JP2008109593A - Filter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filter device as a band-pass filter which reduces an increase in characteristic impedance of a line due to widening of the band of a filter and can easily be made compact. <P>SOLUTION: The filter device has first and second ground electrodes 11 and 12 disposed oppositely to each other, first to fifth dielectric layers 21 to 25 stacked between them, and first to fourth conductor patterns 31 to 34 which are formed among the first to the fifth dielectric layers 21 to 25 and have short-circuited end and open ends electrically connected to the first and second ground electrodes 11 and 12, where parallel resonance circuits are formed in the dielectric layers 21 to 25 from the first ground electrode 11 to the second ground electrode 12 and a through conductor 41 having one end connected to the first and fourth conductor patterns 32 and 34 is formed penetrating the second and third dielectric layers 22 and 23 along outer peripheries of the second and third conductor patterns 32 and 33 other than the short-circuited ends. The filter device is easily made compact and a decrease in characteristic due to stray capacitance is suppressed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  In recent years, filter devices used in mobile communication devices such as mobile phones have been distributed from filters using dielectric coaxial resonators in response to demands for thinner and smaller mobile communication devices. Progress has been made in laminated stripline filters used in resonators.

  This multilayer stripline filter has an attenuation pole in the low frequency side and high frequency side attenuation bands of the pass frequency band and has sharp band pass characteristics. Is used as a band-pass filter to allow high-quality communication by preventing unwanted signals from being mixed in the signal band close to the low frequency side and high frequency side of the pass band. ing.

  An example of such a conventional multilayer stripline filter is disclosed in Patent Document 1. FIG. 11 is a circuit configuration diagram, FIG. 12 is a perspective plan view, and FIG. 13 is a cross-sectional view of a conventional multilayer stripline filter disclosed in Patent Document 1. FIGS. 13A and 13B are cross-sectional views taken along lines a-a ′ and b-b ′ shown in FIG. 12, respectively.

  As shown in FIG. 11, the conventional multilayer stripline filter is composed of tip short-circuited lines 121 to 125 and tip-opened lines 131 to 135. And the parallel resonance circuit B1 is formed by connecting the front end short circuit line 121 and the front end open line 131 in parallel. Further, the tip short-circuit line 122 and the tip open line 132 are connected in parallel to form a parallel resonance circuit B2. Further, the tip short circuit line 123 and the tip open line 133 are connected in parallel to form a parallel resonance circuit B3. Moreover, the tip short circuit line 124 and the tip open line 134 are connected in parallel to form a parallel resonance circuit B4. Further, the tip short circuit line 125 and the tip open line 135 are connected in parallel to form a parallel resonance circuit B5.

  One terminal of the parallel resonance circuit B2 is grounded via the parallel resonance circuit B1 and one of the input / output terminals is connected, and the other terminal of the parallel resonance circuit B2 is grounded via the parallel resonance circuit B3. And one terminal of the parallel resonant circuit B4 is connected, and the other terminal of the parallel resonant circuit B4 is grounded via the parallel resonant circuit B5 and the other input / output terminal is connected to form a bandpass filter. is doing.

  In this configuration, in general, in order to narrow the pass band of the bandpass filter, the characteristic impedances ZL1b, ZL3b, and the short-circuited ends 121, 123, and 125 that form the grounded parallel resonant circuits B1, B3, and B5, ZL5b and the characteristic impedances ZC1b, ZC3b, ZC5b of the open-ended lines 121, 123, 125 are reduced, or the short-circuited lines 122 forming the parallel resonant circuits B2, B4 connected in series between the input and output terminals, It is necessary to reduce the characteristic impedances ZL2b and ZL4b of 124 and the characteristic impedances ZC2b and ZC4b of the open-ended lines 132 and 134.

  However, in order to move the attenuation pole near the narrow pass band closer to the pass band in the pass frequency band, the characteristic impedance of the grounded parallel resonant circuits B1, B3, B5 is increased, or Since it is necessary to reduce the characteristic impedance of the parallel resonant circuits B2, B4 connected in series between the input and output terminals, the characteristic impedance of the grounded parallel resonant circuits B1, B3, B5 tends to conflict with the narrowing of the band. It is in.

