JP5489745B2 - Filter device - Google Patents

Description

  The present invention relates to a filter device used in, for example, a wireless communication device such as a mobile phone and a wireless local area network (LAN) and other various communication devices.

  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 addition, it is necessary to selectively pass only a signal in a desired frequency band and to prevent undesired signals from being mixed in a signal band close to a low frequency side and a high frequency side of the pass band so that high-quality communication can be performed.

  In response to such a demand, a filter device having a coupling adjustment electrode 25 whose end portion faces each of the two resonator electrodes 23 and 23 as shown in an exploded perspective view in FIG. 7 has been proposed. (For example, refer to Patent Document 1). In this filter device, since the coupling adjustment electrode 25 is provided, not only inductive coupling but also capacitive coupling can be generated between the resonator electrodes 23 and 23, so that the pass bandwidth is adjusted. In addition, a signal in a frequency band near a predetermined pass band can be sharply attenuated by a parallel resonant circuit of inductive coupling and capacitive coupling.

  In addition, with the recent miniaturization of wireless devices, the filter devices used therein are also required to be miniaturized. On the other hand, the filter apparatus provided with the shortening electrode in the position facing the open end side of a resonator electrode is proposed (for example, refer patent document 2). By disposing the wavelength shortening electrode at a position facing the open end side of the resonator electrode, the resonator electrode can be shortened by the wavelength shortening effect of the wavelength shortening electrode, and the filter device can be downsized. .

JP-A-6-120703 JP 2006-166136 A

  However, in the conventional filter device, since the coupling adjustment electrode is disposed so as to face each resonator electrode, when the resonator electrode width is narrow in a small filter device, capacitive coupling by the coupling adjustment electrode is performed. The bandwidth is difficult to adjust, and a steep attenuation characteristic can be obtained only on one side of the passband, so the attenuation characteristic on the other side of the passband is not steep. .

  The present invention has been devised in view of the above problems, and its purpose is to be small and easy to adjust the passband bandwidth, and to have a steep attenuation characteristic on both sides of the passband, and on the high frequency side. An object of the present invention is to provide a filter device having a small damping characteristic jump.

The filter device of the present invention includes a laminated body in which a plurality of dielectric layers are laminated, a first ground electrode and a second ground electrode arranged so as to face each other with the laminated body interposed therebetween, and the laminated body. A plurality of resonator electrodes that are arranged side by side in a plan view so as to be electromagnetically coupled to each other, one end of which is a short-circuited end and the other end is an open end, and the second ground electrode and the resonator electrode A plurality of shortened capacitance electrodes facing the second ground electrode with the dielectric layer interposed therebetween,
The two shortening electrodes are arranged adjacent to the plurality of shortening capacitor electrodes on the opposite side of the second ground electrode across the dielectric layer with respect to the plurality of shortening capacitor electrodes, and their end portions are adjacent to each other. A coupling capacitive electrode facing the capacitive electrode;
The coupling capacitor electrode is opposite to the plurality of shortened capacitor electrodes across the dielectric layer, and is opposed to the end of the coupling capacitor electrode, and one end of each of the plurality of resonator electrodes. And the other end of each of the shortened capacitor electrodes is connected to each end of the plurality of shortening capacitor electrodes by a second through conductor. And a plurality of auxiliary capacitance electrodes, and two external terminals electrically connected to the first and last stages of the plurality of auxiliary capacitance electrodes.

Further, the filter device of the present invention, in the above configuration, the coupling capacitor electrode in a plan perspective, together are disposed in the second through conductor side, characterized in that facing the shortening capacitor electrode is there.

  In the filter device according to the present invention, in each of the above configurations, the auxiliary capacitance electrode includes a facing portion facing the coupling capacitance electrode, a width smaller than the facing portion, the facing portion and the first through conductor. And a second connection part that connects the opposing part and the second through conductor and has a width smaller than that of the opposing part.

