JP3898590B2 - Multilayer stripline filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laminated stripline filter used in, for example, wireless communication devices such as mobile phones and wireless LANs and other various communication devices.
[0002]
[Prior art]
In recent years, filters used in mobile communication devices such as mobile phones have resonated distributed constant circuits from filters using dielectric coaxial resonators in response to demands for thinner and smaller mobile communication devices. It has progressed to the laminated stripline filter used in the vessel.
[0003]
As such a conventional multilayer stripline filter, Japanese Patent Application Laid-Open No. 9-331201 proposes a configuration shown in a perspective perspective view in FIG. 6 and a perspective plan view in FIG.
[0004]
6 and 7, 10 is a first dielectric layer, 11 is a second dielectric layer stacked on the first dielectric layer 10, and 12 is on the second dielectric layer 11. The laminated third dielectric layer, 13 is a first ground electrode disposed on the lower surface of the first dielectric layer 10, and 14 is a second ground disposed on the upper surface of the third dielectric layer 12. Electrodes 15 and 16 are a first one-end open rectangular resonance electrode and a first one-end short-circuited rectangular resonance electrode 17 and 18 disposed between the first dielectric layer 10 and the second dielectric layer 11. A second one-end open rectangular resonance electrode and a second one-end short-circuited rectangular resonance electrode arranged between the second dielectric layer 11 and the third dielectric layer 12.
[0005]
The first and second one-end open rectangular resonance electrodes 15 and 17 have substantially the same shape, and are parallel to each other when viewed from the stacking direction, and part of the first one-end open rectangular resonance electrode 15 and the second one. A part of the one-end open rectangular resonance electrode 17 is arranged so as to overlap each other with the second dielectric layer 11 in between.
[0006]
The first and second one-end short-circuited rectangular resonance electrodes 16 and 18 have substantially the same shape, and are parallel to each other when viewed from the stacking direction, and a part of the first one-end short-circuited rectangular resonance electrode 16. A part of the second one-end short-circuited rectangular resonance electrode 18 is arranged so as to overlap each other with the second dielectric layer 11 interposed therebetween.
[0007]
Further, the end portion of the first one-end open rectangular resonance electrode 15 opposite to the open end 19 and the end portion of the first one-end short-circuit rectangular resonance electrode 16 opposite to the short-circuit end 20 are electrically connected. The end of the second one-end open rectangular resonance electrode 17 opposite to the open end 19 is electrically connected to the end of the second one-end short-circuited rectangular resonance electrode 18 opposite to the short-circuit end 20. It became the composition to be. In FIG. 7, the first and second ground electrodes 13 and 14 are not shown.
[0008]
The width W1 of the first and second one-end open rectangular resonance electrodes 15 and 17, the width W2 of the first and second one-end short-circuited rectangular resonance electrodes 16 and 18, and the first one-end open rectangular resonance electrode 15 And the second one-end open rectangular resonance electrode 17 and the second dielectric layer 11 across the width W3, and the first one-end short-circuited rectangular resonance electrode 16 and the second one-end short-circuited rectangular resonance electrode 18 By adjusting the width W4 that overlaps each other with the second dielectric layer 11 in between, the first and second one-end open rectangular resonance electrodes 15 and 17 and the first and second one-end short-circuited rectangular resonances When capacitive coupling is dominant as the coupling formed between the electrodes 16 and 18, a filter characteristic having one attenuation pole on the low band side with respect to the passband is considered, and conversely, inductive coupling is dominant. If this is the case, realize a filter characteristic that has one attenuation pole on the high frequency side of the passband. It was.
[0009]
[Problems to be solved by the invention]
However, in such a conventional multilayer stripline filter, the first one-end open rectangular resonance electrode 15 and the second one are caused by the misalignment generated in the process of laminating the first to third dielectric layers 10-12. The one end open rectangular resonant electrode 17 overlaps with the second dielectric layer 11 across the width W3, and the first one end shorted rectangular resonant electrode 16 and the second one end shorted rectangular resonant electrode 18 The width W4 that overlaps with each other across the two dielectric layers 11 changes, so that the electromagnetic field coupling amount between the first and second one-end open rectangular resonance electrodes 15 and 17 and the first and second one-end short-circuits The amount of electromagnetic field coupling between the rectangular resonance electrodes 16 and 18 changes, which causes a problem that the center frequency and attenuation pole vary greatly with respect to desired filter characteristics.
