JP2009225408A - Laminated dielectric filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated dielectric filter that is capable of obtaining a sufficient attenuation amount in a stopband for high-frequency signal components and that has an excellent signal-selectivity property. <P>SOLUTION: The laminated dielectric filter 10 comprises: a laminated body 1 comprised of a plurality of laminated dielectric layers; input/output terminal electrodes 3, 4 and ground terminal electrodes 2 adhered to the external surface of the laminated body 1; coil conductors 5, 6 that are disposed between the dielectric layers in the laminated body 1, with one end of each being electrically connected to the input/output terminal electrodes 3, 4; and ring-shaped ground conductors 7 that are disposed between dielectric layers 1a-1b, 1l-1m located above and below the coil conductors 5, 6 in the lamination direction inside the lamination body 1, outside the region where the coil conductors 5, 6 are disposed when viewed in the lamination direction, and that are electrically connected to the ground terminal electrodes 2. Since the capacity by the coil conductors 5, 6 is small, the laminated dielectric filter 10 can be used for a digital signal circuit. External electromagnetic wave noise is significantly removed by the ring-shaped ground conductors 7. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multilayer dielectric filter used for removing high-frequency noise in a circuit handling a high-frequency signal or removing harmonic components in an RF (Radio Frequency) circuit block.

  As a conventional multilayer dielectric filter, for example, a multilayer body in which a plurality of dielectric layers are stacked, an input / output terminal electrode and a ground terminal electrode that are attached to the outer surface of the multilayer body, and the interior of the multilayer body There is known a multilayer dielectric filter having a coil conductor disposed between dielectric layers and having one end electrically connected to an input / output terminal electrode (see, for example, Patent Document 1).

Such a conventional multilayer dielectric filter can attenuate high-frequency noise or harmonic components of an electric signal input from the input / output terminal electrode to the inside of the multilayer body by the inductance of the coil conductor. The filter functions as a filter that is used to remove high-frequency noise contained in an electrical signal in a circuit that handles or remove harmonic components in an RF circuit block.
JP 2004-229268 A

  However, in the conventional multilayer dielectric filter described above, for example, electromagnetic noise may enter from the main surface side of the multilayer body. In this case, the electromagnetic noise is input from the input / output terminal electrodes to the inside of the multilayer body. Therefore, there is a problem in that electromagnetic wave noise cannot be sufficiently removed because an attenuation effect on high frequency noise or harmonic components using the entire coil conductor cannot be obtained.

  As a means for preventing electromagnetic noise from entering from the main surface side of the multilayer body, there is a method in which ground conductors are arranged in substantially the entire area between the dielectric layers located above and below the coil conductor in the lamination direction inside the multilayer body. . However, when this means is used, a large capacitance is generated between the coil conductor and the ground conductor, and it takes time to accumulate charges in the capacitance. There is a problem that a time delay occurs in the rising and falling of each waveform, and the steepness of the waveform of the digital signal deteriorates, making it difficult to maintain the signal waveform.

  The present invention has been devised in view of the problems in the conventional multilayer dielectric filter as described above, and its purpose is to sufficiently remove electromagnetic noise entering from the outside, and to achieve high frequency. It is an object of the present invention to provide a laminated dielectric filter that can be suitably used in a digital signal circuit.

  The multilayer dielectric filter of the present invention includes a multilayer body formed by laminating a plurality of dielectric layers, an input / output terminal electrode and a ground terminal electrode that are attached to the outer surface of the multilayer body, and an interior of the multilayer body. A coil conductor, one end of which is electrically connected to the input / output terminal electrode, and a dielectric layer positioned above and below the coil conductor in the stacking direction inside the stack. When viewed in the direction, an annular ground conductor disposed outside the region where the coil conductor is disposed and electrically connected to the ground terminal electrode is provided.