According to the filter device of the present invention, a plurality of shortened capacitor electrodes opposed to the second ground electrode with a dielectric layer interposed between the second ground electrode and the resonator electrode, and a plurality of shortened capacitor electrodes A coupling capacitor electrode disposed adjacent to the plurality of shortening capacitor electrodes on the opposite side of the second ground electrode across the dielectric layer, and having two end portions facing each of the adjacent shortening capacitor electrodes, A dielectric layer opposite to the plurality of shortened capacitive electrodes across the dielectric layer with respect to the electrodes, facing each of the ends of the coupling capacitive electrodes, and having one end at the open end of each of the plurality of resonator electrodes A plurality of auxiliary capacitance electrodes connected by a first through conductor that passes through the dielectric layer, and connected at the other end by a second through conductor that penetrates the dielectric layer to each end of the plurality of shortened capacitance electrodes. Therefore, it has a shortened capacitance electrode Therefore, the resonator electrode can be shortened, so that the resonator can be made small. Also, inductive coupling generated between adjacent resonator electrodes and capacitive coupling between the shortened capacitive electrodes by the coupled capacitive electrodes, that is, shortened An attenuation pole is generated by a parallel resonance circuit formed by capacitive coupling between the resonator electrodes to which the capacitance electrodes are connected, and the signal on the low frequency side of the passband can be rapidly attenuated. Even if the width of the capacitor is thin, the coupling capacitor electrode is capacitively coupled between the shortened capacitor electrode and the auxiliary capacitor electrode, so that the capacitive coupling between the resonator electrode to which the shortened capacitor electrode and the auxiliary capacitor electrode are connected is sufficient. Therefore, the pass bandwidth can be easily adjusted.

  The parallel resonant circuit is also generated by inductive coupling generated between the second through conductors and capacitive coupling generated between the shortened capacitive electrode and the coupled capacitive electrode and between the auxiliary capacitive electrode and the coupled capacitive electrode. As a result, an attenuation pole also appears on the high frequency side of the pass band, so that the signal on the high frequency side of the pass band can be rapidly attenuated. Therefore, the filter device has steep attenuation characteristics on both sides of the passband.

Further, according to the filter device of the present invention, in the above configuration, the coupling capacitor electrode is disposed on the second through conductor side in a plan view , and when facing the shortened capacitor electrode, A shortened capacitive electrode in a parallel resonant circuit formed by inductive coupling generated between them and capacitive coupling between the shortened capacitive electrodes by the coupled capacitive electrode, that is, capacitive coupling between the resonator electrodes to which the shortened capacitive electrode is connected. Since unnecessary capacitive coupling formed with the auxiliary capacitance electrode is reduced, higher-order resonance can be shifted to the high frequency side to reduce the jump of the attenuation characteristic, and the attenuation characteristic on the high frequency side of the passband Will be good.

  According to the filter device of the present invention, in each of the above configurations, the auxiliary capacitance electrode connects the facing portion that faces the coupling capacitance electrode, and the facing portion that is smaller in width than the facing portion and the first through conductor. When the first connection portion and the second connection portion that is smaller in width than the facing portion and connects the facing portion and the second through conductor, only between the facing portion of the auxiliary capacitance electrode and the coupling capacitance electrode Since capacitive coupling occurs, inductive coupling that occurs between adjacent resonator electrodes and capacitive coupling between the shortened capacitive electrodes by the coupled capacitive electrodes, that is, capacitive coupling between the resonator electrodes to which the shortened capacitive electrodes are connected. The unnecessary capacitive coupling formed between the shortened capacitive electrode and the auxiliary capacitive electrode is reduced in the parallel resonant circuit formed by the above, so that the higher-order resonance shifts to the high frequency side, and the damping characteristic jumps up. I can make it smaller In addition, since the widths of the first connection portion and the second connection portion are small, the inductor component increases, and inductive coupling generated between the second through conductors, the shortened capacitance electrode, the coupling capacitance electrode, Since the inductive coupling of the parallel resonant circuit due to the capacitive coupling generated between the auxiliary capacitive electrode and the coupling capacitive electrode increases, the frequency at which the attenuation pole on the high-frequency side of the passband due to this parallel resonant circuit appears is reduced. However, the attenuation on the high frequency side of the pass band becomes steeper.