[0010]
In addition, the multilayer stripline filter configured as described above also has a problem that a desired filter characteristic must be realized and a size reduction request for a filter used in a mobile communication device or the like must be met. .
[0011]
The present invention has been devised in view of the above problems, and an object of the present invention is to provide a center frequency and an attenuation pole of filter characteristics due to a stacking deviation caused in a step of stacking a plurality of dielectric layers in a multilayer stripline filter. It is an object of the present invention to provide a small laminated stripline filter that can reduce fluctuations in the size of the filter.
[0012]
[Means for Solving the Problems]
  The laminated stripline filter of the present invention is laminated on a first dielectric layer, a second dielectric layer laminated on the first dielectric layer, and the second dielectric layer. A third dielectric layer; a fourth dielectric layer stacked on the third dielectric layer; a first ground electrode disposed on a lower surface of the first dielectric layer; Between the first one-end open rectangular resonance electrode and the first one-end short-circuited rectangular resonance electrode arranged between the first and second dielectric layers, and the second and third dielectric layers A second ground electrode disposed, a second one-end open rectangular resonance electrode and a second one-end short-circuited rectangular resonance electrode disposed between the third and fourth dielectric layers, and the fourth And a third ground electrode disposed on the upper surface of the dielectric layer,
The second ground electrode is, Connected continuouslyHaving first and second rectangular openings;
The first and second one-end open rectangular resonance electrodes have substantially the same width W1, and the width W2 of the first rectangular opening with respect to the width W1 is W1> W2, and further, the first The first and second one-end open rectangular resonance electrodes and the first rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second one-end open rectangular shapes A resonant electrode is arranged to cover the first rectangular opening,
The first and second one-end short-circuited rectangular resonant electrodes have substantially the same width W3, and the width W4 of the second rectangular opening with respect to this width W3 is W3> W4, and the first The first and second one-end short-circuited rectangular resonant electrodes and the second rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second one-end short-circuited rectangular shapes A resonant electrode is arranged to cover the second rectangular opening;
The width W3 of the first and second one-end short-circuited rectangular resonance electrodes is W1> W3 with respect to the width W1 of the first and second one-end open rectangular resonance electrodes, and the first rectangular opening The width W4 of the second rectangular opening with respect to the width W2 is W2> W4,
The first to third ground electrodes are arranged so as to cover the first and second one-end open rectangular resonance electrodes and the first and second one-end short-circuited rectangular resonance electrodes,
An end opposite to the open end of the first one-end open rectangular resonance electrode and an end opposite to the short-circuit end of the first one-end short-circuited rectangular resonance electrode are electrically connected,
An end portion on the opposite side to the open end of the second one-end open rectangular resonance electrode and an end portion on the opposite side to the short-circuit end of the second one-end short-circuited rectangular resonance electrode are electrically connected, The first and second one-end open rectangular resonance electrodes and the central axis in the length direction of the first rectangular opening are arranged so as to substantially overlap each other when viewed from the stacking direction, and the first and second The two single-ended short-circuited rectangular resonance electrodes and the central axis in the length direction of the second rectangular opening are arranged so as to substantially overlap each other when viewed from the stacking direction.