  In the multilayer dielectric filter of the present invention, in the above configuration, the input / output terminal electrodes are attached from the side surface of the multilayer body to both main surfaces, and the portions attached to both main surfaces are Each is opposed to the annular ground conductor with the dielectric layer in between.

  According to the multilayer dielectric filter of the present invention, between the dielectric layers located above and below the coil conductor in the stacking direction inside the stack, outside the region where the coil conductor is disposed when viewed in the stacking direction. Since the annular ground conductor that is electrically connected to the ground terminal electrode is disposed, the annular ground conductor can block and remove the intrusion of electromagnetic wave noise from the main surface side of the multilayer body. . In addition, since the capacitance generated between the annular ground conductor and the coil conductor is small, the steepness of the waveform of the digital signal input / output to / from the coil conductor does not deteriorate so as to cause a practical problem. Therefore, it can be suitably used for a digital signal circuit that handles high-frequency signals.

  In addition, between the dielectric layers located above and below the coil conductor in the stacking direction within the stack, the ground terminal electrode is electrically connected to the outside of the region where the coil conductor is disposed when viewed in the stacking direction. Since the annular ground conductor is disposed, the region where the annular ground conductor is disposed and the coil conductor are disposed outside the region where the coil conductor of the multilayer body is disposed. The difference in thickness in the stacking direction with the region can be reduced. Accordingly, it is possible to suppress the occurrence of peeling between dielectric layers and the occurrence of cracks in the dielectric layer in a dielectric filter composed of a laminate of dielectric layers.

  In addition, since the annular ground conductor is annular, current flows in a direction around the annular ground conductor so as to generate an inductance that prevents electromagnetic noise generated by the inductance of the coil conductor from leaking to the outside. Therefore, an effect of providing a multilayer dielectric filter with less radiation of electromagnetic noise to the outside can be obtained.

  Further, according to the multilayer dielectric filter of the present invention, the input / output terminal electrodes are applied from the side surface of the multilayer body to both main surfaces, and the portions applied to both main surfaces are respectively dielectric layers. Since the portion of the input / output terminal electrode that faces the annular ground conductor does not form a capacitance with the coil conductor, the laminated body of the input / output terminal electrodes Capacitance generation between the parts attached to both main surfaces and the coil conductor can be suppressed, and the capacitance can be reduced, reducing the high-frequency noise transmitted to the output side through the capacitance. Therefore, the attenuation characteristics of high frequency noise or harmonic components can be improved.

  Hereinafter, the multilayer dielectric filter of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is an external perspective view showing an example of an embodiment of a multilayer dielectric filter of the present invention. 2 is a cross-sectional view of the multilayer dielectric filter 10 shown in FIG. FIG. 3 is an exploded perspective view of the laminate 1 shown in FIG. The multilayer dielectric filter 10 of the present invention shown in these drawings includes, as a basic configuration, a multilayer body 1, input / output terminal electrodes 3 and 4 attached to the outer surface of the multilayer body 1, and a ground terminal electrode. 2, coil conductors 5 and 6 and an annular ground conductor 7 disposed inside the laminate 1.

  Such a multilayer dielectric filter 10 is used, for example, for removing high-frequency noise in a circuit handling a high-frequency signal or removing harmonic components in an RF circuit block. It has an impedance characteristic that attenuates high-frequency noise and harmonic components of the electric signal before the electric signal input to the conductor 5 is output from the input / output terminal electrode 4.

The laminated body 1 is a rectangular parallelepiped dielectric block in which a plurality of rectangular dielectric layers 1a to 1m are laminated. The dielectric layers 1a to 1m are formed by a dielectric material mainly composed of TiO ₂ —Nd ₂ O ₃ —BaTiO ₃ or the like with a thickness of 5 μm to 300 μm per layer.