It is a disassembled perspective view which shows typically an example of embodiment of the filter apparatus of this invention. (A) is sectional drawing which shows the cross section in the AA of FIG. 1, (b) shows the position of the resonator electrode of the filter apparatus shown in FIG. 1, a shortening capacity electrode, a coupling capacity electrode, and an auxiliary capacity electrode. It is a top view. It is a disassembled perspective view which shows typically another example of embodiment of the filter apparatus of this invention. (A) is sectional drawing which shows the cross section in the AA of FIG. 3, (b) shows the position of the resonator electrode of the filter apparatus shown in FIG. 3, a shortening capacity electrode, a coupling capacity electrode, and an auxiliary capacity electrode. It is a top view. It is a disassembled perspective view which shows typically another example of embodiment of the filter apparatus of this invention. It is a figure which shows the simulation result of the transmission characteristic of the filter apparatus of this invention. It is a disassembled perspective view which shows typically an example of embodiment of the conventional filter apparatus.

  The filter device of the present invention will be described in detail below. 1 to 6, 1 a is a dielectric layer, 1 is a laminate formed by laminating a dielectric layer 1 a, 2 a is a first ground electrode, 2 b is a second ground electrode, 3 is a resonator electrode, 4 Is a shortened capacitance electrode, 5 is a coupling capacitance electrode, 6 is an auxiliary capacitance electrode, 7 is a first through conductor, 8 is a second through conductor, 9 is a third through conductor, 10 is an input terminal electrode, and 10a is an input. A coupling electrode, 11 is an output terminal electrode, and 11a is an output coupling electrode. 2 (b) and 4 (b) show the positional relationship of the resonator electrode 3, the shortened capacitor electrode 4, the coupling capacitor electrode 5 and the auxiliary capacitor electrode 6 in plan view. It is omitted.

In the example shown in FIGS. 1 to 5, the laminate 1 is configured by laminating five dielectric layers 1 a. The number of the dielectric layers 1 a depends on the thickness of each dielectric layer 1 a and the relative dielectric constant. Or the first ground electrode 2a, the second ground electrode 2b, the resonator electrode 3, the shortened capacitor electrode 4, the coupling capacitor electrode 5, the auxiliary capacitor electrode 6, the input coupling electrode 10a, and the output coupling electrode 11a. It can be appropriately changed depending on the arrangement or the like. For example, in the example shown in FIG. 1, the first ground electrode 2a and the second ground electrode 2b are arranged so as to face each other with the laminate 1 interposed therebetween, and the dielectric layer on which the first ground electrode 2a is arranged. An input terminal electrode 10 and an output terminal electrode 11 are arranged on 1a so as to be electrically insulated from the first ground electrode 2a. An insulating layer 1a is further laminated on the first ground electrode 2a. The input terminal electrode 10 and the output terminal electrode 11 may be disposed thereon. The input terminal electrode 10 and the output terminal electrode 11 are connected to the auxiliary capacitance electrodes 6 at both ends of the line, that is, the first and last auxiliary capacitance electrodes 6 by the third through conductors 9, respectively. By connecting the electrode 11 to an external circuit board or the like, it becomes an input / output point for a signal to the filter device. Further, as in the example shown in FIG. 5, the input terminal electrode 10 and the output terminal electrode 11 are connected to the first stage and the final stage through the input coupling electrode 10a and the output coupling electrode 11a facing the first stage and final stage auxiliary capacitance electrodes 6, respectively. The auxiliary capacitance electrode 6 may be electrically connected to the stage.

  The resonator electrodes 3 each have one end short-circuited and the other end open-ended, and are arranged side by side in a plan view so as to be electromagnetically coupled to each other between the dielectric layers 1a and 1a of the multilayer body 1. They are aligned and arranged in a so-called comb line type, and are inductively coupled (edge coupled) to each other. The shape and interval of the resonator electrode 3 are appropriately set according to required characteristics (passband frequency and passband width). To obtain stable inductive coupling (edge coupling), the length of the opposing edge portions is long. It is desirable to have a long, elongated strip shape.

  1 to 4 show an example including two resonator electrodes 3, and FIG. 5 illustrates an example including three resonator electrodes 3. However, four or more resonator electrodes may be provided, and loss may occur. It is sufficient that the number is such that does not increase. In applications such as wireless LAN, the number of resonator electrodes 3 is preferably two or three from the balance between loss and attenuation characteristics.

  Further, the shortened capacitance electrode 4 is disposed between the second ground electrode 2b and the resonator electrode 3 so as to face the second ground electrode 2b with the dielectric layer 1a interposed therebetween. Each open end is electrically connected via the first through conductor 7, the auxiliary capacitance electrode 6, and the second through conductor 8. Thereby, since the resonator electrode 3 can be shortened, the resonator can be made small, and the filter device can also be miniaturized.

