Filter Device

Abstract

To suppress reduction in the pass characteristics due to an external shielding electrode in a filter device.SOLUTION: A filter device 100 includes a laminate 110 in which multiple dielectric layers are stacked, an input terminal T1, an output terminal T2, a ground terminal GND, a ground electrode PG1 connected to the ground terminal GND, a flat plate electrode PC30, and first to fourth lines. The laminate 110 has main surfaces 111, 112. The input terminal T1, the output terminal T2 and the ground terminal GND are arranged on the main surface 112. The flat plate electrode PC30 is arranged on the main surface 111 side with respect to the ground electrode GND. The first line is electrically connected to the input terminal T1 and the flat plate electrode PC30. The second line is electrically connected to the output terminal T2 and the flat plate electrode PC30. A third line VG10 and a fourth line VG20 connect the flat plate electrode PC30 with the ground electrode PG1. The first line is capacitively coupled to the second line. In the plan view of the laminate 110 from the laminate direction, the flat plate electrode PC30 covers a portion where the first line is capacitively coupled to the second line.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a filter device, and more particularly to a technique for suppressing degradation of pass characteristics in a filter device. [Background technology]

[0002] Japanese Patent Laid-Open Publication No. 2008-167157 (Patent Document 1) discloses a laminated high-pass filter including two LC parallel resonators. The high-pass filter of Patent Document 1 has a configuration in which the two LC parallel resonators are coupled by a capacitor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-167157 Summary of the Invention [Problem to be solved by the invention]

[0004] The high-pass filter of Patent Document 1 has a structure in which a capacitor coupling two resonators is located near the top surface of the laminate. In the structure of Patent Document 1, the capacitor coupling the resonators is not grounded, so the electrostatic potential of the capacitor electrode constituting the capacitor is higher than the ground potential. Therefore, if a low-potential component, such as an external shield of an external device, is placed near the top surface of the high-pass filter, the capacitor electrode of the high-pass filter and the shield electrode of the external device may couple, forming a shunt capacitance. This may lower the frequency of the reflection zero generated by the capacitor, which may ultimately cause a degradation of the pass characteristics of the high-pass filter.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to suppress degradation of transmission characteristics caused by an external shield electrode in a filter device. [Means for solving the problem]

[0006] The filter device according to the present disclosure includes a laminate formed by stacking a plurality of dielectric layers, an input terminal, an output terminal, a ground terminal, a ground electrode connected to the ground terminal, a plate electrode, and first to fourth lines. The laminate has a first surface and a second surface. The input terminal, the output terminal, and the ground terminal are arranged on the second surface. The plate electrode is arranged closer to the first surface than the ground electrode. The first line is electrically connected to the input terminal and the plate electrode. The second line is electrically connected to the output terminal and the plate electrode. The third line and the fourth line connect the plate electrode and the ground electrode. The first line is capacitively coupled to the second line. When the laminate is viewed from above in the stacking direction, the plate electrode covers the portion where the first line and the second line are capacitively coupled. [Effects of the Invention]

[0007] In the filter device according to the present disclosure, a shunt path connected to an input terminal and a shunt path connected to an output terminal are capacitively coupled to each other, and the portion where the two paths are capacitively coupled is covered by a plate electrode. The plate electrode is connected to the ground electrode by the third line and the fourth line, and therefore has a lower electrostatic potential than the capacitively coupled portion. Therefore, the plate electrode functions as a shield for the capacitively coupled portion. Therefore, even if a shield electrode of an external device approaches the laminate, fluctuations in the electrostatic potential of the capacitive coupling portion can be suppressed, thereby suppressing degradation of the pass characteristics caused by the external shield electrode. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an equivalent circuit diagram of a filter device according to a first embodiment. [Figure 2] 1 is an external perspective view of a filter device according to a first embodiment. [Figure 3] 1 is a transparent perspective view showing the internal structure of a filter device according to a first embodiment. [Figure 4]10A and 10B are diagrams illustrating the configuration of a filter device of a comparative example and the influence of an external shield electrode on transmission characteristics. [Figure 5] 5A and 5B are diagrams for explaining the influence of the presence or absence of an external shield electrode on the pass characteristics in the filter device according to the first embodiment. [Figure 6] FIG. 10 is an equivalent circuit diagram of a filter device according to a first modification. [Figure 7] FIG. 10 is a transparent perspective view showing the internal structure of a filter device according to a first modified example. [Figure 8] 10A and 10B are diagrams illustrating the influence of the presence or absence of an external shield electrode on the pass characteristics of the filter device of the first modification. [Figure 9] FIG. 10 is a transparent perspective view showing the internal structure of a filter device according to a second modification. [Figure 10] FIG. 11 is a transparent perspective view showing the internal structure of a filter device according to a third modified example. [Figure 11] FIG. 10 is a transparent perspective view showing the internal structure of a filter device according to a fourth modified example. [Figure 12] FIG. 13 is a transparent perspective view showing the internal structure of a filter device according to a fifth modified example. [Figure 13] FIG. 10 is an equivalent circuit diagram of a filter device according to a second embodiment. [Figure 14] FIG. 10 is a transparent perspective view showing the internal structure of a filter device according to a second embodiment. [Figure 15] 10A and 10B are diagrams illustrating the influence of the presence or absence of an external shield electrode on the pass characteristics of the filter device according to the second embodiment. [Figure 16] FIG. 13 is an equivalent circuit diagram of a filter device according to a sixth modification. [Figure 17] FIG. 13 is a transparent perspective view showing the internal structure of a filter device according to a sixth modified example. [Figure 18] FIG. 13 is an equivalent circuit diagram of a filter device according to a seventh modification. [Figure 19] FIG. 13 is a transparent perspective view showing the internal structure of a filter device according to a seventh modified example. [Figure 20] 13 is a diagram illustrating the influence of the presence or absence of an external shield electrode on the pass characteristics of a filter device according to a seventh modification. FIG. [Figure 21] FIG. 13 is an equivalent circuit diagram of a filter device according to Modification 8. [Figure 22] FIG. 13 is a transparent perspective view showing the internal structure of a filter device according to an eighth modified example. [Figure 23] 13 is a diagram illustrating the influence of the presence or absence of an external shield electrode on the pass characteristics in a filter device according to Modification 8. FIG. [Figure 24] FIG. 13 is an equivalent circuit diagram of a filter device according to a ninth modification. [Figure 25] FIG. 13 is a transparent perspective view showing the internal structure of a filter device according to a ninth modified example. [Figure 26] 13 is a diagram illustrating the influence of the presence or absence of an external shield electrode on the pass characteristics in the filter device of the ninth modification. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0010] [Embodiment 1] 1 is an equivalent circuit diagram of a filter device 100 according to Embodiment 1. The filter device 100 includes an input terminal T1, an output terminal T2, a ground terminal GND, a capacitor C1, and inductors L1, L11, L12, L21, and L22.

[0011] The capacitor C1 is connected between the input terminal T1 and the output terminal T2. The inductors L11 and L12 are connected in series between the input terminal T1 and the ground terminal GND. The inductors L21 and L22 are connected in series between the output terminal T2 and the ground terminal GND. The inductor L1 is connected between a connection node N1 between the inductors L11 and L12 and a connection node N2 between the inductors L21 and L22. In other words, the filter device 100 has a configuration in which two shunt inductors in a so-called π-type high-pass filter are connected together.