[0013]
  According to the multilayer stripline filter of the present invention, the second ground electrode is, Connected continuouslyThe first and second rectangular openings have the same length, and the first and second one-end open rectangular resonance electrodes and the first rectangular openings have substantially the same length and are viewed from the stacking direction. The first and second one-end open rectangular resonance electrodes are arranged so as to cover the first rectangular opening, and the first and second one-end short-circuited rectangular resonance electrodes and the second rectangular shape The openings have substantially the same length, are parallel to each other when viewed from the stacking direction, and are arranged so that the first and second one-end short-circuited rectangular resonant electrodes cover the second rectangular openings. Thus, the electromagnetic field between the first and second one-end open rectangular resonance electrodes is coupled through the first rectangular opening, and the electromagnetic field between the first and second one-end short-circuited rectangular resonance electrodes. Will be coupled through the second rectangular opening, thus the first and second one-end open rectangles The amount of electromagnetic coupling between the resonant electrodes is controlled by the first rectangular opening, and the amount of electromagnetic coupling between the first and second one-end short-circuited rectangular resonant electrodes is controlled by the second rectangular opening. Will be. Furthermore, the first and second one-end open rectangular resonant electrodes have substantially the same width W1, and the width W2 of the first rectangular opening with respect to this width W1 is W1> W2, and the first and second The two one-end open rectangular resonance electrodes and the first rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second one-end open rectangular resonance electrodes are the first. The first and second one-end short-circuited rectangular resonant electrodes have substantially the same width W3, and the width of the second rectangular opening with respect to this width W3. W4 is W3> W4, the first and second one-end short-circuited rectangular resonance electrodes and the second rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second The second one-end short-circuited rectangular resonance electrode is arranged to cover the second rectangular opening., W1> W3 and W2> W4Therefore, even when a stacking shift occurs in the step of stacking the first to third dielectric layers, the amount of electromagnetic coupling between the first and second one-end open rectangular resonant electrodes due to the stacking shift The change and the change of the electromagnetic field coupling amount between the first and second one-end short-circuited rectangular resonant electrodes can be reduced, and as a result, the fluctuation of the center frequency and the attenuation pole of the filter characteristic can be reduced.
[0014]
According to the multilayer stripline filter of the present invention, the first one-end open rectangular resonance electrode and the first one-end short-circuited rectangular resonance electrode are connected to the first and second dielectric layers via the first and second dielectric layers. And the second one-end open rectangular resonance electrode and the second one-end short-circuited rectangular resonance electrode are interposed between the second and second dielectric layers via the third and fourth dielectric layers. Since the structure is sandwiched between three ground electrodes, the ground capacities of the first and second one-end open rectangular resonance electrodes and the first and second one-end short-circuited rectangular resonance electrodes can be increased. As a result, the width W1 of the first and second one-end open rectangular resonance electrodes and the width W2 of the first and second one-end short-circuited rectangular resonance electrodes can be reduced, thereby realizing a smaller multilayer stripline filter. can do.
[0015]
Further, according to the multilayer stripline filter of the present invention, when electromagnetic field coupling between the first and second one-end open rectangular resonance electrodes formed through the first rectangular opening is dominant, A filter with capacitive coupling is formed, and a filter characteristic having one attenuation pole on the low frequency side with respect to the passband can be formed. Conversely, when the electromagnetic field coupling between the first and second one-end short-circuited rectangular resonant electrodes formed through the second rectangular opening is dominant, it becomes an inductive coupling filter, and in the passband. On the other hand, a filter characteristic having one attenuation pole on the high frequency side can be formed.
[0016]
In the multilayer stripline filter of the present invention, the ground electrode and / or the short-circuited end of each short-circuited rectangular resonance electrode is formed on the through conductor and / or the side surface formed inside the dielectric layer. The terminal electrodes are electrically connected in the stacking direction.
