JP2009218756A - Laminated type band-pass filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminated type band-pass filter which can secure sufficient inductive coupling using a conductor pattern arranged face-to-face in a laminating direction, and obtain a large attenuation amount at a high frequency side of the pass band. <P>SOLUTION: This laminated type band-pass filter is provided with: a lamination body 10 which is formed by laminating a plurality of dielectric layers; a first conductive inductor which is formed including via-hole conductors 60, 62 which pierce the dielectric layer in a laminating direction and a conductor pattern 48 arranged on the dielectric layer, and constitute a first resonator; a second conductive inductor which is formed including via-hole conductors 61, 63 which pierce the dielectric layer in a laminating direction and a conductor pattern 49 arranged on the dielectric layer, and constitute a second resonator. The conductor pattern 48 of the first conductive inductor and the conductor pattern 49 of the second conductive inductor are arranged face-to-face in the laminating direction separated from each other at a predetermined space by which they mutually induction-coupled to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a multilayer bandpass filter mounted on a high-frequency circuit such as a portable device, and more particularly to a multilayer bandpass filter in which a resonator is configured using a conductor pattern formed on a multilayer multilayer substrate. .

In a high frequency circuit of a portable device, a band pass filter that removes unnecessary frequency components is used. For example, as shown in Patent Documents 1 and 2, a multilayer bandpass filter including a resonator configured on a multilayer laminated substrate has been proposed. Patent Document 1 discloses a method of electromagnetically coupling conductor patterns of a plurality of dielectric layers to form a plurality of spiral electrodes that serve as inductor conductors, thereby forming a resonator of a multilayer bandpass filter. Yes. According to this method, the length of the spiral electrode can be adjusted to match the resonance frequency by adjusting the number of dielectric layers on which the conductor pattern is formed. Therefore, the overall size of the multilayer bandpass filter can be reduced as compared with the case where the conductor pattern is formed on one dielectric layer. Japanese Patent Application Laid-Open No. 2004-228561 discloses a method of configuring a resonator using an inductor conductor formed by via holes penetrating a plurality of dielectric layers.
Japanese Patent No. 2988500 Japanese Patent No. 3127792

  A typical multilayer bandpass filter includes two resonators that match a passband, and each resonator can be configured using an inductor conductor. When designing a multilayer bandpass filter, it is important to adjust the respective inductor conductors to a desired inductance and appropriately adjust the mutual inductance of the two to provide sufficient electromagnetic coupling. However, when a multilayer bandpass filter is configured by the method of Patent Document 1, the inductances of the two spiral electrodes serving as the two inductor conductors can be easily increased, but the electromagnetic coupling between the two is appropriately set. It is difficult to adjust. This is because the inductive coupling between patterns is inevitably reduced because the arrangement in which two spiral electrodes are arranged in the plane direction is employed. Also, in the case of forming a multilayer bandpass filter by the method of Patent Document 2, since the two inductor conductors are respectively formed by via holes, there is a limit to increasing each inductance and the mutual inductance between them. It is difficult to properly adjust the electromagnetic coupling between the two.

  In the case where the electromagnetic coupling between the two inductor conductors constituting the resonator is insufficient, for example, a configuration in which a capacitive element adjacent to both is provided can be considered. However, in this case, the capacitive coupling between the two inductor conductors becomes strong, and the multilayer bandpass filter has a low-band polar filter characteristic. Therefore, it is a disadvantageous configuration when realizing a filter characteristic that sufficiently attenuates an unnecessary frequency component in a high band in the multilayer bandpass filter.

  Therefore, the present invention has been made to solve these problems, and when a pair of inductor conductors constituting each resonator is formed on a multilayer substrate, it is sufficient to use a conductor pattern opposed to each other in the stacking direction. It is an object of the present invention to provide a multilayer bandpass filter that can secure inductive coupling and can realize filter characteristics with a large attenuation on the high-pass side of the passband.

  In order to solve the above problems, a multilayer bandpass filter according to the present invention is a multilayer bandpass filter including a plurality of electromagnetically coupled resonators, in which a plurality of dielectric layers are laminated, A first inductor conductor forming a first resonator formed by including a via-hole conductor penetrating the dielectric layer in a laminating direction and a conductor pattern disposed on the dielectric layer, and laminating the dielectric layer A via hole conductor penetrating in a direction and a conductor pattern disposed on the dielectric layer, and a second inductor conductor constituting a second resonator, the conductor pattern of the first inductor conductor And the conductor pattern of the second inductor conductor are arranged opposite to each other in the stacking direction with a predetermined interval inductively coupled to each other.