[0012] Next, the structure of the filter device 100 will be described with reference to Figures 2 and 3. Figure 2 is an external perspective view of the filter device 100, and Figure 3 is a see-through perspective view showing an example of the internal structure of the filter device 100.

[0013] 3 and 4, the filter device 100 includes a rectangular or approximately rectangular parallelepiped laminate 110 in which a plurality of dielectric layers are stacked in a stacking direction. Each dielectric layer is formed of ceramic, such as low-temperature co-fired ceramics (LTCC), or resin. Inside the laminate 110, the inductor and capacitor described in FIG. 1 are configured by a plurality of electrodes provided on each dielectric layer and a plurality of vias provided between the dielectric layers. In this specification, the term "via" refers to a columnar conductor provided in a dielectric layer to connect electrodes provided on different dielectric layers. The vias are formed, for example, by conductive paste, plating, and / or metal pins.

[0014] In the following description, the stacking direction of the dielectric layers in the laminate 110 is referred to as the "Z-axis direction," the direction perpendicular to the Z-axis direction and along the long side of the laminate 110 is referred to as the "X-axis direction," and the direction along the short side of the laminate 110 is referred to as the "Y-axis direction." In the following, the positive direction of the Z-axis in each drawing may be referred to as the upper side, and the negative direction may be referred to as the lower side.

[0015] A directionality mark DM for identifying the orientation of the filter device 100 is disposed on an upper surface 111 of the laminate 110. External terminals (an input terminal T1, an output terminal T2, and a ground terminal GND) for connecting the filter device 100 to an external device are disposed on a lower surface 112 of the laminate 110. The input terminal T1, the output terminal T2, and the ground terminal GND are each a flat electrode, and are LGA (Land Grid Array) terminals regularly arranged on the lower surface 112 of the laminate 110.

[0016] The input terminal T1 is disposed near the center in the Y-axis direction and close to the end of the negative X-axis on the lower surface 112. The output terminal T2 is disposed near the center in the Y-axis direction and close to the end of the positive X-axis on the lower surface 112. The ground terminals GND are disposed along the two long sides of the lower surface 112.

[0017] The input terminal T1 is connected to a plate electrode PL1 arranged on a dielectric layer near the center in the stacking direction by a via V10, a plate electrode P1, and a via V11 arranged inside the laminate 110. The vias V10 and V11 are offset at the portion of the plate electrode P1.

[0018] The plate electrode PL1 is a strip-shaped electrode that has a substantially C-shape when the laminate 110 is viewed from above in the stacking direction (Z-axis direction), and a via V11 is connected to a first end thereof. A via V12 is connected to a second end thereof. The via V12 extends from the plate electrode PL1 toward the upper surface 111 and is connected to a plate electrode PC30 that is arranged on a dielectric layer close to the upper surface 111.

[0019] The output terminal T2 is connected to the plate electrode PL2 arranged on the dielectric layer near the center in the stacking direction by a via V20, a plate electrode P2, and a via V21 arranged inside the laminate 110. The via V20 and the via V21 are offset at the portion of the plate electrode P2.

[0020] The plate electrode PL2 is a strip-shaped electrode having a substantially C-shape similar to the plate electrode PL1, and is arranged on the same dielectric layer as the plate electrode PL1 but spaced apart from the plate electrode PL1 in the positive direction of the X-axis. A via V21 is connected to a first end of the plate electrode PL2, and a via V22 is connected to a second end of the plate electrode PL2. The via V22 extends from the plate electrode PL2 toward the upper surface 111 and is connected to the plate electrode PC30.

[0021] The plate electrode PC30 is an electrode having a substantially rectangular shape when the laminate 110 is viewed from above in the stacking direction, and covers the plate electrodes PL1 and PL2. The plate electrode PC30 is connected to a ground electrode PG1 disposed between the plate electrodes PL1 and PL2 and the lower surface 112 by vias VG10 and VG20.

[0022] The ground electrode PG1 has a substantially H-shape when viewed from above in the stacking direction of the laminate 110. The ground electrode PG1 is connected to a plurality of ground terminals GND arranged on the lower surface 112 by a plurality of vias VG1, respectively.

[0023] A capacitor electrode PC31 is connected via a via to a portion of the path from the first end to the second end of the plate electrode PL1. The capacitor electrode PC31 is disposed on a dielectric layer different from the plate electrode PL1, and extends in the positive direction of the X-axis from the connection portion with the plate electrode PL1. When the laminate 110 is viewed from above in the stacking direction, a portion of the capacitor electrode PC31 overlaps with the plate electrode PL2.

[0024] Similarly, a capacitor electrode PC32 is connected via a via to a portion of the path from the first end to the second end of the plate electrode PL2. The capacitor electrode PC32 is disposed on a dielectric layer different from the plate electrode PL2, and extends in the negative direction of the X-axis from the connection portion with the plate electrode PL2. When the laminate 110 is viewed from above in the stacking direction, a portion of the capacitor electrode PC32 overlaps with the plate electrode PL1.

[0025] That is, the path connecting the input terminal T1 and the plate electrode PL1 and the path connecting the output terminal T2 and the plate electrode PL2 are capacitively coupled. The portion where the two paths are capacitively coupled, i.e., the capacitor electrodes PC31 and PC32, is covered by the plate electrode PC30 when the laminate 110 is viewed from above in the stacking direction.

[0026] In Fig. 3, the path from via V10 to plate electrode PC30 via plate electrode P1, via V11, plate electrode PL1, and via V12 corresponds to inductor L11 in Fig. 1, and via VG10 corresponds to inductor L12 in Fig. 1. In Fig. 3, the path from via V20 to plate electrode PC30 via plate electrode P2, via V21, plate electrode PL2, and via V22 corresponds to inductor L21 in Fig. 1, and via VG20 corresponds to inductor L22 in Fig. 1. Plate electrode PC30 in Fig. 3 corresponds to inductor L1 in Fig. 1.

[0027] 3, the plate electrode PL1 and the capacitor electrode PC32, and the plate electrode PL2 and the capacitor electrode PC31 form the capacitor C1 in Fig. 1. It is not necessary to provide both the capacitor electrodes PC31 and PC32, and a configuration in which only one of the capacitor electrodes PC31 and PC32 is provided may be used as long as the desired capacitive coupling of the two paths is ensured.

[0028] (effect of external shield electrode) In a π-type high-pass filter such as the equivalent circuit diagram shown in FIG. 1, the opposing electrodes of capacitor C1, which is connected between input terminal T1 and output terminal T2, are not directly connected to ground terminal GND. Therefore, the electrodes of capacitor C1 have a relatively higher electrostatic potential than ground terminal GND. In this case, if a low-potential component, such as an external shield electrode or ground electrode of an external device, approaches filter device 100, a shunt capacitance may be formed between the electrodes of capacitor C1 and the low-potential component, resulting in capacitive coupling. This may lower the frequency of the reflection zero generated by capacitor C1, potentially degrading the pass characteristics of the filter device.

[0029] Fig. 4 shows the results of a simulation performed on the filter device 100X of the comparative example to verify the above-mentioned problems. Specifically, Fig. 4 shows the configuration of the filter device 100X of the comparative example and the change in pass characteristics depending on whether or not an external shield electrode is provided.