[0017]
As a result, the degree of freedom in designing the laminated stripline filter formed inside the plurality of laminated dielectric layers can be improved, and a small and high performance laminated stripline can be provided.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the laminated stripline filter of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a perspective view showing an example of an embodiment of a laminated stripline filter of the present invention, and FIG. 2 is a perspective plan view of FIG. 1 viewed from the lamination direction. 1 and 2, 21 is a first dielectric layer, 22 is a second dielectric layer laminated on the first dielectric layer 21, and 23 is on the second dielectric layer 22. The third dielectric layer laminated, 24 is the fourth dielectric layer laminated on the third dielectric layer 23, and 30 is the first dielectric layer disposed on the lower surface of the first dielectric layer 21. A ground electrode, 31 is a second ground electrode disposed between the second and third dielectric layers 22 and 23, 32 is a third ground electrode disposed on the upper surface of the fourth dielectric layer 24, Reference numerals 33 and 34 respectively denote a first one-end open rectangular resonance electrode and a first one-end short-circuited rectangular resonance electrode disposed between the first and second dielectric layers 21 and 22, respectively. The second one-end open rectangular resonance electrode and the second one-end short-circuited rectangular resonance electrode 37 and 38 disposed between the fourth dielectric layers 23 and 24 are provided on the second ground electrode 31, respectively. Second rectangular opening , 39 each open end of the first and second one-end open rectangular resonant electrodes 33, 35, 40 are respectively short-circuited ends of the first and second one end short rectangular resonant electrodes 34, 36. In FIG. 2, the first to third ground electrodes 30 to 32 are not shown.
[0020]
  As shown in FIG. 2, the first and second one-end open rectangular resonant electrodes 33 and 35 have substantially the same width W1, and the width W2 of the first rectangular opening 37 with respect to this width W1. W1> W2, and the first and second one-end open rectangular resonant electrodes 33 and 35 and the first rectangular opening 37 have substantially the same length L1 and are parallel when viewed from the stacking direction. In addition, the first and second one-end open rectangular resonance electrodes 33 and 35 are arranged so as to cover the first rectangular opening 37. The first and second one-end short-circuited rectangular resonant electrodes 34 and 36 have substantially the same width W3, and the width W4 of the second rectangular opening 38 is W3> W4 with respect to this width W3. Further, the first and second one-end short-circuited rectangular resonant electrodes 34 and 36 and the second rectangular opening 38 have substantially the same length L2, parallel to each other when viewed from the stacking direction, and the first and second Two short-circuited rectangular resonance electrodes 34 and 36 are arranged so as to cover the second rectangular opening 38.The width W3 of the first and second one-end short-circuited rectangular resonance electrodes 34 and 36 is W1> W3 with respect to the width W1 of the first and second one-end open rectangular resonance electrodes 33 and 35, and the first The width W4 of the second rectangular opening 38 is W2> W4 with respect to the width W2 of the rectangular opening 37.The first to third ground electrodes 30 to 32 are arranged so as to cover the first and second one-end open rectangular resonance electrodes 33 and 35 and the first and second one-end short-circuited rectangular resonance electrodes 34 and 36. Has been. AndThe first and second rectangular openings 37 and 38 are continuously connected,An end of the first one-end open rectangular resonance electrode 33 opposite to the open end 39 and an end of the first one-end short-circuited rectangular resonance electrode 34 opposite to the short-circuit end 40 are electrically connected, The end of the second one-end open rectangular resonance electrode 35 opposite to the open end 39 and the end of the second one-end short-circuited rectangular resonance electrode 36 opposite to the short-circuit end 40 are electrically connected. Yes. Further, the longitudinal axes of the first and second one-end open rectangular resonance electrodes 33 and 35 and the first rectangular opening 37 are arranged so that they substantially overlap when viewed from the stacking direction. The first and second one-end short-circuited rectangular resonant electrodes 34 and 36 and the second rectangular opening 38 are arranged so that the central axes in the length direction are substantially overlapped when viewed from the stacking direction.
[0021]
The laminated stripline filter of the present invention having such a configuration has the first to third ground electrodes 30 to 32 and / or the short-circuited ends 40 of the first and second single-ended short-circuited rectangular resonant electrodes 34 and 36 in the stacking direction. As a ground connection conductor and a connection conductor that are electrically connected to each other, a through conductor (not shown) formed inside the dielectric layer and / or a terminal electrode (not shown) formed on the side surface are used. As a result, the degree of freedom in designing the multilayer stripline filter formed inside the plurality of laminated dielectric layers can be improved, and a small and high-performance multilayer stripline can be provided.
[0022]
In forming the multilayer stripline filter of the present invention, the first to fourth dielectric layers 21 to 24, the first to third ground electrodes 30 to 32, the first and second one-end open rectangular resonance electrodes 33 are provided. 35, the first and second one-end short-circuited rectangular resonant electrodes 34 and 36 can be made of various materials and forms used for known high-frequency wiring boards.
