piezoelectric layer to which the external connection terminals are formed.

Abstract: A piezoelectric resonator comprises a piezoelectric material layer 101, a first electrode 102 formed on one major surface of the piezoelectric material layer 101, and having a cross-section in the shape of a trapezoid whose longer side contacts the piezoelectric material layer 101, and a second electrode 103 formed on the other major surface of the piezoelectric material layer 101, and having a cross-section in the shape of a trapezoid whose longer side contacts the piezoelectric material layer 101.

Abstract: An upper electrode (50) includes a first electrode section (51) formed in a circle and a second electrode section (52) formed in an annulus outside of the first electrode section (51). The first electrode section (51) and the second electrode section (52) are electrically separated from each other via an insulating region and have shapes of a circle and an annulus which are concentric. A lower electrode (30) includes a third electrode section (31) formed in a circle and a fourth electrode section (32) formed in an annulus outside of the third electrode section (31). Similarly, the third electrode section (31) and the fourth electrode section (32) are electrically separated from each other via an insulating region and have shapes of a circle and an annulus which are concentric.

Abstract: The area of an opening C of a cavity is equal to or greater than the area of a horizontal cross section D of a vibrating section. The vibrating section is placed on a support section at a position such that a vertical projection of the vibrating section onto a substrate is accommodated within the opening C of the cavity. Moreover, the sum of a vertical thickness t1 of the vibrating section and a vertical thickness t2 of the support section is equal to one wavelength of a resonance frequency fr of an acoustic resonator (one wavelength=t1+t2), while the thickness t1 of the vibrating section and the thickness t2 of the support section are different from each other (t1?t2). Thus, neither the thickness t1 of the vibrating section nor the thickness t2 of the support section is equal to the half wavelength of the resonance frequency fr.

Abstract: A first supporting section 30 is provided between a substrate section 40 and a second supporting section 20. The first supporting section 30 is structured by, e.g., a film formed from a material having a higher acoustic impedance than a piezoelectric body 11 and the substrate section 40, or a film formed from a material having a smaller Q value than the piezoelectric body 11 and substrate section 40. By inserting the first supporting section 30, most vibration from the second supporting section 20 toward the substrate section 40 is reflected (arrow a), and also a vibration having been transmitted to the substrate section 40 from the second supporting section 20 is prevented from reflecting at the bottom of the substrate section 40 and then returning in a direction of the vibration section 10 (arrow b).

Abstract: A series piezoelectric resonator 11 is connected in series between an input terminal 15a and an output terminal 15b. A first electrode of a parallel piezoelectric resonator 12a is connected to a connection point between the input terminal 15a and the series piezoelectric resonator 11, and a second electrode of the parallel piezoelectric resonator 12a is connected to a first terminal of an inductor 13a. A first electrode of a parallel piezoelectric resonator 12b is connected to a connection point between the series piezoelectric resonator 11 and the output terminal 15b, and a second electrode of the parallel piezoelectric resonator 12b is connected to a first terminal of an inductor 13b. Second terminals of the inductors 13a and 13b are grounded. An additional piezoelectric resonator 14 is connected between the second electrode of the parallel piezoelectric resonator 12a and the second electrode of the parallel piezoelectric resonator 12b.

Abstract: An electromechanical switch includes a first beam, a second beam arranged in parallel with the first beam and connected to the first beam through a connecting portion, a first electrode formed so as to have a first gap with respect to the first beam, a voltage applying portion which applies a voltage between the first beam and the first electrode, and a second electrode formed so as to have a second gap with respect to the second beam. The second gap is greater than the first gap. The first beam is displaced when the voltage applying portion applies the voltage between the first beam and the first electrode, so that switching between the second beam and the second electrode is performed in a state that the first beam is not electrically connected to the first electrode.

Abstract: A piezoeletric resonator includes: a substrate; a lower electrode formed on or above the substrate; a piezoeletric body formed on or above the lower electrode; an upper electrode formed on or above the piezoeletric body; and a cavity under a vibrating portion formed by the lower electrode, the piezoeletric body, and the upper electrode. Where a resonant frequency of vibration with a thickness of the vibrating portion being a half of a wavelength is taken as fr, an average of ultrasonic velocity in a material forming the cavity is taken as Vc, and a value determined based on the resonant frequency fr and the average of ultrasonic velocity Vc is taken as ?c (=Vc/fr), a depth of the cavity is set so as to be equal to or larger than n×?c/2??c/8 and equal to or smaller than n×?c/2+?c/8.