Therefore, in order to secure the necessary passband and realize narrowing with an attenuation pole in the vicinity of the passband, the characteristic impedance of the grounded parallel resonant line is also connected in series between the input and output terminals. A narrow-band filter with a steep attenuation pole in the vicinity of the passband is achieved by reducing both the characteristic impedance of the parallel resonant lines and making their size sufficiently smaller than the input / output impedance of the filter circuit. It was realized.
JP-A-10-276005

  However, with an increase in information transmission capacity in recent years, wireless communication devices have become insufficient in the conventional frequency band, and the information transmission capacity has been secured by expanding the use bandwidth with higher frequency and wider band. . Therefore, a filter having a wide pass band and having an attenuation pole in the vicinity of the pass band has been demanded.

  In such a situation, in the conventional multilayer stripline filter, in order to widen the pass band and obtain an attenuation pole in the vicinity of the pass band, it is necessary to increase the characteristic impedance of the grounded parallel resonant line. In order to increase the characteristic impedance of the grounded parallel resonant line, it is necessary to increase the thickness of the dielectric layers 131 and 133 shown in FIG. Therefore, there is a problem that it is difficult to reduce the size and thickness of the filter.

  The present invention has been devised in view of the above problems, and has an object of having a first attenuation pole in the vicinity of the low frequency side of the passband and a second attenuation pole in the vicinity of the high frequency side. In a filter device composed of laminated stripline filters with frequency band characteristics, the increase in the characteristic impedance of the line due to the widening of the passband of the filter is reduced, resulting in a reduction in the increase in thickness, resulting in a reduction in size and thickness Is to provide a filter device that is easy to handle.

  The filter device of the present invention includes first and second ground electrodes disposed so as to face each other, and first to fifth dielectric layers sequentially stacked between the first and second ground electrodes, First to fourth conductor patterns, which are sequentially formed between the first to fifth dielectric layers and have a short-circuited end and an open end electrically connected to the first and second ground electrodes. Each of the conductor patterns facing each other with the dielectric layer of the first to fourth conductor patterns sandwiched between the first ground electrode and the first conductor pattern. The second to fourth parallel resonant circuits are formed by each of the groups, and the fifth parallel resonant circuit is formed by the second ground electrode and the fourth conductor pattern. Along the outer periphery other than the short-circuit end, the first A through conductor having one end connected to the first conductor pattern is formed, and the fourth dielectric layer is formed along an outer periphery of the third conductor pattern other than the short-circuited end. And a through conductor having one end connected to the fourth conductor pattern is formed.

  In the filter device according to the present invention, in the configuration described above, between the second dielectric layer and the third dielectric layer, the other end of the through conductor penetrating the second dielectric layer is provided. A fifth conductor pattern is formed which is connected and has a shape along the through conductor, and penetrates the fourth dielectric layer between the third dielectric layer and the fourth dielectric layer. A sixth conductor pattern connected to the other end of the through conductor and formed along the through conductor is formed, and the fifth conductor pattern and the sixth conductor pattern form the third dielectric layer. It is characterized by being sandwiched and opposed.

  In the filter device according to the present invention, the length from the short-circuit end to the open end of the first to fourth conductor patterns in each of the above configurations is ½ or less of the wavelength of the center frequency of the passband. It is a feature.

  In the filter device according to the present invention, in each of the above configurations, the first and fourth conductor patterns are wider than the second and third conductor patterns, and the second and third conductor patterns are It is arranged so as to overlap the entire surface in plan view.

  According to the filter device of the present invention, the first parallel resonant circuit is formed by the first ground electrode and the first conductor pattern, and the respective conductors facing each other with the dielectric layers of the first to fourth conductor patterns interposed therebetween The second to fourth parallel resonant circuits are formed by the pattern sets, and the fifth parallel resonant circuit is formed by the second ground electrode and the fourth conductor pattern. Since the increase in impedance can be reduced and the increase in the thickness of the dielectric layer due to the increase in characteristic impedance can be reduced, it is possible to provide a filter device that can be easily reduced in size, and in addition to the short-circuited end of the second conductor pattern A through-conductor is formed along the outer circumference of the third conductor pattern, the through-conductor being formed through the second dielectric layer and having one end connected to the first conductor pattern. A through conductor that passes through the fourth dielectric layer along one end and is connected to the fourth conductor pattern is formed along the first conductor electrode and the second conductor pattern by the through conductor. The generation of stray capacitance can be eliminated by preventing the electromagnetic coupling between the second ground electrode and the third conductor pattern, so that the characteristics of the second to fourth resonance circuits due to the stray capacitance can be eliminated. It is possible to provide a high-performance filter device that can be reduced in size and thickness and has a wide pass band and a steep attenuation characteristic in the vicinity of the pass band.