[0023]
Examples of the first to fourth dielectric layers 21 to 24 used in the multilayer stripline filter of the present invention include ceramic materials such as alumina ceramics and mullite ceramics, inorganic materials such as glass ceramics, or tetrafluoroethylene resin ( Polytetrafluoroethylene (PTFE) / tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE) / tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perflutero) Fluorine resin such as alkyl vinyl ether copolymer resin (PFA) or resin-based material such as glass epoxy resin or polyimide is used. The shapes and dimensions (thickness, width, and length) of the first to fourth dielectric layers 21 to 24 made of these materials are set according to the used frequency, application, and the like.
[0024]
The first to third ground electrodes 30 to 32, the first and second one-end open rectangular resonance electrodes 33 and 35, and the first and second one-end short-circuit rectangular resonance electrodes 34 and the like in the multilayer stripline filter of the present invention. 36. The connecting conductor is a conductor layer of a metal material for high-frequency signal transmission, such as a Cu layer, a Mo-Mn metallized layer, a Ni-plated layer and an Au-plated layer, and a W-metallized layer. Plated layer and Au plated layer deposited ・ Cr-Cu alloy layer ・ Cr-Cu alloy layer deposited Ni plated layer and Au plated layerTa₂Ni-Cr alloy layer and Au plating layer deposited on N layer, Pt layer and Au plating layer deposited on Ti layer, or Pt layer and Au plating on Ni-Cr alloy layer It is formed by a thick film printing method, various thin film forming methods, a plating method, or the like using a layer to which a layer is applied. The thickness and width are also set according to the frequency and application of the high-frequency signal transmitted.
[0025]
In the production of the first to fourth dielectric layers 21 to 24 used in the multilayer stripline filter of the present invention, for example, if the dielectric layer is made of glass ceramics, the glass ceramic green that becomes the dielectric layer first. A sheet is prepared, and a predetermined punching process is performed on the sheet to form a through hole to be a through conductor. Then, a conductive paste such as Cu is filled into the through hole by a screen printing method, and a predetermined transmission line pattern and other The pattern of the conductor layer is printed and applied. Next, baking is performed at 850 to 1000 ° C., and finally Ni plating and Au plating are performed on each conductor layer.
[0026]
FIG. 3 shows filter characteristics obtained when capacitive coupling is dominant in the multilayer stripline filter of the present invention having the configuration shown in FIGS. 1 and 2 and the conventional multilayer stripline filter shown in FIGS. It is a thing. In FIG. 3, the horizontal axis represents frequency (unit: GHz), the vertical axis represents insertion loss (unit: dB), f0 represents the center frequency, BW represents the passband, and fr represents the attenuation pole. The filter characteristic shown in FIG. 3 has a characteristic that one attenuation pole fr is formed on the low band side of the pass band BW.
[0027]
FIGS. 4 and 5 show a structure model of the multilayer stripline filter of the present invention having the structure shown in FIGS. 1 and 2 and the conventional multilayer stripline filter shown in FIGS. 6 and 7 created by a three-dimensional electromagnetic field analysis simulator. FIG. 10 is a diagram illustrating changes in the center frequency f0 and the attenuation pole fr in the simulation results when ± 100 μm is considered as the stacking misalignment in the width direction.
[0028]
1 and 2, when the thicknesses of the first to fourth dielectric layers 21 to 24 are h1 to h4, h1 = 0.15 mm, h2 = 0.05 mm, h3 = 0.05 mm, h4 = 0.15 mm, W1 = 0.93 mm, W2 = 0.68 mm, W3 = 0.80 mm, W4 = 0.44 mm, L1 = L2 = 2.26 mm, and ± 100 μm is considered as the misalignment amount in the width direction, and FIG. 7, when the thicknesses of the first to third dielectric layers 10 to 12 are h1 to h3, h1 = 0.15 mm, h2 = 0.10 mm, h3 = 0.15 mm, W1 = 1.54 mm, W2 = A study was conducted when 1.64 mm, W3 = 0.52 mm, W4 = 0.28 mm, L1 = L2 = 2.26 mm, and ± 100 μm was taken into account as the amount of misalignment in the width direction. The relative dielectric constant of each dielectric layer used in the simulation was set to 10. The calculation result obtained by the simulation is in good agreement with the measured value.