  According to the multilayer bandpass filter of the present invention, a pair of inductor conductors constituting a pair of resonators are formed by via-hole conductors in a stacking direction and a conductor pattern in a planar direction, respectively, and the conductor patterns of each other are stacked in the stacking direction. A large inductive coupling occurs due to the opposing arrangement. Therefore, the electromagnetic coupling between a pair of inductor conductors is dominated by inductive coupling between conductor patterns compared to capacitive coupling, so that a filter characteristic having an attenuation pole on the high band side of the pass band should be realized. Can do. In addition, since the pair of inductor conductors can be formed by widely using the plane of the dielectric layer, the area required for obtaining a predetermined inductance can be reduced.

  In the present invention, the first inductor conductor is configured by connecting a first short-circuit-end-side inductor conductor and a first open-end-side inductor conductor, and the second inductor-conductor is configured as a second short-circuit-end. The inductor conductor on the side and the second open-end inductor conductor may be connected to each other.

  In the present invention, a first node between the first short-circuit end side inductor conductor and the first open-end side inductor conductor, the second short-circuit end-side inductor conductor and the second open-end side A first capacitor may be connected between the second node between the inductor conductors.

  In the present invention, a second capacitor may be connected between the input terminal and the first node, and a third capacitor may be connected between the output terminal and the second node.

  In the present invention, a first trap circuit is inserted between an input terminal and the first node, a second trap circuit is inserted between an output terminal and the second node, and the first trap circuit is inserted. The resonance frequency of each of the second trap circuits may be set on the low band side of the pass band.

  In the present invention, the conductor pattern of the first short-circuit end side inductor conductor and the conductor pattern of the second short-circuit end side inductor conductor may be arranged to face each other in the stacking direction.

  In the present invention, each of the conductor patterns opposed to the first inductor conductor and the second inductor conductor may be formed in a spiral pattern. In this case, each of the spiral patterns may be formed across two or more of the dielectric layers, and the conductor patterns may be arranged to face each other in the stacking direction in each of the dielectric layers.

  According to the present invention, a multilayer bandpass filter includes a pair of inductor conductors formed by via-hole conductors in the stacking direction and conductor patterns in the planar direction, and is disposed so as to face each other so that inductive coupling between the respective conductor patterns is large Therefore, it is possible to realize a filter characteristic of a high-frequency polarized type based on inductive coupling rather than a low-frequency polarized type based on capacitive coupling. Therefore, when the multilayer bandpass filter of the present invention is used, it is possible to sufficiently secure the attenuation amount on the high band side of the passband that is generally problematic. In addition, since a pair of inductor conductors can form a conductor pattern using a wide dielectric layer, a predetermined inductance value can be obtained in a small area, and the multilayer bandpass filter can be miniaturized. it can.

  Embodiments of the present invention will be described with reference to the drawings. Below, three embodiment is described regarding the laminated type band pass filter mounted in the high frequency circuit of a portable apparatus.

[First Embodiment]
FIG. 1 is a diagram illustrating an equivalent circuit of the multilayer bandpass filter according to the first embodiment. The multilayer band-pass filter shown in FIG. 1 includes five capacitors C10, C11, C12, C13, and C14 and four inductor conductors L10, L11, L12, and L13. The input signal input from the input terminal Tin passes through a predetermined frequency band, and operates so as to block unnecessary frequency components on the low frequency side and the high frequency side.

  In the configuration of FIG. 1, three capacitors C10, C12, and C14 are connected in series between the input terminal Tin and the output terminal Tout. A node N10 between the capacitors C10 and C12 is connected to a first resonator composed of a pair of inductor conductors L10 and L11, and a node N11 between the capacitors C12 and C14 is connected to a pair of inductor conductors L12, Connected to the second resonator composed of L13. In the first resonator, the inductor conductor L10 on the open end side is connected between the node N10 and the capacitor C11, one end of the capacitor C11 is connected to the ground, and the inductor conductor L11 on the short-circuit end side is connected between the node N10 and the ground. Connected to. In the second resonator, the inductor conductor L12 on the open end side is connected between the node N11 and the capacitor C13, one end of the capacitor C13 is connected to the ground, and the inductor conductor L13 on the short circuit end side is connected to the node N11 and the ground. Connected between.

  The inductance values of the inductor conductors L10, L11, L12, and L13 are determined depending on the conductor pattern formed on the multilayer substrate as will be described later. Further, between the first resonator and the second resonator, electromagnetic coupling is generated between the inductor conductors L10 and L12 on the open end side, and electromagnetic is generated between the inductor conductors L11 and L13 on the short circuit end side. Binding occurs. These electromagnetic couplings are mainly generated based on the fact that some of the conductor patterns that form the inductor conductors L10 to L13 are opposed to each other in the stacking direction of the stacked substrate. For the inductor conductors L10 to L13, desired filter characteristics can be imparted to the multilayer bandpass filter by appropriately adjusting the inductance value and the electromagnetic coupling, details of which will be described later.