  Further, according to the filter device of the present invention, the through conductor is connected between the second dielectric layer and the third dielectric layer and connected to the other end of the through conductor that penetrates the second dielectric layer. A fifth conductor pattern having a shape along the first dielectric layer is formed, and is connected between the third dielectric layer and the fourth dielectric layer to the other end of the through conductor penetrating the fourth dielectric layer. Since the sixth conductor pattern having a shape along the through conductor is formed and the fifth conductor pattern and the sixth conductor pattern are opposed to each other with the third dielectric layer interposed therebetween, the first parallel pattern is formed. Since the resonance circuit and the fifth parallel resonance circuit are connected by a capacitor and an inductor, the phase of the transmitted signal can be changed. Therefore, since the phase can be changed abruptly at a frequency lower than the pass band and at a frequency higher than the pass band, an attenuation pole can be provided at a position closer to the pass band on the lower frequency side and the higher frequency side than the pass band. Therefore, a high-performance filter device having a steeper attenuation characteristic can be provided.

  According to the filter device of the present invention, when the length from the short-circuit end to the open end of the first to fourth conductor patterns is ½ or less of the wavelength of the center frequency of the pass band, the conductor pattern is Since the short-circuited end line and the open-ended line are configured to have a length that is likely to cause resonance, which is not more than ¼ of the wavelength of the center frequency of the passband, it is easy to operate as a parallel resonant circuit and can be downsized. An easier filter device can be provided.

  According to the filter device of the present invention, the first and fourth conductor patterns are wider than the second and third conductor patterns and overlap the entire surfaces of the second and third conductor patterns in plan view. When the first and second conductor patterns overlap with each other in the plan view, the first and fourth conductor patterns are surely located between the first and second ground electrodes and the second and third conductor patterns. Therefore, stray capacitance that occurs between the first and second ground electrodes and the second and third conductor patterns and causes deterioration of characteristics can be further reduced, and a higher performance filter device is provided. be able to.

  The filter device of the present invention will be described in detail below. 1 and 5 to 8 are perspective perspective views showing an example of an embodiment of the filter of the present invention. FIG. 2 is a plan view of each layer in the filter device of the present invention shown in FIG. 3) is a plan view showing an example, FIG. 3 is a perspective plan view in which the overlapping of conductor patterns in the filter device of the embodiment of the filter device of the present invention is viewed in plan, and FIGS. 4 and 9 are views of the filter device of the present invention. It is a circuit block diagram of an example of embodiment.

  1 to 3 and 5 to 8, 11 is a first ground electrode, 21 is a first dielectric layer disposed under the first ground electrode, and 22 is a first dielectric layer 21. A second dielectric layer laminated underneath, 23 a third dielectric layer laminated under the second dielectric layer 22, and 24 laminated under the third dielectric layer 23 4th dielectric layer, 25 is a 5th dielectric layer laminated | stacked under the 4th dielectric layer 24, 12 is the 2nd ground electrode arrange | positioned under the 5th dielectric layer . 31 is a first conductor pattern disposed between the first and second dielectric layers 21 and 22, and 32 is a second conductor disposed between the second and third dielectric layers 22 and 23. Pattern 33 is a third conductor pattern disposed between the third and fourth dielectric layers 23 and 24, and 34 is a fourth conductor disposed between the fourth and fifth dielectric layers 24 and 25. , 35 is disposed between the second and third dielectric layers 22, 23, and 35 is disposed between the third and fourth dielectric layers 23, 24. It is a 6th conductor pattern. 41 includes a penetrating conductor that penetrates the second dielectric layer 22 along the outer periphery of the second conductor pattern 32 and has one end connected to the first conductor pattern 31; A penetrating conductor that penetrates the fourth dielectric layer 24 along the outer periphery and has one end connected to the fourth conductor pattern 34.

