Stacked LC filter

Abstract

The present invention provides a stacked LC filter that suppresses passband narrowing and improves return loss. In a multilayer substrate (1), the end of the first inductor L1 on the ground terminal (G1, G2) side, that is, the via hole electrode (2q) is connected to the shielding electrode (5), and in the stacking direction of the base material layers (1a to 1q), the end on the signal line (6) side (the connection point between the capacitor electrode (4e) and the via hole electrode (2k)) is located closer to the first main surface ( ) than the end on the ground terminal (G1, G2) side (the connection point between the via hole electrode (2q) and the shielding electrode (5)). 1A) side, the end portion on the ground terminal (G1, G2) side of the second inductor L2, namely the via electrode (2r), is connected to the shielding electrode (5), and in the stacking direction of the substrate layers (1a to 1q), the end portion on the signal line (6) side (the connection point between the capacitor electrode (4f) and the via electrode (2l)) is located closer to the first main surface (1A) than the end portion on the ground terminal (G1, G2) side (the connection point between the via electrode (2r) and the shielding electrode (5)).

Description

Technical Field

[0001] The present invention relates to a stacked LC filter in which an inductor and a capacitor are formed inside a multilayer substrate. Background Art

[0002] A stacked LC filter is disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2008-167157). The stacked LC filter disclosed in Patent Document 1 is a high-pass filter.

[0003] The stacked LC filter disclosed in Patent Document 1 includes a multilayer substrate having a plurality of laminated base layers. Via electrodes are formed through the base layers. Line electrodes and capacitor electrodes are formed between the base layers. The via electrodes and line electrodes form an inductor, while the capacitor electrodes form a capacitor.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-167157

[0005] In the stacked LC filter disclosed in Patent Document 1, shield electrodes are sometimes required between layers or on the main surface of a multilayer substrate to suppress noise intrusion from the outside and noise radiation from the inside. Furthermore, a shunt inductor is sometimes provided within the multilayer substrate, with one end connected to a signal line and the other end connected to ground.

[0006] Since the shield electrode is typically connected to ground, if the signal-line-side end of a shunt inductor is close to the shield electrode within a multilayer substrate, significant stray capacitance may occur between the signal-line-side end and the shield electrode. This stray capacitance is formed in parallel with the shunt inductor, so if it is large, the passband may become narrower and the return loss may increase. Summary of the Invention

[0007] Therefore, an object of the present invention is to provide a multilayer LC filter that suppresses generation of stray capacitance between the end portion of an inductor on the signal line side and a shield electrode, thereby suppressing narrowing of the passband and improving return loss.

[0008] To solve the existing problems, a stacked LC filter according to one embodiment of the present invention comprises: a multilayer substrate having a plurality of base material layers stacked together, the multilayer substrate having a first main surface and a second main surface; via electrodes formed to penetrate the base material layers; line electrodes and capacitor electrodes formed between the base material layers; and a first terminal, a second terminal, and a ground terminal formed on the first main surface of the multilayer substrate. An inductor is formed by at least one of the via electrodes and the line electrodes, and a capacitor is formed by the capacitor electrodes. A signal line is formed between the first terminal and the second terminal, a third capacitor is connected midway along the signal line, and the first capacitor and the first inductor are connected in series, in that order, between the signal line between the first terminal and the third capacitor and the ground terminal. The signal line between the third capacitor and the second terminal is connected in series with the first capacitor and the first inductor. The multilayer LC filter further comprises a second capacitor and a second inductor connected in series between the signal line and the ground terminal, in that order. The multilayer LC filter further comprises: a shield electrode formed between layers of the base layer on a side closer to the second main surface of the multilayer substrate, or formed on the second main surface of the multilayer substrate; and a third inductor connected between the shield electrode and the ground terminal. In the multilayer substrate, an end of the first inductor on the ground terminal side is connected to the shield electrode, an end of the first inductor on the signal line side is located closer to the first main surface than an end of the first inductor on the ground terminal side in a stacking direction of the base layers, and an end of the second inductor on the ground terminal side is connected to the shield electrode, and an end of the second inductor on the signal line side is located closer to the first main surface than an end of the second inductor on the ground terminal side in the stacking direction of the base layers.

[0009] The stacked LC filter of the present invention suppresses stray capacitance generated between the end of the first inductor on the signal line side and the shield electrode, and between the end of the second inductor on the signal line side and the shield electrode, thereby suppressing passband narrowing and improving return loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 (A) is a perspective view of the multilayer LC filter 100 according to the embodiment as viewed from the second main surface side. Figure 1 (B) is a perspective view of the multilayer LC filter 100 as viewed from the first main surface side.

[0011] Figure 2 It is an exploded perspective view of the multilayer LC filter 100 .

[0012] Figure 3 1 is an equivalent circuit diagram of the multilayer LC filter 100 .

[0013] Figure 4 It is an exploded perspective view of a multilayer LC filter 500 according to a comparative example.

[0014] Figure 5 : is an equivalent circuit diagram of the multilayer LC filter 500 .

[0015] Figure 6 1 is a characteristic diagram of the multilayer LC filter 100 .

[0016] Figure 7 4 is a characteristic diagram of the multilayer LC filter 500 . DETAILED DESCRIPTION

[0017] The following, with the attached Figure 1 First, the mode for implementing the present invention will be described.

[0018] In addition, each embodiment exemplifies the manner in which the present invention is implemented, and the present invention is not limited to the contents of the embodiment. In addition, the contents described in different embodiments can also be combined for implementation, and the implementation contents in this case are also included in the present invention. In addition, the drawings are used to help understand the description, and sometimes they are schematically depicted, and sometimes the ratio of the dimensions of the depicted components or components is inconsistent with the ratio of their dimensions described in the description. In addition, there are cases where the components described in the description are omitted in the drawings, or the number of components is omitted and depicted, etc.