  The input / output terminal electrode 3 has, for example, Cu, Ag, or an Ag-based alloy as a main component at a plurality of locations on one first side surface 1w of the pair of side surfaces in the longitudinal direction of the stacked body 1 in the stacking direction. A conductive material is used to form a belt with a thickness of 10 μm to 70 μm. In addition, on the second side surface 1x facing the first side surface 1w of the multilayer body 1, a plurality of input / output terminal electrodes 4 are formed at the positions facing the input / output terminal electrodes 3 with the same material and the same thickness as the input / output terminal electrodes 3. It is applied in a strip shape in the stacking direction.

  Further, the ground terminal electrode 2 is provided on each of the third side surface 1y and the fourth side surface 1z different from the first side surface 1w and the second side surface 1x of the multilayer body 1 on which the input / output terminal electrodes 3 and 4 are respectively formed. The same material and the same thickness as the input / output terminal electrodes 3 and 4 are applied in the stacking direction. Note that the area per ground terminal electrode 2 is larger than that of the input / output terminal electrodes 3 and 4, so that the ground potential is easily stabilized.

  These input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 are mounted connections that are bonded to terminal electrode pads of the circuit board by solder or the like when the multilayer dielectric filter 10 is mounted on an external circuit board or the like. It is also a terminal. The input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 are attached in a continuous and integral shape from the respective side surfaces 1w to 1z of the multilayer body 1 to a part of both main surfaces, thereby enabling soldering. The mounting area is increased by increasing the bonding area.

  The coil conductor 5 includes coil pattern conductors 5a, 5b, 5c, and 5d that are internal conductors formed in the dielectric layers 1b-1c, 1c-1d, 1d-1e, and 1e-1f, respectively. The dielectric layers 1c to 1e between 5d are formed by sequentially connecting through through conductors (not shown) indicated by broken lines. In addition, the coil conductor 6 includes coil pattern conductors 6a, 6b, 6c, and 6d, which are internal conductors formed in the dielectric layers 1h-1i, 1i-1j, 1j-1k, and 1k-1l. The dielectric layers 1i to 1k between 6a to 6d are formed by sequentially connecting through conductors (not indicated) indicated by broken lines.

  Further, one end of the coil conductor 5 is drawn out to the first side face 1 w on the upper side of the multilayer body 1 and is electrically connected to the input / output terminal electrode 3, and the other end is drawn out to the second side face 1 x on the upper side of the multilayer body 1. Thus, the input / output terminal electrode 4 is electrically connected. Further, one end of the coil conductor 6 is drawn out to the first side surface 1w at the lower side of the multilayer body 1 and is electrically connected to the input / output terminal electrode 3, and the other end is disposed at the lower side of the multilayer body 1 at the second side surface 1x. To the input / output terminal electrode 4. Further, the coil conductor 5 and the coil conductor 6 are alternately drawn out to the first side surface 1w and the second side surface 1x, respectively. The coil conductor 5 and the coil conductor 6 serve as a filter capable of attenuating high-frequency noise or harmonic components of an electrical signal input from the input / output terminal electrodes 3 and 4 into the laminated body 1 by the inductances of the coil conductor 5 and the coil conductor 6. It has a function.

  As described above, the multilayer dielectric filter 10 of this example includes the input / output terminal electrodes 3 alternately formed on the first side surface 1w and the second side surface 1x, which are side surfaces in the longitudinal direction of the rectangular parallelepiped multilayer body 1, respectively. , 4 are electrically connected to the individual coil conductors 5 and 6 formed inside the multilayer body 1, so that a multi-layered multilayer dielectric body having a plurality of independent filter functions is provided. It is a filter.

  Each of the dielectric layers 1f-1g and 1g-1h is formed with an internal conductor ground conductor 9 in an area occupying most of the respective dielectric layers 1f-1g and 1g-1h, and a part of the laminated layers 1 is pulled out to the third side surface 1y and the fourth side surface 1z and is electrically connected to the ground terminal electrode 2, and the ground conductor 9 is formed with the coil conductor 5 in the stacking direction and the coil conductor 6. By arranging the coil conductor 5 between the coil conductor 5 and the coil conductor 6, the capacitive coupling between the coil conductor 5 and the coil conductor 6 is prevented. Further, since the ground conductor 9 is formed between the two dielectric layers, the dielectric layer 1f-1g and the dielectric layer 1g-1h, the ground potential in each ground conductor 9 is less changed. Yes.