  As shown in FIG. 2, the first to fourth conductor patterns 31 to 34 are connected to the first to fourth tip short-circuit electrodes 31b to 34b and the first to fourth tip open electrodes 31a to 34a. A short-circuit end having one end on the first to fourth tip short-circuit electrodes 31b to 34b side connected to the first and second ground electrodes 11 and 12 by a connection conductor (not shown); It has an open end where the other ends on the first to fourth tip open electrodes 31a to 34a side are open.

  Further, the first ground electrode 1 and the first conductor pattern 31 form the first parallel resonance circuit A1 shown in FIG. 4, and the first conductor pattern 31 and the second conductor pattern 32 form the second parallel resonance. In the circuit A2, the third parallel resonance circuit A3 is formed by the second conductor pattern 32 and the third conductor pattern 33, and the fourth parallel resonance circuit A4 is formed by the third conductor pattern 33 and the fourth conductor pattern 34. Thus, a fifth parallel resonant circuit A5 is formed by the second ground electrode 2 and the fourth conductor pattern 34.

  Specifically, the first ground electrode 11 and the first tip short-circuit electrode 31a constitute the first tip short-circuit line 101 shown in FIG. 4, and the second ground electrode 12 and the fifth tip short-circuit electrode 34a A fifth tip short-circuit line 105 is configured. The first tip short-circuit electrode 31a and the second tip short-circuit electrode 32a constitute a second tip short-circuit line 102, and the second tip short-circuit electrode 32a and the third tip short-circuit electrode 33a constitute a third tip short-circuit. The line 103 is configured, and the third tip short-circuit electrode 33a and the fourth tip short-circuit electrode 34a constitute the fourth tip short-circuit line 104.

  Similarly, the first ground electrode 11 and the first tip open electrode 31b constitute the first tip open line 111 shown in FIG. 4, and the second ground electrode 12 and the fifth tip open electrode 34b constitute the first tip open electrode 31b. A fifth open-ended line 115 is configured. The first tip open electrode 31b and the second tip open electrode 32b constitute a second tip open line 112, and the second tip open electrode 32b and the third tip open electrode 33b open the third tip open. A line 113 is formed, and a fourth tip open line 114 is constituted by the third tip open electrode 33b and the fourth tip open electrode 34b.

  Then, the tip short circuit line 101 and the tip open line 111 are connected in parallel to form a parallel resonance circuit A1 shown in FIG. Moreover, the parallel short circuit line 102 and the open end line 112 are connected in parallel to form a parallel resonance circuit A2. In addition, the parallel short circuit 103 and the open circuit 113 are connected in parallel to form a parallel resonance circuit A3. Further, the parallel short circuit 104 and the open end line 114 are connected in parallel to form a parallel resonance circuit A4. Moreover, the parallel resonance circuit A5 is formed by connecting the tip short circuit line 105 and the tip open line 115 in parallel.

  Since the filter device of the present invention is configured by such first to fifth parallel resonant circuits A1 to A5, it is possible to reduce an increase in characteristic impedance of a pattern due to a wider band than the conventional configuration, and as a result Thus, an increase in thickness is reduced, and a filter and a filter device that can be easily reduced in size and thickness are obtained. Further, the through conductor 41 penetrates the second dielectric layer 22 along the outer periphery of the second conductor pattern 32, one end is connected to the first conductor pattern 31, and the outer periphery of the third conductor pattern 33 is The first dielectric layer 24 passes through the fourth dielectric layer 24 and one end thereof is connected to the fourth conductor pattern 34, so that the through conductor 41 connects the first ground electrode 11 and the second conductor pattern 32. Since the stray capacitance can be eliminated by preventing the electromagnetic coupling between the second ground electrode and the third conductor pattern 33, the characteristics of the second to fourth resonance circuits due to the stray capacitance can be eliminated. A filter device as a high-performance band-pass filter having a wide pass band and a steep attenuation characteristic in the vicinity of the pass band, in which the decrease is suppressed.