[0019] Figure 1 (A), (B), Figure 2 、 Figure 3 : shows a multilayer LC filter 100 according to an embodiment of the present invention. Figure 1 FIG. 1(A) is a perspective view of the multilayer LC filter 100 as viewed from the second principal surface (upper principal surface) side. Figure 1 FIG. 1(B) is a perspective view of the multilayer LC filter 100 as viewed from the first principal surface (lower principal surface) side. Figure 2 It is an exploded perspective view of the multilayer LC filter 100 . Figure 3 1 is an equivalent circuit diagram of the multilayer LC filter 100 .

[0020] In addition, Figure 1 (A), (B), Figure 2 In the figure, arrows indicate the height direction T, length direction L, and width direction W of the stacked LC filter 100, respectively. However, these directions may be referred to in the following description. The height direction T refers to the direction in which the multilayer substrate 1, described later, is stacked. The length direction L refers to the direction in which the first terminal T1 and the second terminal T2, described later, are arranged. The width direction W refers to a direction perpendicular to the height direction T and the length direction L.

[0021] A stacked LC filter 100 includes a multilayer substrate 1. The multilayer substrate 1 includes a first main surface 1A and a second main surface 1B facing each other in a height direction T, a first side surface 1C and a second side surface 1D facing each other in a width direction W, and a first end surface 1E and a second end surface 1F facing each other in a length direction L.

[0022] A first terminal T1, a second terminal T2, two ground terminals G1 and G2, a first floating terminal F1, and a second floating terminal F2 are formed on the first main surface 1A of the multilayer substrate 1. On the first main surface 1A, the first terminal T1 and the first floating terminal F1 are arranged side by side in the width direction W. The ground terminal G1 and the ground terminal G2 are arranged side by side in the width direction W. The second terminal T2 and the second floating terminal F2 are arranged side by side in the width direction W. The first terminal T1 and the first floating terminal F1, the ground terminal G1 and the ground terminal G2, and the second terminal T2 and the second floating terminal F2 are arranged side by side in the length direction L.

[0023] Multilayer substrate 1 is composed of a substrate having a plurality of base material layers 1a to 1q stacked on top of each other. Multilayer substrate 1 (base material layers 1a to 1q) can be formed, for example, from low-temperature co-fired ceramic. However, the material of multilayer substrate 1 is not limited to low-temperature co-fired ceramic and may also be other types of ceramics, resins, etc.

[0024] Hereinafter, the structure of each of the base material layers 1a to 1q will be described.

[0025] As described above, the first terminal T1, the second terminal T2, the two ground terminals G1 and G2, the first floating terminal F1, and the second floating terminal F2 are formed on the lower main surface (first main surface 1A) of the base layer 1a. Figure 2 In FIG. 1 , for ease of illustration, the first terminal T1 , the second terminal T2 , the ground terminals G1 and G2 , the first floating terminal F1 , and the second floating terminal F2 are shown with dotted lines away from the base material layer 1 a .

[0026] Via-hole electrodes 2a, 2b, 2c, 2d, 2e, and 2f are formed to penetrate between both main surfaces of the base material layer 1a.

[0027] The above-mentioned via hole electrodes 2 a , 2 b , 2 c , 2 d , 2 e , and 2 f are formed to penetrate between the two main surfaces of the base material layer 1 b .

[0028] Line electrodes 3 a , 3 b , and 3 c are formed on the upper main surface of the base material layer 1 c .

[0029] The above-mentioned via hole electrodes 2 a , 2 b , 2 e , and 2 f are formed to penetrate between the two main surfaces of the base material layer 1 c .

[0030] Line electrodes 3d, 3e, and 3f are formed on the upper main surface of the base material layer 1d.

[0031] The aforementioned via hole electrodes 2a, 2b, 2e, and 2f and new via hole electrodes 2g, 2h, and 2i are formed to penetrate between the two main surfaces of the base material layer 1d.

[0032] Line electrodes 3g are formed on the upper main surface of the base material layer 1e.

[0033] The above-mentioned via hole electrodes 2g, 2h, and 2i are formed to penetrate between the two main surfaces of the base material layer 1e.

[0034] Capacitor electrodes 4a and 4b are formed on the upper main surface of base material layer 1f. Capacitor electrode 4a and capacitor electrode 4b are connected to each other.

[0035] The aforementioned via hole electrodes 2g and 2h and a new via hole electrode 2j are formed to penetrate between the two main surfaces of the base material layer 1f.

[0036] Capacitor electrodes 4c and 4d are formed on the upper main surface of the base layer 1g.

[0037] The above-mentioned via hole electrodes 2g, 2h, and 2j are formed to penetrate between the two main surfaces of the base material layer 1g.

[0038] Capacitor electrodes 4e and 4f are formed on the upper main surface of the base layer 1h.

[0039] The above-mentioned via hole electrode 2 j is formed to penetrate between the two main surfaces of the base material layer 1 h.

[0040] Line electrodes 3h and 3i are formed on the upper main surface of the base material layer 1i.

[0041] The above-mentioned via hole electrode 2 j and new via hole electrodes 2 k and 2 l are formed to penetrate between the two main surfaces of the base material layer 1 i.

[0042] Line electrodes 3j and 3k are formed on the upper main surface of the base material layer 1j.

[0043] The aforementioned via hole electrodes 2j, 2k, and 2l and new via hole electrodes 2m and 2n are formed to penetrate between the two main surfaces of the base material layer 1j.

[0044] Line electrodes 31 and 3m are formed on the upper main surface of the base layer 1k.

[0045] The above-mentioned via hole electrodes 2 j , 2 m , and 2 n are formed to penetrate between the two main surfaces of the base material layer 1 k .