[0029]
In FIG. 4, the horizontal axis represents the stacking misalignment in the width direction (unit: μm), the vertical axis represents the amount of change in the center frequency f0 (unit: MHz), and each characteristic curve is shown in FIG. 1 and FIG. B shows the results in the multilayer strip line filter of the present invention shown, and B shows the results in the conventional multilayer strip line filter shown in FIGS.
[0030]
In FIG. 5, the horizontal axis represents the stacking misalignment in the width direction (unit: μm), the vertical axis represents the amount of change in the attenuation pole fr (unit: MHz), and each characteristic curve is shown in FIG. 2 shows the results in the multilayer stripline filter of the present invention shown in FIG. 2, and B shows the results in the conventional multilayer stripline filter shown in FIGS.
[0031]
As is apparent from the results shown in FIGS. 4 and 5, according to the multilayer stripline filter of the present invention, the center frequency of the filter characteristics and the attenuation pole due to the misalignment generated in the process of laminating a plurality of dielectric layers are obtained. Variations can be reduced.
[0032]
For example, regarding the amount of change in the center frequency f0 and the amount of change in the attenuation pole fr when the stacking deviation amount is −100 μm,
A: Change amount of center frequency f0: −5 MHz, change amount of attenuation pole fr: 0 MHz
B: Change amount of the center frequency f0: −36 MHz, change amount of the attenuation pole fr: −320 MHz. Compared with the result (B) of the conventional multilayer stripline filter, the result (A ) Can reduce the amount of change in the center frequency f0 and the amount of change in the attenuation pole fr.
[0033]
Further, from the viewpoint of the size of the multilayer stripline filter, in the conventional multilayer stripline filter and the multilayer stripline filter of the present invention, the total thickness of the dielectric layers is 0.4 mm, and one end of the rectangular stripline filter is rectangular. The length of the resonator formed by connecting the shape resonator and the one-end short-circuited rectangular resonator is 4.52 mm. When compared in terms of the dimension in the width direction, the conventional multilayer stripline filter has a dimension in the width direction of 2 × W 2. Whereas -W4 = 3.00 mm, the laminated stripline filter of the present invention has a widthwise dimension of W1 = 0.93 mm. That is, it can be seen that the multilayer strip line filter of the present invention can realize a smaller multilayer strip line filter than the conventional multilayer strip line filter.
[0034]
In the multilayer stripline filter of the present invention, the ground connection conductor for electrically connecting the first to third ground electrodes 30 to 32 in the stacking direction and the second and second one-end short-circuited rectangular resonances in the above configuration. The connection conductor that electrically connects the short-circuit ends 40 of the electrodes 34 and 36 in the stacking direction is a through conductor formed inside the dielectric layer and / or a terminal electrode formed on the side surface. With this, the degree of freedom in designing the laminated stripline filter formed inside the plurality of laminated dielectric layers is improved, and a small and high-performance laminated stripline filter can be provided.
[0035]
It should be noted that the present invention is not limited to the examples of the embodiments described above, and various modifications and improvements can be added without departing from the scope of the present invention.
[0036]
【The invention's effect】
  According to the multilayer stripline filter of the present invention, the second ground electrode is, Connected continuouslyThe first and second rectangular openings have the same length, and the first and second one-end open rectangular resonance electrodes and the first rectangular openings have substantially the same length and are viewed from the stacking direction. The first and second one-end open rectangular resonance electrodes are arranged so as to cover the first rectangular opening, and the first and second one-end short-circuited rectangular resonance electrodes and the second rectangular shape The openings have substantially the same length, are parallel to each other when viewed from the stacking direction, and are arranged so that the first and second one-end short-circuited rectangular resonant electrodes cover the second rectangular openings. Thus, the electromagnetic field between the first and second one-end open rectangular resonance electrodes is coupled through the first rectangular opening, and the electromagnetic field between the first and second one-end short-circuited rectangular resonance electrodes. Will be coupled through the second rectangular opening, thus the first and second one-end open rectangles The amount of electromagnetic coupling between the resonant electrodes is controlled by the first rectangular opening, and the amount of electromagnetic coupling between the first and second one-end short-circuited rectangular resonant electrodes is controlled by the second rectangular opening. Will be.
