JP3911283B2 - Multilayer dielectric filter - Google Patents

Description

  The present invention relates to a multilayer dielectric filter that constitutes a resonance circuit in a microwave band of several hundred MHz to several GHz. In particular, the present invention can suppress manufacturing variations, and can reduce the size and yield of a multilayer dielectric filter. The present invention relates to a multilayer dielectric filter that can be realized.

  In recent years, with the diversification of wireless communication systems such as mobile phones, there has been a strong demand for miniaturization and low loss for multilayer dielectric filters.

  In order to reduce the size of the multilayer dielectric filter, the resonator (resonant electrode) must be made small.

  Therefore, conventionally, a method of adding capacitance to the open end of the resonance electrode is generally performed. In particular, in the multilayer dielectric filter 100, for example, as shown in FIG. 12, the same in the dielectric substrate 102 is used. For example, three resonant electrodes 104A, 104B, and 104C having the same width are formed on the surface, and two upper and lower inner ground electrodes (106A, 108A), (for each resonant electrode 104A, 104B, and 104C, respectively) 106B, 108B) and (106C, 108C), and the upper and lower inner ground electrodes (106A, 108A), (106B, 108B) and (106C, 108C) respectively correspond to the resonance electrodes 104A, 104B and 104C. The method of sandwiching the open end of is adopted.

  By the way, in such a multilayer dielectric filter 100, in order to determine the attenuation pole and the bandwidth (pass band), the open end capacitance of the resonance electrode (capacitance between the open end portion and the inner ground electrode) is adjusted. Alternatively, a coupling electrode is formed between the resonance electrodes.

  Normally, the resonance frequencies of the resonance electrodes on both sides are made substantially the same (for example, f1), and the resonance frequency of the center resonance electrode is set to a resonance frequency f2 different from the resonance frequency f1. The attenuation pole depends on the degree of coupling between the resonance electrodes, but the degree of coupling between the resonance electrodes is set to the inductance between the resonance electrodes and the capacitance between the resonance electrodes (capacity between the resonance electrode and the coupling electrode). .

  With such a setting, there is a possibility that a limit may arise with respect to widening the bandwidth. Therefore, a method has been proposed in which the bandwidth is widened by setting the three resonant electrodes to different resonant frequencies. This can be achieved by making the open end capacities of the resonance electrodes different.

  However, since the attenuation pole needs to be changed in connection with the widening of the bandwidth, it is possible to change the capacitance between each resonance electrode and the coupling electrode, or change the distance between each resonance electrode. It has been. Note that changing the distances between the resonance electrodes is described in, for example, Patent Document 1.

JP-A-5-251905

  By the way, in the above-described multilayer dielectric filter 100, when realizing miniaturization and high performance simultaneously, for example, in the dielectric substrate 302 like the multilayer dielectric filter 300 according to the proposed example shown in FIG. For example, three resonance electrodes 304A, 304B, and 304C are formed, and coupling electrodes 306 and 308 are disposed between adjacent resonance electrodes 304A and 304B and between 304B and 304C, respectively.

  Normally, in the case of a comb line resonator, the resonators are always inductively coupled. Therefore, in the example of FIG. 13, the coupling between the resonators is made capacitive by adjusting the area of the coupling electrode and the like. For example, when the coupling capacitance between the central resonance electrode 304B and the coupling electrode 306 is increased, the inductivity is reduced, and when the coupling capacitance is further increased, the coupling capacitance is changed to capacitive coupling. That is, the change to inductive and capacitive can be adjusted by the coupling capacitance between the central resonance electrode 304B and the coupling electrodes 306 and 308.

  The reason why the distance d1 between the input-side resonance electrode 304A and the center resonance electrode 304B is made larger than the distance d2 between the output-side resonance electrode 304C and the center resonance electrode 304B is to adjust the attenuation characteristics.

  In such a multilayer dielectric filter 300, as shown in FIG. 13, when a λ / 4 resonator is used as a resonator, one end (short-circuited end) of each of resonance electrodes 304A, 304B and 304C constituting the resonator. Is connected to the ground electrode 310 formed on the side surface of the dielectric substrate 302, the resonator length is determined by cutting at the time of individual division (chip division).