  Also, a coupling capacitor electrode 5 disposed opposite to the second ground electrode 2b across the dielectric layer 1a with respect to the shortening capacitor electrode 4 and having an end facing each of the two shortening capacitor electrodes 4 adjacent to each other; The coupling capacitor electrode 5 is disposed on the opposite side of the plurality of shortened capacitor electrodes 4 across the dielectric layer 1a so as to face the end portions of the coupling capacitor electrodes 5, and one end thereof is the resonator electrode 3 Are connected to the respective open ends by a first through conductor 7 that penetrates the dielectric layer 1a, and the other end is connected to each end of the shortened capacitance electrode 4 by a second through conductor 8 that penetrates the dielectric layer 1a. A plurality of auxiliary capacitance electrodes 6 connected to each other. The first stage and the last stage of the auxiliary capacitance electrode 6 are electrically connected to the input terminal electrode 10 and the output terminal electrode 11 by the third through conductor 9, respectively.

  Thus, inductive coupling generated between the adjacent resonator electrodes 3 and 3 and capacitive coupling between the shortened capacitor electrodes 4 and 4 by the coupling capacitor electrode 5, that is, the resonator electrode to which the shortened capacitor electrodes 4 and 4 are connected. An attenuation pole is generated by the parallel resonance circuit formed by the capacitive coupling between 3 and 3, and the signal on the low frequency side of the pass band can be rapidly attenuated. Even if the resonator electrode 3 is narrow, the coupling capacitor electrode 5 is capacitively coupled between the shortened capacitor electrode 4 and the auxiliary capacitor electrode 6, so that the shortened capacitor electrode 4 and the auxiliary capacitor electrode 6 are connected. The capacitive coupling between the resonator electrodes 3 and 3 is sufficient, and the passband width can be easily adjusted.

  Further, by inductive coupling generated between the second through conductors 8 and capacitive coupling generated between the shortened capacitive electrode 4 and the coupling capacitive electrode 5 and between the auxiliary capacitive electrode 6 and the coupling capacitive electrode 5. Since a parallel resonance circuit is formed and an attenuation pole appears on the high frequency side of the pass band, the signal on the high frequency side of the pass band can be rapidly attenuated. Therefore, the filter device has steep attenuation characteristics on both sides of the passband.

Further, as in the example shown in FIGS. 3 and 4, the filter device of the present invention has a configuration in which the coupling capacitor electrode 5 is adjacent to the shortened capacitor electrode 4 on the second through conductor 8 side. Inductive coupling generated between the matching resonator electrodes 3 and 3 and capacitive coupling between the shortened capacitive electrodes 4 and 4 by the coupling capacitive electrode 5, that is, the resonator electrodes 3 and 3 to which the shortened capacitive electrodes 4 and 4 are connected. Since unnecessary capacitive coupling formed between the shortened capacitive electrode 4 and the auxiliary capacitive electrode 6 is reduced in the parallel resonant circuit formed by the capacitive coupling between them, the higher-order resonance shifts to the high frequency side. Thus, the jump of the attenuation characteristic can be reduced, and the attenuation characteristic on the high frequency side of the pass band becomes good.

  Further, as in the examples shown in FIGS. 3 and 4, the filter device according to the present invention has a facing portion in which the auxiliary capacitance electrode 6 faces the coupling capacitance electrode 5 and a width that is smaller than the facing portion in each of the above configurations. A first connecting portion that connects the first through conductor 7 and a second connecting portion that is smaller in width than the opposing portion and connects the opposing portion and the second through conductor 8. Since the capacitive coupling is generated only between the opposing portion of the auxiliary capacitive electrode 6 and the coupling capacitive electrode 5, the inductive coupling generated between the resonator electrodes 3 and 3 and the shortened capacitive electrode 4 · 4 by the coupling capacitive electrode 5 are generated. Between the shortened capacitive electrode 4 and the auxiliary capacitive electrode 6 in a parallel resonant circuit formed by capacitive coupling between them, that is, capacitive coupling between the resonator electrodes 3 and 3 to which the shortened capacitive electrodes 4 and 4 are connected. Unnecessary capacitive coupling formed is reduced, so higher order resonances are And the jump of the attenuation characteristic can be reduced, and since the widths of the first connection portion and the second connection portion are small, the inductor component increases, and the plurality of second through conductors 8 are connected to each other. Inductive coupling of the resonant circuit due to inductive coupling generated between the short-circuited capacitive electrode 4 and the coupled capacitive electrode 5 and capacitive coupling generated between the auxiliary capacitive electrode 6 and the coupled capacitive electrode 5 increases. The frequency at which the attenuation pole on the high frequency side of the pass band is developed by the parallel resonance circuit is lowered, and the attenuation on the high frequency side of the pass band becomes steeper.