[0030] The upper part of Fig. 4 shows an equivalent circuit diagram of the filter device 100X. In the filter device 100X, capacitors C11 and C21 are provided instead of the inductors L1, L12, and L22 in the filter device 100 of Fig. 1. The capacitor C11 is connected between the inductor L11 and the ground terminal GND. Furthermore, the capacitor C21 is connected between the inductor L21 and the ground terminal GND. In other words, the filter device 100X is a π-type high-pass filter configured by two shunt-connected LC series resonators (L11+C11, L21+C21) and a capacitor C1.

[0031] 4 shows a side perspective view of the filter device 100X. In the filter device 100X, a capacitor electrode PC10X is disposed at the lower end of a via V12X that is connected to pass through the second end of the plate electrode PL1, and the capacitor electrode PC10X and the ground electrode PG1 form a capacitor C11. Also, a capacitor electrode PC20X is disposed at the lower end of a via V22X that is connected to pass through the second end of the plate electrode PL2, and the capacitor electrode PC20X and the ground electrode PG1 form a capacitor C21.

[0032] Capacitor electrodes PC41 and PC42 are connected to the upper ends of vias V12X and V22X, respectively. Capacitor electrode PC40 is disposed so as to partially face both of capacitor electrodes PC41 and PC42. Capacitor electrodes PC40, PC41, and PC42 form a capacitor C1.

[0033] In the filter device 100X configured as described above, when a low-potential member (external shield electrode SH) of an external device approaches the upper surface 111 of the laminate 110, the capacitor electrodes PC40, PC41, and PC42 constituting the capacitor C1 may become capacitively coupled to the external shield electrode SH.

[0034] The lower part of Fig. 4 shows a graph illustrating the change in the pass characteristics of the filter device 100X depending on whether or not an external shield electrode SH is present. In this graph, the horizontal axis represents frequency, and the vertical axis represents insertion loss (solid lines LN10, LN10A, dashed lines LN11, LN11A) and return loss (solid lines LN15, dashed lines LN16). In the graph, the solid lines LN10, LN10A, and LN15 represent characteristics when there is no external shield electrode SH, while the dashed lines LN11, LN11A, and LN16 represent characteristics when the external shield electrode SH is closer. Note that the insertion losses indicated by the solid lines LN10A and dashed lines LN11A are enlarged views of the insertion losses indicated by the solid lines LN10 and dashed lines LN11, and correspond to the vertical axis on the right side of the graph.

[0035] As shown in the graph of FIG. 4, when the external shield electrode SH approaches, the frequency of the attenuation pole decreases (dashed line LN16), and this reduces the insertion loss on the high frequency side of the passband (dashed lines LN11, LN11A).

[0036] Fig. 5 is a diagram showing changes in the transmission characteristics of the filter device 100 according to the first embodiment depending on whether or not an external shield electrode is present on the top surface 111 of the laminate 110. In Fig. 5 as well, the horizontal axis represents frequency, and the vertical axis represents insertion loss (solid lines LN20, LN20A, dashed lines LN21, LN21A) and reflection loss (solid line LN25, dashed line LN26). The solid lines LN20, LN20A, and LN25 represent characteristics when there is no external shield electrode, and the dashed lines LN21, LN21A, and LN26 represent characteristics when the external shield electrode is closer.

[0037] As shown in FIG. 5, in the filter device 100 of the first embodiment, the change in insertion loss and return loss when the external shield electrode approaches the upper surface 111 is smaller than the change in the filter device 100X of the comparative example, and it can be seen that the influence of the external shield electrode is reduced.

[0038] This is because the plate electrodes PL1, PL2 and capacitor electrodes PC31, PC32 that make up capacitor C1 are covered by the plate electrode PC30, which has a lower electrostatic potential than these electrodes, and therefore the plate electrode PC30 functions as an internal shield and suppresses coupling between each electrode that makes up capacitor C1 and the external shield electrode.

[0039] In this way, by covering the portion where the two shunt paths that make up the high-pass filter are capacitively coupled with a flat electrode connected to the ground electrode, it is possible to suppress the degradation of pass characteristics caused by the external shield electrode.

[0040] In the first embodiment, the path passing through via V10, plate electrode P1, via V11, plate electrode PL1, and via V12 corresponds to the "first path" in the present disclosure. In the first embodiment, the path passing through via V20, plate electrode P2, via V21, plate electrode PL2, and via V22 corresponds to the "second path" in the present disclosure. "Via VG10" and "via VG20" in the first embodiment correspond to the "third path" and "fourth path," respectively. "Top surface 111" and "bottom surface 112" in the first embodiment correspond to the "first surface" and "second surface" in the present disclosure. "Capacitor electrode PC31" and "capacitor electrode PC32" in the first embodiment correspond to the "first capacitor electrode" and "second capacitor electrode," respectively. "Plate electrode PC30" in the first embodiment corresponds to the "plate electrode" in the present disclosure.

[0041] In the above "first line," the "plate electrode PL1" corresponds to the "first wiring pattern" of the present disclosure, the "vias V10 and V11" correspond to the "first via" of the present disclosure, and the "via V12" corresponds to the "second via" of the present disclosure. Also, in the above "second line," the "plate electrode PL2" corresponds to the "second wiring pattern" of the present disclosure, the "vias V20 and V21" correspond to the "third via" of the present disclosure, and the "via V22" corresponds to the "fourth via" of the present disclosure.

[0042] (Variation 1) In the first modification, a configuration in which an LC series resonator is applied to the shunt path of the filter device 100 of the first embodiment will be described. In other words, in FIG. Comparative Example An example in which the features of the first embodiment are applied to the filter device 100X will be described.

[0043] Fig. 6 is an equivalent circuit diagram of a filter device 100A according to Modification 1. In filter device 100A, a capacitor C11 is added between inductor L11 and connection node N1 in Fig. 1, and a capacitor C21 is added between inductor L21 and connection node N2. The other configuration is the same as that of filter device 100, and description of elements that overlap with those in Fig. 1 will not be repeated.

[0044] Fig. 7 is a see-through perspective view showing the internal structure of a filter device 100A of Modification 1. In Fig. 7, the filter device 100A is roughly configured such that capacitor electrodes PC10 and PC20 are added to the filter device 100 described in Fig. 3.

[0045] The capacitor electrode PC10 is connected to an end of the via V12, which is connected to the second end of the plate electrode PL1, on the upper surface 111 side. The capacitor electrode PC10 has a substantially rectangular shape when the laminate 110 is viewed from above in the stacking direction, and is disposed opposite the plate electrode PC30. The capacitor electrode PC10 and the plate electrode PC30 together form the capacitor C11 in FIG. 6.

[0046] The capacitor electrode PC20 is connected to the end of the via V22, which is connected to the second end of the plate electrode PL2, on the upper surface 111 side. The capacitor electrode PC20 has a substantially rectangular shape when the laminate 110 is viewed from above in the stacking direction, and is disposed opposite the plate electrode PC30. The capacitor electrode PC20 and the plate electrode PC30 together form the capacitor C21 in FIG. 6.

[0047] When the laminate 110 is viewed from above in the lamination direction, the plate electrode PC30 covers the capacitor electrodes PC10 and PC20.

[0048] In this way, by forming an LC series resonator in the shunt path, an attenuation pole can be added to the non-pass band, thereby improving the attenuation characteristics of the filter device. Furthermore, since the capacitor electrodes PC10 and PC20, which are electrodes on the high electrostatic potential side of the capacitors constituting the LC series resonator, are covered by the plate electrode PC30, which can function as an internal shield electrode, fluctuations in the electrostatic potential of the capacitor electrodes PC10 and PC20 are suppressed even when an external shield electrode approaches the top surface 111 of the laminate 110. This makes it possible to suppress degradation of the pass characteristics caused by the external shield electrode.