  In this cutting step, if a length Lc (hereinafter referred to as a cutting length) from the end of the inner layer ground electrode 312 to the short-circuit end side surface of the dielectric substrate 302 is deviated from a specified length, the length Lc depends on the amount of deviation. The frequency fluctuates.

  In particular, the example shown in FIG. 13 is an excellent structure that achieves both miniaturization and high performance. However, unlike the multilayer dielectric filter 100 according to the conventional example of FIG. Since the side resonance electrode 304C is not symmetrically and capacitively formed with respect to the center resonance electrode 304B, the amount of frequency fluctuation due to the cutting of the dielectric substrate 302 may be different for each resonator.

  In such a case, the yield is reduced, so that a certain margin must be secured as an allowable range, and the superiority as a multilayer dielectric filter having both capacitive coupling and inductive coupling may not be exhibited. .

  The present invention has been made in consideration of such problems, and an object thereof is to provide a multilayer dielectric filter capable of reducing manufacturing variations.

The multilayer dielectric filter according to the present invention includes three or more resonance electrodes and an open end side of the three or more resonance electrodes facing each other in a dielectric substrate formed by laminating a plurality of dielectric layers. In the laminated dielectric filter in which the strip-shaped inner layer ground electrode is formed , all or a part of the three or more resonance electrodes are each formed in a protruding manner in the lateral direction at the open end portion. It has an electrode part, and the both ends of the said overhanging electrode part are located in the part which protruded from the both edge parts of the said inner-layer earth electrode, respectively .
In addition, the multilayer dielectric filter according to the present invention includes three or more resonance electrodes and an open end side of the three or more resonance electrodes in a dielectric substrate formed by laminating a plurality of dielectric layers. And the three or more resonance electrodes are connected to the ground electrode, and the short-circuit end on at least one main surface of each electrode surface. The vicinity is connected to a ground electrode via a connecting member, and all or a part of the three or more resonance electrodes each have a protruding electrode portion formed in the lateral direction at the open end portion. The both ends of the overhanging electrode portion are located at portions protruding from both edge portions of the inner layer ground electrode.

  As a result, first, in the manufacturing stage of the multilayer dielectric filter, when the dielectric substrate is cut by dividing into pieces (chip division), even if the cut length deviates from the specified length, Since at least the vicinity of the short-circuited end on one main surface is connected to the ground electrode via the connecting member, the resonator length of each resonant electrode viewed from the ground electrode hardly changes regardless of the cutting length. Therefore, the frequency variation due to the variation in the cutting length is small.

  The said structure WHEREIN: Each short-circuit end vicinity in both the main surfaces of each said electrode surface may be connected to the earth electrode via the connection member. In this case, it is possible to further suppress frequency fluctuation due to variation in cutting length.

  The connection member may be a via hole formed in the dielectric substrate. In this case, the vicinity of the short-circuited end of the resonance electrode formed in the dielectric substrate and the ground electrode on the surface of the dielectric substrate can be easily connected.

That is, in the present invention, even if there is a stacking deviation of the resonance electrode with respect to the inner-layer ground electrode, the open end capacitance does not change in each resonance electrode, so that fluctuations in the passband can also be suppressed.

In addition, in the present invention, it is possible to suppress frequency fluctuation due to variation in the cutting length with respect to the dielectric substrate, and it is possible to suppress a change in the return loss waveform caused by stacking deviation of the resonance electrode with respect to the inner ground electrode.

  As described above, according to the multilayer dielectric filter of the present invention, it is possible to reduce the manufacturing variation of the multilayer dielectric filter.

  Hereinafter, embodiments of a multilayer dielectric filter according to the present invention will be described with reference to FIGS.

  First, as shown in FIG. 1, the multilayer dielectric filter 10A according to the first embodiment includes a plurality of dielectric layers (S1 to S7: see FIG. 2) laminated, baked and integrated, and a surface. A dielectric substrate 14 having a ground electrode 12 formed thereon is formed. In the dielectric substrate 14, three resonance electrodes 16A, 16B and 16C are formed.

