Laminated filter

Abstract

A laminated filter (1) includes a first ground electrode (111) and a second ground electrode (112), a first LC resonator (LC1), and a second LC resonator (LC2). The first LC resonator (LC1) includes a first line electrode (101), a first capacitor electrode (102), a first via conductor (V11), and a second via conductor (V12). The second via conductor (V12) extends from the first line electrode (101) to a side on which the first capacitor electrode (102) is disposed, and connects the first line electrode (101) and the first ground electrode (111). The second LC resonator (LC2) includes a second line electrode (201), a second capacitor electrode (202), a third via conductor (V21), and a fourth via conductor (V22). The fourth via conductor (V22) extends from the second line electrode (201) to a side on which the second capacitor electrode (202) is disposed, and connects the second line electrode (201) and the second ground electrode (112).

Description

TECHNICAL FIELD

[0001] The present application relates to a laminated filter. BACKGROUND

[0002] In the past, a laminated filter formed as a laminate of a plurality of dielectric layers has been known. For example, a laminated band-pass filter is disclosed in International Publication No. 2002 / 009225 (Patent Document 1). In this laminated band-pass filter, two strip lines that constitute resonators are arranged at a constant interval in the same layer. By arranging the two strip lines in parallel, electromagnetic coupling can be caused. As a result, a capacitor between the resonators can be omitted, and thinning of the laminate can be achieved.

[0003] In addition, a laminated band-pass filter in which the direction of the loop of the inductor electrode based on the input-side LC parallel resonator and the direction of the loop of the inductor electrode based on the LC parallel resonator adjacent to the input-side LC parallel resonator are opposite each other is disclosed in International Publication No. 2007 / 119356 (Patent Document 2). In addition, a laminated band-pass filter in which three ground electrodes are formed in the same layer so as to be separated from each other is also disclosed.

[0004] Patent Document 1: International Publication No. 2002 / 009225

[0005] Patent Document 2: International Publication No. 2007 / 119356

[0006] In order to improve the attenuation characteristic (frequency characteristic of the insertion loss through the frequency band) of the laminated filter, it is necessary to balance the electromagnetic coupling (electric field coupling and magnetic field coupling) between the resonators, to make both the steepness of the change in the attenuation amount at the boundary of the pass band and the securing of the attenuation amount through the stop band. However, in the laminated band-pass filter disclosed in Patent Document 1, the balance of the electromagnetic coupling generated between the two strip lines arranged in parallel is not considered.

[0007] In the case where the directions of the loops of the inductor electrodes of two LC parallel resonators adjacent to each other are opposite each other as disclosed in Patent Document 2, the magnetic field coupling can be weakened, but fine adjustment of the magnetic field coupling is difficult. In addition, in the case where a plurality of ground electrodes are formed in the same dielectric layer, manufacturing variations are likely to occur. SUMMARY

[0008] The present application has been achieved in order to solve the above-described problems, and aims at improving the attenuation characteristic of the laminated filter.

[0009] The stacked filter of the present invention includes a first ground electrode and a second ground electrode, a first LC resonator, and a second LC resonator. The first LC resonator is connected to the first ground electrode. The second LC resonator is connected to the second ground electrode. The first LC resonator includes a first line electrode, a first capacitor electrode, a first via conductor, and a second via conductor. The first capacitor electrode is disposed between the first ground electrode and the first line electrode. The first via conductor connects the first line electrode and the first capacitor electrode. The second via conductor extends from the first line electrode toward the side where the first capacitor electrode is disposed and connects the first line electrode and the first ground electrode. The second LC resonator includes a second line electrode, a second capacitor electrode, a third via conductor, and a fourth via conductor. The second capacitor electrode is disposed between the second ground electrode and the second line electrode. The third via conductor connects the second line electrode and the second capacitor electrode. The fourth via conductor extends from the second line electrode toward the side where the second capacitor electrode is disposed and connects the second line electrode and the second ground electrode.

[0010] According to the stacked filter of the present invention, the first LC resonator is connected to the first ground electrode, and the second LC resonator is connected to the second ground electrode, thereby improving the attenuation characteristics. Attached Figure Description

[0011] Figure 1 This is the equivalent circuit diagram of the cascaded filter in Implementation Method 1.

[0012] Figure 2 yes Figure 1 A three-dimensional view of the appearance of the stacked filter.

[0013] Figure 3 It means in Figure 2 A diagram showing multiple electrodes formed inside the stacked body.

[0014] Figure 4 Viewed from above along the X-axis (second direction). Figure 2 A diagram of a stacked filter.

[0015] Figure 5 Viewed from above along the Y-axis (first direction). Figure 2 A diagram of a stacked filter.

[0016] Figure 6 This is the equivalent circuit diagram of the cascaded filter for the comparative example.

[0017] Figure 7 It is shown together Figures 1-5 The pass characteristics of the stacked filter (solid line) and Figure 6 The graph shows the pass characteristics (dashed lines) of the stacked filter.