[0037]
  Further, for the first and second one-end open rectangular resonant electrodes having substantially the same width W1, the width W2 of the first rectangular opening is W1> W2, and when viewed from the stacking direction, The first and second one-end open rectangular resonance electrodes are arranged so as to cover the first rectangular opening, and the first and second one-end short-circuited rectangular resonance electrodes having substantially the same width W3, The width W4 of the second rectangular opening is W3> W4, and the first and second one-end short-circuited rectangular resonant electrodes are arranged so as to cover the second rectangular opening when viewed from the stacking direction. Is, W1> W3 and W2> W4Therefore, even when a stacking shift occurs in the step of stacking the first to third dielectric layers, the electromagnetic field formed between the first and second one-end open rectangular resonance electrodes due to the stacking shift. It is possible to reduce the change in the coupling amount and the change in the electromagnetic coupling amount formed between the first and second one-end short-circuited rectangular resonant electrodes, thereby reducing the fluctuation of the center frequency and attenuation pole of the filter characteristics. And the size of the resonator in the width direction can be reduced.
[0038]
According to the multilayer stripline filter of the present invention, the first one-end open rectangular resonance electrode and the first one-end short-circuited rectangular resonance electrode are connected to the first and second dielectric layers via the first and second dielectric layers. And the second one-end open rectangular resonance electrode and the second one-end short-circuited rectangular resonance electrode are interposed between the second and second dielectric layers via the third and fourth dielectric layers. Since the structure is sandwiched between three ground electrodes, the ground capacities of the first and second one-end open rectangular resonance electrodes and the first and second one-end short-circuited rectangular resonance electrodes can be increased. As a result, the width W1 of the first and second one-end open rectangular resonance electrodes and the width W2 of the first and second one-end short-circuited rectangular resonance electrodes can be reduced, thereby realizing a smaller multilayer stripline filter. can do.
[0039]
Further, according to the multilayer stripline filter of the present invention, when electromagnetic field coupling between the first and second one-end open rectangular resonance electrodes formed through the first rectangular opening is dominant, A filter with capacitive coupling is formed, and a filter characteristic having one attenuation pole on the low frequency side with respect to the passband can be formed. Conversely, when the electromagnetic field coupling between the first and second one-end short-circuited rectangular resonant electrodes formed through the second rectangular opening is dominant, it becomes an inductive coupling filter, and in the passband. On the other hand, a filter characteristic having one attenuation pole on the high frequency side can be formed.
[0040]
In the multilayer stripline filter of the present invention, the ground electrode and / or the short-circuited end of each short-circuited rectangular resonance electrode is formed on the through conductor and / or the side surface formed inside the dielectric layer. It is characterized in that it is electrically connected in the laminating direction by the terminal electrode formed, thereby improving the design freedom of the laminated stripline filter formed inside a plurality of laminated dielectric layers. In addition, a small and high-performance laminated strip line can be provided.
[0041]
As described above, according to the present invention, in the multilayer stripline filter, it is possible to reduce the fluctuation of the center frequency and attenuation pole of the filter characteristics due to the stacking deviation generated in the step of stacking the plurality of dielectric layers. A multilayer stripline filter could be provided.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of a multilayer stripline filter of the present invention.
FIG. 2 is a perspective plan view showing an example of an embodiment of a laminated stripline filter of the present invention.
FIG. 3 is a diagram showing an example of insertion loss in the multilayer strip line filter of the present invention and the conventional multilayer strip line filter.