  Further, on the surface of the dielectric substrate 14, an input terminal 18 is formed on one side surface, and an output terminal 20 is formed on the other side surface. Insulating regions (portions where the dielectric substrate 14 is exposed) 22 and 24 are provided between the input terminal 18 and the ground electrode 12, and between the output terminal 20 and the ground electrode 12, respectively.

  When the three resonance electrodes 16A, 16B, and 16C are quarter-wave resonance electrodes, for example, as shown in FIGS. 3 and 5, the resonance electrodes 16A, 16B, and 16C on the side surface of the dielectric substrate 14 are used. A structure is adopted in which the ground electrode 12 is formed on the surface where the ground electrode 12 is exposed and one end (short-circuit end) of each resonance electrode 16A, 16B and 16C is short-circuited to the ground electrode 12.

  Further, in the first embodiment, as shown in FIGS. 2 and 3, two inner-layer ground electrodes 30 and 32 that are vertically opposed to the open ends of the three resonance electrodes 16A, 16B, and 16C are formed. Like to do. In this case, the open ends of the resonance electrodes 16A, 16B, and 16C are capacitively coupled to the ground electrode 12 via the inner-layer ground electrodes 30 and 32, respectively, thereby shortening the electrical length of the resonance electrodes 16A, 16B, and 16C. be able to.

  Each of the inner ground electrodes 30 and 32 is formed in a plate shape so as to include the open ends of the three resonance electrodes 16A, 16B, and 16C in common, and the side surface of the dielectric substrate 14, particularly the three resonance electrodes 16A, 16B, and 16C is connected to the ground electrode 12 formed on the side surface facing the open end of 16C.

  Specifically, the configuration of the multilayer dielectric filter 10A according to the first embodiment will be described with reference to FIG. 2. First, the dielectric substrate 14 includes first to seventh dielectric layers S1 to S7. Are sequentially stacked. Each of the first to seventh dielectric layers S1 to S7 is composed of one or a plurality of layers.

  Then, three resonance electrodes 16A, 16B and 16C are formed on one main surface of the fourth dielectric layer S4, and of these, the resonance electrode 16A (input-side resonance electrode) adjacent to one side surface of the dielectric substrate 14 and The resonance electrode 16C (output-side resonance electrode) adjacent to the other side surface of the dielectric substrate 14 is formed with lead electrodes 33 and 34 for direct connection with the input terminal 18 and the output terminal 20 (see FIG. 1), respectively. Yes.

  An inner layer ground electrode 30 is formed on one main surface of the third dielectric layer S3 in a plane including the open ends of the resonance electrodes 16A, 16B, and 16C. A first coupling electrode 36 for forming a capacitance is formed between the resonance electrodes 16B.

  An inner layer ground electrode 32 is formed on one main surface of the fifth dielectric layer S5 in a plane including the open ends of the resonance electrodes 16A, 16B, and 16C. A second coupling electrode 38 for forming a capacitance is formed between the resonance electrodes 16B.

  The first coupling electrode 36 includes a planar electrode portion 36A that is L-shaped in plan and a via hole 36B that electrically connects the planar electrode portion 36A and the output-side resonance electrode 16C. The electrode portion 36A overlaps the first resonance portion 16Aa extending from above the output-side resonance electrode 16C to above the center resonance electrode 16B, and the center resonance electrode 16B, and extends along the center resonance electrode 16B. The second electrode portion 36Ab is integrally formed.

  Similarly to the first coupling electrode 36, the second coupling electrode 38 also electrically connects the planar electrode portion 38A having a planar L shape and the planar electrode portion 38A and the input-side resonance electrode 16A. The planar electrode portion 38A overlaps with the first electrode portion 38Aa extending from the upper side of the input side resonance electrode 16A to the upper side of the center resonance electrode 16B, and the center resonance electrode 16B. The second electrode portion 38Ab extending along the resonance electrode 16B is integrally formed.