  Here, the relationship between the filter characteristics and the coupling between the resonators will be described with respect to the multilayer bandpass filter of the first embodiment. FIG. 2 shows a model of the main part of the equivalent circuit of FIG. FIG. 2A shows a circuit model including a pair of inductor conductors LA and LB. For example, the relationship between the inductor conductors L11 and L13 in FIG. 1 corresponds to FIG. The coupling between the inductor conductors LA and LB can be expressed by a capacitance C and a mutual inductance M (inductive coupling). The inductor conductors LA and LB in FIG. 2A can be replaced with a parallel circuit of inductance and capacitance, respectively. Therefore, as shown in FIG. 2B, the inductor conductor LA is replaced with a parallel circuit composed of an inductance L1 and a capacitor C1, and the inductor conductor LB is replaced with a parallel circuit composed of an inductance L2 and a capacitor C2.

  At this time, the relationship between the two inductances L1 and L2 and the mutual inductance M is equivalent to a circuit including the inductance L1-M, the inductance L2-M, and the mutual inductance M, as shown in FIG. Note that when Y-Δ conversion is performed on the circuit in FIG. 2C, the circuit can be converted into a circuit including three inductances La, Lb, and Lc, as shown in FIG.

  The relationship among the capacitors C, C1, C2, inductances L1, L2, mutual inductance M and filter characteristic parameters in FIG. 2B will be described. First, the two frequencies F1 and F2 corresponding to the convex poles of the pass band can be expressed as follows.

  Further, the attenuation pole position F in the filter characteristics is obtained by the following equation.

  Note that the inductances La, Lb, and Lc in FIG. 2D can be expressed as follows.

  When designing a band-pass filter, desirable values for the inductances L1 and L2 and the capacitors C1 and C2 are determined depending on a preset passband. On the other hand, the attenuation pole position F changes due to the effects of the mutual inductance M and the capacitance C with respect to the values of the applied inductances L1 and L2. As shown in Equation 3, when the mutual inductance M decreases and the capacitance C increases, the attenuation pole position F decreases. Therefore, when realizing a filter characteristic that increases the attenuation on the high frequency side of the passband, it is desirable to increase the mutual inductance M and decrease the capacitance C.

  Next, a specific structure of the multilayer bandpass filter according to the first embodiment will be described with reference to FIGS. FIG. 3 is an external perspective view of the multilayer body 10 in which the multilayer bandpass filter according to the first embodiment is configured. The laminated body 10 shown in FIG. 3 is formed by laminating a large number of dielectric layers (eight layers) on which conductor patterns are formed. An input terminal Tin, an output terminal Tout, and six ground terminals Tg are formed on the side surface of the multilayer body 10 and can be externally connected. Each of these terminals is connected to the conductor pattern inside the laminate 10.

  4 and 5 are plan views showing the structure of each layer of the laminate 10. In the laminated body 10, dielectric layers M1 to M8 using ceramic green sheets are laminated in order from the lower layer. In the dielectric layers M1 to M8, a large number of conductor patterns are formed, and a large number of via hole conductors penetrating in the stacking direction are formed in order to connect the conductor patterns of the respective layers. The thickness and dielectric constant of each of the dielectric layers M1 to M8 are appropriately set according to necessary electrical characteristics. Note that each via-hole conductor is partially shown by a curve (see FIG. 5), but is actually formed linearly in the stacking direction.

  First, as shown in FIG. 4, a wide ground pattern 40 is formed in the lowermost dielectric layer M1, and its outer edge is connected to the six ground terminals Tg in FIG. Note that a conductor pattern is formed at the position of each terminal in FIG. 3 on the back surface (not shown) of the dielectric layer M1.

  On the dielectric layer M2, the capacitor electrode 41 of the capacitor C11 and the capacitor electrode 42 of the capacitor C13 are formed. These capacitor electrodes 41 and 42 are arranged to face the ground pattern 40 in the lower layer. A via hole conductor 60 extending upward is connected to one end of the capacitor electrode 41, and a via hole conductor 61 extending upward is connected to one end of the capacitor electrode 42. The via-hole conductor 60 becomes a part of the inductor conductor L10 on the open end side of one resonator, and the via-hole conductor 61 becomes a part of the inductor conductor L12 on the open end side of the other resonator.

  A capacitor electrode 43 of the capacitor C12 is formed on the dielectric layer M3. A capacitor electrode 44 on the node N10 side of the capacitors C10 and C12 and a capacitor electrode 45 on the node N11 side of the capacitors C12 and C14 are formed on the dielectric layer M4. These capacitor electrodes 44 and 45 are disposed opposite to the capacitor electrode 43 in the lower layer. The via-hole conductors 60 and 61 extend upward through the capacitor electrodes 44 and 45.

