JP5709669B2 - Filter device - Google Patents

Description

  The present invention relates to a filter device used in, for example, a wireless communication device.

  In recent years, wireless communication devices have been used in various applications such as mobile phones and wireless LANs, and the frequencies used in each wireless communication device are close to each other. In order to selectively pass only signals in the desired frequency band, and to prevent unwanted signals from being mixed in the signal band close to the low frequency side and high frequency side of the pass band so that high quality communication can be performed. A filter device having band pass characteristics having attenuation poles in the low frequency side and high frequency side attenuation bands of the pass frequency band is mounted.

  Along with the increase in information transmission capacity, wireless communication devices have secured the information transmission capacity by expanding the use bandwidth by increasing the frequency and bandwidth in the usable frequency band. Therefore, a filter device having a wide pass band and having an attenuation pole in the vicinity of the pass band (having a steep attenuation characteristic) has been demanded.

  In response to the demand for such a broadband bandpass filter having attenuation poles near both sides of the passband, a filter device having a coupling electrode for electrically connecting the short-circuit ends of a plurality of resonator electrodes has been proposed. . In this filter device, by providing the coupling electrode, not only capacitive coupling but also inductive coupling can be generated between the plurality of resonator electrodes. Thereby, a signal in a frequency band near a predetermined pass band can be sharply attenuated.

JP 2008-118615 A

  In the filter device, due to the influence of the structure in the upper layer or the lower layer of the layer in which the plurality of resonator electrodes are provided, the height positions of the adjacent resonator electrodes may be shifted at the time of stacking. There is a possibility that the facing area between the resonator electrodes is reduced, and the amount of capacitive coupling between adjacent resonator electrodes is reduced. When the amount of capacitive coupling between adjacent resonator electrodes is reduced, the filter characteristics may be deteriorated.

According to one aspect of the present invention, a filter device includes a stacked body in which a plurality of dielectric layers are stacked, a first ground electrode and a second ground disposed so as to face each other with the stacked body interposed therebetween. A plurality of resonator electrodes arranged side by side in a plan view so as to be electromagnetically coupled to each other in the stacked body, one end being a short-circuited end and the other end being an open end, and a resonator in the stacked body One end is disposed on the second ground electrode side with a dielectric layer between the electrode and the short-circuit end of the first-stage resonator electrode, and is electrically connected to the short-circuit end of the opposite resonator electrode. A coupling electrode electrically connected to the short-circuited end of the opposite resonator electrode and an end facing the short-circuited end of the resonator electrode of the final stage, and a dielectric layer sandwiched in a shape along the first-stage resonator electrode The first contact so that it faces the first-stage resonator electrode. An input terminal electrode that is disposed on the electrode side and electromagnetically couples with the first-stage resonator electrode, and has a shape along the last-stage resonator electrode so as to face the last-stage resonator electrode with the dielectric layer in between A final stage resonator electrode disposed on the first ground electrode side and an output terminal electrode for electromagnetic field coupling are provided. Of the plurality of resonator electrodes, adjacent resonator electrodes have different thicknesses.

  According to one aspect of the present invention, in the filter device, a layer above a layer provided with a plurality of resonator electrodes by the thickness of adjacent resonator electrodes being different among the plurality of resonator electrodes. Alternatively, even if there is a deviation in the height position of adjacent resonator electrodes during stacking due to the structure of the lower layer, the amount of reduction in the facing area between adjacent resonator electrodes can be suppressed, and adjacent A reduction in capacitive coupling between the resonator electrodes can be reduced. Therefore, it is possible to reduce the deterioration of the filter characteristics.

The disassembled perspective view of the filter apparatus in the 1st Embodiment of this invention is shown. FIG. 2 shows a plan perspective view of a portion of the filter device shown in FIG. 1. FIG. 2 shows a longitudinal sectional view of a part of the filter device shown in FIG. 1. It is a longitudinal cross-sectional view which shows the other structural example of the filter apparatus shown by FIG. FIG. 6 shows a plan perspective view of a part of a filter device according to a second embodiment of the present invention. FIG. 6 is a longitudinal sectional view of a part of the filter device shown in FIG. 5.

  Hereinafter, some exemplary embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
As shown in FIGS. 1 and 2, the filter device according to the first embodiment of the present invention includes a laminated body 1 and a first ground electrode 2 arranged so as to face the laminated body 1. And a plurality of resonator electrodes 41 to 44 arranged side by side in a plan view so as to be electromagnetically coupled to each other in the laminate 1, and a plurality of resonator electrodes 41 in the laminate 1. To 44 and the second ground electrode 3, and an input terminal electrode 6 and an output terminal electrode 7 provided in the laminate 1. In FIG. 1, the broken line indicates that the resonator electrode 41 and the coupling electrode 5 are electrically connected by, for example, a conductor penetrating the dielectric layer 12. Other broken lines also indicate electrical connection relationships. An alternate long and short dash line indicates that the plurality of dielectric layers 11 to 14, the first ground electrode 2, and the second ground electrode 3 are laminated. In FIG. 2, the coupling electrode 5 is indicated by a broken line in a state where the resonator electrode 41 or the like is seen through, for example.