[0046] Line electrodes 3n and 3o are formed on the upper main surface of the base layer 11.

[0047] The aforementioned via hole electrodes 2 j , 2 m , and 2 n and new via hole electrodes 2 o and 2 p are formed to penetrate between the two main surfaces of the base material layer 11 .

[0048] Line electrodes 3 p and 3 q are formed on the upper main surface of the base material layer 1 m.

[0049] The above-mentioned via hole electrodes 2 j , 2 o , and 2 p are formed to penetrate between the two main surfaces of the base material layer 1 m .

[0050] Line electrodes 3 r and 3 s are formed on the upper main surface of the base material layer 1 n.

[0051] The aforementioned via hole electrodes 2j, 2o, and 2p and new via hole electrodes 2q and 2r are formed to penetrate between the two main surfaces of the base material layer 1n.

[0052] The above-mentioned via hole electrodes 2j, 2q, and 2r are formed to penetrate between the two main surfaces of the base material layer 1o.

[0053] A shield electrode 5 is formed on the upper main surface of the base material layer 1 p .

[0054] The above-mentioned via hole electrodes 2 j , 2 q , and 2 r are formed to penetrate between the two main surfaces of the base material layer 1 p .

[0055] The base material layer 1q is a protective layer and no electrode is formed thereon.

[0056] The materials of the first terminal T1, the second terminal T2, the ground terminals G1 and G2, the first floating terminal F1, the second floating terminal F2, the via electrodes 2a to 2r, the line electrodes 3a to 3s, the capacitor electrodes 4a to 4f, and the shield electrode 5 are arbitrary; for example, copper, silver, aluminum, or alloys thereof can be used as the main component. Furthermore, a plating layer may be formed on the surfaces of the first terminal T1, the second terminal T2, the ground terminals G1 and G2, the first floating terminal F1, and the second floating terminal F2.

[0057] The multilayer LC filter 100 can be manufactured by a manufacturing method used in conventional multilayer LC filters.

[0058] Next, the connection relationship among the first terminal T1, the second terminal T2, the ground terminals G1 and G2, the first floating terminal F1, the second floating terminal F2, the via electrodes 2a to 2r, the line electrodes 3a to 3s, the capacitor electrodes 4a to 4f, and the shield electrode 5 in the multilayer LC filter 100 will be described.

[0059] The first terminal T1 is connected to one end of each of the line electrode 3 a and the line electrode 3 d through the via electrode 2 a .

[0060] The other ends of the line electrodes 3a and 3d are connected to the capacitor electrode 4c through the via electrode 2g.

[0061] The capacitor electrode 4e is connected to one end of each of the line electrode 3h and the line electrode 3j through the via electrode 2k.

[0062] The other ends of the line electrodes 3h and 3j are connected to one ends of the line electrodes 31 and 3n via the via electrodes 2m.

[0063] The other ends of the line electrodes 31 and 3n are connected to one ends of the line electrodes 3p and 3r via the via electrodes 2o.

[0064] The other ends of the line electrodes 3 p and 3 r are connected to the shield electrode 5 through the via electrode 2 q .

[0065] The second terminal T2 is connected to one end of each of the line electrode 3b and the line electrode 3e through the via electrode 2b.

[0066] The other ends of the line electrodes 3b and 3e are connected to the capacitor electrode 4d via the via electrode 2h.

[0067] The capacitor electrode 4f is connected to one end of each of the line electrode 3i and the line electrode 3k through the via electrode 21.

[0068] The other ends of the line electrodes 3i and 3k are connected to one ends of the line electrodes 3m and 3o via the via electrodes 2n.

[0069] The other ends of the line electrodes 3m and 3o are connected to one ends of the line electrodes 3q and 3s through the via electrodes 2p.

[0070] The other ends of the line electrodes 3q and 3s are connected to the shield electrode 5 through the via electrode 2r.

[0071] The shield electrode 5 is connected to one end of the line electrode 3g through the via electrode 2j.

[0072] The other end of the line electrode 3g is connected to the middle of each of the line electrode 3f and the line electrode 3c through the via electrode 2i.

[0073] One end of each of the line electrode 3f and the line electrode 3c is connected to the ground terminal G1 through the via electrode 2e.

[0074] The other ends of the line electrodes 3f and 3c are connected to the ground terminal G2 via the via electrode 2f.

[0075] The first floating terminal F1 is connected to the via hole electrode 2c. The via hole electrode 2c is not connected to any other electrodes except the first floating terminal F1.

[0076] The second floating terminal F2 is connected to the via hole electrode 2d. The via hole electrode 2d is not connected to any other electrodes except the second floating terminal F2.

[0077] The multilayer LC filter 100 having the above structure is composed of Figure 3 The equivalent circuit shown here constitutes a high-pass filter.

[0078] The multilayer LC filter 100 includes a first terminal T1, a second terminal T2, and ground terminals G1 and G2. A signal line 6 is formed between the first terminal T1 and the second terminal T2. The ground terminals G1 and G2 are connected to the ground.

[0079] A third capacitor C3 is connected midway along the signal line 6 .

[0080] One end of the first capacitor C1 is connected to the signal line 6 between the first terminal T1 and the third capacitor C3. The connection point of the first capacitor C1 to the signal line 6 is referred to as a first connection point P1. One end of the first inductor L1 is connected to the other end of the first capacitor C1.

[0081] One end of the second capacitor C2 is connected to the signal line 6 between the third capacitor C3 and the second terminal T2. The connection point of the second capacitor C2 to the signal line 6 is referred to as a second connection point P2. One end of the second inductor L2 is connected to the other end of the second capacitor C2.