  The internal conductors such as the coil conductors 5 and 6 and the ground conductor 9 are formed with a thickness of 10 μm to 70 μm using, for example, a conductor material mainly composed of Cu, Au, or an Ag-based alloy. In addition, the through conductor is formed in a cylindrical shape having a diameter of 30 μm to 300 μm, for example, using the same material as the internal wiring conductor.

  In the multilayer dielectric filter 10 of this example, the annular ground of the inner conductor is placed between the dielectric layers 1a-1b and 11-1m located above and below the coil conductors 5 and 6 in the stacking direction in the multilayer body 1. Conductors 7 are respectively disposed. The annular ground conductor 7 disposed in the dielectric layer 1a-1b is disposed outside the region where the coil conductor 5 is disposed when viewed in the stacking direction, and is disposed in the dielectric layer 1l-1m. The annular ground conductor 7 is disposed outside the region where the coil conductor 6 is disposed when viewed in the stacking direction. Furthermore, one end of each annular ground conductor 7 is drawn out to the third side surface 1 y and the fourth side surface 1 z of the multilayer body 1 and is electrically connected to the ground terminal electrode 2.

  As described above, according to the multilayer dielectric filter 10 of this example, the dielectric layer 1a-1b, 11-1m located above and below the coil conductors 5 and 6 in the stacking direction in the stack 1 is stacked in the stacking direction. Since the annular ground conductor 7 electrically connected to the ground terminal electrode 2 is disposed outside the region where the coil conductors 5 and 6 are disposed, the annular ground conductor 7 is laminated. The electromagnetic wave noise from the main surface side of the body 1 is effectively blocked and removed, and the capacitance generated between the annular ground conductor 7 and the coil conductors 5 and 6 is small. Further, the steepness of the waveform of the digital signal input / output to / from the coil conductors 5 and 6 is not deteriorated so as to cause a problem in practical use, and can be used for a digital signal circuit that handles a high-frequency signal.

  In addition, the coil conductors 5 and 6 are disposed in the dielectric layer 1a-1b and 11-1m located above and below the coil conductors 5 and 6 in the stacking direction inside the stacked body 1 when viewed in the stacking direction. Since the annular ground conductor 7 electrically connected to the ground terminal electrode 2 is arranged outside the region, the annular ground is out of the region outside where the coil conductors 5 and 6 of the multilayer body 1 are arranged. About the area | region where the conductor 7 is arrange | positioned, the difference of the whole thickness in the lamination direction with the area | region where the coil conductors 5 and 6 are arrange | positioned can be made small.

  Furthermore, since the annular ground conductor 7 is annular, current flows in a direction around the annular ground conductor 7 so that an inductance is generated in a direction that prevents electromagnetic waves generated by the inductance of the coil conductors 5 and 6 from leaking to the outside. As a result, the laminated dielectric filter 10 with less leakage of electromagnetic waves to the outside can be obtained.

  In the multilayer dielectric filter 10 of this example, ground coil pattern conductors 8a, 8b, 8c as internal conductors are formed in the dielectric layers 1c-1d, 1d-1e, 1e-1f, respectively. A ground coil conductor 8 is formed by sequentially connecting through through conductors (not indicated) indicated by broken lines formed in the dielectric layers 1d and 1e between the ground coil pattern conductors 8a to 8c. The ground coil conductor 8 is electrically connected to the ground conductor 9 at one end via a through conductor formed on the dielectric layer 1f, and the other end is open. A part of the ground coil pattern conductor 8b constituting the ground coil conductor 8 is opposed to the coil pattern conductors 5b and 5d to generate a capacitance. The capacitance and the inductance of the ground coil conductor 8 cause series resonance. Thus, a frequency band that is greatly attenuated is created, so that the multilayer dielectric filter 10 with higher frequency band selectivity is obtained.