[0049] Fig. 8 is a diagram illustrating the effect on the pass characteristics of the filter device 100A of Modification 1 of the present invention of the presence or absence of an external shield electrode. In Fig. 8, the horizontal axis also represents frequency, and the vertical axis represents insertion loss (solid lines LN30, LN30A, dashed lines LN31, LN31A) and return loss (solid lines LN35, dashed line LN36). The solid lines LN30, LN30A, and LN35 represent the characteristics when there is no external shield electrode, and the dashed lines LN31, LN31A, and LN36 represent the characteristics when the external shield electrode is closer.

[0050] 8, in filter device 100A of Modification 1, the insertion loss and reflection loss when the external shield electrode is close to upper surface 111 are almost the same as when there is no external shield electrode. Therefore, the configuration of filter device 100A can also suppress degradation of transmission characteristics caused by the external shield electrode.

[0051] The "capacitor electrode PC10" and the "capacitor electrode PC20" in Modification 1 correspond to the "fourth capacitor electrode" and the "fifth capacitor electrode" in the present disclosure, respectively.

[0052] (Variation 2) Modification 2 describes another example of the capacitive coupling configuration between two shunt paths in a filter device having a circuit configuration similar to that of Modification 1 shown in Fig. 6. Fig. 9 is a see-through perspective view showing the internal structure of filter device 100B of Modification 2. In filter device 100B, the plate electrodes PL1 and PL2 in filter device 100A of Modification 1 shown in Fig. 7 are replaced with plate electrodes PL1B and PL2B, and capacitor electrodes PC31 and PC32 are deleted. The other configuration of filter device 100B is similar to that of filter device 100A, and description of elements that overlap with those in Fig. 7 will not be repeated.

[0053] 9, each of the plate electrodes PL1B, PL2B is a strip-shaped electrode having a substantially C-shape when the laminate 110 is viewed from above in the stacking direction. A via V11 is connected to a first end of the plate electrode PL1B, and a via V12 is connected to a second end. A via V21 is connected to a first end of the plate electrode PL2B, and a via V22 is connected to a second end.

[0054] The plate electrodes PL1B and PL2B are disposed on different dielectric layers. When the laminate 110 is viewed from above in the stacking direction, a portion of the plate electrode PL1B overlaps a portion of the plate electrode PL2B. In other words, the plate electrodes PL1B and PL2B are capacitively coupled to each other, thereby forming the capacitor C1 in FIG. 6. When the laminate 110 is viewed from above in the stacking direction, the plate electrodes PL1B and PL2B and the capacitor electrodes PC10 and PC20 are covered by the plate electrode PC30 disposed on the upper surface 111.

[0055] In the configuration of filter device 100B of Modification 2, the plate electrodes PL1B, PL2B and capacitor electrodes PC10, PC20 on the high electrostatic potential side that constitute the capacitor are also covered by plate electrode PC30 that can function as an internal shield electrode, so that fluctuations in the electrostatic potential of these electrodes are suppressed even when an external shield electrode approaches top surface 111 of laminate 110. This makes it possible to suppress degradation of pass characteristics caused by the external shield electrode.

[0056] In Modification 2, the path passing through via V10, plate electrode P1, via V11, plate electrode PL1B, and via V12 corresponds to the "first path" in this disclosure. In Modification 2, the path passing through via V20, plate electrode P2, via V21, plate electrode PL2B, and via V22 corresponds to the "second path" in this disclosure.

[0057] (Variation 3) In the third modification, another example of the configuration for forming capacitive coupling between the plate electrodes PL1 and PL2 in the filter device 100A of the first modification will be described.

[0058] FIG. 10 shows a filter device according to a third modification. 100C 1 is a transparent perspective view showing the internal structure of the filter device. 100C In the filter device 100A, the capacitor electrodes PC31 and PC32 are replaced with a capacitor electrode PC35. 100C The other configurations in the filter device 100A are substantially the same as those in the filter device 100A, although some of the electrodes have different shapes, and therefore description of overlapping elements will not be repeated.

[0059] 10, the capacitor electrode PC35 has a configuration in which four linear electrodes are arranged to form a rectangle with an opening therein. The capacitor electrode PC35 is arranged on a dielectric layer between the dielectric layer on which the plate electrodes PL1 and PL2 are arranged and the dielectric layer on which the plate electrode PC30 is arranged. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC35 partially overlaps with the plate electrodes PL1 and PL2. The capacitor electrode PC35 and the plate electrodes PL1 and PL2 form the capacitor C1 in FIG. 6.

[0060] Furthermore, when the laminate 110 is viewed from above in the lamination direction, the capacitor electrode PC35, the plate electrode PL1, and the plate electrode PL2 , and the capacitor electrodes PC10, PC20 are covered by a plate electrode PC30 arranged on the top surface 111 side of the laminate 110. This suppresses fluctuations in the electrostatic potential of these electrodes even when an external shield electrode approaches the top surface 111 side of the laminate 110. This makes it possible to suppress degradation of transmission characteristics caused by the external shield electrode.

[0061] The "capacitor electrode PC35" in the third modification corresponds to the "third capacitor electrode" in the present disclosure.

[0062] (Variation 4) In the fourth modification, another example of the configuration for forming capacitive coupling between the plate electrodes PL1 and PL2 in the filter device 100A of the first modification will also be described.

[0063] 11 is a see-through perspective view showing the internal structure of a filter device 100D of Modification 4. In the filter device 100D, the plate electrode PL1 in the filter device 100A is replaced with plate electrodes PL1D1 and PL1D2, and the plate electrode PL2 is replaced with plate electrodes PL2D1 and PL2D2. Furthermore, capacitor electrodes PT10, PT15, PT20, and PT25 are provided instead of the capacitor electrodes PC31 and PC32 of the filter device 100A. The other configuration of the filter device 100D is similar to that of the filter device 100A, and description of overlapping elements will not be repeated. Note that the plate electrodes PL1D1 and PL1D2 may be collectively referred to as the "plate electrode PL1D," and the plate electrodes PL2D1 and PL2D2 may be collectively referred to as the "plate electrode PL2D."

[0064] 11, the plate electrodes PL1D1 and PL1D2 have the same shape when the laminate 110 is viewed in a plane from the stacking direction, and are arranged to overlap each other on dielectric layers that are different in the stacking direction. In FIG. 11, the plate electrode PL1D2 is arranged closer to the upper surface 111 than the plate electrode PL1D1. A via V11 is connected to first ends of the plate electrodes PL1D1 and PL1D2, and a via V12 is connected to second ends of the plate electrodes PL1D1 and PL1D2. A capacitor electrode PT15 extending in the positive direction of the X-axis on the same dielectric layer is connected to the plate electrode PL1D1. Furthermore, a capacitor electrode PT10 extending in the negative direction of the Y-axis on the same dielectric layer is connected to the plate electrode PL1D2. When the laminate 110 is viewed in a plane from the stacking direction, the connection position of the capacitor electrode PT15 on the plate electrode PL1D1 is different from the connection position of the capacitor electrode PT10 on the plate electrode PL1D2.