[0082] As described above, the multilayer LC filter 100 includes the shield electrode 5 inside the multilayer substrate 1. Figure 3 In the equivalent circuit diagram shown, the position of the shielding electrode 5 in the equivalent circuit is indicated by reference numeral 5 .

[0083] The other end of the first capacitor C1 and the other end of the second capacitor C2 are respectively connected to the shielding electrode 5 .

[0084] The shield electrode 5 is connected to the ground terminals G1 and G2 via the third inductor L3. As described above, the ground terminals G1 and G2 are connected to the ground.

[0085] A fourth inductor L4 is connected between the first terminal T1 and the first connection point P1 .

[0086] A fifth inductor L5 is connected between the second connection point P2 and the second terminal T2 .

[0087] Next, Figure 2 The structure of the stacked LC filter 100 shown is similar to Figure 3 The relationship between the equivalent circuit of the stacked LC filter 100 shown in FIG2 is described. In addition, in the stacked LC filter 100, when forming an inductor, in order to improve Q, etc., a plurality of line electrodes are sometimes arranged in a stacked manner and connected in parallel by via electrodes.

[0088] A fourth inductor L4, comprising a via electrode 2a, line electrodes 3a and 3d, and a via electrode 2g, is connected between the first terminal T1 and the capacitor electrode 4c. In the fourth inductor L4, the via electrode 2a is sometimes referred to as the first portion, the line electrodes 3a and 3d are sometimes referred to as the second portion, and the via electrode 2g is sometimes referred to as the third portion.

[0089] The connection point between the via electrode 2g and the capacitor electrode 4c corresponds to the first connection point P1.

[0090] A fifth inductor L5, comprising a via electrode 2b, line electrodes 3b and 3e, and a via electrode 2h, is connected between the second terminal T2 and the capacitor electrode 4d. In the fifth inductor L5, the via electrode 2b is sometimes referred to as the fourth portion, the line electrodes 3b and 3e are sometimes referred to as the fifth portion, and the via electrode 2h is sometimes referred to as the sixth portion.

[0091] The connection point between the via electrode 2h and the capacitor electrode 4d corresponds to the second connection point P2.

[0092] As described above, the capacitor electrode 4 a and the capacitor electrode 4 b are connected to each other.

[0093] A capacitor formed by capacitance generated between the capacitor electrode 4c and the capacitor electrode 4a and a capacitor formed by capacitance generated between the capacitor electrode 4b and the capacitor electrode 4d are connected in series to form a third capacitor C3.

[0094] Based on the above, the first terminal T1, the fourth inductor L4, the first connection point P1, the third capacitor C3, the second connection point P2, the fifth inductor L5, and the second terminal T2 are connected in the order of the first terminal T1, the fourth inductor L4, the first connection point P1, the third capacitor C3, the second connection point P2, the fifth inductor L5, and the second terminal T2 to form a signal line 6.

[0095] The first capacitor C1 is formed by the capacitance generated between the capacitor electrode 4 c and the capacitor electrode 4 e .

[0096] The first inductor L1 is formed by the via electrode 2k, line electrodes 3h and 3j, via electrodes 2m, line electrodes 3l and 3n, via electrodes 2o, line electrodes 3p and 3r, and via electrode 2q, which connect the capacitor electrode 4e and the shield electrode 5. In the first inductor L1, the connection point between the capacitor electrode 4e and the via electrode 2k is the end portion on the signal line 6 side, and the connection point between the via electrode 2q and the shield electrode 5 is the end portion on the ground terminals G1 and G2 side.

[0097] According to the above, between the first connection point P1 and the shield electrode 5 , the first capacitor C1 and the first inductor L1 are connected in series in this order.

[0098] The second capacitor C2 is formed by the capacitance generated between the capacitor electrode 4d and the capacitor electrode 4f.

[0099] The second inductor L2 is formed by the via electrode 21, the line electrodes 3i and 3k, the via electrodes 2n, the line electrodes 3m and 3o, the via electrodes 2p, the line electrodes 3q and 3s, and the via electrode 2r, which connect the capacitor electrode 4f and the shield electrode 5. In the second inductor L2, the connection point between the capacitor electrode 4f and the via electrode 21 is the end on the signal line 6 side, and the connection point between the via electrode 2r and the shield electrode 5 is the end on the ground terminals G1 and G2 side.

[0100] According to the above, between the second connection point P2 and the shield electrode 5 , the second capacitor C2 and the second inductor L2 are connected in series in this order.

[0101] The third inductor L3 is formed by the via electrode 2j, the line electrode 3g, the via electrode 2i, the line electrode 3f, the line electrode 3c, the via electrode 2e, and the via electrode 2f that connect the shield electrode 5 to the ground terminals G1 and G2.

[0102] As above, through Figure 2 The structure of the stacked LC filter 100 shown in FIG. Figure 3 The equivalent circuit of the multilayer LC filter 100 is shown.

[0103] The multilayer LC filter 100 according to the embodiment having the above-described structure and equivalent circuit suppresses stray capacitance generated between the end of the first inductor L1 on the signal line 6 side and the shield electrode 5 , and between the end of the second inductor L2 on the signal line 6 side and the shield electrode 5 .