  In the multilayer dielectric filter 10A according to the first embodiment, the resonance frequencies of the three resonance electrodes 16A, 16B, and 16C are made different in order to increase the bandwidth. Therefore, the width of the part (first electrode part) that is completely included in the inner-layer ground electrodes 30 and 32 among the open ends of all or part of the three resonant electrodes 16A, 16B, and 16C is expanded. Like to do.

  In this example, as shown in FIG. 5, the widths HB1 and HC1 of the first electrode portions 16Ba1 and 16Ca1 at the open end portions 16Ba and 16Ca of the central resonance electrode 16B and the output-side resonance electrode 16C are expanded. Yes. In particular, the center resonance electrode 16B extends the width HB1 of the first electrode portion 16Ba1 in the open end portion 16Ba toward the input side resonance electrode 16A, and the output side resonance electrode 16C extends in the open end portion 16Ca. The width of one electrode portion 16Ca1 is expanded toward the center output terminal 20 side.

  Further, in the first embodiment, the position of the attenuation pole on the frequency characteristic is also adjusted in accordance with the characteristic of the filter used. For example, an attenuation pole due to inductive coupling and an attenuation pole due to capacitive coupling appear.

  Normally, in the case of a comb line resonator as in the present embodiment, inductive coupling always occurs between the resonators. Therefore, in order to make the coupling between the resonators capacitive, a method such as increasing the interval between the resonators or increasing the capacitance between the resonators is preferably employed.

  In the example of FIG. 2, the distances d1 and d2 between adjacent resonance electrodes 16A and 16B and between 16B and 16C are not uniform, and the distance d1 between the input-side resonance electrode 16A and the center resonance electrode 16B is the center resonance electrode. It is set to be larger than the interval d2 between 16B and the output side resonance electrode 16C. As a result, the inductive coupling between the input side resonance electrode 16A and the center resonance electrode 16B is weakened, and the attenuation pole corresponding to the degree of coupling between the input side resonance electrode 16A and the center resonance electrode 16B is more than the passband. Appear at low frequencies.

  Fine adjustment of the position of the attenuation pole is performed by adjusting the area of the second coupling electrode 38 and the like. For example, when the coupling capacitance between the center resonance electrode 16B and the second coupling electrode 38 is increased, the attenuation pole is positioned at a lower frequency, and the coupling between the center resonance electrode 16B and the second coupling electrode 38 is increased. As the capacitance is reduced, the attenuation pole is located at a frequency closer to the passband.

  On the other hand, by reducing the distance between the center resonance electrode 16B and the output side resonance electrode 16C, inductive coupling between the center resonance electrode 16B and the output side resonance electrode 16C is strengthened, and the center resonance electrode 16B and the output side resonance electrode 16C. The attenuation pole corresponding to the degree of coupling between the electrodes 16C appears at a frequency higher than the passband.

  Fine adjustment of the position of the attenuation pole is performed by adjusting the area of the first coupling electrode 36 and the like. For example, when the coupling capacitance between the center resonance electrode 16B and the second coupling electrode 38 is increased, the attenuation pole is positioned at a lower frequency, and the coupling between the center resonance electrode 16B and the second coupling electrode 38 is increased. As the capacitance is reduced, the attenuation pole is located at a frequency closer to the passband.

  In the multilayer dielectric filter 10A according to the first embodiment, as shown in FIG. 2, the vicinity of the short-circuit ends and the upper and lower ground electrodes 12 on both main surfaces of the resonance electrodes 16A, 16B, and 16C. Are electrically connected to each other through a via hole. Specifically, the vicinity of the short-circuit ends on both main surfaces of the input-side resonance electrode 16A and the upper and lower ground electrodes 12 are connected via via holes 40Aa and 40Ab, respectively, and the short-circuit ends on both main surfaces of the center resonance electrode 16B. And the upper and lower ground electrodes 12 are connected via via holes 40Ba and 40Bb, respectively, and the vicinity of the short-circuited end and the upper and lower ground electrodes 12 on both main surfaces of the output-side resonance electrode 16C are connected via via holes 40Ca and 40Cb, respectively. Connected.

  Therefore, the multilayer dielectric filter 10A according to the first embodiment has the following operational effects.