  In the shortened capacitor electrode 4, when the shortened capacitor electrode 4 and the resonator electrode 3 overlap in plan view, the coupling between the resonator electrode 3 and the first and second ground electrodes 2a and 2b is reduced by an amount corresponding to the overlapped area. Further, for example, when the shortened capacitance electrode 4 connected to the resonator electrode 3 and another resonator electrode 3 overlap in plan view, the coupling amount between the resonator electrode 3 and the adjacent resonator electrode 3 is increased. Therefore, as shown in the example shown in FIG. 1, the shortened capacitor electrode 4 is formed in an elongated shape such as a rectangle or an ellipse, and the open end of the resonator electrode 3 and one end of the shortened capacitor electrode 4 are seen in plan view. It is good to arrange so that it may overlap and the other end of shortening capacity electrode 4 may be turned to the direction which extends the open end of resonator electrode 3.

  The auxiliary capacitor electrode 6 is disposed at the same position as the shortened capacitor electrode 4 in plan view, and has one end connected to the open end of the resonator electrode 3 by the first through conductor 7 and the other end connected to the other end of the shortened capacitor electrode 4. Connect to the end. The auxiliary capacitor electrode 6 may have the same shape as the shortened capacitor electrode 4 as in the example shown in FIGS. 1 and 2, but for the reason described above, As shown in FIG. 3 and FIG. 4, the portion of the auxiliary capacitance electrode 6 facing the coupling capacitance electrode 5 is arranged at the end of the coupling capacitance electrode 5 so as to reduce unnecessary capacitive coupling formed between It is preferable to provide a connection part having a smaller width than the facing part as the same size and shape.

  In addition, the characteristic impedance of the portion from the connection portion of the auxiliary capacitance electrode 6 to the first through conductor 7 to the connection portion of the input terminal electrode 10 or the output terminal electrode 11 approximates the characteristic impedance of the resonator electrode 3. If this is the case, this portion behaves like a resonator and a wavelength shortening effect is obtained, so that the resonator electrode 3 can be further shortened. Therefore, it is preferable that the first connection portion of the auxiliary capacitance electrode 6 located in this portion has a width such that the characteristic impedance of the first connection portion is equal to the characteristic impedance of the resonator electrode 3.

The coupling capacitor electrode 5 preferably has a small portion protruding from the shortened capacitor electrode 4 in plan view. A portion that protrudes from the shortened capacitance electrode 4 in a plan view of the coupling capacitance electrode 5 (a portion that does not overlap the shortened capacitance electrode 4 in a plan view of the coupling capacitance electrode 5), the second ground electrode 2b, and the first ground electrode 2a This is because unnecessary capacitive coupling appears between the two and affects the filter characteristics of the resonator electrode 3. For this reason, the shape of the coupling capacitor electrode 5 is preferably a shape in which both ends facing the shortened capacitor electrode 4 are connected by thin conductors as in the examples shown in FIGS.

  When there are three or more resonator electrodes 3 as in the example shown in FIG. 5, two or more coupling capacitor electrodes 5 facing two adjacent shortened capacitor electrodes 4 are arranged. At this time, for example, as in the example shown in FIG. 5, when there are three resonator electrodes 3 and three shortening capacitor electrodes 4 connected thereto, the first stage (first stage) shortening capacitor electrode 4 is provided. 2 of the coupling capacitor electrode 5 facing the second-stage shortened capacitor electrode 4 and the coupling capacitor electrode 5 facing the last-stage (third-stage) shortened capacitor electrode 4 and the second-stage shortened capacitor electrode 4. Two coupling capacitance electrodes 5 and 5 are arranged side by side. The ends of the two adjacent coupling capacitor electrodes 5 are opposed to the second-stage shortened capacitor electrode 4. In the example shown in FIG. 5, the sizes of the two ends of one coupling capacitor electrode 5 are different, but this is not a big problem in terms of characteristics.