  Next, as shown in FIG. 5, a capacitor electrode 46 on the input terminal Tin side of the capacitor C10 and a capacitor electrode 47 on the output terminal Tout side of the capacitor C14 are formed on the dielectric layer M5. The capacitor electrodes 46 and 47 are disposed to face the lower capacitor electrodes 44 and 45.

  On the dielectric layer M6, a conductor pattern 48 is formed which becomes a part of the inductor conductor L11 on the short-circuit end side. The above-described via-hole conductor 60 extending downward is connected to one end of the conductor pattern 48, and the via-hole conductor 62 extending upward is connected to the other end of the conductor pattern 48.

  In the dielectric layer M7, a conductor pattern 49 is formed which becomes a part of the inductor conductor L13 on the short-circuit end side. The above-described via hole conductor 61 extending downward is connected to one end of the conductor pattern 49, and the via hole conductor 63 extending upward is connected to the other end of the conductor pattern 49.

  A wide ground pattern 50 is formed on the dielectric layer M8, and its extended portion is connected to the six ground terminals Tg in FIG. Two via-hole conductors 62 and 63 extending downward are connected to the ground pattern 50. Note that a dielectric layer (not shown) on which no element is formed is provided as a cover of the multilayer body 10 on the dielectric layer M8.

  Here, FIG. 6 shows a cross-sectional structure of the laminate 10 corresponding to the structure of FIGS. 4 and 5. In FIG. 6, each conductor pattern formed on each of the dielectric layers M1 to M5, M8, a conductor pattern 48 formed on the dielectric layer M6, a conductor pattern 49 formed on the dielectric layer M7, Via-hole conductors 60-63 are shown. The thicknesses of the dielectric layers M1 to M8 of the stacked body 10 are greatly different because different electrical characteristics are required. 4 and 5, the via-hole conductors 60 to 63 are represented by a thin diameter for convenience, but actually, as shown in FIG. 6, the via-hole conductors 60 to 63 are formed with a relatively large diameter. In FIG. 6, the position of the half height H / 2 with respect to the height H of the laminate 10 is indicated by a dotted line.

  In the multilayer bandpass filter according to the first embodiment, when attention is paid to the two inductor conductors L11 and L13 on the short-circuit end side, the electromagnetic coupling between the two is a conductor pattern 48 disposed opposite to the dielectric layers M6 and M7, 49 is strongly influenced. As shown in FIG. 6, since the pair of conductor patterns 48 and 49 are disposed to face each other in the stacking direction, inductive coupling between the inductor conductors L11 and L13 can be strengthened. As a result, the bandpass filter can have a high-band polar type filter characteristic.

  FIG. 7 is a diagram illustrating filter characteristics of the multilayer bandpass filter configured in the multilayer body 10 of the first embodiment. For comparison, FIG. 7 shows a reference characteristic S0 when the opposed conductive patterns 48 and 49 are not used, and a characteristic S1 of the multilayer bandpass filter of the first embodiment. The characteristics S0 and S1 correspond to the frequency characteristics of the S parameter S21, respectively, and the vicinity of 3 to 4 GHz is set as the pass band. First, in the characteristic S0, the attenuation pole P0 appears on the lower side of the pass band. This reflects that the electromagnetic coupling between the two inductor conductors of the resonator is mainly capacitive coupling.

  On the other hand, in the characteristic S1 in the case of the first embodiment, the attenuation pole P1 appears on the high band side of the pass band. As described above, this is an effect that the inductive coupling between the inductor conductors L11 and L13 is strengthened by the conductor patterns 48 and 49 arranged to face each other in the stacking direction. Therefore, in FIG. 7, when the attenuation in the vicinity of 5 to 6 GHz in particular is compared, the characteristic S1 is significantly larger than the characteristic S0. With this, when using the multilayer bandpass filter of the first embodiment, Desirable filter characteristics in which the amount of attenuation increases on the high frequency side can be realized.

[Second Embodiment]
In the multilayer bandpass filter of the second embodiment, the inductor conductors L10 to L13 of the multilayer bandpass filter of the first embodiment are formed in different forms. Regarding the multilayer band-pass filter of the second embodiment, the equivalent circuit and the appearance of the multilayer body 10 are the same as those in FIGS.

  A specific structure of the multilayer bandpass filter according to the second embodiment will be described with reference to FIGS. 10 layers of dielectric layers M1 to M10 are laminated on the laminated body 10 of the second embodiment. Among these, the dielectric layers M1 to M5 are the dielectric layers M1 to M5 of the first embodiment (see FIG. 4 and FIG. 5), the description is omitted. On the other hand, FIG. 8 is a plan view showing the structure of the dielectric layers M6 to M10 in the multilayer body 10 of the second embodiment.