[0104] Specifically, in the multilayer LC filter 100, the end of the first inductor L1 on the ground terminals G1 and G2 side, namely, the via electrode 2q, is connected to the shield electrode 5. Furthermore, in the stacking direction of the base layers 1a to 1q, the end of the first inductor L1 on the signal line 6 side (the connection point between the capacitor electrode 4e and the via electrode 2k) is located closer to the first principal surface 1A than the end of the first inductor L1 on the ground terminals G1 and G2 side (the connection point between the via electrode 2q and the shield electrode 5). Furthermore, in the multilayer LC filter 100, the end of the second inductor L2 on the ground terminals G1 and G2 side, namely, the via electrode 2r, is connected to the shield electrode 5. Furthermore, in the stacking direction of the base layers 1a to 1q, the end of the second inductor L2 on the signal line 6 side (the connection point between the capacitor electrode 4f and the via electrode 21) is located closer to the first main surface 1A than the end of the second inductor L2 on the ground terminals G1 and G2 side (the connection point between the via electrode 2r and the shield electrode 5). Therefore, the multilayer LC filter 100 suppresses stray capacitance generated in parallel with the first inductor L1 between the end of the first inductor L1 on the signal line 6 side and the shield electrode 5, as well as stray capacitance generated in parallel with the second inductor L2 between the end of the second inductor L2 on the signal line 6 side and the shield electrode 5.

[0105] As a result, the stacked LC filter 100 suppresses narrowing of the passband. Furthermore, the stacked LC filter 100 improves return loss. Furthermore, the stacked LC filter 100 improves insertion loss as the return loss is improved.

[0106] Furthermore, in the multilayer LC filter 100 , the fourth inductor L4 is connected between the first terminal T1 and the first connection point P1 , and the fifth inductor L5 is connected between the second terminal T2 and the second connection point P2 , thereby increasing impedance and improving return loss.

[0107] Furthermore, by connecting the fourth inductor L4 and the fifth inductor L5, the stacked LC filter 100 shifts the second peak of return loss toward the high-frequency side, thereby reducing the area of ​​the capacitor electrodes 4a and 4b of the third capacitor C3, which serves as an impedance adjustment capacitor. Consequently, the stacked LC filter 100 can make the capacitor electrodes 4a and 4b of the third capacitor C3 elongated in the longitudinal direction L, thereby suppressing interruption of the air-core diameter of the first inductor L1 and the second inductor L2 by the capacitor electrodes 4a and 4b, and improving insertion loss degradation.

[0108] Furthermore, by reducing the areas of the first terminal T1 and the second terminal T2, the stacked LC filter 100 suppresses the stray capacitance generated between the ground of the substrate, etc., on which the stacked LC filter 100 is mounted, and the first terminal T1, and the stray capacitance generated between the ground and the second terminal T2. As a result, the stacked LC filter 100 widens the passband and improves return loss. Furthermore, while the stacked LC filter 100 reduces the areas of the first terminal T1 and the second terminal T2, the first floating terminal F1 and the second floating terminal F2 are formed on the first main surface 1A in place of the first terminal T1 and the second terminal T2. This prevents degradation in the mounting strength of the stacked LC filter 100 on the substrate, etc.

[0109] Furthermore, in the stacked LC filter 100, although no electrical connection is made, the first floating terminal F1 is connected to the via electrode 2c, and the second floating terminal F2 is connected to the via electrode 2d. This produces an anchoring effect, thereby increasing the bonding strength between the first floating terminal F1 and the multilayer substrate 1, and the bonding strength between the second floating terminal F2 and the multilayer substrate 1.

[0110] (experiment)

[0111] In order to confirm the effectiveness of the present invention, the following experiments were conducted.

[0112] First, as an example, the multilayer LC filter 100 according to the above-described embodiment was produced.

[0113] In addition, for comparison, Figure 4 、 Figure 5 The stacked LC filter 500 according to the comparative example shown. Figure 4 It is an exploded perspective view of the multilayer LC filter 500 . Figure 5 : is an equivalent circuit diagram of the multilayer LC filter 500 .

[0114] The multilayer LC filter 500 according to the comparative example is obtained by partially changing the structure of the multilayer LC filter 100 according to the embodiment.

[0115] The stacked LC filter 500 includes a multilayer substrate on which base material layers 11 a to 11 n are stacked.

[0116] A first terminal T11 , a second terminal T12 , and a ground terminal G11 are formed on the lower main surface of the base layer 11 a .

[0117] Line electrodes 13 a , 13 b , and 13 c are formed on the upper main surface of the base layer 11 a .

[0118] Via hole electrodes 12 a , 12 b , 12 c , and 12 d are formed to penetrate between the two main surfaces of the base material layer 11 a .

[0119] Capacitor electrodes 14a and 14b are formed on the upper main surface of the base material layer 11b. The capacitor electrode 14a and the capacitor electrode 14b are connected to each other.

[0120] The above-mentioned via hole electrode 12 d and new via hole electrodes 12 e , 12 f , 12 g , and 12 h are formed to penetrate between the two main surfaces of the base material layer 11 b .

[0121] Capacitor electrodes 14 c and 14 d are formed on the upper main surface of the base layer 11 c .

[0122] The above-mentioned via hole electrodes 12 d , 12 e , 12 f , 12 g , and 12 h are formed to penetrate between the two main surfaces of the base material layer 11 c .

[0123] Capacitor electrodes 14e and 14f are formed on the upper main surface of the base layer 11d.

[0124] The above-mentioned via hole electrodes 12d, 12g, and 12h are formed to penetrate between the two main surfaces of the base material layer 11d.

[0125] The aforementioned via hole electrodes 12 d , 12 g , and 12 h and new via hole electrodes 12 i and 12 j are formed to penetrate between the two main surfaces of the base material layer 11 e .

[0126] The above-mentioned via hole electrodes 12 d , 12 g , 12 h , 12 i , and 12 j are formed to penetrate between the two main surfaces of the base material layer 11 f .

[0127] Line electrodes 13h and 13i are formed on the upper main surface of the base layer 11g.

[0128] The above-mentioned via hole electrodes 12d, 12g, 12h, 12i, and 12j are formed to penetrate between the two main surfaces of the base material layer 11g.

[0129] Line electrodes 13j and 13k are formed on the upper main surface of the base layer 11h.