[0018] Figure 8 is a graph showing a change in insertion loss of the multilayer filter in a case where the ground via conductor of Figure 4

[0019] Figure 9 is a graph showing an electrode structure inside the multilayer body of the multilayer filter of the modification example of Embodiment 1 as viewed from the Y-axis direction.

[0020] Figure 10 is an equivalent circuit diagram of the multilayer filter of Embodiment 2.

[0021] Figure 11 is a graph showing an electrode structure inside the multilayer body of the multilayer filter of Embodiment 2 as viewed from the Y-axis direction. Figure 10

[0022] Figure 12 is a graph showing a pass characteristic (solid line) of the multilayer filter of Figure 11 Figure 5

[0023] Figure 13 is a graph showing a 4 GHz to 7 GHz portion of Figure 12

[0024] Figure 14 is an equivalent circuit diagram of the multilayer filter of Embodiment 3.

[0025] Figure 15 is an equivalent circuit diagram of the multilayer filter of Embodiment 4.

[0026] Figure 16 is an equivalent circuit diagram of the multilayer filter of the modification example of Embodiment 4.

[0027] Figure 17 is an equivalent circuit diagram of the multilayer filter of Embodiment 5.

[0028] Figure 18 is an equivalent circuit diagram of the multilayer filter of the modification example of Embodiment 5.

[0029] Figure 19 is an equivalent circuit diagram of the multilayer filter of Embodiment 6.

[0030] Figure 20 is an equivalent circuit diagram of the multilayer filter of the modification example of Embodiment 6. DETAILED DESCRIPTION

[0031] Embodiments will be described in detail below with reference to the accompanying drawings. In addition, the same or corresponding portions in the drawings are added with the same reference numerals and their explanations will not be repeated in principle.

[0032] ​​​​​[Embodiment 1]

[0033] Figure 1 is an equivalent circuit diagram of the laminated filter 1 of Embodiment 1. Figure 1 The equivalent circuit shown is the same as that of the laminated filter 1A of the modification example of Embodiment 1 described later. Hereinafter, the electric field coupling generated between two circuit elements is expressed by a capacitor. That is, the two circuit elements are connected to each other via the capacitor. In addition, in the case where the two circuit elements are electrically connected, the case where the two circuit elements are directly connected, and the case where the two circuit elements are electrically field-coupled (capacitively coupled) are included.

[0034] As shown in Figure 1 , the laminated filter 1 includes an input / output terminal P1 (first terminal), an input / output terminal P2 (second terminal), an LC parallel resonator LC1 (first LC resonator), an LC parallel resonator LC2 (second LC resonator), an LC parallel resonator LC3 (fourth LC resonator), an LC parallel resonator LC4 (third LC resonator), and capacitors C10, C12, C14, C20, C23, and C34.

[0035] In Figure 1 , the LC parallel resonator LC1 and the LC parallel resonator LC2 are electromagnetically field-coupled to each other. The magnetic field coupling M1 and the capacitor C12 respectively represent the magnetic field coupling and the electric field coupling between the LC parallel resonator LC1 and the LC parallel resonator LC2. The LC parallel resonator LC2 and the LC parallel resonator LC3 are electromagnetically field-coupled to each other. The magnetic field coupling M2 and the capacitor C23 respectively represent the magnetic field coupling and the electric field coupling between the LC parallel resonator LC2 and the LC parallel resonator LC3. The LC parallel resonator LC3 and the LC parallel resonator LC4 are electromagnetically field-coupled to each other. The magnetic field coupling M3 and the capacitor C34 respectively represent the magnetic field coupling and the electric field coupling between the LC parallel resonator LC3 and the LC parallel resonator LC4. In addition, there is also a case where the electric field coupling is connected via a capacitor.

[0036] The input / output terminal P1 is electrically connected to the LC parallel resonator LC1. In Figure 1 , a case where the input / output terminal P1 is connected to the LC parallel resonator LC1 via the capacitor C10 is shown. The input / output terminal P1 can also be directly connected to the LC parallel resonator LC1.

[0037] The input / output terminal P2 is electrically connected to the LC parallel resonator LC4. In Figure 1 , a case where the input / output terminal P2 is connected to the LC parallel resonator LC4 via the capacitor C20 is shown. The input / output terminal P2 can also be directly connected to the LC parallel resonator LC4.

[0038] LC parallel resonators LC1 and LC2 are connected via capacitor C12. LC parallel resonators LC2 and LC3 are connected via capacitor C23. LC parallel resonators LC3 and LC4 are connected via capacitor C34. LC parallel resonators LC1 and LC4 are connected via capacitor C14.

[0039] The LC parallel resonator LC1 includes an inductor L1 and a capacitor C1. The inductor L1 and the capacitor C1 are connected in parallel between the ground point G1 and the connection point of capacitors C10 and C12.

[0040] The LC parallel resonator LC2 includes an inductor L2 and a capacitor C2. The inductor L2 and the capacitor C2 are connected in parallel between the ground point G2 and the connection point of capacitors C12 and C23.