FIG. 4 is a diagram illustrating an example of a change amount of a center frequency with respect to a stacking shift amount in a width direction in the multilayer stripline filter of the present invention and the conventional multilayer stripline filter.
FIG. 5 is a diagram showing an example of a change amount of an attenuation pole with respect to a stacking shift amount in the width direction in the multilayer stripline filter of the present invention and the conventional multilayer stripline filter.
FIG. 6 is a perspective view illustrating an example of a conventional multilayer stripline filter.
FIG. 7 is a perspective plan view showing an example of a conventional multilayer stripline filter.
[Explanation of symbols]
21 ... first dielectric layer
22 ... Second dielectric layer
23 ... Third dielectric layer
24 ... Fourth dielectric layer
30: First ground electrode
31 ... Second ground electrode
32 ... Third ground electrode
33 ... 1st one end open rectangular resonance electrode
34... First short-ended rectangular resonance electrode
35 ... 2nd one end open rectangular resonance electrode
36 ... 2nd one end short-circuited rectangular resonance electrode
37 ... first rectangular opening
38 ... second rectangular opening
39 ・ ・ ・ Open end
40 ... Short-circuit end

Claims (2)

A first dielectric layer; a second dielectric layer stacked on the first dielectric layer; a third dielectric layer stacked on the second dielectric layer; A fourth dielectric layer stacked on the third dielectric layer; a first ground electrode disposed on a lower surface of the first dielectric layer; and the first and second dielectrics A first one-end open rectangular resonance electrode and a first one-end short-circuited rectangular resonance electrode disposed between the layers; a second ground electrode disposed between the second and third dielectric layers; A second one-end open rectangular resonance electrode and a second one-end short-circuited rectangular resonance electrode arranged between the third and fourth dielectric layers, and an upper surface of the fourth dielectric layer. A third ground electrode,
The second ground electrode has first and second rectangular openings that are continuously connected ,
The first and second one-end open rectangular resonance electrodes have substantially the same width W1, and the width W2 of the first rectangular opening with respect to the width W1 is W1> W2, and further, the first The first and second one-end open rectangular resonance electrodes and the first rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second one-end open rectangular shapes A resonant electrode is arranged to cover the first rectangular opening,
The first and second one-end short-circuited rectangular resonant electrodes have substantially the same width W3, and the width W4 of the second rectangular opening with respect to this width W3 is W3> W4, and the first The first and second one-end short-circuited rectangular resonant electrodes and the second rectangular opening have substantially the same length, are parallel to each other when viewed from the stacking direction, and the first and second one-end short-circuited rectangular shapes A resonant electrode is arranged to cover the second rectangular opening;
The width W3 of the first and second one-end short-circuited rectangular resonance electrodes is W1> W3 with respect to the width W1 of the first and second one-end open rectangular resonance electrodes, and the first rectangular opening The width W4 of the second rectangular opening with respect to the width W2 is W2> W4,
The first to third ground electrodes are arranged so as to cover the first and second one-end open rectangular resonance electrodes and the first and second one-end short-circuited rectangular resonance electrodes,
An end opposite to the open end of the first one-end open rectangular resonance electrode and an end opposite to the short-circuit end of the first one-end short-circuited rectangular resonance electrode are electrically connected,
An end portion on the opposite side to the open end of the second one-end open rectangular resonance electrode and an end portion on the opposite side to the short-circuit end of the second one-end short-circuited rectangular resonance electrode are electrically connected, The first and second one-end open rectangular resonance electrodes and the central axis in the length direction of the first rectangular opening are arranged so as to substantially overlap each other when viewed from the stacking direction, and the first and second 2. A laminated stripline filter, characterized in that the two single-end short-circuited rectangular resonance electrodes and the central axis in the length direction of the second rectangular opening are substantially overlapped when viewed from the lamination direction.   The short-circuited ends of the ground electrodes and / or the short-circuited rectangular resonance electrodes are electrically connected in the stacking direction by through conductors formed inside the dielectric layer and / or terminal electrodes formed on side surfaces. The multilayer stripline filter according to claim 1, wherein the multilayer stripline filter is connected.

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