As the dielectric layer 1a, for example, alumina, mullite, aluminum nitride, BaO—TiO ₂ series, CaO—TiO ₂ series, MgO—TiO ₂ series, ceramic materials such as glass ceramics, or tetrafluoroethylene resin (polytetra Fluoroethylene: PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin: ETFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluteroalkyl vinyl ether) Fluorine resin such as copolymer resin (PFA), glass epoxy resin, organic resin material such as polyimide is used. The shape and dimensions (thickness, width, length) of the dielectric layer 1a made of these materials are set according to the frequency used, the application, and the like. In the case of a ceramic material, low-temperature fired ceramics 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.

  First ground electrode 2a, second ground electrode 2b, resonator electrode 3, shortened capacitor electrode 4, coupling capacitor electrode 5, auxiliary capacitor electrode 6, input terminal electrode 10, output terminal electrode 11, input coupling electrode 10a and output When the dielectric layer 1a is made of a ceramic material, the coupling electrode 11a is formed of a metallized layer containing a metal such as W, Mo, Mo—Mn, Au, Ag, or Cu as a main component. When the dielectric layer 1a is 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 a plating layer on such a metal layer is formed. A formed layer, for example, a Cu layer, a Cr—Cu alloy layer or a Cr—Cu alloy layer coated with a Ni plating layer and an Au plating layer, and a TaN layer coated with a Ni—Cr alloy layer and an Au plating layer. Examples thereof include those deposited, those obtained by depositing a Pt layer and an Au plating layer on a Ti layer, 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.

First ground electrode 2a, second ground electrode 2b, resonator electrode 3, shortened capacitor electrode 4, coupling capacitor electrode 5, auxiliary capacitor electrode 6, input terminal electrode 10, output terminal electrode 11, input coupling electrode 10a and output A known method may be used to form the coupling electrode 11a. For example, if the dielectric layer 1a is made of glass ceramics, first prepare green sheets of glass ceramics to be the dielectric layers 1a, and print a conductor paste such as Ag in a predetermined shape on the green sheets by screen printing. First electrode 2a, second electrode 2b, resonator electrode 3, shortened capacitor electrode 4, coupling capacitor electrode 5, auxiliary capacitor electrode 6, input terminal electrode 10, output terminal electrode 11,
The electrode patterns of the input coupling electrode 10a and the output coupling electrode 11a are formed. Next, a green body with these electrode patterns formed thereon is stacked and pressure-bonded, for example, to produce a laminate, and this laminate is formed by firing at 850 to 1000 ° C. Thereafter, a plating film such as Ni plating or Au plating is formed on the electrode exposed on the outer surface. When the dielectric layer 1a is made of an organic resin material, for example, the first ground electrode 2a and the second ground electrode are formed on the organic resin sheet.
The electrode patterns of the ground electrode 2b, resonator electrode 3, shortened capacitor electrode 4, coupling capacitor electrode 5, auxiliary capacitor electrode 6, input terminal electrode 10, output terminal electrode 11, input coupling electrode 10a and output coupling electrode 11a The processed Cu foil is transferred, and an organic resin sheet to which the Cu foil is transferred is laminated and bonded with an adhesive.

  The first to third through conductors 7 to 9 are, for example, the first ground electrode 2 a, the second ground electrode 2 b, the resonator electrode 3, the shortened capacitor electrode 4, the coupling capacitor electrode 5, and the auxiliary in the manufacturing method described above. Before forming the electrode patterns of the capacitive electrode 6, the input terminal electrode 10, the output terminal electrode 11, the input coupling electrode 10a, and the output coupling electrode 11a, the green sheet was previously formed by die machining or laser machining. By filling the hole with the same conductor paste by a printing method or the like, it can be formed as a metallized conductor. Alternatively, a metal layer is formed on the inner surface of a through hole formed in the same manner on the organic resin sheet by plating, the through hole is filled with metal by plating, or a conductive paste that is cured by heating or the like is filled. Can be formed.