[0065] Similarly, the plate electrodes PL2D1 and PL2D2 have the same shape when the laminate 110 is viewed in a plane from the stacking direction, and are arranged to overlap each other on dielectric layers that are different in the stacking direction. In FIG. 11, the plate electrode PL2D1 is arranged on the same dielectric layer as the plate electrode PL1D1, and the plate electrode PL2D2 is arranged on the same dielectric layer as the plate electrode PL1D2. A via V21 is connected to first ends of the plate electrodes PL2D1 and PL2D2, and a via V22 is connected to second ends of the plate electrodes PL2D1 and PL2D2. A capacitor electrode PT25 extending in the negative direction of the X-axis on the same dielectric layer is connected to the plate electrode PL2D1. Furthermore, a capacitor electrode PT20 extending in the positive direction of the Y-axis on the same dielectric layer is connected to the plate electrode PL2D2. The capacitor electrode PT25 is connected to the plate electrode PL2D1 so as to partially overlap with the plate electrode PT10 when the laminate 110 is viewed in a plane from the stacking direction. Furthermore, the capacitor electrode PT20 is connected to the plate electrode PL2D1 so as to partially overlap the plate electrode PT15 when the laminate 110 is viewed from above in the lamination direction.

[0066] That is, the pair of capacitor electrodes PT10 and PT25 and the capacitor electrode PT15 and capacitor electrodes PT20 The capacitor C1 in Fig. 6 is configured by the pair of the capacitor electrode PT10 and the capacitor electrode PT25, and the capacitor electrode PT15 and capacitor electrodes PT20 Alternatively, only one of the pair may be provided.

[0067] When the laminate 110 is viewed from above in the stacking direction, the capacitor electrodes PT10, PT15, PT20, PT25, the plate electrodes PL1D, PL2D, and the capacitor electrodes PC10, PC20 are covered by the plate electrode PC30. This suppresses fluctuations in the electrostatic potential of these electrodes even when an external shield electrode approaches the top surface 111 of the laminate 110. This suppresses degradation of the transmission characteristics caused by the external shield electrode.

[0068] "Capacitor electrodes PT10, PT15" in Modification 4 correspond to "first capacitor electrodes" in the present disclosure. "Capacitor electrodes PT20, PT25" in Modification 4 correspond to "second capacitor electrodes" in the present disclosure. In Modification 4, the path passing through via V10, plate electrode P1, via V11, plate electrode PL1D, and via V12 corresponds to "first path" in the present disclosure. In Modification 4, the path passing through via V20, plate electrode P2, via V21, plate electrode PL2D, and via V22 corresponds to "second path" in the present disclosure.

[0069] (Variation 5) In the fifth modification, another example of the configuration for forming capacitive coupling between the plate electrodes PL1 and PL2 in the filter device 100A of the first modification will also be described.

[0070] 12 is a see-through perspective view showing the internal structure of a filter device 100E of Modification 5. In filter device 100E, plate electrode PL1 in filter device 100A is replaced with plate electrodes PL1E1 and PL1E2, and plate electrode PL2 is replaced with plate electrodes PL2E1 and PL2E2. Furthermore, a capacitor electrode PC36 is provided instead of capacitor electrodes PC31 and PC32 in filter device 100A. The other configuration of filter device 100E is similar to that of filter device 100A, and description of overlapping elements will not be repeated. Note that plate electrodes PL1E1 and PL1E2 may be collectively referred to as "plate electrode PL1E," and plate electrodes PL2E1 and PL2E2 may be collectively referred to as "plate electrode PL2E."

[0071] 12, the plate electrodes PL1E1 and PL1E2 have the same shape when the laminate 110 is viewed in plan from the stacking direction, and are arranged so as to overlap each other on dielectric layers with different stacking directions. In Fig. 12, the plate electrode PL1E2 is arranged closer to the upper surface 111 than the plate electrode PL1E1. A via V11 is connected to first ends of the plate electrodes PL1E1 and PL1E2, and a via V12 is connected to second ends thereof.

[0072] Similarly, the plate electrodes PL2E1 and PL2E2 have the same shape when the laminate 110 is viewed from above in the stacking direction, and are arranged so as to overlap each other on dielectric layers that are different in the stacking direction. In Fig. 12, the plate electrode PL2E1 is arranged on the same dielectric layer as the plate electrode PL1E1, and the plate electrode PL2E2 is arranged on the same dielectric layer as the plate electrode PL1E2. A via V21 is connected to first ends of the plate electrodes PL2E1 and PL2E2, and a via V22 is connected to second ends thereof.

[0073] The capacitor electrode PC36 is disposed on a dielectric layer between the dielectric layer on which the plate electrodes PL1E1 and PL2E1 are disposed and the dielectric layer on which the plate electrodes PL1E2 and PL2E2 are disposed. In Fig. 12, the capacitor electrode PC36 is a strip-shaped electrode extending in the X-axis direction. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC36 partially overlaps with the plate electrodes PL1E and PL2E. That is, the capacitor electrode PC36 and the plate electrodes PL1E and PL2E form the capacitor C1 in Fig. 6.

[0074] When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC36, the plate electrodes PL1E, PL2E, and the capacitor electrodes PC10, PC20 are covered by the plate electrode PC30. This suppresses fluctuations in the electrostatic potential of these electrodes even when an external shield electrode approaches the top surface 111 of the laminate 110. This suppresses deterioration in transmission characteristics caused by the external shield electrode.

[0075] The "capacitor electrode PC36" in Modification 5 corresponds to the "third capacitor electrode" in the present disclosure. In Modification 5, the path passing through via V10, plate electrode P1, via V11, plate electrode PL1E, and via V12 corresponds to the "first path" in the present disclosure. In Modification 5, the path passing through via V20, plate electrode P2, via V21, plate electrode PL2E, and via V22 corresponds to the "second path" in the present disclosure.

[0076] [Embodiment 2] In the second embodiment and the following modifications 6 to 9, a configuration will be described in which an LC series resonator is added to the configuration of the filter device of the first embodiment or modifications 1 to 5. As described above, by adding a resonator, the number of attenuation poles can be increased, thereby improving the attenuation characteristics of the filter device in the non-pass bands.

[0077] Fig. 13 is an equivalent circuit diagram of a filter device 100F according to embodiment 2. The filter device 100F has a configuration in which the inductor L1 in the filter device 100 according to embodiment 1 shown in Fig. 1 is replaced with a circuit shown in an area AR1 enclosed by a dashed line in Fig. 13.

[0078] Specifically, in the filter device 100F, inductors L41 and L42 are connected in series between a connection node N1 between inductors L11 and L12 and a connection node N2 between inductors L21 and L22. One end of inductor L43 is connected to a connection node N3 between inductors L41 and L42. The other end of inductor L43 is connected to ground terminal GND via capacitor C41.

[0079] Note that the inductors L41 and L42 substantially correspond to the inductor L1 in Fig. 1. Therefore, the filter device 100F corresponds to a configuration in which an LC series resonant circuit (L43+C41) is connected between the inductor L1 of the filter device 100 of the first embodiment and the ground terminal GND.

[0080] Fig. 14 is a see-through perspective view showing the internal structure of a filter device 100F according to the second embodiment. The filter device 100F has a configuration in which a capacitor electrode PC55 and a via VG55 are added to the filter device 100 according to the first embodiment shown in Fig. 3. In Fig. 14, the description of elements that overlap with those in Fig. 3 will not be repeated.