The stacked body 1 includes a plurality of dielectric layers 11 to 14 stacked on each other. The plurality of dielectric layers 11 to 14 are made of, for example, ceramic materials such as alumina, mullite, aluminum nitride, BaO—TiO ₂ , CaO—TiO ₂ , MgO—TiO _2, glass ceramics, or ethylene tetrafluoride resin. (Polytetrafluoroethylene: PTFE), Tetrafluoroethylene-ethylene copolymer resin (Tetrafluoroethylene-ethylene copolymer resin: ETFE), Tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (Tetrafluoroethylene-Perful) An organic resin material such as fluororesin such as teloalkyl vinyl ether copolymer resin (PFA), glass epoxy resin, or polyimide is used. The shapes or dimensions (thickness, width, or length) of the plurality of dielectric layers 11 to 14 made of these materials are set in accordance with the frequency or application used. In the case of a ceramic material, a low-temperature fired ceramic that can be fired simultaneously with a conductor material made of a low-resistance metal such as Au, Ag, or Cu that can transmit a higher frequency signal is preferable.

  The first ground electrode 2 is formed on the upper surface of the dielectric layer 14, and the second ground electrode 3 is formed on the lower surface of the dielectric layer 11.

  Each of the plurality of resonator electrodes 41 to 44 has a short-circuited end and an open end. The plurality of resonator electrodes 41 to 44 are surrounded by the internal ground electrode 8 formed on the upper surface of the dielectric layer 12 in plan view. With such a configuration, leakage of electromagnetic waves generated from the plurality of resonator electrodes 41 to 44 to the surroundings can be reduced. This effect can reduce the influence of the module substrate other than the filter device when the filter device is formed on a part of the module substrate, for example. The internal ground electrode 8 is provided so as to sandwich the plurality of resonator electrodes 41 to 44 in the arrangement direction of the region for connecting the short-circuit ends of the plurality of resonator electrodes 41 to 44 and the plurality of resonator electrodes 41 to 44. And an annular region including the region formed.

  The distance between the internal ground electrode 8 and the resonator electrode 41 or the distance between the internal ground electrode 8 and the resonator electrode 44 reduces the influence of the resonator electrodes 41 and 44 on the magnetic field, and decreases the Q value of the filter. The distance between the resonator electrode 41 or 44 and the first ground electrode 2 or the second ground electrode 3 is preferably larger so as to reduce the loss of the pass band.

  As shown in FIG. 3, adjacent resonator electrodes among the plurality of resonator electrodes 41 to 44 have different thicknesses. For example, in the adjacent resonator electrodes 41 and 42, the thickness 42T of the resonator electrode 42 is larger than the thickness 41T of the resonator electrode 41. Similarly, in the adjacent resonator electrodes 44 and 43, the resonator electrode 44 is thicker than the resonator electrode 43.

  As shown in FIG. 4, for example, as a method of forming the resonator electrodes 42 and 44 thicker than the resonator electrodes 41 and 43, the resonator electrodes 42 and 44 are electrically connected to a plurality of conductor layers by via conductors. It is good also as a structure connected to each other. In this structure, for example, the thickness 42T of the resonator electrode 42 refers to the distance from the lower ends of the lower conductor layers of the plurality of conductor layers constituting the resonator electrode 42 to the upper ends of the upper conductor layers.

  Referring again to FIG. 2, the coupling electrode 5 has a first end 51 and a second end 52. The first end portion 51 is opposed to the short-circuit end portion of the first-stage resonator electrode 41 among the plurality of resonator electrodes 41 to 44 and is electrically connected to the short-circuit end of the first-stage resonator electrode 41. Yes. The second end 52 is opposed to the short-circuited end of the final-stage resonator electrode 44 among the plurality of resonator electrodes 41 to 44 and is electrically connected to the short-circuited end of the final-stage resonator electrode 44. Has been.

  Referring again to FIG. 1, the input terminal electrode 6 (particularly the internal input terminal electrode 62) has a shape along the first stage resonator electrode 41, and the first stage so as to face the first stage resonator electrode 41. The resonator electrode 41 and the first ground electrode 2 are provided. The input terminal electrode 6 is electromagnetically coupled to the first-stage resonator electrode 41.