  The connection conductor connecting the first ground electrode 2a and the second ground electrode 2b and the short-circuited end of the resonator electrode 3 is a through conductor or a dielectric layer formed in the dielectric layer 1a located between them. By forming it in the form of an end face conductor formed on the end face of 1a, the degree of freedom in designing the filter device formed inside the laminated dielectric layers 1a is improved, and a more compact and high-performance filter device is provided. can do.

  When the dielectric layer 1a is made of ceramics such as glass ceramics, the through conductors and side conductors serving as such connection conductors are formed in the same manner as the first to third through conductors 7 to 9. The end face conductor can be formed, for example, by forming a green sheet laminate in which internal electrodes are exposed on the end face, and then printing the same conductor paste on the side surface of the green sheet laminate. The end face conductor has a through hole formed in the green sheet, the first ground electrode 2a and the second ground electrode 2b are formed so as to be in contact with the through hole, and before or after the green sheet is laminated. It can also be formed by printing the conductor paste on the inner surface of the through hole, or filling the through hole and cutting at the through hole portion. Similarly, when the dielectric layer 1a is made of a resin 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 a side conductor is formed by a thin film method or the like. May be formed.

Specifically, a filter device as a bandpass filter having a passband frequency of 5.15 to 5.85 GHz, which is used in a wireless LAN standard, has the form shown in FIG. 1, for example, the dielectric layer 1a. Glass ceramics having a dielectric constant of 7.7 as the first ground electrode 2
a, second ground electrode 2b, resonator electrode 3, shortened capacitor electrode 4, coupling capacitor electrode 5, auxiliary capacitor electrode 6, input terminal electrode 10, output terminal electrode 11, input coupling electrode 10a, output coupling electrode 11a, and It is obtained by using Cu metallization for the first to third through conductors 7 to 9. Glass ceramics having a relative dielectric constant of 7.4 are, for example, PbO, B ₂ O ₃ , SiO ₂ ,
Al 2 and O _{3, ZnO} and crystallized glass as a main component an alkaline earth metal oxide is 50 wt%, alumina as a filler component may be used those composed of 50 mass%.

At this time, the thickness of the dielectric layer 1a is 260 μm, 110 μm, 25 μm, 25 μm, and 35 μm in order from the top. The first ground electrode 2a and the second ground electrode 2b have dimensions of 1.4 mm × 1.9 mm. The first ground electrode 2 a is provided with two 0.5 mm × 0.5 mm openings for arranging the input terminal electrode 10 and the output terminal electrode 11. The two resonator electrodes 3 have dimensions of 0.13mm x 0.7
are arranged side by side at intervals of 0.125 mm, and the respective short-circuit ends are connected to the ground electrodes 2a and 2b by end surface conductors formed on the entire side surface of the multilayer body 1 on the short-circuit end side. The auxiliary capacitance electrode 6 has a dimension of 0.4 mm.
× 1.25mm, arranged in a position of 0.0125mm inside the resonator electrode 3 in plan view,
It arrange | positions so that it may overlap with the edge part of each open end side of the resonator electrode 3 in the range of 0.13 mm x 0.15 mm, and it connects to the resonator electrode 3 by the 1st through-conductor 7 with a diameter of 0.075 mm in the center of the overlapping part. .
Each of the shortened capacitive electrodes 4 has a size of 0.4 mm × 1.25 mm, and each auxiliary capacitive electrode 6 in plan view.
Are arranged at the same position as the auxiliary capacitance electrode 6 by the second through conductor 8 having a diameter of 0.075 mm at a position 0.0875 mm outward from the inner corner of the other end of the auxiliary capacitance electrode 6 and 0.075 mm toward the one end. Connecting. The input terminal electrode 10 and the output terminal electrode 11 have a size of 0.2 mm × 0.2 mm, are arranged at the center of the opening, and are arranged so as to overlap with the center part of each of the two auxiliary capacitance electrodes 6 in plan view. In addition, the third through conductor 9 having a diameter of 0.075 mm is connected. Coupling capacitance electrode 5
Is a shape in which ends having dimensions of 0.25 mm × 0.765 mm are connected by conductors having dimensions of 0.25 mm × 0.25 mm, and each end is 0.185 mm from the short-circuit end side of each shortened capacitance electrode 4. It arrange | positions so that it may overlap with the shortening capacity | capacitance electrode 4. FIG.