[0041] The LC parallel resonator LC3 includes an inductor L3 and a capacitor C3. The inductor L3 and the capacitor C3 are connected in parallel between the ground point G2 and the connection point of capacitors C23 and C34.

[0042] The LC parallel resonator LC4 includes an inductor L4 and a capacitor C4. The inductor L4 and the capacitor C4 are connected in parallel between the ground point G1 and the connection point of capacitors C34 and C20.

[0043] Figure 2 yes Figure 1 A three-dimensional view of the appearance of the stacked filter 1. Figure 2 In this diagram, the X-axis, Y-axis, and Z-axis are orthogonal to each other. This will be explained later. Figures 3-5 , Figure 9 , Figure 11 The same applies to China.

[0044] like Figure 2 As shown, the stacked filter 1 is formed as a stacked body 100 with multiple dielectric layers stacked in the Z-axis direction. The stacked body 100 is, for example, a cuboid shape. The outermost surface of the stacked body 100 perpendicular to the Z-axis direction is designated as the upper surface UF and the bottom surface BF. The upper surface UF and the bottom surface BF are opposite each other in the Z-axis direction.

[0045] Input / output terminals P1 and P2, and a ground terminal 110 are formed on the bottom surface BF. The input / output terminals P1 and P2, and the ground terminal 110, are, for example, LGA (Land Grid Array) terminals with planar electrodes regularly arranged on the bottom surface BF. The bottom surface BF is connected to a circuit board (not shown).

[0046] Figure 3 It means in Figure 2 A diagram showing multiple electrodes formed inside the laminate 100. Figure 4is a view of the laminated filter 1 viewed from the X-axis direction (second direction). Figure 2 is a view of the laminated filter 1 viewed from the X-axis direction (second direction). Figure 5 is a view of the laminated filter 1 viewed from the Y-axis direction (first direction). Figure 2 is a view of the laminated filter 1 viewed from the Y-axis direction (first direction).

[0047] Referring to Figure 1 , Figures 3-5 A ground electrode 111 (first ground electrode) and a ground electrode 112 (second ground electrode) are formed inside the laminate 100. The ground electrode 111 is disposed between the ground terminal 110 and the ground electrode 112. The ground electrode 111 is connected to the ground terminal 110 through via conductors V1, V2, V3, V4, V5, V6 (second via conductors). The ground electrode 112 is connected to the ground electrode 111 through a via conductor V81 (first ground via conductor) and a via conductor V82 (first ground via conductor), respectively. The ground electrodes 111, 112 correspond to the ground points G1, G2 of Figure 1 , respectively. The ground electrodes 111, 112 are formed as mutually independent conductors.

[0048] The LC parallel resonator LC1 includes a line electrode 101 (first line electrode), a capacitor electrode 102 (first capacitor electrode), a capacitor electrode 103, a via conductor V11 (first via conductor), and a via conductor V12 (second via conductor). The line electrode 101 extends in the Y-axis direction. The capacitor electrode 102 is disposed between the ground electrode 112 and the line electrode 101. The via conductor V11 connects the line electrode 101 and the capacitor electrode 102. The via conductor V12 extends from the line electrode 101 to a side on which the capacitor electrode 102 is disposed, and connects the line electrode 101 and the ground electrode 111. The capacitor electrode 103 is disposed between the capacitor electrode 102 and the ground electrode 112. The capacitor electrode 103 is connected to the ground electrode 112 through a via conductor V13. In the extension direction of the via conductor V11, the line electrode 101 is closer to the ground electrode 112 than to the ground electrode 111.

[0049] A capacitor electrode 104 (fifth capacitor electrode) is disposed between the input / output terminal P1 and the capacitor electrode 102. The capacitor electrode 104 is connected to the input / output terminal P1 through a via conductor V10.

[0050] A capacitor C10 is formed by the capacitor electrodes 102 and 104. An inductor L1 is formed in a ring shape by the via conductor V12, the line electrode 101, and the via conductor V11. A capacitor C1 is formed by the capacitor electrodes 102 and 103.

[0051] The LC parallel resonator LC2 includes a line electrode 201 (second line electrode), a capacitor electrode 202 (second capacitor electrode), a capacitor electrode 203, a via conductor V21 (third via conductor), and a via conductor V22 (fourth via conductor). The line electrode 201 extends in the Y-axis direction. The capacitor electrode 202 is disposed between the ground electrode 112 and the line electrode 201. The via conductor V21 connects the line electrode 201 and the capacitor electrode 202. The via conductor V22 extends from the line electrode 201 to the side on which the capacitor electrode 202 is disposed, and connects the line electrode 201 and the ground electrode 112. The capacitor electrode 203 is disposed between the capacitor electrode 202 and the ground electrode 112. The capacitor electrode 203 is connected to the ground electrode 112 by a via conductor V23.

[0052] An inductor L2 is formed in a ring shape by the via conductor V22, the line electrode 201, and the via conductor V21. A capacitor C2 is formed by the capacitor electrodes 202 and 203.