  In the filter device of the present invention, as shown in FIGS. 7 and 8, the second dielectric layer 22 is provided between the second dielectric layer 22 and the third dielectric layer 23 in the above configuration. A fifth conductor pattern 35 connected to the other end of the penetrating through conductor 41 and formed along the through conductor 41 is formed between the third dielectric layer 23 and the fourth dielectric layer 24. The sixth conductor pattern 36 connected to the other end portion of the through conductor 41 penetrating the fourth dielectric layer 24 and having a shape along the through conductor 41 is formed, and the fifth conductor pattern 35 and the sixth conductor pattern 35 are formed. The conductor pattern 36 is preferably opposed to the third dielectric layer 23. As a result, as shown in the circuit configuration diagram of FIG. 9, the first parallel resonant circuit A1 and the fifth parallel resonant circuit A5 are connected by the capacitor C and the inductor L, so that the transmission is performed. The signal phase can be changed. Therefore, since the phase can be changed abruptly at a frequency lower than the pass band and at a frequency higher than the pass band, the first attenuation pole is located closer to the low frequency side of the pass band and closer to the high frequency side. A high-performance filter device having a steep attenuation characteristic can be provided.

  Moreover, in the said structure, it is preferable that the length from the short circuit end of the 1st thru | or 4th conductor patterns 31-34 to an open end is 1/2 or less of the wavelength of the center frequency of the passband by this filter apparatus. . As a result, the first to fourth conductor patterns 31 to 34 become the tip short-circuited lines 101 to 105 and the tip-opened lines 111 to 115 having a length equal to or less than ¼ of the wavelength of the center frequency of the passband. Therefore, since it easily operates as a parallel resonant circuit, a small filter device can be easily provided.

  Further, as shown in FIG. 3, the first and fourth conductor patterns 31, 34 are wider than the second and third conductor patterns 32, 33, and the second and third conductor patterns 32, 33 are formed. It is preferable to be disposed so as to overlap the entire surface of the substrate in plan view. As a result, the first and fourth ground patterns 11 and 34 overlap with the first and second ground electrodes 11 and 12 and the second and third conductor patterns 32 and 33 in a plan view. Therefore, the stray capacitance that causes the characteristic deterioration generated between the second and third conductor patterns 32 and 33 and the first and second ground electrodes 1 and 2 is further reduced. And a high-performance filter device can be provided.

  Examples of the first to fifth dielectric layers 21 to 25 used in the filter device of the present invention include ceramic materials such as alumina, mullite, aluminum nitride and glass ceramics, or ethylene tetrafluoride resin (polytetrafluoroethylene; PTFE), tetrafluoroethylene-ethylene copolymer resin (tetrafluoroethylene-ethylene copolymer resin; ETFE), tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin (tetrafluoroethylene-perfluteroalkyl vinyl ether copolymer resin) Organic resin materials such as fluorine resin such as PFA), glass epoxy resin, and polyimide are used. The shapes and dimensions (thickness, width, and length) of the first to fifth dielectric layers 21 to 25 made of these materials are set according to the frequency and application used. In the case of a ceramic material, glass ceramics that can be simultaneously fired with a conductor material made of a low-resistance metal such as Au, Ag, or Cu that can transmit a higher frequency signal is preferable.

  The first and second ground electrodes 11 and 12 and the first to sixth conductor patterns 31 to 36 in the filter device of the present invention are used when the first to fifth dielectric layers 21 to 25 are made of a ceramic material. , W, Mo, Mo—Mn, Au, Ag, Cu, etc. When the first to fifth dielectric layers 21 to 25 are made of a resin material, a metal layer formed by a thick film printing method, various thin film forming methods, a plating method, a foil transfer method, or the like, A plated layer formed on a metal layer, for example, a Cu layer, a Cr—Cu alloy layer, a Ni—Cr layer deposited on a Cr—Cu alloy layer, a Ni—Cr layer on a Ta 2 N layer Alloy layer and Au plating layer deposited, Pt layer and Au plating layer deposited on Ti layer, Pt layer and Au plating layer deposited on Ni-Cr alloy layer, etc. Is mentioned. The thickness and width are set according to the frequency and application of the transmitted high-frequency signal.