  First, in a general multilayer dielectric filter manufacturing stage, the dielectric substrate 14 is usually cut and divided into chips (chips). At this time, the cutting length Lc (see FIGS. 5 and 5) is used. When the deviation (see FIG. 13) deviates from the prescribed length, the resonator length changes according to the deviation amount, and the resonance frequency at each resonance electrode changes.

  On the other hand, in the multilayer dielectric filter 10A according to the first embodiment, the vicinity of the short-circuited ends and the upper and lower earth electrodes 12 on both main surfaces of the resonance electrodes 16A, 16B and 16C are respectively connected to via holes (40Aa, 40Ab), (40Ba, 40Bb), and (40Ca, 40Cb) are electrically connected to each other, the resonator lengths of the resonance electrodes 16A, 16B, and 16C viewed from the ground electrode 12 are equal to the cutting length Lc. Regardless, it will not change. Therefore, the frequency fluctuation due to the variation in the cutting length Lc is small.

  Here, one experimental example is shown. This experimental example shows the frequency characteristics when the cutting length Lc is set to 0, −30 μm, and +30 μm with respect to the specified length for the comparative example and the example.

  The comparative example has a configuration in which the vicinity of the short-circuited ends on the main surfaces of the resonance electrodes 16A, 16B, and 16C are not connected to the upper and lower ground electrodes 12 in the multilayer dielectric filter 10A according to the first embodiment. The example has the same configuration as the multilayer dielectric filter 10A according to the first embodiment. The result of the comparative example is shown in FIG. 6, and the result of the example is shown in FIG.

  From FIG. 6, in the comparative example, when the cutting length Lc is deviated (increased) in the + direction, the pass band is shifted to a lower frequency side than the specified band (see the alternate long and short dash line), and the cutting length Lc is in the − direction. When shifted (becomes shorter), it can be seen that the pass band is shifted to a higher frequency side than the specified band (see broken line).

  On the other hand, in the embodiment, as shown in FIG. 7, it can be understood that there is no fluctuation in the pass band and the band length Lc is almost constant regardless of whether the cutting length Lc is shifted in the + direction or the − direction.

  In the above example, the case where the present invention is applied to a multilayer dielectric filter having three resonant electrodes 16A, 16B, and 16C has been shown, but in addition, a multilayer dielectric filter having two resonant electrodes and four or more resonant electrodes are used. The present invention can also be applied to a laminated dielectric filter having

  Next, a multilayer dielectric filter 10B according to a second embodiment will be described with reference to FIG.

  As shown in FIG. 8, the multilayer dielectric filter 10B according to the second embodiment has substantially the same configuration as the multilayer dielectric filter 10A according to the first embodiment described above. Is different.

  That is, all or part of the three resonance electrodes 16A, 16B, and 16C have respective open end portions, in addition to the first electrode portion described above, a second electrode portion.

  Specifically, regarding the resonant electrode 16B, the open end portion 16Ba is opposed to the first electrode portion 16Ba1 completely included in the inner layer ground electrodes 30 and 32 and the edge of the inner layer ground electrodes 30 and 32. A second electrode portion 16Ba2 (a portion indicated by oblique lines) is integrally provided.

  Further, regarding the resonant electrode 16C, the open end portion 16Ca includes a first electrode portion 16Ca1 that is completely included in the inner layer ground electrodes 30 and 32, and a second electrode that faces the edges of the inner layer ground electrodes 30 and 32. The electrode portion 16Ca2 (a portion indicated by oblique lines) is integrally provided.

  The widths HB2 and HC2 of the second electrode portions 16Ba2 and 16Ca2 are set so that the frequency fluctuation amounts of the resonance electrodes 16A, 16B, and 16C due to the stacking deviation of the three resonance electrodes 16A, 16B, and 16C are substantially the same. Is set.

  Specifically, as a premise, in order to increase the bandwidth, the resonance frequencies of the three resonance electrodes 16A, 16B, and 16C are made different from each other. Therefore, the width of the first electrode portion at the open end portion of all or part of the three resonance electrodes 16A, 16B and 16C is expanded. In FIG. 8, the widths HB1 and HC1 of the first electrode portions 16Ba1 and 16Ca1 of the open end portions 16Ba and 16Ca in the central resonance electrode 16B and the output-side resonance electrode 16C are expanded. Therefore, the open end capacities (capacities between the open end and the ground electrode 12) of the resonance electrodes 16A, 16B, and 16C are different from each other.