[0053] Between the line electrode 101 and the capacitor electrode 102, a coupling electrode 121 (third coupling electrode) is connected to the via conductor V11. The coupling electrode 121 opposes each of the capacitor electrodes 102 and 202. A capacitor C12 is formed by the capacitor electrodes 102 and 202 and the coupling electrode 121.

[0054] The LC parallel resonator LC3 includes a line electrode 301 (second line electrode), a capacitor electrode 302 (second capacitor electrode), a capacitor electrode 303, a via conductor V31 (third via conductor), and a via conductor V32 (fourth via conductor). The line electrode 301 extends in the Y-axis direction. The capacitor electrode 302 is disposed between the ground electrode 112 and the line electrode 301. The via conductor V31 connects the line electrode 301 and the capacitor electrode 302. The via conductor V32 extends from the line electrode 301 to the side on which the capacitor electrode 302 is disposed, and connects the line electrode 301 and the ground electrode 112. The capacitor electrode 303 is disposed between the capacitor electrode 302 and the ground electrode 112. The capacitor electrode 303 is connected to the ground electrode 112 by a via conductor V33.

[0055] An inductor L3 is formed in a ring shape by the via conductor V32, the line electrode 301, and the via conductor V31. A capacitor C3 is formed by the capacitor electrodes 302 and 303.

[0056] Between the line electrode 201 and the capacitor electrode 202, a coupling electrode 222 is disposed. The coupling electrode 222 opposes each of the capacitor electrodes 202 and 302. A capacitor C23 is formed by the capacitor electrodes 202 and 302 and the coupling electrode 222.

[0057] The LC parallel resonator LC4 includes a line electrode 401 (third line electrode), a capacitor electrode 402 (third capacitor electrode), a capacitor electrode 403, a via conductor V41 (fifth via conductor), and a via conductor V42 (sixth via conductor). The line electrode 401 extends in the Y-axis direction. The capacitor electrode 402 is disposed between the ground electrode 112 and the line electrode 401. The via conductor V41 connects the line electrode 401 and the capacitor electrode 402. The via conductor V42 extends from the line electrode 401 to the side on which the capacitor electrode 402 is disposed, and connects the line electrode 401 and the ground electrode 111. The capacitor electrode 403 is disposed between the capacitor electrode 402 and the ground electrode 112. The capacitor electrode 403 is connected to the ground electrode 112 through the via conductor V43.

[0058] A capacitor electrode 404 (sixth capacitor electrode) is disposed between the input-output terminal P2 and the capacitor electrode 402. The capacitor electrode 404 is connected to the input-output terminal P2 through the via conductor V20.

[0059] A capacitor C20 is formed by the capacitor electrodes 402 and 404. An inductor L4 is formed in a ring shape by the via conductor V42, the line electrode 401, and the via conductor V41. A capacitor C4 is formed by the capacitor electrodes 402 and 403.

[0060] Between the line electrode 201 and the capacitor electrode 202, a coupling electrode 221 is disposed. The coupling electrode 221 opposes each of the coupling electrodes 121 and 122. A capacitor C14 is formed by the coupling electrodes 121, 122, and 221.

[0061] Reference Figure 4 In the Y-axis direction, each of the via conductors V21, V31, and V41 is closer to the via conductor V11 than to the via conductor V12. In the Y-axis direction, each of the via conductors V22, V32, and V42 is closer to the via conductor V11 than to the via conductor V12. The winding directions of the inductors LI to L4 from the ground electrode to the capacitor electrode are the same. The hollow portions of the inductors LI to L4 overlap. In the Y-axis direction, each of the via conductors V81 and V82 is closer to the via conductor V11 than to the via conductor V12.

[0062] Figure 6 is an equivalent circuit diagram of the comparative example of the laminated filter 10. The equivalent circuit of the laminated filter 10 is obtained by removing the ground point G2 from the equivalent circuit of the laminated filter 1, and short-circuiting the LC parallel resonators LC1 to LC4 to the ground point Gl. The same applies to the comparative example, and thus the description is not repeated. Figure 1

[0063] Figure 7 ​are shown together Figures 1-5 A graph of the pass characteristic (solid line) of the laminated filter 1 and the pass characteristic (dotted line) of the laminated filter 10 of Figure 6 The pass characteristic refers to the frequency characteristic of the insertion loss. Figure 7 The attenuation amount of the vertical axis increases in the downward direction from 0 dB. The same applies to the laminated filter 1 of Figure 8 , Figure 12 , Figure 13 described later.

[0064] Referring to Figure 1 , Figure 5 , and Figure 7 , by physically separating the ground points G1 (ground electrodes 111) that short-circuit the respective LC parallel resonators LC1, LC4 and the ground points G2 (ground electrodes 112) that short-circuit the respective LC parallel resonators LC2, LC3, it is possible to reduce the magnetic field coupling M1, M3. As a result, it is possible to improve the attenuation characteristic of the laminated filter 1.