  The first to fifth dielectric layers 21 to 25, the first and second ground electrodes 11 and 12, and the first to sixth conductor patterns 31 to 36 may be formed by a conventionally known method. For example, if the first to fifth dielectric layers 21 to 25 are made of glass ceramics, first, glass ceramic green sheets to be the dielectric layers 21 to 25 are prepared, and screen printing is performed on the green sheets. First and second ground electrodes 11 and 12 and first to sixth conductor patterns 31 to 36 are formed by printing and applying a conductor paste such as Cu in a predetermined shape. Next, a laminate is produced by stacking and pressing the green sheets on which the first and second ground electrodes 11 and 12 and the first to sixth conductor patterns 31 to 36 are formed. It is formed by firing at 850 to 1000 ° C. Thereafter, a plating film such as Ni plating or Au plating is formed on the conductor layer exposed on the outer surface. If the first to fifth dielectric layers 21 to 25 are made of an organic resin material, for example, the second ground electrodes 11 and 12 and the first to sixth conductor patterns 31 to 36 are formed on the organic resin sheet. The Cu foil processed into a shape is transferred, and an organic resin sheet to which the Cu foil is transferred is laminated and bonded with an adhesive.

  The connection conductor that connects the first and second ground electrodes 11 and 12 and the short-circuit ends (first to fifth tip short-circuit electrodes 31b to 34b) of the first to fourth conductor patterns 31 to 34 is a first conductor. These are laminated by forming them in the form of through conductors formed in the fifth to fifth dielectric layers 21-25 or side conductors formed on the side surfaces of the first to fifth dielectric layers 21-25. The degree of freedom in designing the filter device formed inside the dielectric layers 21 to 25 is improved, and a smaller and higher performance filter device can be obtained.

  In the case where the first to fifth dielectric layers 21 to 25 are made of glass ceramics, the through conductors and side conductors serving as such connection conductors are the first and second through conductors in the manufacturing method described above. Before forming the ground electrodes 11 and 12 and the first to sixth conductor patterns 31 to 36, a similar conductor paste is printed in a through-hole formed in advance on the green sheet by die machining or laser machining. The side conductors can be formed by filling the same conductor paste after forming a laminate in which the short-circuit ends of the first to fourth conductor patterns 31 to 34 are exposed on the side surfaces. It can be formed by printing on the side surface. Similarly, when the first to fifth dielectric layers 21 to 25 are made of a resin material, an organic resin sheet is used instead of the green sheet, and a through conductor is formed in the through hole by printing or plating a conductor paste. Or a side conductor may be formed by a thin film method or the like. In order to expose the short-circuit ends of the first to fourth conductor patterns 31 to 34 on the side surfaces of the laminate, the short-circuit ends of the first to fourth conductor patterns 31 to 34 are the ends of the green sheet (or organic resin sheet). After the green sheets (organic resin sheets) on which the first to fourth conductor patterns 31 to 34 are formed are stacked, the short-circuit ends of the first to fourth conductor patterns 31 to 34 are formed. The laminated body may be cut so that is exposed to the side surface.

  The through conductor 41 is formed through the second and fourth dielectric layers 22 and 24 along the outer periphery of the second and third conductor patterns 32 and 33 other than the short-circuited ends, respectively, and one end portion of each. Are connected to the first and fourth conductor patterns 31, 34, respectively. When the through conductor 41 is formed as a continuous one, when the through hole for forming the through conductor 41 is formed in the green sheet (or organic resin sheet) by die processing or laser processing, the through hole is formed. Since the green sheet (organic resin sheet) is easily deformed, the through conductor 41 may be divided into a plurality of shapes as shown in FIGS. The number of divisions and the arrangement of the divided through conductors 41 are not particularly limited. In the case where the through conductor 41 has a divided shape, as shown in FIGS. 5 and 8, a large number of cylindrical through conductors 41 used in a normal wiring board may be arranged. These through conductor molds and punching pins can be used, and they can be simultaneously formed by using a method of forming a through hole for a connecting conductor. In this case, as shown in FIG. 6, when the second and third conductor patterns 32 and 33 are arranged in a double or more manner and the through conductors 41 are arranged as far as possible when viewed from the side, the first ground electrode 11 and the second conductor pattern 32 and the coupling between the second ground electrode and the third conductor pattern 33 can be prevented reliably by the through conductor 41 located between them. This is preferable in that the generation of stray capacitance can be eliminated.