  As shown in FIG. 8, the dielectric layer M6 is formed with a conductor pattern 70 that becomes a part of the inductor conductor L11 on the short-circuit end side of one resonator. A via hole conductor 60 (FIG. 4) extending downward is connected to one end of the conductor pattern 70, and a via hole conductor 64 extending upward is connected to the other end of the conductor pattern 70.

  In the dielectric layer M7, a conductor pattern 71 is formed which becomes a part of the inductor conductor L13 on the short-circuit end side of the other resonator. A via hole conductor 61 (FIG. 4) extending downward is connected to one end of the conductor pattern 71, and a via hole conductor 65 extending upward is connected to the other end of the conductor pattern 71.

  In the dielectric layer M8, a conductor pattern 72 is formed that becomes a part of the inductor conductor L11 on the short-circuit end side described above. A via hole conductor 64 extending downward is connected to one end of the conductor pattern 72, and a via hole conductor 66 extending upward is connected to the other end of the conductor pattern 72.

  The dielectric layer M9 is provided with a conductor pattern 73 that becomes a part of the above-described short-circuited inductor conductor L13. A via hole conductor 65 extending downward is connected to one end of the conductor pattern 73, and a via hole conductor 67 extending upward is connected to the other end of the conductor pattern 73.

  A wide ground pattern 74 is formed in the dielectric layer M10, and the extended portion thereof is connected to the six ground terminals Tg in FIG. Two via-hole conductors 66 and 67 extending downward are connected to the ground pattern 74. Note that a dielectric layer (not shown) on which no element is formed is provided as a cover of the multilayer body 10 on the dielectric layer M10.

  In the second embodiment, the inductor conductor L11 on one short-circuit end side includes a spiral pattern composed of the conductor pattern 70 of the dielectric layer M6 and the conductor pattern 72 of the dielectric layer M8. The inductor conductor L13 on the other short-circuit end side includes a spiral pattern composed of the conductor pattern 71 of the dielectric layer M7 and the conductor pattern 73 of the dielectric layer M9. That is, the two inductor conductors L11 and L13 have a structure in which the respective spiral patterns are alternately stacked and the respective layers are arranged to face each other. Thus, if the inductor conductors L11 and L13 are formed using a spiral pattern, a long pattern length can be easily secured, and a sufficient inductance value can be set with a relatively small area.

  Here, FIG. 9 shows a cross-sectional structure of the laminate 10 described above. In FIG. 9, the conductor patterns and via-hole conductors 60 and 61 of the dielectric layers M1 to M5 similar to those in FIG. 6 of the first embodiment, and conductor patterns 70 to 74 formed on the dielectric layers M6 to M10, Via-hole conductors 64-67 are shown. In FIG. 9, based on the spiral pattern structure of the inductor conductors L <b> 11 and L <b> 13 as described above, the conductor patterns 70 and 71 are disposed opposite to each other on the lower side of the multilayer substrate 10, and the conductor patterns 72 and 72 are disposed on the upper side of the multilayer substrate 10. 73 are arranged to face each other. Also in this case, the inductive coupling is strengthened between the inductor conductors L11 and L13, and the bandpass filter can have a high-band polar type filter characteristic.

  FIG. 10 is a diagram illustrating filter characteristics of the multilayer bandpass filter configured in the multilayer body 10 of the second embodiment. FIG. 10 shows a characteristic S0 as a reference similar to that in FIG. 7 for comparison, and also shows a characteristic S2 possessed by the multilayer bandpass filter of the second embodiment. The characteristics S0 and S2 correspond to the frequency characteristics of the S parameter S21, respectively, and the vicinity of 3 to 4 GHz is set as the pass band. In the characteristic S0, the low-frequency attenuation pole P0 described with reference to FIG. 7 appears, whereas in the characteristic S2, the high-frequency attenuation pole P2 appears in the same manner as the attenuation pole P1 of the characteristic S1 in FIG. ing. Therefore, even when the multilayer bandpass filter according to the second embodiment is used, it is possible to achieve desirable filter characteristics in which the amount of attenuation increases on the high frequency side, as in the first embodiment.

  Here, a method of adjusting the characteristic S2 shown in FIG. 10 based on the structure of the laminate 10 in FIG. 9 will be described. FIG. 9 shows a distance da between the conductor patterns 72 and 73, a distance db between the conductor patterns 71 and 72, and a distance dc between the conductor patterns 70 and 71, respectively. FIG. 11 is a diagram illustrating a change in the characteristic S2 in FIG. 10 when the above-described three distances da, db, and dc are adjusted. Using the characteristic S2 as a reference, the characteristic S2a indicates a case where the distance da is shortened, the characteristic S2b indicates a case where the distance db is shortened, and a characteristic S2c indicates a case where the distance dc is shortened. The degree of shortening of each distance da, db, dc is approximately 1/2 to 1/3 with reference to FIG. 9, and other design conditions are slightly adjusted so that other characteristics are maintained. .