[0130] The aforementioned via hole electrodes 12 d , 12 g , 12 h , 12 i , and 12 j and new via hole electrodes 12 k and 12 l are formed to penetrate between the two main surfaces of the base material layer 11 h .

[0131] Line electrodes 131 and 13m are formed on the upper main surface of the base layer 11i.

[0132] The via hole electrodes 12 d , 12 i , 12 j , 12 k , and 12 l described above are formed to penetrate between the two main surfaces of the base material layer 11 i .

[0133] Line electrodes 13n and 13o are formed on the upper main surface of the base layer 11j.

[0134] The aforementioned via hole electrodes 12 d , 12 i , 12 j , 12 k , and 12 l and new via hole electrodes 12 m and 12 n are formed between the two main surfaces of the base material layer 11 j .

[0135] Line electrodes 13 p and 13 q are formed on the upper main surface of the base layer 11 k .

[0136] The via hole electrodes 12 d , 12 i , 12 j , 12 m , and 12 n described above are formed to penetrate between the two main surfaces of the base material layer 11 k .

[0137] Line electrodes 13 r and 13 s are formed on the upper main surface of the base layer 11 l .

[0138] The via hole electrodes 12 d , 12 i , 12 j , 12 m , and 12 n described above are formed to penetrate between the two main surfaces of the base material layer 11 l .

[0139] A shield electrode 15 is formed on the upper main surface of the base layer 11 m .

[0140] The base material layer 11n is a protective layer and no electrode is formed thereon.

[0141] Next, the connection relationship among the first terminal T11 , the second terminal T12 , the ground terminal G11 , the via electrodes 12 a to 12 n , the line electrodes 13 a to 13 s , the capacitor electrodes 14 a to 14 f , and the shield electrode 15 in the multilayer LC filter 500 according to the comparative example will be described.

[0142] The first terminal T11 is connected to one end of the line electrode 13 a through the via electrode 12 a .

[0143] The other end of the line electrode 13a is connected to the capacitor electrode 14c through the via electrode 12e.

[0144] The capacitor electrode 14e is connected to one end of each of the line electrode 13r and the line electrode 13p through the via electrode 12i.

[0145] The other ends of the line electrodes 13 r and 13 p are connected to one ends of the line electrodes 13 n and 13 l through the via electrodes 12 m .

[0146] The other ends of the line electrodes 13n and 131 are connected to one ends of the line electrodes 13j and 13h via the via electrodes 12k.

[0147] The other ends of each of the line electrodes 13j and 13h are connected to one end of the line electrode 13c via the via electrode 12g.

[0148] The second terminal T12 is connected to one end of the line electrode 13b through the via electrode 12b.

[0149] The other end of the line electrode 13b is connected to the capacitor electrode 14d through the via electrode 12f.

[0150] The capacitor electrode 14f is connected to one end of each of the line electrode 13s and the line electrode 13q through the via electrode 12j.

[0151] The other ends of the line electrodes 13s and 13q are connected to one ends of the line electrodes 13o and 13m through the via electrodes 12n.

[0152] The other ends of the line electrodes 13 o and 13 m are connected to one ends of the line electrodes 13 k and 13 i through the via electrodes 12 l .

[0153] The other ends of each of the line electrode 13k and the line electrode 13i are connected to the other end of the line electrode 13c via the via electrode 12h.

[0154] The center of the line electrode 13c is connected to the ground terminal G11 through the via electrode 12c.

[0155] The shield electrode 15 is connected to the ground terminal G11 through the via electrode 12 d .

[0156] In the multilayer LC filter 500 according to the comparative example, a capacitor formed by capacitance between the capacitor electrodes 14c and 14a and a capacitor formed by capacitance between the capacitor electrodes 14b and 14d are connected in series to form a third capacitor C13.

[0157] A first capacitor C11 is formed by the capacitance generated between the capacitor electrode 14 c and the capacitor electrode 14 e .

[0158] The first inductor L11 is formed by the via electrode 12i, line electrodes 13r and 13p, via electrodes 12m, line electrodes 13n and 13l, via electrodes 12k, line electrodes 13j and 13h, via electrodes 12g, line electrodes 13c, and via electrode 12c, which connect the capacitor electrode 14e to the ground terminal G11. In the first inductor L11, the connection point between the capacitor electrode 14e and the via electrode 12i is the end on the signal line 16 side, and the connection point between the via electrode 12c and the ground terminal G11 is the end on the ground terminal G11 side.

[0159] The second capacitor C12 is formed by the capacitance generated between the capacitor electrode 14 d and the capacitor electrode 14 f .

[0160] The second inductor L12 is formed by the via electrode 12j, line electrodes 13s and 13q, via electrodes 12n, line electrodes 13o and 13m, via electrode 12l, line electrodes 13k and 13i, via electrode 12h, line electrode 13c, and via electrode 12c, which connect the capacitor electrode 14f to the ground terminal G11. In the second inductor L12, the connection point between the capacitor electrode 14f and the via electrode 12j is the end on the signal line 16 side, and the connection point between the via electrode 12c and the ground terminal G11 is the end on the ground terminal G11 side.

[0161] In the stacked LC filter 500 according to the comparative example, Figure 5 As shown, the first terminal T11, first connection point P11, third capacitor C13, second connection point P12, and second terminal T12 are connected to the signal line 16 in the order of first terminal T11, first connection point P11, third capacitor C13, second connection point P12, and second terminal T12. Furthermore, the first capacitor C11 and the first inductor L11 are connected between the first connection point P11 and the ground terminal G11 in the order of first capacitor C11 and first inductor L11. The second capacitor C12 and the second inductor L12 are connected between the second connection point P12 and the ground terminal G11 in the order of second capacitor C12 and second inductor L12. Furthermore, in the stacked LC filter 500 according to the comparative example, the fourth inductor L4 and the fifth inductor L5 of the stacked LC filter 100 are omitted.