  If a stacking error occurs during the formation of each of the resonance electrodes 16A, 16B, and 16C, the open end capacitance in each of the resonance electrodes 16A, 16B, and 16C changes, but the rate of change is different for each resonance electrode. As a result, the amount of frequency fluctuation due to the stacking deviation is different for each resonance electrode.

  As an example, when focusing on two resonators (for example, two resonators including the input-side resonance electrode 16A and the center resonance electrode 16B), the impedance of one resonator is 16Ω, The impedance is 12Ω. In this case, the resonance frequency fluctuation amount due to the stacking shift (stacking shift amount) differs for each resonator as shown in FIG. 9, for example. In one resonator, the amount of fluctuation of the resonance frequency changes sharply with respect to the stacking deviation (see the straight line A), and the fluctuation is 2.5 times that in the case of the other resonator (see the straight line B).

  Therefore, when considering only the input-side resonance electrode 16A and the center resonance electrode 16B, if the width HB2 of the second electrode portion 16Ba2 of the open end portion 16Ba in the center resonance electrode 16B (characteristic impedance 12Ω) is made larger, FIG. As shown by the straight line C in FIG. 10, the frequency fluctuation amount of the central resonance electrode 16B increases and approaches the frequency fluctuation amount of the input-side resonance electrode 16A (characteristic impedance 16Ω). Thereby, although the pass band shifts in the filter waveform, the waveform change of the return loss can be reduced.

  The same applies to the output-side resonance electrode 16C. By increasing the width HC2 of the second electrode portion 16Ca2 in the open end portion 16Ca, the frequency fluctuation amount of the input-side resonance electrode 16A can be approximated. Return loss waveform change can be reduced.

  In the example of FIG. 8, the first and second electrode portions 16Ba1 and 16Ba2 in the open end portion 16Ba of the central resonance electrode 16B are projected toward the input side resonance electrode 16A, and the open end portion of the output side resonance electrode 16C is formed. The first and second electrode portions 16Ca1 and 16Ca2 of 16Ca are projected toward the output terminal 20.

  As described above, in the multilayer dielectric filter 10B according to the second embodiment, the amount of frequency variation is adjusted to the open end portions of all or some of the three resonance electrodes 16A, 16B, and 16C. Therefore, by adjusting the width of the second electrode portion, it is possible to make the frequency fluctuation amount of each resonance electrode due to the stacking deviation of the resonance electrodes almost the same, and the characteristic Deterioration can be suppressed.

  Next, a multilayer dielectric filter 10C according to a third embodiment will be described with reference to FIG.

  As shown in FIG. 11, the multilayer dielectric filter 10C according to the third embodiment has substantially the same configuration as the multilayer dielectric filter 10B according to the second embodiment described above. The ground electrodes 30 and 32 are formed in a strip shape, and the center resonance electrode 16B and the output-side resonance electrode 16C are extended to the open end portions 16Ba and 16Ca, respectively. 16Ca3 (shown by oblique lines), and both ends of the overhanging electrode portions 16Ba3 and 16Ca3 are different from each other in that they protrude from both edge portions of the inner layer ground electrodes 30 and 32, respectively. Note that the open end portion 16Aa of the input side resonance electrode 16A is also located at a portion protruding from the end portions of the inner layer ground electrodes 30 and 32.

  The width HB1 including the extended electrode portion 16Ba3 in the open end portion 16Ba of the central resonance electrode 16B and the width HC1 including the extended electrode portion 16Ca3 in the open end portion 16Ca of the output-side resonance electrode 16C are expanded, and the extended electrode portion 16Ba3 and The lengths LB and LC of 16Ca3 are set to be larger than the width W of the inner layer ground electrodes 30 and 32.