[0081] 14, the via VG55 is connected to approximately the center of the plate electrode PC30. The via VG55 extends from the plate electrode PC30 toward the lower surface 112 and is connected to a capacitor electrode PC55 disposed opposite the ground electrode PG1. The capacitor electrode PC55 and the ground electrode PG1 form the capacitor C41 in FIG. 13. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC55 and the via VG55 are covered by the plate electrode PC30.

[0082] The portion of the plate electrode PC30 from the via V12 to the via VG55 corresponds to the inductor L41 in Fig. 13. The portion of the plate electrode PC30 from the via V22 to the via VG55 corresponds to the inductor L42 in Fig. 13. The via VG55 corresponds to the inductor L43 in Fig. 13.

[0083] Fig. 15 is a diagram illustrating the effect on the pass characteristics of the filter device 100F according to the second embodiment of the present invention of the presence or absence of an external shield electrode. In Fig. 15, the horizontal axis also represents frequency, and the vertical axis represents insertion loss (solid lines LN40, LN40A, dashed lines LN41, LN41A) and return loss (solid line LN45, dashed line LN46). The solid lines LN40, LN40A, and LN45 represent the characteristics when there is no external shield electrode, and the dashed lines LN41, LN41A, and LN46 represent the characteristics when the external shield electrode is closer.

[0084] 15, in filter device 100F of the second embodiment, the insertion loss and reflection loss when the external shield electrode is close to upper surface 111 are almost the same as those when there is no external shield electrode. Therefore, the configuration of filter device 100F can also suppress degradation of transmission characteristics caused by the external shield electrode.

[0085] The "via VG55" in the second embodiment corresponds to the "fifth line" in the present disclosure. Furthermore, the "capacitor electrode PC55" in the second embodiment corresponds to the "sixth capacitor electrode" in the present disclosure.

[0086] (Variation 6) In the sixth modification, a configuration will be described in which the LC series resonators in the filter device 100F of the second embodiment are connected in reverse.

[0087] Fig. 16 is an equivalent circuit diagram of a filter device 100G according to Modification 6. In the filter device 100G, in the equivalent circuit of the filter device 100F according to the second embodiment shown in Fig. 13, a capacitor C41 is connected to the connection node N3, and an inductor L43 is connected between the capacitor C41 and the ground terminal GND (broken line area AR2).

[0088] 17 is a perspective view showing the internal structure of a filter device 100G according to Modification 6. In the filter device 100G, the capacitor electrode PC55 and the vias in the filter device 100F of FIG. VG55 Instead, the capacitor electrode PC50 and the via VG50 will be established.

[0089] The capacitor electrode PC50 is disposed opposite the plate electrode PC30 in the dielectric layer between the plate electrode PC30 and the ground electrode PG1. The capacitor electrode PC50 is connected to the ground electrode PG1 by a via VG50. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC50 and the via VG50 are covered with the plate electrode PC30.

[0090] The capacitor electrode PC50 and the plate electrode PC30 form a capacitor C41 in Fig. 16. The via VG50 corresponds to the inductor L43 in Fig. 16.

[0091] In this configuration, as in the second embodiment, it is possible to suppress the degradation of transmission characteristics caused by the external shield electrode.

[0092] The "via VG50" in the sixth modification corresponds to the "sixth line" in the present disclosure. Also, the "capacitor electrode PC50" in the sixth modification corresponds to the "seventh capacitor electrode" in the present disclosure.

[0093] (Variation 7) In the seventh modification, a configuration will be described in which an LC series resonator similar to that in the second embodiment is added to the filter device 100C of the third modification shown in FIG.

[0094] Fig. 18 is an equivalent circuit diagram of a filter device 100H according to Modification 7. The equivalent circuit in Fig. 18 has a configuration in which the inductor L1 in the equivalent circuit shown in Fig. 6 is replaced with the circuit in the dashed line area AR3. That is, inductors L41 and L42 connected in series are connected between the connection node N1 and the connection node N2, and an LC series resonator formed by an inductor L43 and a capacitor C41 is connected between the connection node N3 of the inductors L41 and L42 and the ground terminal GND.

[0095] Fig. 19 is a see-through perspective view showing the internal structure of a filter device 100H according to Modification 7. The filter device 100H has a configuration in which a capacitor electrode PC55 and vias VG55, VG21, and VG22 are added to the configuration of the filter device 100C shown in Fig. 10. In Fig. 19, descriptions of elements that overlap with those in Fig. 10 will not be repeated.

[0096] Referring to FIG. 19, the via VG55 is connected to the approximate center of the plate electrode PC30. R The via VG55 extends from the plate electrode PC30 toward the lower surface 112 and is connected to a capacitor electrode PC55 disposed opposite the ground electrode PG1. The capacitor electrode PC55 and the ground electrode PG1 form a capacitor C41 in FIG. 18. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC55 and the via VG55 are covered with the plate electrode PC30.

[0097] The portion of the plate electrode PC30 from via V11 to via VG55 corresponds to inductor L41 in Fig. 18. The portion of the plate electrode PC30 from via V21 to via VG55 corresponds to inductor L42 in Fig. 18. Via VG55 corresponds to inductor L43 in Fig. 18.

[0098] The via VG11 is disposed adjacent to the via VG10 and is connected to the plate electrode PC30 and the ground electrode PG1. Similarly, the via VG21 is disposed adjacent to the via VG20 and is connected to the plate electrode PC30 and the ground electrode PG1. The vias VG11 and VG21 are provided to reduce the inductance values ​​of the inductors L12 and L22 in FIG. 18 and are not necessarily required components. If the desired inductance value can be achieved, only the vias VG10 and VG20 may be used.

[0099] Fig. 20 is a diagram illustrating the effect on the pass characteristics of the filter device 100H of Modification 7 of the present invention of the presence or absence of an external shield electrode. In Fig. 20, the horizontal axis also represents frequency, and the vertical axis represents insertion loss (solid lines LN50, LN50A, dashed lines LN51, LN51A) and return loss (solid line LN55, dashed line LN56). The solid lines LN50, LN50A, and LN55 represent the characteristics when there is no external shield electrode, and the dashed lines LN51, LN51A, and LN56 represent the characteristics when the external shield electrode is closer.

[0100] 20 , in filter device 100H of the second embodiment, the insertion loss and reflection loss when the external shield electrode is close to upper surface 111 are almost the same as those when there is no external shield electrode. Therefore, the configuration of filter device 100H can also suppress degradation of the transmission characteristics caused by the external shield electrode.

[0101] (Variation 8) In the eighth modification, a configuration will be described in which the LC series resonators in the filter device 100H of the seventh modification are connected in reverse.

[0102] Fig. 21 is an equivalent circuit diagram of a filter device 100I according to Modification 8. In the filter device 100I, in the equivalent circuit of the filter device 100H according to Modification 7 shown in Fig. 18, a capacitor C41 is connected to the connection node N3, and an inductor L43 is connected between the capacitor C41 and the ground terminal GND (broken line area AR4).

[0103] 22 is a see-through perspective view showing the internal structure of a filter device 100I of Modification 8. In the filter device 100I, the capacitor electrode PC55 and the vias in the filter device 100H of FIG. VG55 Instead, the capacitor electrode PC50 and the via VG50 will be established.