  As shown in FIG. 11, in the characteristic S2a, the attenuation pole P2 shifts to the higher frequency side than the characteristic S2, the characteristic S2b does not change the position of the characteristic S2 and the attenuation pole P2, and the characteristic S2c has an attenuation pole P2 that is more than the characteristic S2. Shift to the low frequency side. That is, the attenuation pole P2 is shifted to the low frequency side when the distances are shortened in the order of distances da, db, and dc from the upper part of the laminate 10. This means that the filter characteristics in which the attenuation pole P2 appears on the high frequency side can be adjusted as the coupling of the conductor patterns is strengthened at a position closer to the short-circuit end side of the multilayer body 10. In actually designing a multilayer bandpass filter, it is necessary to appropriately set the positions and intervals of the conductor patterns to be opposed to each other according to the required filter characteristics.

[Third Embodiment]
The multilayer bandpass filter of the third embodiment is obtained by changing the circuit configuration of the multilayer bandpass filter of the first embodiment. FIG. 12 is a diagram illustrating an equivalent circuit of the multilayer bandpass filter according to the third embodiment. The multilayer bandpass filter shown in FIG. 12 includes three capacitors C11, C12, and C13 and four inductor conductors L10, L11, L12, and L13 similar to those in FIG. 1 of the first embodiment. Instead of the capacitors C10 and C14 of FIG. 1, a trap circuit TC0 inserted between the input terminal Tin and the node N10 and a trap circuit TC1 inserted between the output terminal Tout and the node N11 are provided. In addition, description is abbreviate | omitted about the same component as the lamination type band pass filter of a 1st embodiment.

  The input-side trap circuit TC0 is configured by connecting an inductor L20 and a capacitor C20 in parallel. Similarly, the output-side trap circuit TC1 is configured by connecting an inductor L21 and a capacitor C21 in parallel. The trap circuit TC0 attenuates a resonance frequency component determined by the inductor L20 and the capacitor C20, and the trap circuit TC1 attenuates a resonance frequency component determined by the inductor L21 and the capacitor C21. In the third embodiment, for each stacked bandpass filter of the first or second embodiment, the amount of attenuation is increased in the low frequency region in addition to the high frequency region based on the action of the trap circuits TC0 and TC1. Yes.

  A specific structure of the multilayer bandpass filter according to the third embodiment will be described with reference to FIGS. 13 and 14. Fourteen dielectric layers M1 to M14 are stacked on the multilayer body 10 of the third embodiment. Among these, the dielectric layers M1 to M5 are the dielectric layers M1 to M5 of the first embodiment (see FIG. 4 and FIG. 5), the description is omitted. On the other hand, in the laminated body 10 of 3rd Embodiment, FIG. 13 is a top view which shows the structure of the dielectric material layers M6-M10, and FIG. 14 is a top view which shows the structure of the dielectric material layers M11-M14.

  As shown in FIG. 13, a capacitor electrode 80 on the node N10 side of the capacitor C20 of the trap circuit TC0 and a capacitor electrode 81 on the node N11 side of the capacitor C21 of the trap circuit TC1 are formed on the dielectric layer M6. The capacitor electrode 80 is connected to a via-hole conductor 60 (FIG. 4) penetrating vertically and a via-hole conductor 100 extending upward. The capacitor electrode 81 is connected to a via-hole conductor 61 (FIG. 4) penetrating vertically and a via-hole conductor 101 extending upward. In the dielectric layer M5 of FIG. 5, the capacitor electrode 46 corresponds to the capacitor electrode on the input terminal Tin side of the capacitor C20, and the capacitor electrode 47 corresponds to the capacitor electrode on the output terminal Tout side of the capacitor C21.

  In the dielectric layer M7, a conductor pattern 82 that is a part of the inductor conductor L11 on the short-circuit end side and a conductor pattern 83 that is a part of the inductor L21 of the trap circuit TC1 are formed. A via hole conductor 60 extending downward is connected to one end of the conductor pattern 82, and a via hole conductor 102 extending upward is connected to the other end of the conductor pattern 82. A via hole conductor 101 extending downward is connected to one end of the conductor pattern 83, and a via hole conductor 103 extending upward is connected to the other end of the conductor pattern 83.