[0162] As described above, in the multilayer LC filter 500, the connection point between the capacitor electrode 14e and the via electrode 12i corresponds to the end of the first inductor L11 on the signal line 16 side. In the multilayer LC filter 500, the line electrode 13r, which is connected to the end of the first inductor L11 on the signal line 16 side via the via electrode 12i and has a potential close to that of the end of the first inductor L11 on the signal line 16 side, is located close to the shield electrode 15 connected to the ground terminal G11. Therefore, a large stray capacitance is likely to be generated between the line electrode 13r and the shield electrode 15. In other words, the multilayer LC filter 500 is likely to generate a large stray capacitance in parallel with the first inductor L11.

[0163] Furthermore, in the multilayer LC filter 500, as described above, the connection point between the capacitor electrode 14f and the via electrode 12j corresponds to the end of the second inductor L12 on the signal line 16 side. In the multilayer LC filter 500, the line electrode 13s, which is connected to the end of the second inductor L12 on the signal line 16 side via the via electrode 12j and has a potential close to that of the end of the second inductor L12 on the signal line 16 side, is located close to the shield electrode 15 connected to the ground terminal G11. Therefore, a large stray capacitance is likely to be generated between the line electrode 13s and the shield electrode 15. In other words, the multilayer LC filter 500 is likely to generate a large stray capacitance in parallel with the second inductor L12.

[0164] Figure 6 The S(1, 1) characteristic and the S(2, 1) characteristic of the multilayer LC filter 100 according to the embodiment are shown. Here, the first terminal T1 is set as the first terminal, and the second terminal T2 is set as the second terminal. Figure 7 The S(1, 1) characteristic and the S(2, 1) characteristic of the multilayer LC filter 500 according to the comparative example are shown, wherein the first terminal T11 is referred to as the first terminal, and the second terminal T12 is referred to as the second terminal.

[0165] Will Figure 6 and Figure 7 Comparison reveals that the stacked LC filter 100 according to the embodiment has a wider passband than the stacked LC filter 500 according to the comparative example. Furthermore, the stacked LC filter 100 according to the embodiment exhibits improved return loss compared to the stacked LC filter 500 according to the comparative example. Specifically, while the return loss of the stacked LC filter 500 in M02 is approximately -12 dB, the return loss of the stacked LC filter 100 in M02 is improved to approximately -23 dB.

[0166] From the above, the effectiveness of the present invention has been confirmed.

[0167] The multilayer LC filter 100 according to the embodiment has been described above. However, the multilayer LC filter of the present invention is not limited to the above-described contents, and various modifications can be made within the spirit of the invention.

[0168] For example, in the multilayer LC filter 100 , the shield electrode 5 is provided between the base layer 1 p and the base layer 1 q of the multilayer substrate 1 . Alternatively, the shield electrode 5 may be formed on the second main surface 1B of the multilayer substrate 1 .

[0169] The multilayer LC filter according to one embodiment of the present invention is as described in the “Summary of the Invention” column.

[0170] It is also preferable to configure a high-pass filter using this stacked LC filter.

[0171] It is also preferable that the first and second inductors be formed primarily of line electrodes and via electrodes, respectively, and that the third inductor be formed primarily of via electrodes. If the first and second inductors include line electrodes, significant stray capacitance is likely to occur, particularly between the first inductor and the shield electrode, and between the second inductor and the shield electrode. However, the present invention suppresses stray capacitance in these locations. Furthermore, "the third inductor being formed primarily of via electrodes" means that at least 50% of the third inductor's inductance is generated by the via electrodes.

[0172] Furthermore, when the point on the signal line connected to the first capacitor is the first connection point and the point on the signal line connected to the second capacitor is the second connection point, it is also preferable to provide a fourth inductor between the first terminal and the first connection point, and a fifth inductor between the second connection point and the second terminal. In this case, the impedance can be increased, thereby improving the return loss.

[0173] In this case, it is also preferable that the multilayer substrate has a rectangular parallelepiped shape having width, length, and height directions. The fourth inductor includes: a first portion comprising a via electrode, one end of which is connected to the first terminal and extends along the second principal surface; a second portion comprising a line electrode, one end of which is connected to the other end of the first portion and the other end of which is spaced a constant distance in the width direction relative to the first end; and a third portion comprising a via electrode, one end of which is connected to the other end of the second portion and extends along the second principal surface. The fifth inductor includes: a fourth portion comprising a via electrode, one end of which is connected to the second terminal and extends along the second principal surface; a fifth portion comprising a line electrode, one end of which is connected to the other end of the fourth portion and the other end of which is spaced a constant distance in the width direction relative to the first end; and a sixth portion comprising a via electrode, one end of which is connected to the other end of the fifth portion and extends along the second principal surface. In this case, the volume of the multilayer substrate can be efficiently utilized, thereby increasing the inductance values ​​of the fourth and fifth inductors.

[0174] Alternatively, the multilayer substrate preferably comprises a rectangular parallelepiped having width, length, and height dimensions, and includes a first floating terminal arranged parallel to the first terminal in the width direction, and a second floating terminal arranged parallel to the second terminal in the width direction on the first principal surface. In this case, the areas of the first and second terminals can be reduced without compromising the mounting strength of the multilayer LC filter on the substrate, etc., and stray capacitance generated between the ground of the substrate, etc., on which the multilayer LC filter is mounted, and the first terminal, and between the second terminal and the ground, respectively, can be reduced. Furthermore, this can prevent the passband of the mounted multilayer LC filter from being narrowed, improving return loss.