[0104] The capacitor electrode PC50 is disposed opposite the plate electrode PC30 on a dielectric layer between the plate electrode PC30 and the ground electrode PG1. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC50 is disposed between the capacitor electrodes PC10 and PC20 and does not overlap with the capacitor electrodes PC10 and PC20. The capacitor electrode PC50 may be disposed on the same dielectric layer as the capacitor electrodes PC10 and PC20, or on a different dielectric layer. The capacitor electrode PC50 is connected to the ground electrode PG1 by a via VG50. The via VG50 passes through an opening of the capacitor electrode PC35. When the laminate 110 is viewed from above in the stacking direction, the capacitor electrode PC50 and the via VG50 are covered by the plate electrode PC30.

[0105] Fig. 23 is a diagram illustrating the effect on the pass characteristics of the filter device 100I of Modification 8 of the present invention of the presence or absence of an external shield electrode. In Fig. 23, the horizontal axis also represents frequency, and the vertical axis represents insertion loss (solid lines LN60, LN60A, dashed lines LN61, LN61A) and return loss (solid line LN65, dashed line LN66). The solid lines LN60, LN60A, and LN65 represent the characteristics when there is no external shield electrode, and the dashed lines LN61, LN61A, and LN66 represent the characteristics when the external shield electrode is closer.

[0106] 23 , in filter device 100I of Modification 8, the insertion loss and reflection loss when the external shield electrode is close to upper surface 111 are almost the same as when there is no external shield electrode. Therefore, the configuration of filter device 100I can also suppress degradation of transmission characteristics caused by the external shield electrode.

[0107] The "via VG50" in the eighth modification corresponds to the "seventh line" in the present disclosure. Also, the "capacitor electrode PC50" in the eighth modification corresponds to the "eighth capacitor electrode" in the present disclosure.

[0108] (Variation 9) In the ninth modification, a configuration will be described in which the capacitor electrode PC50 in the filter device 100I of the eighth modification is capacitively coupled to the capacitor electrodes PC10 and PC20 connected to the respective lines.

[0109] Fig. 24 is an equivalent circuit diagram of a filter device 100J according to Modification 9. In the equivalent circuit diagram shown in Fig. 6, a circuit in a dashed line area AR5 is added between a connection node N4 between the inductor L11 and the capacitor C11 and a connection node N5 between the inductor L21 and the capacitor C21.

[0110] Specifically, capacitors C31 and C32 are connected in series between connection nodes N4 and N5. An inductor L31 is connected between a connection node N6 of the capacitors C31 and C32 and the ground terminal GND. The capacitors C31 and C32 and the inductor L31 form an LC series resonator.

[0111] Fig. 25 is a see-through perspective view showing the internal structure of a filter device 100J of Modification 9. The filter device 100J essentially has a configuration in which a capacitor electrode PC60 and vias VG60 and VG61 are added to the filter device 100A shown in Fig. 7. In Fig. 25, the description of elements that overlap with Fig. 7 will not be repeated.

[0112] 25, the capacitor electrode PC60 has a substantially rectangular shape when the laminate 110 is viewed in a plane in the stacking direction, and is disposed on a dielectric layer closer to the lower surface 112 than the capacitor electrodes PC10 and PC20. When the laminate 110 is viewed in a plane in the stacking direction, the capacitor electrode PC60 partially overlaps the capacitor electrodes PC10 and PC20. The capacitor electrode PC60 is connected to the ground electrode PG1 by vias VG60 and VG61. Note that two vias are not necessarily required to connect the capacitor electrode PC60 and the ground electrode PG1; one via may be used as long as the desired inductance value can be achieved.

[0113] The capacitor electrodes PC60 and PC10 form a capacitor C31 in Fig. 24. The capacitor electrodes PC60 and PC20 form a capacitor C32 in Fig. 24.

[0114] Fig. 26 is a diagram illustrating the effect on the pass characteristics of the filter device 100J of Modification 9 of the present invention of the presence or absence of an external shield electrode. In Fig. 26, the horizontal axis also represents frequency, and the vertical axis represents insertion loss (solid lines LN70, LN70A, dashed lines LN71, LN71A) and return loss (solid line LN75, dashed line LN76). The solid lines LN70, LN70A, and LN75 represent the characteristics when there is no external shield electrode, and the dashed lines LN71, LN71A, and LN76 represent the characteristics when the external shield electrode is closer.

[0115] 26 , in filter device 100J of Modification 9, the insertion loss and reflection loss when the external shield electrode is close to upper surface 111 are almost the same as when there is no external shield electrode. Therefore, the configuration of filter device 100J can also suppress degradation of transmission characteristics caused by the external shield electrode.

[0116] The "vias VG60 and VG61" in the ninth modification correspond to the "seventh line" in the present disclosure. Also, the "capacitor electrode PC60" in the ninth modification corresponds to the "eighth capacitor electrode" in the present disclosure. [Aspect] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0117] (Item 1) A filter device according to one aspect includes a laminate formed by stacking a plurality of dielectric layers, an input terminal, an output terminal, a ground terminal, a ground electrode connected to the ground terminal, a plate electrode, and first to fourth lines. The laminate has a first surface and a second surface. The input terminal, the output terminal, and the ground terminal are arranged on the second surface. The plate electrode is arranged closer to the first surface than the ground electrode. The first line is electrically connected to the input terminal and the plate electrode. The second line is electrically connected to the output terminal and the plate electrode. The third line and the fourth line connect the plate electrode and the ground electrode. The first line is capacitively coupled to the second line. When the laminate is viewed from above in the stacking direction, the plate electrode covers the portion where the first line and the second line are capacitively coupled.

[0118] (Item 2) The filter device described in item 1 further includes a first capacitor electrode disposed between the plate electrode and the second surface and connected to the first line. When the laminate is viewed from above in the stacking direction, the first capacitor electrode and the second line partially overlap, and the plate electrode covers the first capacitor electrode.

[0119] (Item 3) The filter device according to Items 1 or 2 further includes a second capacitor electrode disposed between the plate electrode and the second surface and connected to the second line. When the laminate is viewed from above in the stacking direction, the second capacitor electrode and the first line partially overlap, and the plate electrode covers the second capacitor electrode.

[0120] (Item 4) The filter device according to item 1 further includes a first capacitor electrode and a second capacitor electrode disposed between the plate electrode and the second surface and connected to the first line and the second line, respectively. When the laminate is viewed from above in the stacking direction, the first capacitor electrode and the second capacitor electrode partially overlap, and the plate electrode covers the first capacitor electrode and the second capacitor electrode.

[0121] (Item 5) The filter device according to item 1 further includes a third capacitor electrode disposed between the plate electrode and the second surface. When the laminate is viewed from above in the stacking direction, the third capacitor electrode partially overlaps with both the first line and the second line, and the plate electrode covers the third capacitor electrode.

[0122] (Item 6) In the filter device described in item 1, when the laminate is viewed in a plane from the stacking direction, at least a portion of the first line overlaps with the second line, and the plate electrode covers the overlapping portion of the first line and the second line.

[0123] (7) The filter device according to any one of paragraphs 1 to 6 further includes a fourth capacitor electrode and a fifth capacitor electrode. The fourth capacitor electrode is connected to the first line and is arranged opposite the plate electrode. The fifth capacitor electrode is connected to the second line and is arranged opposite the plate electrode.

[0124] (Item 8) The filter device according to any one of items 1 to 7 further includes an LC series resonator disposed between the plate electrode and the ground electrode. The LC series resonator includes a sixth capacitor electrode disposed opposite the ground electrode, and a fifth line connected to the sixth capacitor electrode and the plate electrode.