  In the dielectric layer M8, a conductor pattern 84 that becomes a part of the inductor L20 of the trap circuit TC0 and a conductor pattern 85 that becomes a part of the inductor L21 are formed. A via hole conductor 100 extending downward is connected to one end of the conductor pattern 84, and a via hole conductor 104 extending upward is connected to the other end of the conductor pattern 84. A via hole conductor 103 extending downward is connected to one end of the conductor pattern 85, and a via hole conductor 105 extending upward is connected to the other end of the conductor pattern 85.

  The dielectric layer M9 has a conductor pattern 86 that becomes a part of the inductor conductor L13 on the short-circuit end side, a conductor pattern 87 that becomes a part of the inductor L20, and a conductor pattern 88 that becomes a part of the inductor L21. Is formed. A via hole conductor 61 extending downward is connected to one end of the conductor pattern 86, and a via hole conductor 106 extending upward is connected to the other end of the conductor pattern 86. A via hole conductor 104 extending downward is connected to one end of the conductor pattern 87, and a via hole conductor 107 extending upward is connected to the other end of the conductor pattern 87. A via hole conductor 105 extending downward is connected to one end of the conductor pattern 88, and a via hole conductor 108 extending upward is connected to the other end of the conductor pattern 88.

  In the dielectric layer M10, a conductor pattern 89 that is a part of the inductor L20 and a conductor pattern 90 that is a part of the inductor L21 are formed. A via hole conductor 107 extending downward is connected to one end of the conductor pattern 89, and the other end of the conductor pattern 89 is connected to the input terminal Tin. In addition, a via hole conductor 108 extending downward is connected to one end of the conductor pattern 90, and a via hole conductor 109 extending upward is connected to the other end of the conductor pattern 90.

  Next, as shown in FIG. 14, the dielectric layer M11 is formed with a conductor pattern 91 that becomes a part of the inductor conductor L11 on the short-circuit end side and a conductor pattern 92 that becomes a part of the inductor L21. Yes. A via hole conductor 102 extending downward is connected to one end of the conductor pattern 91, and a via hole conductor 110 extending upward is connected to the other end of the conductor pattern 91. Also, a via hole conductor 109 extending downward is connected to one end of the conductor pattern 92, and a via hole conductor 111 extending upward is connected to the other end of the conductor pattern 92.

  The dielectric layer M12 is provided with a conductor pattern 93 that becomes a part of the above-described inductor L21. A via hole conductor 111 extending downward is connected to one end of the conductor pattern 93, and a via hole conductor 112 extending upward is connected to the other end of the conductor pattern 93.

  In the dielectric layer M13, a conductor pattern 94 that is a part of the inductor conductor L13 on the short-circuit end side and a conductor pattern 95 that is a part of the inductor L21 are formed. A via-hole conductor 106 extending downward is connected to one end of the conductor pattern 94, and a via-hole conductor 113 extending upward is connected to the other end of the conductor pattern 94. Also, a via hole conductor 112 extending downward is connected to one end of the conductor pattern 95, and the other end of the conductor pattern 95 is connected to the output terminal Tout.

  A wide ground pattern 96 is formed on the dielectric layer M14, and its extended portion is connected to the six ground terminals Tg in FIG. Two via-hole conductors 110 and 113 extending downward are connected to the ground pattern 96. Note that a dielectric layer (not shown) on which no element is formed is provided as a cover of the multilayer body 10 on the dielectric layer M14.

  FIG. 15 is a diagram illustrating filter characteristics of the multilayer bandpass filter configured in the multilayer body 10 of the third embodiment. For comparison, FIG. 15 shows the characteristic S2 (FIG. 10) of the second embodiment and the characteristic S3 of the multilayer bandpass filter of the third embodiment. The characteristics S2 and S3 correspond to the frequency characteristics of the S parameter S21, respectively, and the vicinity of 3 to 4 GHz is set as the pass band. Compared to the characteristic S2, two attenuation poles pa and pb appear on the low frequency side of the characteristic S3. These attenuation poles pa and pb are generated according to the respective resonance frequencies of the trap circuits TC0 and TC1 in FIG. As described above, the multilayer bandpass filter according to the third embodiment secures a sufficient attenuation amount on the high band side of the pass band by the action of the inductor conductors L11 and L13, and also at the low band side, the trap circuit TC0, A sufficient amount of attenuation can be ensured based on TC1.

  The contents of the present invention have been specifically described above based on the three embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. it can. For example, in each of the above-described embodiments, the configuration in which the conductor patterns of the inductor conductors L11 and L13 on the short-circuit end side among the inductor conductors L10 to L13 of the pair of resonators are arranged to face each other in the stacking direction has been described. A configuration in which the conductor patterns of the inductor conductors L10 and L12 are arranged opposite to each other in the stacking direction may be employed. The present invention can also be applied to a multilayer bandpass filter including inductor conductors only on the short-circuit end side or only on the open-end side. Furthermore, when using the laminated body 10 with many lamination | stacking numbers, there is no restriction | limiting also about the number of the conductor patterns opposingly arranged by the lamination direction.