  Therefore, in the multilayer dielectric filter 10C according to the third embodiment, the resonance electrodes 16A, 16B, and 16C can be arranged even when there is a stacking displacement of the resonance electrodes 16A, 16B, and 16C with respect to the inner-layer ground electrodes 30 and 32. Since the open-end capacity does not change, the change in the return loss waveform can be reduced, and fluctuations in the passband can also be suppressed.

  In the above-described second and third embodiments, the case where the present invention is applied to a multilayer dielectric filter having three resonant electrodes 16A, 16B, and 16C has been shown, but in addition, a multilayer type having four or more resonant electrodes. It can also be applied to a dielectric filter.

  In each of the above-described embodiments, the distance d1 between the input-side resonance electrode 16A and the central resonance electrode 16B is larger than the distance d2 between the output-side resonance electrode 16C and the center resonance electrode 16B, but the distances d1 and d2 are It may be almost the same.

  Of course, the multilayer dielectric filter according to the present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

1 is a perspective view showing a multilayer dielectric filter according to a first embodiment. 1 is an exploded perspective view showing a multilayer dielectric filter according to a first embodiment. It is a longitudinal cross-sectional view at the time of cut | disconnecting along the centerline of the center resonance electrode about the laminated dielectric filter which concerns on 1st Embodiment. It is a longitudinal cross-sectional view at the time of cut | disconnecting along the line | wire toward the output terminal from the input terminal about the laminated dielectric filter which concerns on 1st Embodiment. It is explanatory drawing which shows the laminated dielectric filter which concerns on 1st Embodiment seeing from a plane. It is a figure which shows the frequency characteristic at the time of setting a cutting length to 0, -30 micrometers, +30 micrometers with respect to a regular length about a comparative example. It is a figure which shows the frequency characteristic at the time of setting a cutting length to 0, -30 micrometers, +30 micrometers with respect to a regular length about an Example. It is explanatory drawing which shows the laminated dielectric filter which concerns on 2nd Embodiment seeing from a plane. It is a figure which shows the change of the resonant frequency variation | change_quantity with respect to lamination | stacking shift | offset | difference of the resonator of characteristic impedance 16ohm, and the resonator of characteristic impedance 12ohm. It is a figure which shows the example which improved the change of the resonant frequency variation | change_quantity with respect to the lamination | stacking shift | offset | difference of the resonator of characteristic impedance 12ohm. It is explanatory drawing which shows the laminated dielectric filter which concerns on 3rd Embodiment seeing from a plane. It is a disassembled perspective view which shows the laminated dielectric filter which concerns on a prior art example. It is explanatory drawing which shows the laminated dielectric filter which concerns on a proposal example seeing from a plane.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10A, 10B, 10C ... Multilayer dielectric filter 12 ... Ground electrode 14 ... Dielectric substrate 16A ... Input side resonance electrode 16B ... Center resonance electrode 16C ... Output side resonance electrode 30, 32 ... Inner layer earth electrode 36 ... First Coupling electrode 38 ... second coupling electrode 40Aa, 40Ab, 40Ba, 40Bb, 40Ca, 40Cb ... via hole

Claims (2)

Three or more resonant electrodes and a strip-shaped inner ground electrode facing the open end side of the three or more resonant electrodes are formed in a dielectric substrate formed by laminating a plurality of dielectric layers. In multilayer dielectric filters,
All or some of the three or more resonant electrodes each have an extended electrode portion formed in the lateral direction at the open end portion,
The laminated dielectric filter according to claim 1, wherein both ends of the projecting electrode portion are located at portions protruding from both edge portions of the inner-layer ground electrode. Three or more resonant electrodes and a strip-shaped inner ground electrode facing the open end side of the three or more resonant electrodes are formed in a dielectric substrate formed by laminating a plurality of dielectric layers. In multilayer dielectric filters,
Each of the three or more resonant electrodes has each short-circuit end connected to the ground electrode, and at least one main surface of each electrode surface is connected to the ground electrode through a connection member,
All or some of the three or more resonant electrodes each have an extended electrode portion formed in the lateral direction at the open end portion,
The laminated dielectric filter according to claim 1, wherein both ends of the projecting electrode portion are located at portions protruding from both edge portions of the inner-layer ground electrode.

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