Abstract: A ladder filter includes at least one series resonator connected in series between an input terminal and an output terminal, at least one parallel resonator connected in parallel with the at least one series resonator, and an inductor connected in parallel with the at least one series resonator. The at least one series resonator and the inductor generate a first attenuation pole at a frequency equal to or lower than a frequency band defined by the at least one series resonator and the at least one parallel resonator. The first attenuation pole is located at a frequency that is equal to or higher than a resonance frequency of a parallel resonator that is included in the at least one parallel resonator and has a highest resonance frequency and that is equal to or lower than a high-frequency end of the pass band.

Abstract: An acoustic wave element includes: a piezoelectric substrate; an IDT (Interdigital Transducer) formed on the piezoelectric substrate; and an end face of the piezoelectric substrate that is formed on at least one end of the IDT in a propagation direction of an acoustic wave; wherein when a wavelength of the acoustic wave which the IDT excites is expressed by “?” and a metallization ratio of the IDT is expressed by “D”, a distance between an inner end of an electrode finger of the IDT nearest to the end face and the end face is equal to or more than 7?/16+D×?/4 and equal to or less than 3?/4+D?/4.

Abstract: A ladder filter includes at least one series resonator connected in series between an input terminal and an output terminal, at least one parallel resonator connected in parallel with the at least one series resonator, an additional resonator connected in series between the at least one series resonator and one of the input terminal and the output terminal, and an inductor connected in series to the additional resonator, the additional resonator having a resonance frequency higher than an anti-resonance frequency of the at least one series resonator.

Abstract: A filter circuit includes a filter part connected between an input terminal and an output terminal and configured to have a passband, and a path connected in parallel with the filter part between the input terminal and the output terminal, the path having an impedance that enables a first signal passing through the path from the input terminal to the output terminal and a second signal passing through the filter part from the input terminal to the output terminal to have an opposite phase relationship in a frequency band outside of the passband and have almost equal amplitudes in the frequency band.

Abstract: A switching device includes: a switch that selects and connects one of at least three terminals including a first terminal, a second terminal, and a third terminal to a common terminal; and a compensating circuit that shifts a phase of at least one of a first signal transmitted through the second terminal and a second signal transmitted through the third terminal so that the first signal and the second signal compensate each other and unifies and outputs the first signal and the second signal to a fourth terminal as a third signal, or that branches a third signal input to the fourth terminal into the first signal and the second signal.

Abstract: A ladder type filter includes series resonators S1˜S4 connected in series between an input terminal In and an output terminal Out, parallel resonators P1˜P3 connected in parallel between the input terminal In and the output terminal Out, a resonator RP connected in series with the series resonators S1˜S4 between the input terminal and the output terminal, the resonator RP having a resonance frequency lower than resonance frequencies of the series resonators S1˜S4, and an inductor Lp connected in parallel with the resonator. According to the present ladder filter, signals having frequencies away from the pass band can be suppressed by an attenuation pole formed by the inductor. It is further possible to suppress the insertion loss in the pass band by the resonator.

Abstract: A duplexer includes: an insulation substrate having an upper surface on which a transmission filter and a reception filter are mounted, and a lower surface on which a foot pad layer electrically connected to the transmission filter and the reception filter is formed; a transmission pad provided on the upper surface and electrically connected to the transmission filter; a reception pad provided on the upper surface and electrically connected to the reception filter, a ring-shaped electrode provided on the upper surface and configured to surround the transmission pad and the reception pad; a ground foot pad included in the foot pad layer, and a via interconnection configured to electrically interconnect the ring-shaped electrode and the ground foot pad and to be provided in the ring-shaped electrode in a section along a shorter one of routes that connect the transmission pad and the reception pad to each other along the ring-shaped electrode.

Abstract: A method of manufacturing an elastic wave device is provided with a lamination step of forming, on a substrate (1), a plurality of elastic wave devices, each of which includes a lower electrode (2), a piezoelectric film (3), and an upper electrode (4); a measuring step for measuring the operation frequency distribution of the elastic wave devices on the substrate (1); and an adjusting step for forming an adjusting region, in which the thickness of the elastic wave device is different from the thicknesses of other portions in a resonance portion of each elastic wave device, corresponding with the distribution of the operation frequencies. The adjusting region is formed so that the size of the area of the adjusting region of the resonator portion of each elastic wave device is different in accordance with the operation frequency distribution that is measured. Thus, the frequency characteristics of the elastic wave devices are easily adjusted by a small number of steps.

Abstract: The filter includes one or more series resonators and one or more parallel resonators. An inductance is connected in series to at least a parallel resonator of the parallel resonators, and a antiresonance frequency of the parallel resonator to which the inductance is connected in series is equal to or higher than that of the series resonators. The duplexer, the communication module and the communication device are provided with the filter.