It is a figure which shows the equivalent circuit of the laminated | stacked band pass filter of 1st Embodiment. FIG. 2 is a diagram showing a model of a main part of the equivalent circuit of FIG. 1. It is a figure which shows the external appearance perspective view of the laminated body by which the multilayer band pass filter of 1st Embodiment is comprised. It is a 1st top view showing the structure of each layer of the layered product of a 1st embodiment. It is a 2nd top view which shows the structure of each layer of the laminated body of 1st Embodiment. 6 shows a cross-sectional structure of a laminate corresponding to the structure of FIGS. 4 and 5. It is a figure which shows the filter characteristic of the multilayer band pass filter comprised by the laminated body of 1st Embodiment. It is the 2nd top view showing the structure of each layer of the layered product of a 2nd embodiment. The cross-sectional structure of the laminated body corresponding to the structure of FIG. 8 is shown. It is a figure which shows the filter characteristic of the laminated | stacked band pass filter comprised by the laminated body of 2nd Embodiment. FIG. 10 is a diagram illustrating a change in the characteristic S2 in FIG. 10 when the three distances da, db, and dc in FIG. 9 are adjusted. It is a figure which shows the equivalent circuit of the laminated | stacked band pass filter of 3rd Embodiment. It is a 2nd top view showing the structure of each layer of the layered product of a 3rd embodiment. It is a 3rd top view showing the structure of each layer of the layered product of a 3rd embodiment. It is a figure which shows the filter characteristic of the laminated | stacked band pass filter comprised by the laminated body of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Laminated body 40, 50, 96 ... Ground pattern 41-47, 80, 81 ... Capacitor electrode 48, 49, 70-73, 82-95 ... Conductor pattern 60-67, 100-113 ... Via-hole conductor L10, L11, L12, L13: Inductor conductors C10, C11, C12, C13, C14, C20, C21 ... Capacitors L20, L21 ... Inductors TC0, TC1 ... Trap circuit Tin ... Input terminal Tout ... Output terminal Tg ... Ground terminals M1-M14 ... Dielectric layer

Claims (8)

A laminated bandpass filter comprising a plurality of electromagnetically coupled resonators,
A laminate in which a plurality of dielectric layers are laminated;
A first inductor conductor that includes a via-hole conductor penetrating the dielectric layer in the stacking direction and a conductor pattern disposed on the dielectric layer, and that constitutes a first resonator;
A second inductor conductor that includes a via hole conductor penetrating the dielectric layer in the stacking direction and a conductor pattern disposed on the dielectric layer, and constitutes a second resonator;
The conductor pattern of the first inductor conductor and the conductor pattern of the second inductor conductor are arranged to face each other in the stacking direction with a predetermined interval inductively coupled to each other. Multilayer bandpass filter.   The first inductor conductor is configured by connecting a first short-circuit-end-side inductor conductor and a first open-end-side inductor conductor, and the second inductor conductor is a second short-circuit-end-side inductor conductor. The multilayer bandpass filter according to claim 1, wherein the laminated open-side inductor conductor is connected to the multilayer band-pass filter.   Between a first node between the first short-circuit-end side inductor conductor and the first open-end-side inductor conductor, and between the second short-circuit-end-side inductor conductor and the second open-end-side inductor conductor The multilayer bandpass filter according to claim 2, wherein a first capacitor is connected between the first node and the second node.   The multilayer capacitor according to claim 3, wherein a second capacitor is connected between the input terminal and the first node, and a third capacitor is connected between the output terminal and the second node. Type bandpass filter.   A first trap circuit is inserted between the input terminal and the first node, a second trap circuit is inserted between the output terminal and the second node, and the first trap circuit and the second node 4. The multilayer bandpass filter according to claim 3, wherein a resonance frequency of each of the trap circuits is set to a low band side of the pass band. 5.   3. The multilayer according to claim 2, wherein the conductor pattern of the first short-circuit end side inductor conductor and the conductor pattern of the second short-circuit end side inductor conductor are arranged to face each other in the stack direction. Type bandpass filter.   2. The multilayer bandpass filter according to claim 1, wherein, in the first inductor conductor and the second inductor conductor, each of the conductor patterns opposed to each other is formed in a spiral pattern. 8. The spiral pattern according to claim 7, wherein each of the spiral patterns is formed across two or more of the dielectric layers, and the conductor patterns are disposed to face each other in the stacking direction in each of the dielectric layers. Multilayer bandpass filter.

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