  The through conductor 41 may be formed by a method similar to the method of forming the through conductor to be the connection conductor described above. Further, particularly when the through conductor 41 is as shown in FIG. 1 or FIG. 7 or a relatively large one that is not divided, the same thickness as the green sheet (or organic resin sheet) is formed when the through hole is formed. The conductive sheet is stacked on the green sheet (organic resin sheet) and punched out together with the green sheet (organic resin sheet), and the green sheet (organic resin sheet) is punched into the through hole formed by punching. A method of fitting a sheet may be used. When the dielectric layers 21 to 25 are made of a ceramic material, the conductive sheet is produced in the same manner as the green sheet by adding a binder using the same metal powder as the first to sixth conductor patterns 31 to 36, etc. When the dielectric layers 21 to 25 are made of a resin material, a metal foil such as a copper foil may be used.

Specifically, a filter device as a bandpass filter with a center frequency of 4 GHz used in the UWB (Ultra Wide Band) standard, which is a next-generation communication standard, has the form shown in FIG. For example, glass ceramics having a relative dielectric constant of 9.4 is used for the first to fifth dielectric layers 21 to 25, and the first and second ground electrodes 11 and 12, the first to sixth conductor patterns and the through conductor 41 are used. It can be obtained by using Ag metallization. At this time, the thickness of the first dielectric layer is 300 μm, the thickness of the second dielectric layer is 50 μm, the thickness of the third dielectric layer is 300 μm, the thickness of the fourth dielectric layer is 50 μm, The thickness of the dielectric layer is 250 μm, the dimensions of the first and second ground electrodes 11 and 12 are 3.5 mm × 5.5 mm, and the first and fourth conductor patterns 31 and 34 are 0.8 mm × 3.4 mm. The tip short-circuit electrodes 31b, 34b and the 3.0mm × 1.7mm tip open electrodes 31a, 34a are configured so that the length from the short-circuit end to the open end is 5.1 mm, and the second and third conductor patterns 32, 33 is configured such that the length from the short-circuited end to the open end is 4.8 mm by the tip short-circuited electrodes 32b and 33b having dimensions of 0.4 mm × 3.6 mm and the tip-opened electrodes 32a and 33a having 1.1 mm × 1.2 mm. Then, the second and fourth conductor patterns 32 and 33 are spaced apart by 0.1 mm along the outer peripheries of the second and third conductor patterns 32 and 33, respectively. Arranging the through conductors 41 of 0.1mm width through the conductor layer 22, 24. Glass ceramics having a relative dielectric constant of 9.4 include, for example, 50% by mass of crystallized glass mainly composed of PbO, B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ , ZnO and alkaline earth metal oxide as glass components. And what consists of 50 mass% of alumina as a filler component may be used.

  The filter characteristic of the filter device of the present invention in such an example is as shown by a one-dot chain characteristic curve in the diagram of FIG. Further, with respect to the filter characteristics of the filter device of the present invention in such an example, the filter properties obtained in the conventional filter device without the through conductor 41 are as shown by the broken characteristic curve in FIG. Become.

  In such an example of the filter device of the present invention, for example, in order to obtain a filter device having a fifth conductor pattern 35 and a sixth conductor pattern as shown in FIG. A fifth conductor pattern 35 having a width of 0.2 mm is disposed along the outer periphery of the second conductor pattern 32, and a fifth conductor pattern 35 having a width of 0.2 mm is disposed along the outer periphery of the third conductor pattern 33. 6 conductor patterns 36 are arranged. The filter characteristics obtained by adding the fifth conductor pattern 35 and the sixth conductor pattern 36 to the above-described example of the filter apparatus of the present invention are shown by the solid characteristic curve in FIG. It will be something.

  Further, in the filter device having the conventional structure shown in FIGS. 11 to 13, the filter in the filter device obtained by using the same glass ceramics and Ag metallization as the above-described filter device of the present invention for the dielectric layer and the conductor pattern. The characteristics are shown in FIG. 14 by the same diagram as FIG.

  In the diagrams shown in FIGS. 10 and 14, the vertical axis indicates insertion loss (unit: dB), and the horizontal axis indicates frequency (unit: GHz).