[0175] Alternatively, it is preferable that the first floating terminal be connected to a via electrode that is not connected to any other electrode within the multi-layer substrate, and the second floating terminal be connected to a via electrode that is not connected to any other electrode within the multi-layer substrate. In this case, the via electrodes provide an anchoring effect on the first and second floating terminals, thereby increasing the bonding strength between the first floating terminal and the multi-layer substrate, and the bonding strength between the second floating terminal and the multi-layer substrate.

[0176] Description of Reference Numerals

[0177] 1…multilayer substrate; 1A…first principal surface; 1B…second principal surface; 1C…first side surface; 1D…second side surface; 1E…first end surface; 1F…second end surface; 1a–1q…base material layer; 2a–2r…via electrodes; 3a–3s…line electrodes; 4a–4f…capacitor electrodes; 5…shield electrode; 6…signal line; T1…first terminal; T2…second terminal; G1, G2…ground terminals.

Claims

1. A stacked LC filter comprising: A multilayer substrate having a plurality of base material layers stacked together and having a first main surface and a second main surface; A via electrode is formed through the substrate layer; Line electrodes and capacitor electrodes are formed between the layers of the substrate layer; and The first terminal, the second terminal, and the ground terminal are formed on the first main surface of the multilayer substrate. An inductor is formed by at least one of the via electrode and the line electrode. A capacitor is formed by the capacitor electrodes. forming a signal line between the first terminal and the second terminal, A third capacitor is connected in the middle of the signal line. A first capacitor and a first inductor are connected in series in that order between the signal line between the first terminal and the third capacitor and the ground terminal. A second capacitor and a second inductor are connected in series in this order between the signal line between the third capacitor and the second terminal and the ground terminal; in, The above-mentioned stacked LC filter further has: a shielding electrode formed between layers of the base material layer on a side close to the second main surface of the multilayer substrate, or formed on the second main surface of the multilayer substrate; and A third inductor is connected between the shielding electrode and the ground terminal. In the above multi-layer substrate, An end portion of the first inductor on the ground terminal side is connected to the shield electrode. In the stacking direction of the base layers, an end portion of the first inductor on the signal line side is located closer to the first main surface than an end portion of the first inductor on the ground terminal side. An end portion of the second inductor on the ground terminal side is connected to the shield electrode. In the stacking direction of the base layers, an end portion of the second inductor on the signal line side is located closer to the first main surface than an end portion of the second inductor on the ground terminal side.

2. The stacked LC filter according to claim 1, wherein The above-mentioned stacked LC filter constitutes a high-pass filter.

3. The stacked LC filter according to claim 1, wherein The first inductor and the second inductor are formed by the line electrode and the via electrode, respectively. The third inductor is mainly formed by the via electrode.

4. The stacked LC filter according to claim 2, wherein The first inductor and the second inductor are formed by the line electrode and the via electrode, respectively. The third inductor is mainly formed by the via electrode.

5. The multilayer LC filter according to any one of claims 1 to 4, wherein When the point where the first capacitor is connected to the signal line is defined as a first connection point, and the point where the second capacitor is connected to the signal line is defined as a second connection point, A fourth inductor is provided between the first terminal and the first connection point. A fifth inductor is provided between the second connection point and the second terminal.

6. The stacked LC filter according to claim 5, wherein The multi-layer substrate is formed of a rectangular parallelepiped with width, length and height directions. The fourth inductor includes: A first portion is formed by the via electrode, one end of which is connected to the first terminal and extends in the direction of the second main surface; a second portion, comprising the line electrode, one end of which is connected to the other end of the first portion, and the other end of which is arranged at a constant distance from the one end in the width direction; and The third portion is formed by the via electrode, one end of which is connected to the other end of the second portion and extends in the direction of the second main surface. The fifth inductor includes: a fourth portion, formed by the via electrode, one end of which is connected to the second terminal and extends in the direction of the second main surface; a fifth portion, comprising the line electrode, one end of which is connected to the other end of the fourth portion, and the other end of which is arranged at a constant distance from the one end in the width direction; and The sixth portion is formed of the via hole electrode, has one end connected to the other end of the fifth portion, and extends in the direction of the second main surface.

7. The multilayer LC filter according to any one of claims 1 to 4, wherein The multi-layer substrate is formed of a rectangular parallelepiped with width, length and height directions. In the first main surface, there is: a first floating terminal arranged side by side with the first terminal in the width direction; and The second floating terminal is arranged in parallel with the second terminal in the width direction.

8. The stacked LC filter according to claim 5, wherein The multi-layer substrate is formed of a rectangular parallelepiped with width, length and height directions. In the first main surface, there is: a first floating terminal arranged side by side with the first terminal in the width direction; and The second floating terminal is arranged in parallel with the second terminal in the width direction.

9. The stacked LC filter according to claim 6, wherein The multi-layer substrate is formed of a rectangular parallelepiped with width, length and height directions. In the first main surface, there is: a first floating terminal arranged side by side with the first terminal in the width direction; and The second floating terminal is arranged in parallel with the second terminal in the width direction.

10. The stacked LC filter according to claim 7, wherein The first floating terminal is connected to the via electrode, which is not connected to other electrodes inside the multilayer substrate. The second floating terminal is connected to the via electrode, and the via electrode is not connected to other electrodes inside the multilayer substrate.

11. The stacked LC filter according to claim 8, wherein The first floating terminal is connected to the via electrode, which is not connected to other electrodes inside the multilayer substrate. The second floating terminal is connected to the via electrode, and the via electrode is not connected to other electrodes inside the multilayer substrate.

12. The stacked LC filter according to claim 9, wherein The first floating terminal is connected to the via electrode, which is not connected to other electrodes inside the multilayer substrate. The second floating terminal is connected to the via electrode, and the via electrode is not connected to other electrodes inside the multilayer substrate.

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