[0065] As shown in Figure 7 , the laminated filter 1 is greater than the laminated filter 10 in terms of the minimum value of the insertion loss in the frequency band of 2 GHz to 4 GHz. The laminated filter 1 is able to ensure a greater attenuation amount than the laminated filter 10 in a frequency band lower than the pass band (low frequency side). That is, it is possible to improve the attenuation characteristic of the laminated filter 1 compared to the attenuation characteristic of the laminated filter 10.

[0066] In the laminated filter 1, by moving the via conductors V81, V82 of Figure 4 in the Y-axis direction, Figure 1 the inductor component between the ground points G1 and G2 changes. As a result, it is possible to adjust the frequency of the attenuation pole generated on the high frequency side.

[0067] Figure 8 is a graph showing the change in the insertion loss of the laminated filter 1 in the case where the via conductors V81, V82 of Figure 4 are moved in the Y-axis direction. In Figure 8 , the pass characteristic Al indicates the pass characteristic in the case where the via conductors V81, V82 are disposed at the positions shown in Figure 4 . The pass characteristic A2 indicates the pass characteristic in the case where the via conductors V81, V82 are closer to the via conductor V12 than in the case of the pass characteristic Al. The pass characteristic A3 indicates the pass characteristic in the case where the via conductors V81, V82 are closer to the via conductor V12 than in the case of the pass characteristic A2.

[0068] Referring to Figure 4 and Figure 8Among the pass characteristics A1 to A3, the pass characteristics in the pass band and on the low frequency side are almost the same. An attenuation pole is generated at a frequency fl on the high frequency side of the pass band of the pass characteristic Al. An attenuation pole is generated at a frequency f2 (> fl) on the high frequency side of the pass characteristic A2. An attenuation pole is generated at a frequency f3 (> f2) on the high frequency side of the pass characteristic A3. By bringing the via conductors V81, V82 close to the via conductor V12, the frequency of the attenuation pole generated on the high frequency side can be increased.

[0069] In the laminated filter 1, the case where the capacitor electrodes 102, 202, 302, 402 and the capacitor electrodes 103, 203, 303, 403 to which the ground electrodes 112 are connected, respectively, form capacitors is described. The capacitor electrodes 102, 202, 302, 402 and the ground electrodes 112 can form capacitors.

[0070] Figure 9 FIG. 2 is a diagram of the electrode structure inside the laminate of the laminated filter 1A of the modification of Embodiment 1 viewed from the Y-axis direction. The electrode structure of the laminated filter 1A is the electrode structure of the laminated filter 1 of Embodiment 1 viewed from the Y-axis direction. Figure 5 FIG. 3 is the electrode structure of the laminated filter 1 of Embodiment 1 from which the capacitor electrodes 103, 203, 303, 403 and the via conductors V13, V23, V33, V43 are removed. The same as the electrode structure of the laminated filter 1 of Embodiment 1 except for this, so the description is not repeated.

[0071] Referring to Figure 1 and Figure 9 , the capacitor electrodes 102, 202, 302, 402 and the ground electrodes 112 are opposed to each other. In the laminated filter 1A, the capacitor electrodes 102, 202, 302, 402 and the ground electrodes 112 together form the capacitors Cl to C4, respectively. By selecting either of Embodiment 1 or the modification according to the desired characteristics required of the laminated filter, the distance between the electrodes of each of the capacitors Cl to C4 can be adjusted.

[0072] As described above, according to the laminated filter of Embodiment 1 and the modification, the attenuation characteristics can be improved.

[0073] [Embodiment 2]

[0074] In Embodiment 2, the configuration for further improving the attenuation characteristics of the laminated filter by electrically field-coupling the two terminals of the laminated filter of Embodiment 1 to each other is described.

[0075] Figure 10 FIG. 4 is an equivalent circuit diagram of the laminated filter 2 of Embodiment 2. As shown in Figure 10 , the equivalent circuit of the laminated filter 2 is a circuit obtained by electrically field-coupling the two terminals of the equivalent circuit of the laminated filter 1 of Embodiment 1 to each other. Figure 1The equivalent circuit of the laminated filter 1 of FIG. 1 is added with the equivalent circuit of the capacitor C22. The same is true except for this, so the explanation will not be repeated. As shown in FIG. 2, the input-output terminals P1, P2 are connected to each other via the capacitor C22. Figure 10

[0076] Figure 11 is a view of the electrode structure inside the laminate of the laminated filter 2 from the Y-axis direction. Figure 10 Figure 5 The electrode structure of the laminated filter 2 is the electrode structure after the electrode structure of the laminated filter 1 of FIG. 1 is added with the coupling electrode 231 (first coupling electrode) and the coupling electrode 232 (second coupling electrode). The same is true except for this, so the explanation will not be repeated.