Abstract: Three or more piezoelectric resonators having resonance frequencies different from one another are realized on the same substrate. First through third frequency adjustment layers 107a through 107c of first through third piezoelectric resonators 102a through 102c provided on the same substrate 101 are formed by varying, among the frequency adjustment layers, the ratio of area (depressions 109 and 110) to be etched to area not to be etched.

Abstract: An upper electrode (50) includes a first electrode section (51) formed in a circular shape and a second electrode section (52) and a third electrode section (53) formed in a fan-shaped manner outside of the first electrode section (51). The first, second, and third electrode sections (51 to 53) are electrically separated from one another via an insulating region. A lower electrode (30) includes a fourth electrode section (31) formed in a circular shape and a fifth electrode section (32) and a sixth electrode section (33) formed in a fan-shaped manner outside of the fourth electrode section (31). Similarly, the fourth, fifth, and sixth electrode sections (31 to 33) are electrically separated from one another via an insulating region.

Abstract: An upper electrode is provided on one main surface of a piezoelectric layer, and a lower electrode is provided on the other main surface thereof. A vibration section is an area in which the lower electrode, the piezoelectric layer and the upper electrode overlap in a vertical projection direction. Line electrodes for respectively connecting the lower electrode and the upper electrode to input/output electrodes are provided on the one main surface and the other main surface of the piezoelectric layer. The vibration section is placed on (connected to) the substrate via the support section. The support section is provided on an area of the piezoelectric layer excluding the area on which the vibration section is provided and the area on which the input/output electrodes and the line electrodes are provided.

Abstract: In a balanced/unbalanced type coupled FBAR filter 100, an area size of a first lower electrode 102 is generally equal to a total area size of second and third lower electrodes 104 and 106 and an area for isolating the second and third lower electrodes 104 and 106. An area size of a first upper electrode 103 is generally equal to a total area size of second and third upper electrodes 105 and 107 and an area for isolating the second and third upper electrodes 105 and 107. The third lower electrode 106 and the second upper electrode 105 are located to face each other, and the third upper electrode 107 and the second lower electrode 104 are located to face each other. Apart of the second lower electrode 104 and a part of the second upper electrode 105 are located to face each other.

Abstract: A coupled FBAR filter 100 includes first and second input/output vibration portions 110 and 111 respectively including first and second lower electrodes 104 and 106, first and second upper electrodes 105 and 107, and a piezoelectric thin film 103 interposed therebetween; and a cavity 102 for commonly guaranteeing vibrations of the first and second input/output vibration portions 110 and 111 so as to couple the vibrations. The first and second input/output vibration portions 110 and 111 are located adjacently in contact with each other with a step therebetween, such that the first and second lower electrodes 104 and 106 are not electrically connected to each other and such that the first and second upper electrodes 105 and 107 are not electrically connected to each other. Insulators 108 and 109 are provided in the vicinity of the step.

Abstract: A dual mode piezoelectric filter includes a piezoelectric material layer composed of a piezoelectric thin film of the high-cut type formed on a substrate, a first electrode and a second electrode formed on one of the major surfaces of the piezoelectric material layer with a gap provided therebetween, a third electrode formed on the other major surface of the piezoelectric material layer opposite to the first electrode, the second electrode, and the gap, and an interelectrode mass load element formed in the gap or at a position opposite to the gap on a surface of the piezoelectric material layer. The relationships (p1×h1)?(pa×ha) and (p2×h2)?(pa×ha) are satisfied, where h1 is the thickness and p1 is the density of the first electrode, h2 is the thickness and p2 is the density of the second electrode, and ha is the thickness and pa is the density of the interelectrode mass load element. A filter characteristic with a smooth passband and low losses is obtained.

Abstract: An upper electrode (50) includes a first electrode section (51) formed in a circular shape and a second electrode section (52) and a third electrode section (53) formed in a fan-shaped manner outside of the first electrode section (51). The first, second, and third electrode sections (51 to 53) are electrically separated from one another via an insulating region. A lower electrode (30) includes a fourth electrode section (31) formed in a circular shape and a fifth electrode section (32) and a sixth electrode section (33) formed in a fan-shaped manner outside of the fourth electrode section (31). Similarly, the fourth, fifth, and sixth electrode sections (31 to 33) are electrically separated from one another via an insulating region.