  From the filter characteristics shown in FIG. 10 and FIG. 14, the filter characteristic of the filter device of the present invention (shown by a dashed line characteristic curve in FIG. 10) is the filter characteristic of the conventional filter device (shown by the solid characteristic curve in FIG. 14). Compared with the filter characteristics (shown by the broken line characteristic curve in FIG. 10) of the filter device that has a very wide pass band compared with the filter device that does not have the through conductor 41 even in the same circuit configuration. The filter characteristics of the filter device of the present invention having a wider passband and a steep attenuation characteristic and further provided with the fifth and sixth conductor patterns 35 and 36 (shown by a solid characteristic curve in FIG. 10). ) Indicates that the attenuation poles on the low frequency side and the high frequency side of the pass band are closer to the pass band, and have a steeper attenuation characteristic.

It is a see-through | perspective perspective view which shows an example of embodiment of the filter apparatus of this invention. It is the top view which planarly viewed each layer in an example of embodiment of the filter apparatus of this invention shown in FIG. It is a see-through plan view showing the overlapping of conductor patterns in an example of an embodiment of the filter device of the present invention in plan view. It is a circuit block diagram which shows an example of embodiment of the filter apparatus of this invention. It is a see-through | perspective perspective view which shows an example of embodiment of the filter apparatus of this invention. It is a see-through | perspective perspective view which shows an example of embodiment of the filter apparatus of this invention. It is a see-through | perspective perspective view which shows an example of embodiment of the filter apparatus of this invention. It is a see-through | perspective perspective view which shows an example of embodiment of the filter apparatus of this invention. It is a circuit block diagram which shows an example of embodiment of the filter apparatus of this invention. It is a diagram which shows the example of the passage characteristic in this invention and the conventional filter apparatus. It is a circuit block diagram which shows the example of the conventional filter apparatus. It is a perspective top view which shows the example of the conventional filter apparatus. It is sectional drawing which shows the example of the conventional filter apparatus shown in FIG. 11, (a) is a sectional view on the a-a 'line, (b) is sectional drawing on the b-b' line. It is a diagram which shows the example of the passage characteristic in the conventional filter apparatus.

Explanation of symbols

11: First ground electrode
12 ... Second ground electrode
21 ... first dielectric layer
22 ... Second dielectric layer
23 ... Third dielectric layer
24 ... Fourth dielectric layer
25. Fifth dielectric layer
31 ... 1st conductor pattern
32 ... Second conductor pattern
33 ... Third conductor pattern
34 ... Fourth conductor pattern
35 ... Fifth conductor pattern
36 ... Sixth conductor pattern
41 ... Penetration conductor

Claims (4)

First and second ground electrodes arranged to face each other, first to fifth dielectric layers sequentially stacked between the first and second ground electrodes, and the first to fifth dielectric layers 1st to 4th conductor patterns having a short-circuited end and an open-ended end sequentially formed between the dielectric layers and electrically connected to the first and second ground electrodes, The first parallel resonant circuit is formed by the ground electrode and the first conductor pattern, and the second to fourth pairs of conductor patterns facing each other across the dielectric layer of the first to fourth conductor patterns, respectively. A fourth parallel resonant circuit is formed, and a fifth parallel resonant circuit is formed by the second ground electrode and the fourth conductor pattern, and is along the outer periphery of the second conductor pattern other than the short-circuited end. Through the second dielectric layer and A through conductor having a portion connected to the first conductor pattern is formed, penetrates the fourth dielectric layer along an outer periphery other than the short-circuited end of the third conductor pattern, and one end thereof is the first conductor pattern. A filter device, wherein a through conductor connected to the four conductor patterns is formed. A fifth conductor is connected between the second dielectric layer and the third dielectric layer and connected to the other end of the through conductor passing through the second dielectric layer, and has a shape along the through conductor. Is formed, and is connected between the third dielectric layer and the fourth dielectric layer to the other end of the through conductor that penetrates the fourth dielectric layer, and the through conductor A sixth conductor pattern having a shape extending along the line is formed, and the fifth conductor pattern and the sixth conductor pattern are opposed to each other with the third dielectric layer interposed therebetween. 2. The filter device according to 1. 3. The filter according to claim 1, wherein a length from the short-circuit end to the open end of each of the first to fourth conductor patterns is ½ or less of a wavelength of a center frequency of a pass band. apparatus. The first and fourth conductor patterns are wider than the second and third conductor patterns, and are arranged so as to overlap the entire surfaces of the second and third conductor patterns in plan view. 4. The filter device according to claim 1, wherein the filter device is characterized in that:

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