[0077] As shown in FIG. 3, the coupling electrode 231 is connected to the via conductor V10 between the ground electrodes 111 and 112 and extends from the input-output terminal P1 toward P2. The coupling electrode 232 is connected to the via conductor V20 between the ground electrodes 111 and 112 and extends from the input-output terminal P2 toward P1. The edge of the coupling electrode 231 is opposed to the edge of the coupling electrode 232 in the direction from the input-output terminal P1 toward P2. By the coupling electrodes 231, 232, the capacitor C22 of FIG. 2 is formed. Figure 11 Figure 10

[0078] Figure 12 is a view of the pass characteristic (solid line) of the laminated filter 2 of FIG. 2 and the pass characteristic (broken line) of the laminated filter 1 of FIG. 1. As shown in FIG. 5, in the laminated filter 1, an attenuation pole is generated near the frequency f21 on the low frequency side. On the other hand, in the laminated filter 2, an attenuation pole is generated at f22 (< f21) in addition to the frequency f21 on the low frequency side. As a result, the minimum value of the insertion loss on the low frequency side is larger for the laminated filter 2 than for the laminated filter 1. The laminated filter 2 can ensure a larger attenuation amount on the low frequency side than the laminated filter 1. That is, it is possible to improve the attenuation characteristic of the laminated filter 2 as compared with the attenuation characteristic of the laminated filter 1. Figure 11 Figure 5 Figure 12 is a view of the pass characteristic (solid line) of the laminated filter 2 of FIG. 2 and the pass characteristic (broken line) of the laminated filter 1 of FIG. 1. As shown in FIG. 5, in the laminated filter 1, an attenuation pole is generated near the frequency f21 on the low frequency side. On the other hand, in the laminated filter 2, an attenuation pole is generated at f22 (< f21) in addition to the frequency f21 on the low frequency side. As a result, the minimum value of the insertion loss on the low frequency side is larger for the laminated filter 2 than for the laminated filter 1. The laminated filter 2 can ensure a larger attenuation amount on the low frequency side than the laminated filter 1. That is, it is possible to improve the attenuation characteristic of the laminated filter 2 as compared with the attenuation characteristic of the laminated filter 1.

[0079] Figure 13 is a view of the 4 GHz to 7 GHz portion of FIG. 4 enlarged. As shown in FIG. 6, the minimum value of the insertion loss of the laminated filter 2 is approximately the same as the minimum value of the insertion loss of the laminated filter 1. That is, the pass characteristic under the pass band of the laminated filter 2 maintains the pass characteristic under the pass band of the laminated filter 1. Figure 12 Figure 13

[0080] ​​​​​​​​With the above-described stacked filter according to Embodiment 2, the pass characteristic in the pass band can be maintained, and the attenuation characteristic can be further improved.

[0081] In Embodiments 1 and 2, the stacked filter including four LC resonators was described. The number of LC resonators included in the stacked filter of the embodiments is not limited to four. Hereinafter, the case where the number of LC resonators included in the stacked filter of the embodiments is three, five, six, and seven will be described in Embodiments 3, 4, 5, and 6, respectively.

[0082] [Embodiment 3]

[0083] Figure 14 is an equivalent circuit diagram of the stacked filter 3 of Embodiment 3. The equivalent circuit of the stacked filter 3 is an equivalent circuit obtained by removing the LC parallel resonator LC4 from the equivalent circuit of the stacked filter 1 including the LC parallel resonators LC1 to LC4. Figure 1 is an equivalent circuit diagram of the stacked filter 3 of Embodiment 3. The equivalent circuit of the stacked filter 3 is an equivalent circuit obtained by removing the LC parallel resonator LC4 from the equivalent circuit of the stacked filter 1 including the LC parallel resonators LC1 to LC4.

[0084] As shown in Figure 14 , the LC parallel resonator LC3 (third LC resonator) is connected to the ground point Gl. The LC parallel resonator LC3 is connected to the input / output terminal P2 via the capacitor C20. The LC parallel resonator LC3 is connected to the LC parallel resonator LC1 via the capacitor C13.

[0085] With the above-described stacked filter according to Embodiment 3, the attenuation characteristic can be improved.

[0086] [Embodiment 4]

[0087] Figure 15 is an equivalent circuit diagram of the stacked filter 4 of Embodiment 4. The equivalent circuit of the stacked filter 4 is an equivalent circuit obtained by adding the LC parallel resonator LC5 (third LC resonator) to the equivalent circuit of the stacked filter 1 including the LC parallel resonators LC1 to LC4. Figure 1 is an equivalent circuit diagram of the stacked filter 4 of Embodiment 4. The equivalent circuit of the stacked filter 4 is an equivalent circuit obtained by adding the LC parallel resonator LC5 (third LC resonator) to the equivalent circuit of the stacked filter 1 including the LC parallel resonators LC1 to LC4.