[0125] (Item 9) The filter device according to any one of items 1 to 6 further includes an LC series resonator arranged between the plate electrode and the ground electrode. The LC series resonator includes a seventh capacitor electrode and a sixth line. The seventh capacitor electrode is arranged on the second surface side of the plate electrode so as to face the plate electrode. The sixth line is connected to the seventh capacitor electrode. and The plate electrode is connected to the ground electrode. When the laminate is viewed from above in the lamination direction, the plate electrode further covers the seventh capacitor electrode.

[0126] (Item 10) The filter device according to item 7 further includes an LC series resonator arranged between the plate electrode and the ground electrode. The LC series resonator further includes an eighth capacitor electrode and a seventh line. The eighth capacitor electrode is arranged closer to the second surface than the plate electrode. The seventh line is connected to the eighth capacitor electrode and the ground terminal. When the laminate is viewed from above in the stacking direction, the plate electrode further covers the eighth capacitor electrode.

[0127] (Item 11) In the filter device according to item 10, when the laminate is viewed in a plane in the lamination direction, the eighth capacitor electrode is disposed between the fourth capacitor electrode and the fifth capacitor electrode.

[0128] (Item 12) In the filter device according to item 11, the eighth capacitor electrode is disposed on the same dielectric layer as the fourth capacitor electrode and the fifth capacitor electrode.

[0129] (Item 13) In the filter device according to item 10, when the laminate is viewed in a plane in the lamination direction, the eighth capacitor electrode partially overlaps with the fourth capacitor electrode and the fifth capacitor electrode.

[0130] (Item 14) In the filter device described in any one of items 1 to 13, the first line includes a first wiring pattern arranged on a dielectric layer in the laminate, and a first via and a second via. The first via connects the first wiring pattern to the input terminal. The second via electrically connects the first wiring pattern to the plate electrode. The second line includes a second wiring pattern arranged on a dielectric layer in the laminate, and a third via and a fourth via. The third via connects the second wiring pattern to the output terminal. The fourth via electrically connects the second wiring pattern to the plate electrode.

[0131] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0132] 100, 100A to 100J, 100X filter device, 110 laminate, 111 upper surface, 112 lower surface, C1, C11, C21, C31, C32, C41 capacitors, DM direction mark, GND ground terminal, L1, L11, L12, L21, L22, L31, L41 to L43 inductors, N1 to N6 connection nodes, P1, P2, PC30, PL1, PL2, PL1B, PL1D, PL1D1, PL1D2, PL1E, PL1E1, PL1E2, PL2B, PL2D, PL2D1, PL2D2, PL2E, PL2E1, PL2E2, PT10, PT15 Plate electrodes, PC10, PC10X, PC20, PC20X, PC31, PC32, PC35, PC36, PC40, PC41, PC42, PC50, PC55, PC60, PT10, PT15, PT20, PT25 capacitor electrodes, PG1 ground electrode, SH external shield electrode, T1 input terminal, T2 output terminal, V10 to V12, V12X, V20 to V22, V22X, V50, V55, VG1, VG10, VG11, VG20 to VG22, VG50, VG55, VG60, VG61 vias.

Claims

1. a laminate having a first surface and a second surface and including a plurality of dielectric layers stacked on top of one another; an input terminal, an output terminal, and a ground terminal disposed on the second surface; a ground electrode connected to the ground terminal; a flat plate electrode disposed closer to the first surface than the ground electrode; a first line connected to the input terminal and capacitively coupled to the plate electrode; a second line connected to the output terminal and capacitively coupled to the plate electrode; a third line and a fourth line connecting the plate electrode and the ground electrode; the first line is capacitively coupled to the second line, a filter device, wherein when the laminate is viewed in a plane from the stacking direction, the plate electrode covers a portion where the first line and the second line are capacitively coupled.

2. a first capacitor electrode disposed between the plate electrode and the second surface and connected to the first line; When the laminate is viewed in plan from the stacking direction, the first capacitor electrode and the second line partially overlap; The filter device of claim 1 , wherein the plate electrode covers the first capacitor electrode.

3. a second capacitor electrode disposed between the plate electrode and the second surface and connected to the second line; When the laminate is viewed in plan from the stacking direction, the second capacitor electrode and the first line partially overlap; The filter device of claim 1 , wherein the plate electrode covers the second capacitor electrode.

4. a first capacitor electrode disposed between the plate electrode and the second surface and connected to the first line; a second capacitor electrode disposed between the plate electrode and the second surface and connected to the second line; When the laminate is viewed in plan from the stacking direction, the first capacitor electrode and the second capacitor electrode partially overlap; The filter device according to claim 1 , wherein the plate electrode covers the first capacitor electrode and the second capacitor electrode.

5. a third capacitor electrode disposed between the plate electrode and the second surface; When the laminate is viewed in plan from the stacking direction, the third capacitor electrode partially overlaps both the first line and the second line; The filter device of claim 1 , wherein the plate electrode covers the third capacitor electrode.

6. When the laminate is viewed in plan from the stacking direction, At least a portion of the first line overlaps with the second line, The filter device according to claim 1 , wherein the plate electrode covers an overlapping portion of the first line and the second line.

7. a fourth capacitor electrode connected to the first line and disposed opposite the plate electrode; 7. The filter device according to claim 1, further comprising: a fifth capacitor electrode connected to the second line and disposed opposite the plate electrode.

8. The laminate further comprises an LC series resonator disposed between the plate electrode and the ground electrode, The LC series resonator is a sixth capacitor electrode disposed opposite the ground electrode; 7. The filter device according to claim 1, further comprising a fifth line connected to the sixth capacitor electrode and the plate electrode.

9. The laminate further comprises an LC series resonator disposed between the plate electrode and the ground electrode, The LC series resonator is a seventh capacitor electrode disposed opposite the plate electrode on the second surface side of the plate electrode; a sixth line connected to the seventh capacitor electrode and the ground electrode; 7. The filter device according to claim 1, wherein the plate electrode further covers the seventh capacitor electrode when the laminate is viewed from above in the lamination direction.

10. The laminate further comprises an LC series resonator disposed between the plate electrode and the ground electrode, The LC series resonator is an eighth capacitor electrode disposed closer to the second surface than the plate electrode; a seventh line connected to the eighth capacitor electrode and the ground electrode; The filter device according to claim 7 , wherein the plate electrode further covers the eighth capacitor electrode when the laminate is viewed from above in the lamination direction.

11. The filter device according to claim 10 , wherein the eighth capacitor electrode is disposed between the fourth capacitor electrode and the fifth capacitor electrode when the laminate is viewed in a plan view from the stacking direction.

12. The filter device of claim 11 , wherein the eighth capacitor electrode is disposed on the same dielectric layer as the fourth capacitor electrode and the fifth capacitor electrode.

13. The filter device according to claim 10 , wherein the eighth capacitor electrode partially overlaps with the fourth capacitor electrode and the fifth capacitor electrode when the laminate is viewed in a plan view from the stacking direction.

14. The first line is a first wiring pattern disposed on a dielectric layer within the laminate; a first via for connecting the first wiring pattern and the input terminal; a second via for connecting the first wiring pattern and the fourth capacitor electrode; The second line is a second wiring pattern disposed on a dielectric layer within the laminate; a third via for connecting the second wiring pattern and the output terminal; 8. The filter device according to claim 7, further comprising a fourth via for connecting the second wiring pattern and the fifth capacitor electrode.

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