  The output terminal electrode 7 (especially the internal output terminal electrode 72) has a shape along the final-stage resonator electrode 44, and the final-stage resonator electrode 44 is opposed to the final-stage resonator electrode 44. And the first ground electrode 2. The output terminal electrode 7 is electromagnetically coupled to the final-stage resonator electrode 44.

The first ground electrode 2, the second ground electrode 3, the internal ground electrode 8, the resonator electrodes 41 to 44, the coupling electrode 5, the input terminal electrode 6, and the output terminal electrode 7 have dielectric layers 11 to 14 made of ceramic. When made of a material, it is formed by a metallized layer containing a metal such as W, Mo, Mo-Mn, Au, Ag or Cu as a main component. When the dielectric layers 41 to 44 are made of a resin material, a metal layer formed by a thick film printing method, various thin film forming methods, a plating method, or a foil transfer method, or plating on such a metal layer Layer formed, eg Cu layer, Cr-Cu alloy layer or Cr-
Ni plating layer and Au plating layer deposited on Cu alloy layer, Ni—Cr alloy layer and Au plating layer deposited on TaN layer, Pt layer and Au plating layer on Ti layer Examples include those deposited, and those obtained by depositing a Pt layer and an Au plating layer on a Ni-Cr alloy layer. The thickness and width are set according to the frequency and application of the transmitted high-frequency signal.

Formation of dielectric layers 11-14, first ground electrode 2, second ground electrode 3, internal ground electrode 8, resonator electrodes 41-44, coupling electrode 5, input terminal electrode 6 and output terminal electrode 7 A known method may be used. For example, if the dielectric layers 11 to 14 are made of glass ceramics, first, glass ceramic green sheets to be the dielectric layers 11 to 14 are prepared, and a conductor paste such as Ag is applied on the green sheets by screen printing. The first ground electrode 2, the second ground electrode 3, the internal ground electrode 8, the resonator electrodes 41 to 44, the coupling electrode 5, the input terminal electrode 6, and the output terminal electrode 7 are printed and applied in a predetermined shape. Form a pattern. A laminate is prepared by stacking and pressing the green sheets on which these electrode patterns are formed, and the laminate is formed by firing at 850 to 1000 ° C. Then, N on the conductor layer exposed on the outer surface
A plating film such as i plating or Au plating is formed. If the dielectric layers 11 to 14 are made of an organic resin material, for example, the first ground electrode 2, the second ground electrode 3, the internal ground electrode 8, the resonator electrodes 41 to 44, and the input on the organic resin sheet It forms by transferring Cu foil processed into each electrode pattern shape of the terminal electrode 6, the output terminal electrode 7, and the coupling electrode 5, and laminating | stacking the organic resin sheet to which Cu foil was transcribe | transferred, and adhere | attaching with an adhesive agent.

  The connecting conductor that connects the ground electrodes 2 and 3 and the short-circuited ends of the resonator electrodes 41 to 44 is a through conductor formed in the dielectric layer located between them or an end face formed on the end face of the dielectric layer. By forming it in the form of a conductor, the degree of freedom in designing the filter device formed inside the multilayer body 1 is improved, and a more compact and high-performance filter device can be obtained.

  When the dielectric layers 11 to 14 are made of ceramics such as glass ceramics, the through conductors or the side conductors serving as the connection conductors are, for example, the first ground electrode 2 and the second conductor in the manufacturing method described above. Before forming the electrode patterns of the ground electrode 3, the internal ground electrode 8, the resonator electrodes 41 to 44, the coupling electrode 5, the input terminal electrode 6, and the output terminal electrode 7, mold processing and laser It can be formed by filling the same conductive paste into the through-holes formed in advance by processing by a printing method or the like, and the end face conductor is the end face of the short-circuit end of the electrode pattern of the resonator electrodes 41 to 44, for example. After forming the green sheet laminate exposed to the same, a similar conductor paste can be printed on the side surface of the green sheet laminate. After the end conductor is formed in the green sheet with through holes about the width of the rows of the resonator electrodes 41 to 44, and the shorted ends of the electrode patterns of the resonator electrodes 41 to 44 are formed in contact with the through holes It can also be formed by printing the conductor paste on the inner surface of the through hole before or after the green sheet is laminated, or by filling the through hole and cutting at the through hole portion. Similarly, when the dielectric layers 11 to 14 are made of a resin-based material, an organic resin sheet is used instead of the green sheet, and a through conductor is formed in the through hole by printing or plating a conductor paste, or by a thin film method or the like. A side conductor may be formed. In order to expose the short-circuit ends of the electrode patterns of the resonator electrodes 11 to 14 on the side surfaces of the laminate, the short-circuit ends of the electrode patterns of the resonator electrodes 11 to 14 are located at the end of the green sheet (or organic resin sheet). After stacking the green sheets (organic resin sheets) on which the electrode patterns of the resonator electrodes 11 to 14 are formed, the electrode electrodes of the resonator electrodes 11 to 14 are stacked so that the short-circuit ends are exposed on the side surfaces. Just cut your body.