[0088] As shown in Figure 15 , the magnetic field coupling M4 indicates the magnetic field coupling between the LC parallel resonators LC4 and LC5. The LC parallel resonator LC5 is connected to the LC parallel resonator LC4 (third LC resonator) via the capacitor C45. The LC parallel resonator LC5 is connected to the LC parallel resonator LC1 via the capacitor C15. The LC parallel resonator LC5 is connected to the input / output terminal P2 via the capacitor C20. The LC parallel resonator LC5 is connected to the ground point Gl. The LC parallel resonator LC4 is connected to the ground point G2.

[0089] The LC parallel resonator LC5 includes an inductor L5 and a capacitor C5. The inductor L5 and the capacitor C5 are connected in parallel between the ground point Gl and the connection point of the capacitors C45 and C20.

[0090] Figure 16 is an equivalent circuit diagram of the laminated filter 4A which is a modification of Embodiment 4. The equivalent circuit of the laminated filter 4A is an equivalent circuit in which the ground points connecting the LC parallel resonators LC1, LC5 are changed from Gl to G2, and the ground point connecting the LC parallel resonator LC3 is changed from G2 to Gl. It is the same except for this, so the explanation is not repeated. Figure 15 is an equivalent circuit in which the ground points connecting the LC parallel resonators LC1, LC5 are changed from Gl to G2, and the ground point connecting the LC parallel resonator LC3 is changed from G2 to Gl. It is the same except for this, so the explanation is not repeated.

[0091] With the laminated filter according to Embodiment 4 and the modification, the attenuation characteristic can be improved.

[0092] [Embodiment 5]

[0093] Figure 17 is an equivalent circuit diagram of the laminated filter 5 of Embodiment 5. The equivalent circuit of the laminated filter 5 is an equivalent circuit in which the LC parallel resonators LC1 to LC5 included in the laminated filter 4 of Figure 15 is an equivalent circuit in which the LC parallel resonators LC1 to LC5 included in the laminated filter 4 of Embodiment 4 are added with an LC parallel resonator LC6 (third LC resonator). It is the same except for the change brought by the addition of the LC parallel resonator LC6, so the explanation is not repeated.

[0094] As shown in Figure 17 , the magnetic field coupling M5 indicates the magnetic field coupling between the LC parallel resonators LC5 and LC6. The LC parallel resonator LC6 is connected to the LC parallel resonator LC5 (fourth LC resonator) via the capacitor C56. The LC parallel resonator LC6 is connected to the LC parallel resonator LC1 via the capacitor Cl6. The LC parallel resonator LC6 is connected to the input / output terminal P2 via the capacitor C20. The LC parallel resonator LC6 is connected to the ground point Gl. The LC parallel resonator LC5 is connected to the ground point G2.

[0095] The LC parallel resonator LC6 includes an inductor L6 and a capacitor C6. The inductor L6 and the capacitor C6 are connected in parallel between the ground point Gl and the connection point of the capacitors C56 and C20.

[0096] Figure 18 is an equivalent circuit diagram of the laminated filter 5A which is a modification of Embodiment 5. The equivalent circuit of the laminated filter 5A is an equivalent circuit in which the ground points connecting the LC parallel resonators LC1, LC6 are changed from Gl to G2, and the ground points connecting the LC parallel resonators LC3, LC4 are changed from G2 to Gl. It is the same except for this, so the explanation is not repeated. Figure 17 is an equivalent circuit in which the ground points connecting the LC parallel resonators LC1, LC6 are changed from Gl to G2, and the ground points connecting the LC parallel resonators LC3, LC4 are changed from G2 to Gl. It is the same except for this, so the explanation is not repeated.

[0097] According to the multilayer filter of Embodiment 5 and the modification, the attenuation characteristic can be improved.

[0098] [Embodiment 6]

[0099] Figure 19 is an equivalent circuit diagram of the multilayer filter 6 of Embodiment 6. The equivalent circuit of the multilayer filter 6 is an equivalent circuit in which an LC parallel resonator LC7 (third LC resonator) is added to the multilayer filter 5 of Figure 17 . The same as the multilayer filter 5 except for the change due to the addition of the LC parallel resonator LC7, so the description is not repeated.

[0100] As shown in Figure 19 , the magnetic field coupling M6 represents the magnetic field coupling between the LC parallel resonator LC6 and LC7. The LC parallel resonator LC7 is connected to the LC parallel resonator LC6 (fourth LC resonator) via the capacitor C67. The LC parallel resonator LC7 is connected to the LC parallel resonator LC1 via the capacitor C17. The LC parallel resonator LC7 is connected to the input / output terminal P2 via the capacitor C20. The LC parallel resonator LC7 is connected to the ground point Gl. The LC parallel resonator LC6 is connected to the ground point G2.

[0101] The LC parallel resonator LC7 includes an inductor L7 and a capacitor C7. The inductor L7 and the capacitor C7 are connected in parallel between the ground point Gl and the connection points of the capacitors C67 and C20.