  In addition, ground coil pattern conductors 12a, 12b, and 12c as internal conductors are formed in the dielectric layers 1h-1i, 1i-1j, and 1j-1k, respectively, and a dielectric layer between the ground coil pattern conductors 12a to 12c. A ground coil conductor 12 is formed by sequentially connecting through-conductors (not indicated) indicated by broken lines formed in 1i and 1j. The ground coil conductor 12 is electrically connected to the ground conductor 9 at one end via a through conductor formed in the dielectric layer 1h, and the other end is open. Similarly to the ground coil conductor 8, the ground coil conductor 12 also has an effect of further improving the frequency band selectivity of the multilayer dielectric filter 10. Specifically, a part of the ground coil pattern conductor 12b constituting the ground coil conductor 12 is opposed to the coil pattern conductors 6a and 6b to generate a capacitance, and this capacitance and the inductance of the ground coil conductor 12 are connected in series. By resonating, a frequency band that greatly attenuates is created.

  The multilayer dielectric filter 10 of this example is manufactured by the following method, for example.

  The method of manufacturing the multilayer dielectric filter 10 of this example basically includes a multilayer sheet formed by laminating a plurality of dielectric green sheets having a pattern of a conductor paste corresponding to a predetermined inner conductor and through conductor. A first step to be produced, a second step in which the laminated sheet is cut into a plurality of rectangular parallelepiped pieces, and the individual laminated sheets are sintered by firing to have each internal conductor and through conductor. A third step of producing the rectangular parallelepiped laminate 1 and a fourth step of forming the input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 by applying and baking a conductor paste on the side surface of the laminate 1 are provided.

In the first step, a dielectric ceramic slurry is prepared by adding a suitable organic solvent, an organic binder, and the like to a dielectric green sheet, for example, a metal oxide powder such as BaTiO ₃ , TiO _2, or Nd ₂ O _3. The dielectric ceramic slurry is manufactured to have a predetermined shape and a predetermined thickness by, for example, a doctor blade method. Moreover, a conductor paste is produced by adding and mixing a suitable organic solvent, an organic binder, etc. with the powder of the conductor material which has Cu, Ag, or an Ag type alloy as a main component, for example. The pattern of the conductor paste corresponding to the internal conductor is formed by applying it in a predetermined shape and a predetermined thickness by, for example, screen printing. For the pattern of the conductor paste corresponding to the through conductor, for example, a through hole is formed by punching a predetermined portion of the dielectric green sheet using a mold or the like, and the conductor paste is filled into the through hole by a screen printing method or the like. Formed by.

  And the laminated sheet is produced by laminating and adhering the dielectric green sheets on which the above-mentioned pattern of the conductive paste is formed.

  In the second step, the laminated sheet is cut by using, for example, a cutting blade along the boundary line of the individual pieces corresponding to the laminated dielectric filters 10 arranged in the vertical and horizontal directions. To separate.

  In the third step, the temperature for firing the laminated sheet is set to, for example, the maximum temperature of 930 ° C. to 970 ° C. when the above-described materials are used.

  In the fourth step, the conductive paste for forming the input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 is coated with a suitable organic solvent and organic binder, etc., on the powder of the conductive material mainly composed of Cu, Ag or an Ag-based alloy. The conductor paste prepared by adding and mixing is applied from the side surface to the main surface of the laminate 1 by, for example, screen printing, and baked to form the input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 respectively. To do. Moreover, it is preferable to form a metal film such as Ni and Sn as a plating film on the surfaces of the input / output terminal electrodes 3 and 4 and the ground terminal electrode 2 by plating.