In the filter device of the present embodiment, the layers above the layer where the plurality of resonator electrodes 41 to 44 are provided by the thicknesses of adjacent resonator electrodes among the plurality of resonator electrodes 41 to 44 being different. Alternatively, even if the height position between adjacent resonator electrodes is shifted during the stacking due to the influence of the structure in the lower layer, the amount of reduction in the facing area between the adjacent resonator electrodes can be suppressed and the adjacent resonator electrodes can be suppressed. A reduction in capacitive coupling between the resonator electrodes can be reduced. Therefore, it is possible to reduce the deterioration of the filter characteristics.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. The configuration of the filter device of the second embodiment different from that of the filter device of the first embodiment is that some of the plurality of resonator electrodes 41 to 44 have openings. Other configurations are the same as those of the filter device according to the first embodiment.

  In the resonator electrodes 42 and 43 which are resonator electrodes other than the first-stage resonator electrode 41 and the final-stage resonator electrode 44 among the plurality of resonator electrodes 41 to 44, an opening 42a is formed in the resonator electrode 42 having a large thickness. Is provided. The opening 42 a is provided at a position facing the coupling electrode 5 and immediately above the coupling electrode 5. That is, the opening 42a overlaps the coupling electrode 5 in plan view. The filter device according to the present embodiment has such a configuration, so that the reduction of the coupling state of the first-stage resonator electrode 41 and the final-stage resonator electrode 44 by the coupling electrode 5 is suppressed, and the resonator electrode The capacitive coupling between 42 and the coupling electrode 5 is reduced. Therefore, the filter device according to the present embodiment is improved in terms of signal attenuation in a frequency band near a predetermined pass band, and can shift the resonance frequency due to λ / 2 resonance of the coupling electrode 5 to the high frequency side. .

  Note that when the resonator electrodes 42 and 43 are compared, the resonator electrode 42 is thicker than the resonator electrode 43, and therefore, as shown in FIG. The distance tends to be closer than the distance between the resonator electrode 43 and the coupling electrode 5, and the capacitive coupling between the resonator electrode 42 and the coupling electrode 5 may be increased. Therefore, in the filter device of the present embodiment, the thicknesses of the resonator electrodes 42 and 43, which are resonator electrodes other than the first-stage resonator electrode 41 and the final-stage resonator electrode 44, among the plurality of resonator electrodes 41 to 44. An opening 42a is provided in the resonator electrode 42 having a large diameter.

1 ... Laminated body
11, 12, 13, 14 ... dielectric layer 2 ... first ground electrode 3 ... second ground electrode
41, 42, 43, 44 ... resonator electrode 5 ... coupling electrode 6 ... input terminal electrode 61 ... external input terminal electrode 62 ... internal input terminal electrode 7 ... output terminal electrode 71 ... External output terminal electrode 72 ... Internal output terminal electrode 8 ... Internal ground electrode 9 ... Capacitance electrode

Claims (2)

A laminate in which a plurality of dielectric layers are laminated;
A first ground electrode and a second ground electrode arranged to face each other with the laminate interposed therebetween;
Three or more resonator electrodes that are aligned side by side in a plan view so as to be electromagnetically coupled to each other in the laminate, each having one end short-circuited and the other end open-ended,
The resonance is disposed on the second ground electrode side with the dielectric layer interposed between the resonator electrode and the resonator electrode in the stacked body, and one end of the resonator is opposed to the short-circuited end of the first-stage resonator electrode. A coupling electrode electrically connected to the short-circuited end of the resonator electrode and electrically connected to the short-circuited end of the resonator electrode opposite to the short-circuited end of the resonator electrode at the final stage,
The first-stage resonator electrode and the electromagnetic field are disposed on the first ground electrode side so as to face the first-stage resonator electrode with the dielectric layer interposed therebetween, in a shape along the first-stage resonator electrode. An input terminal electrode to be coupled;
The final-stage resonator electrode is arranged on the first ground electrode side so as to face the final-stage resonator electrode with the dielectric layer interposed therebetween in a shape along the final-stage resonator electrode. And an output terminal electrode for electromagnetic coupling,
The filter device characterized in that adjacent resonator electrodes among the plurality of resonator electrodes have different thicknesses.   Among the plurality of resonator electrodes, a resonator electrode having a large thickness among resonator electrodes other than the first-stage resonator electrode and the final-stage resonator electrode has an opening at a position facing the coupling electrode. The filter device according to claim 1, characterized in that:

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