  The filter characteristic of the filter device of the present invention in such an example is as shown by a broken characteristic curve in the diagram of FIG. In the diagram shown in FIG. 6, the vertical axis represents insertion loss (unit: dB), and the horizontal axis represents frequency (unit: GHz). In the conventional filter device, for example, the filter characteristic has an attenuation pole only on one side of the pass band as shown by a one-dot chain line characteristic curve in the diagram of FIG. It can be seen that steep attenuation characteristics are obtained even on both sides of the pass band (near 3 GHz on the low frequency side and near 16 GHz on the high frequency side).

Further, the filter characteristic of the filter device of the present invention as in the example shown in FIG. 3 is as shown by a solid characteristic curve in the diagram of FIG. The filter device of this example is different from the filter device of the present invention of the example of FIG. 1 in that each of the coupling capacitor electrodes 5 has an end portion at a position of 0.335 mm from the short-circuit end side of each shortened capacitor electrode 4. 4 so as to overlap. Also, the auxiliary capacitance electrode 6
Is connected with the inner side aligned and the opposing part with dimensions of 0.4 mm x 0.815 mm, the first connection part with dimensions of 0.17 mm x 0.31 mm, and the second connection part with dimensions of 0.17 mm x 0.125 mm. The short-circuit end side and the outer side are aligned with each of the shortened capacitance electrodes 4. The two resonator electrodes 3 have dimensions of 0.13 mm × 0.6 mm. Each other electrode and dielectric layer,
The dimensions, shape and arrangement are the same as above.

  From the result of this example, the coupling capacitance electrode 5 is opposed to the shortened capacitance electrode 4 on the second through conductor 8 side, and the auxiliary capacitance electrode 6 is opposed to the coupling capacitance electrode 5, and the width is smaller than the opposed portion. The first connecting portion connecting the facing portion and the first through conductor 7 and the second connecting portion having a width smaller than the facing portion and connecting the facing portion and the second through conductor 8. In this case, the frequency at which the attenuation pole on the high frequency side of the passband appears decreases, the attenuation on the high frequency side of the passband becomes steeper, and the higher-order resonance shifts to the high frequency side. It can be said that a filter characteristic with a better attenuation characteristic on the high frequency side of the pass band can be obtained by reducing the jump of the attenuation characteristic. Further, since the filter characteristics having the same passband are obtained even if the resonator electrode 3 is shortened, it can be said that the filter device can be miniaturized.

DESCRIPTION OF SYMBOLS 1 ...... Laminated body 1a ... Dielectric layer 2a ... 1st ground electrode 2b ... 2nd ground electrode 3 ... Resonator electrode 4 ... Shortening capacity electrode 5- ... Coupling capacitance electrode 6 ... Auxiliary capacitance electrode 7 ... First through conductor 8 ... Second through conductor 9 ... Third through conductor
10 ... Input terminal electrode
10a ・ ・ ・ Input coupling electrode
11 ... Output terminal electrode
11a ... Output coupling electrode

Claims (3)

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;
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, each having one end short-circuited and the other end open-ended;
A plurality of shortened capacitance electrodes facing the second ground electrode across the dielectric layer between the second ground electrode and the resonator electrode;
The two shortening electrodes are arranged adjacent to the plurality of shortening capacitor electrodes on the opposite side of the second ground electrode across the dielectric layer with respect to the plurality of shortening capacitor electrodes, and their end portions are adjacent to each other. A coupling capacitive electrode facing the capacitive electrode;
The coupling capacitor electrode is opposite to the plurality of shortened capacitor electrodes across the dielectric layer, and is opposed to the end of the coupling capacitor electrode, and one end of each of the plurality of resonator electrodes. And the other end of each of the shortened capacitor electrodes is connected to each end of the plurality of shortening capacitor electrodes by a second through conductor. A plurality of auxiliary capacitance electrodes,
A filter device comprising two external terminals electrically connected to the first stage and the last stage of the plurality of auxiliary capacitance electrodes. 2. The filter device according to claim 1, wherein the coupling capacitor electrode is disposed on the second through conductor side in a plan view and faces the shortened capacitor electrode. The auxiliary capacitance electrode includes a facing portion that faces the coupling capacitance electrode, a first connection portion that is smaller in width than the facing portion, connects the facing portion and the first through conductor, and the facing portion. The filter device according to claim 1, wherein the filter device includes a second connection portion that has a small width and connects the facing portion and the second through conductor.

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