  Further, in the multilayer dielectric filter 10 of this example, as shown in FIG. 2, the input / output terminal electrodes 3 and 4 are deposited from the side surface of the multilayer body 1 to both main surfaces. Part of the input / output terminal electrodes 3 and 4 deposited on the surface is opposed to the annular ground conductor 7 across the dielectric layer 1a, and the input / output terminal electrodes 3 and 4 deposited on the other main surface A part is opposed to the annular ground conductor 7 across the dielectric layer 1m. As a result, the portion of the input / output terminal electrodes 3 and 4 that faces the annular ground conductor 7 does not form a capacitance with the coil conductors 5 and 6. It is possible to suppress the generation of capacitance between the portions of the main surfaces 1 and the coil conductors 5 and 6, and among the input / output terminal electrodes 3 and 4 of the main surfaces 1 and 4. Since the capacitance generated between the portions attached to both main surfaces of the laminate 1 and the coil conductors 5 and 6 can be reduced, high frequency noise or harmonic components that are transmitted to the output side through the capacitance. The attenuation characteristics of these high frequency components can be made better.

  The present invention is not limited to the embodiments described above, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, in the example of the embodiment described above, the input / output terminal electrode 3 is on the electric signal input side and the input / output terminal electrode 4 is on the electric signal output side. Thus, any one of the input / output terminal electrodes 3 and 4 may be an input side of an electric signal, and any of them may be an output side.

  Further, in the example of the embodiment described above, the multilayer dielectric filter 10 is a multi-layered multilayer dielectric filter 10 having a plurality of filter functions, but is not limited to such a configuration. It is also possible to have only one filter function.

  Further, the ground conductor 9 for preventing the capacitive coupling between the coil conductor 5 and the coil conductor 6 is formed between the two dielectric layers, but the ground conductor 9 is formed only between the one dielectric layer. It may also be formed, or may be formed between three or more dielectric layers.

  Further, although the coil conductors 5 and 6 are separately disposed above and below the laminated body 1 with the ground conductor 9 interposed therebetween, the coil conductors 5 and 6 may be disposed side by side without forming the ground conductor 9. Good.

  A specific example of the multilayer dielectric filter of the present invention will be described.

As a sample 1, a multilayer dielectric filter 10 which is an example of the present invention was produced. The sample 1 has a rectangular parallelepiped shape with a length of 2.0 mm, a width of 1.25 mm, and a height of 0.8 mm for the laminated body 1, and the input / output terminals as shown in FIGS. It is assumed that the electrodes 3 and 4, the ground terminal electrode 2, the inner conductor and the through conductor are formed, and a multi-layered laminated dielectric filter having four filter circuits is provided. The material constituting Sample 1 was a material mainly composed of TiO ₂ —Nd ₂ O ₃ —BaTiO ₃ for the dielectric material, and a material mainly composed of Ag for the material of the internal conductor and the through conductor.

  Further, as a sample 2, a multilayer dielectric filter of a comparative example was produced. Sample 2 had the same shape, configuration, and material as Sample 1 except that the annular ground conductor 7 of the multilayer dielectric filter 10 of the present invention was not formed.

  Regarding the samples 1 and 2, when the waveform after the input digital signal was output was examined using an oscilloscope, the steepness of the signal waveform for the sample 2 was greatly deteriorated. There was almost no deterioration of the steepness of the signal waveform. This has the effect that the annular ground conductor 7 blocks and removes intrusion of electromagnetic wave noise from the main surface side of the multilayer body 1, and the capacitance generated between the annular ground conductor 7 and the coil conductor 5 is small. This is because the steepness of the waveform of the input / output digital signal is not deteriorated so as to cause a practical problem.