[0102] Figure 20 is an equivalent circuit diagram of the multilayer filter 6A of the modification of Embodiment 6. The equivalent circuit of the multilayer filter 6A is an equivalent circuit in which the ground points connecting the LC parallel resonators LC1 and LC7 are changed from Gl to G2, and the ground point connecting the LC parallel resonator LC4 is changed from G2 to Gl, to the multilayer filter 6 of Embodiment 6. The same as the multilayer filter 6 except for this, so the description is not repeated. Figure 19

[0103] According to the multilayer filter of Embodiment 6 and the modification, the attenuation characteristic can be improved.

[0104] The embodiments disclosed this time can also be implemented by an appropriate combination of hardware and software. The embodiments disclosed this time are examples in all points but should not be understood as being limited to the embodiments. The scope of the present application is not shown by the above description but shown by the scope of the claims to be presented below.

[0105] Explanation of Reference Numerals

[0106] ​1-6, 1A, 4A-6A, 10...laminated filter, 100...laminated body, 101, 201, 301, 401...line electrode, 102-104, 202, 203, 302, 303, 402-404...capacitor electrode, 110...ground terminal, 111, 112...ground electrode, 121, 122, 221, 222, 231, 232...coupling electrode, C1-C7, C10, C12-C17, C20, C22, C23, C34, C45, C56, C67...capacitor, L1-L7...inductor, LC1-LC7...parallel resonator, P1, P2...input / output terminal, V1-V6, V10-V13, V20-V23, V31-V33, V41-V43, V81, V82...via conductor

Claims

1. A laminated filter comprising: a first ground electrode and a second ground electrode; a first LC resonator connected to the first ground electrode; and a second LC resonator connected to the second ground electrode, the first LC resonator including: a first line electrode; a first capacitor electrode disposed between the first ground electrode and the first line electrode; a first via conductor connecting the first line electrode and the first capacitor electrode; and a second via conductor extending from the first line electrode to a side on which the first capacitor electrode is disposed, and connecting the first line electrode and the first ground electrode, the second LC resonator including: a second line electrode; a second capacitor electrode disposed between the second ground electrode and the second line electrode; a third via conductor connecting the second line electrode and the second capacitor electrode; and a fourth via conductor extending from the second line electrode to a side on which the second capacitor electrode is disposed, and connecting the second line electrode and the second ground electrode, the first line electrode and the second line electrode each extending in a first direction, the third via conductor being closer to the first via conductor than the second via conductor in the first direction, the fourth via conductor being closer to the second via conductor than the first via conductor in the first direction, the first direction and an extending direction of the first via conductor being orthogonal to each other, the laminated filter further comprising a first ground via conductor connecting the first ground electrode and the second ground electrode, the first ground via conductor being closer to the first via conductor than the second via conductor in the first direction when viewed from a second direction orthogonal to the first direction and the extending direction of the first via conductor.

2. The laminated filter according to claim 1, further comprising: a ground terminal; and a second ground via conductor connecting the ground terminal and the first ground electrode.

3. The laminated filter according to claim 1 or 2, further comprising: a third LC resonator; a first terminal electrically connected to the first LC resonator; and a second terminal electrically connected to the third LC resonator, the third LC resonator including: a third line electrode; a third capacitor electrode disposed between the first ground electrode and the third line electrode; a fifth via conductor connecting the third line electrode and the third capacitor electrode; and a sixth via conductor extending from the third line electrode to a side on which the third capacitor electrode is disposed, and connecting the third line electrode and the first ground electrode.

4. The laminated filter according to claim 3, further comprising a fourth LC resonator, the fourth LC resonator including: a fourth line electrode; a fourth capacitor electrode disposed between the second ground electrode and the fourth line electrode; a seventh via conductor connecting the fourth line electrode and the fourth capacitor electrode; and an eighth via conductor extending from the fourth line electrode to a side on which the fourth capacitor electrode is disposed, and connecting the fourth line electrode and the second ground electrode. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ An eighth via conductor extends from the fourth line electrode to a side on which the fourth capacitor electrode is disposed, and connects the fourth line electrode and the second ground electrode.

5. The laminated filter according to claim 3, wherein The first capacitor electrode is disposed between the second ground electrode and the first line electrode, The second capacitor electrode is disposed between the second ground electrode and the second line electrode.

6. The laminated filter according to claim 5, wherein In the extending direction of the first via conductor, the distance between the first line electrode and the second ground electrode is shorter than the distance between the first line electrode and the first ground electrode.

7. The laminated filter according to claim 5, further comprising: a first coupling electrode connected to the first terminal and extending from the first terminal toward the second terminal between the first ground electrode and the second ground electrode; a second coupling electrode connected to the second terminal and extending from the second terminal toward the first terminal between the first ground electrode and the second ground electrode; a fifth capacitor electrode opposed to the first capacitor electrode and connected to the first terminal; and a sixth capacitor electrode opposed to the third capacitor electrode and connected to the second terminal, The first coupling electrode is opposed to the second coupling electrode in the direction from the first terminal toward the second terminal.

8. The laminated filter according to claim 1 or 2, wherein a third coupling electrode opposed to the first capacitor electrode and the second capacitor electrode, respectively, is further provided. ​

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