Abstract: In one aspect of the invention, a duplexer including a multilayer substrate with multiple stacked layers and a back surface with a rectangular shape is disclosed. An antenna terminal, a transmission terminal, a reception terminal, a ground terminal, and a conductor are provided in various positions on the multilayer substrate for improved performance.

Abstract: A method of manufacturing a ladder filter including first and second resonators includes: forming a piezoelectric film on an entire surface of a substrate that has respective lower electrodes of the first and second resonator formed thereon, an conductive film on the piezoelectric film, and a second film on the conductive film; forming a pattern of the second film in a prescribed region in the second area; forming a first film on an entire surface of the substrate; etching the first film, forming a pattern of the first film, the second film and the conductive film in the second area, and forming a pattern of the first film and the conductive film in the first area, to form respective upper electrodes from the conductor film; and thereafter, etching the piezoelectric film to form respective patterns of the piezoelectric film in the first and second areas, respectively.

Abstract: An electronic component includes: an element that is located on a substrate; a signal wiring that is located on the substrate and electrically connected to the element; a metal plate that is located so as to form a cavity on a functional part of the element and covers an upper surface of the cavity; a support post that is located on the substrate so as not to be located on the signal wiring, and supports the metal plate; and an insulating portion that covers the metal plate and the support post, and contacts a side surface of the cavity.

Abstract: An acoustic wave device includes a substrate and a plurality of piezoelectric thin film resonators formed over the substrate. Each of the plurality of the piezoelectric thin film resonators includes lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film and opposed to the lower electrode through the piezoelectric film. Each of the piezoelectric thin film resonators is partly supported by the substrate and extends above the substrate to form a cavity between the substrate and each lower electrodes. The cavity continuously extending under the plurality of the piezoelectric thin film resonators.

Abstract: A switching device includes: a switch that selects and connects one of input-output terminals to a common terminal; and a delay line that is connected in parallel to the switch between two terminals of the input-output terminals and delays a signal by using an acoustic wave.

Abstract: According to an aspect of the invention, each of a filter, a duplexer and a communication module includes a plurality of series resonators connected to a signal line in series and a plurality of parallel resonators connected to the signal line in parallel. At least two of the plurality of parallel resonators are connected to the signal line between two of the plurality of series resonators in parallel, inductors are respectively connected to the at least two parallel resonators, and the inductors have different inductances from each other.

Abstract: A piezoelectric thin film resonator of the present has a substrate 1, an intermediate layer 7 disposed on the substrate 1 and is formed of an insulator, a lower electrode 3 disposed on the intermediate layer 7, a piezoelectric film 4 disposed on the lower electrode 3, and an upper electrode 5 disposed on a position facing the lower electrode 3 with the piezoelectric film 4 interposed therebetween, in which, in a resonant region 8 where the lower electrode 3 and the upper electrode 5 face each other, a space 6 is formed in the substrate 1 and the intermediate layer 7 or between the lower electrode 3 and the intermediate layer 7 and the region of the space 6 is included in the resonant region 8. With the structure, the dissipation of the vibrational energy to the substrate from the resonance portion can be suppressed, thereby improving the quality factor.

Abstract: According to an aspect of the invention, each of a filter, a duplexer and a communication module includes a plurality of series resonators connected to a signal line in series and a plurality of parallel resonators connected to the signal line in parallel. At least two of the plurality of parallel resonators are connected to the signal line between two of the plurality of series resonators in parallel, inductors are respectively connected to the at least two parallel resonators, and the inductors have different inductances from each other.

Abstract: An acoustic wave device includes: an acoustic wave filter chip that is mounted on a multilayered substrate including wiring layers; a first wiring that is electrically coupled to an internal circuit of the acoustic wave filter chip and formed in a first wiring layer of the multilayered substrate; a second wiring that is formed in a second wiring layer separate from the first wiring layer; and a via wiring that penetrates at least a part of the multilayered substrate and connects the first wiring to the second wiring; wherein the first wiring, the second wiring, and the via wiring forms a first inductor of which a direction of magnetic flux intersects with a stacking direction of the multilayered substrate.

Abstract: A filter includes at least one series resonator and parallel resonators, the at least one series resonator and the parallel resonators including excitation electrodes and reflectors, the parallel resonators having different resonance frequencies, and at least one of the parallel resonators other than the parallel resonator having the highest resonance frequency being configured to have a pitch of reflectors that is smaller than that of excitation electrodes.

Abstract: A piezoelectric thin-film resonator includes a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the substrate and the lower electrode, an upper electrode provided on the piezoelectric film, and an additional pattern, a cavity being formed between the lower electrode and the substrate in a resonance portion in which the lower electrode and the upper electrode face each other through the piezoelectric film, the additional pattern being provided in a position that is on the lower electrode and includes an interface between the resonance portion and a non-resonance portion.