  In addition, when 10 samples were prepared for each of these samples 1 and 2, and the presence or absence of delamination of the dielectric layers of the laminate was examined, delamination occurred in 2 out of 10 samples. However, in sample 1, there was no sample in which delamination occurred. This is because, in the sample 1, the stacking direction between the region where the coil conductors 5 and 6 of the multilayer body 1 are disposed and the portion where the annular ground conductor 7 is disposed outside the region where the coil conductors 5 and 6 are disposed. This is due to the fact that the difference in the overall thickness in can be reduced.

  In addition, with respect to Samples 1 and 2, a result of measuring a signal output from the input / output terminal electrode 4 when a constant level signal is input from the input / output terminal electrode 3 to the coil conductor 5 in the frequency band of 0 GHz to 3 GHz. Is shown in FIG. FIG. 4 is a diagram showing the attenuation characteristics of the multilayer dielectric filter. The horizontal axis indicates the frequency (unit: Hz) of the output signal, and the vertical axis indicates the attenuation amount (unit: dB) of the output signal. Indicates. Also, a solid characteristic curve X in FIG. 4 indicates the attenuation characteristic of the sample 1, and a broken characteristic curve Y indicates the attenuation characteristic of the sample 2.

  As can be seen from the results shown in FIG. 4, sample 1 has a larger attenuation in the frequency band of 500 MHz to 2000 MHz than sample 2, and in particular, the attenuation in the frequency band near 500 MHz to 1000 MHz near the boundary with the pass band. It is getting bigger. This is because the portion of the input / output terminal electrodes 3, 4 facing the annular ground conductor 7 does not form a capacitance with the coil conductors 5, 6. The annular ground conductor 7 is disposed between the coil conductors 5 and 6 and the coil conductors 5 and 6 between the portions of the input / output terminal electrodes 3 and 4 that are attached to both main surfaces of the laminate 1. This is because the high-frequency noise or harmonic components transmitted to the output side through this capacitance can be reduced.

  As described above, according to the multilayer dielectric filter of the present invention, the region in which the coil conductor is disposed when viewed in the stacking direction between the dielectric layers positioned above and below the coil conductor in the stacking direction within the stack. Since an annular ground conductor that is electrically connected to the ground terminal electrode is arranged outside, the intrusion of electromagnetic noise from the main surface side of the laminate is blocked, and high frequency is generated from the input / output electric signal. It was confirmed that noise or harmonic components could be removed effectively, and that a sharply damped frequency band could be created without deteriorating the steepness of the input / output digital signal waveform to become a practical problem. .

It is an external appearance perspective view which shows an example of embodiment of the laminated dielectric filter of this invention. FIG. 2 is a cross-sectional view of the multilayer dielectric filter shown in FIG. 1 taken along line AA. It is a disassembled perspective view of the laminated body shown in FIG. It is a diagram which shows the attenuation | damping characteristic of a laminated dielectric filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h, 1i, 1j, 1k, 1l, 1m ... Dielectric layer 2 ... Ground terminal electrode 3, 4 ... Input / output terminal electrodes 5, 6 ... coil conductors 5a, 5b, 5c, 5d, 6a, 6b, 6c, 6d ... coil pattern conductors 7 ... annular ground conductor
10 ... Multilayer dielectric filter

Claims (2)

A laminate in which a plurality of dielectric layers are laminated;
An input / output terminal electrode and a ground terminal electrode applied to the outer surface of the laminate;
A coil conductor disposed between the dielectric layers inside the laminate and having one end electrically connected to the input / output terminal electrode;
Inside the laminated body, between the dielectric layers located above and below the coil conductor in the laminating direction, disposed outside the region where the coil conductor is arranged when viewed in the laminating direction, A laminated dielectric filter comprising: an annular ground conductor that is connected electrically.   The input / output terminal electrodes are attached from the side surface of the multilayer body to both main surfaces, and the portions attached to the two main surfaces are opposed to the annular ground conductor with the dielectric layer in between. The multilayer dielectric filter according to claim 1, wherein:

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