LC filter

Abstract

The LC filter (100) of the present application has an input terminal (T1), an output terminal (T2), a laminate (110), flat electrodes (PG1, PG2), connection electrodes (VG11 to VG13) connecting the flat electrodes, a plurality of capacitor electrodes, and a plurality of inductor vias. Each capacitor electrode opposes the flat electrode (PG2). One end of the inductor via (V11) is connected to the input terminal (T1) via the capacitor electrode (P1). The other end of the inductor via (V11) is connected to the middle of the connection electrode (VG11). The inductor via (V12) is connected between the flat electrode (PG1) and the capacitor electrode (P12). The inductor via (V14) is connected between the flat electrode (PG1) and the capacitor electrode (P14). One end of the inductor via (V15) is connected to the output terminal (T2) via the capacitor electrode (P15). The other end of the inductor via (V15) is connected to the middle of the connection electrode (VG13).

Description

Technical Field

[0001] This disclosure relates to LC filters, and more specifically to techniques for improving the characteristics of stacked LC filters. Background Technology

[0002] Japanese Patent Application Publication No. 2000-165171 (Patent Document 1) discloses an LC filter in which a multi-stage resonator consisting of inductors and capacitors is formed within a multilayer substrate. In the LC filter disclosed in Japanese Patent Application Publication No. 2000-165171 (Patent Document 1), the desired filter characteristics are achieved through magnetic coupling and / or capacitive coupling between each stage of the resonator and adjacent resonators.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2000-165171

[0004] The aforementioned LC filters are used in portable communication devices such as mobile phones or smartphones. In such mobile terminals, the demand for miniaturization and thinness remains high, which in turn necessitates the miniaturization of the internal electronic components.

[0005] In LC filters with multi-stage resonators disclosed in Japanese Patent Application Publication No. 2000-165171 (Patent Document 1), it is known that the attenuation characteristics in the non-passband can be improved by increasing the number of resonator stages. However, if the number of resonators formed in the stack increases, the coupling between the resonators is enhanced, and the filter loss is reduced, but there is a possibility that the non-passband signal cannot be sufficiently attenuated. Summary of the Invention

[0006] This disclosure was made to solve such a problem, with the aim of suppressing the increase of filter loss and improving attenuation characteristics in multi-stage stacked LC filters.

[0007] The LC filter disclosed herein includes: an input terminal, an output terminal, a laminate comprising multiple dielectric layers, a first electrode and a second electrode, a connecting electrode connecting the first electrode and the second electrode, a first capacitor electrode, a second capacitor electrode, a third capacitor electrode, and a fourth capacitor electrode, and a first inductor via, a second inductor via, a third inductor via, and a fourth inductor via. The first electrode and the second electrode are disposed in different dielectric layers within the laminate. The first capacitor electrode, the second capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode are opposite to the second electrode. The first capacitor electrode is connected to the first inductor via. The second capacitor electrode is connected to the second inductor via. The third capacitor electrode is connected to the third inductor via. The fourth capacitor electrode is connected to the fourth inductor via. One end of the first inductor via is connected to the input terminal via the first capacitor electrode. The other end of the first inductor via is connected to a position between the first electrode and the second electrode in the connecting electrode. The second inductor via is connected between the first electrode and the second capacitor electrode. The third inductor via is connected between the first electrode and the third capacitor electrode. One end of the fourth inductor via is connected to the output terminal via the fourth capacitor electrode. The other end of the fourth inductor via is connected to the position between the first and second electrodes in the connection electrode.

[0008] According to the LC filter disclosed herein, the resonant circuit connected to the input and output terminals in the multi-stage resonant circuit constituting the filter is directly connected to the connecting electrode connecting the first and second electrodes. Therefore, the magnetic coupling of the resonant circuit connected to the input and output terminals is weakened. Thus, the increase in filter loss can be suppressed, and the attenuation characteristics can be improved. Attached Figure Description

[0009] Figure 1 This is a perspective view of the LC filter according to Embodiment 1.

[0010] Figure 2 yes Figure 1 Side perspective view of an LC filter.

[0011] Figure 3 It is used for Figure 1 A top view illustrating the signal (current) transmission path in the planar electrode PG1 of the LC filter.

[0012] Figure 4 This is a perspective view of the LC filter used in the comparative example.

[0013] Figure 5 This is a diagram used to illustrate the pass characteristics of the LC filter in Embodiment 1 and the comparative example.

[0014] Figure 6 This is a top view of the LC filter in Modified Example 1.

[0015] Figure 7 This is a top view of the LC filter in variation example 2.

[0016] Figure 8 This is a top view of the LC filter in variation example 3.

[0017] Figure 9 This is a perspective view of the LC filter according to Embodiment 2.

[0018] Figure 10 yes Figure 9 Side perspective view of an LC filter.

[0019] Figure 11 This is a perspective view of the LC filter according to embodiment 3. Detailed Implementation

[0020] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same or equivalent parts in the drawings will be labeled with the same reference numerals and their descriptions will not be repeated.

[0021] [Implementation Method 1]

[0022] (Filter structure)

[0023] First, use Figure 1 and Figure 2 The structure of the LC filter 100 according to Embodiment 1 will be described. Figure 1 This is a perspective view of the LC filter 100 from an angle. Additionally, Figure 2 This is a side perspective view of the LC filter 100. The LC filter 100 includes a cuboid or approximately cuboid stack 110 formed by stacking multiple dielectric layers in a stacking direction. Each dielectric layer of the stack 110 is formed, for example, of ceramic. Inside the stack 110, inductors and capacitors are formed by multiple wiring patterns and electrodes disposed in each dielectric layer and multiple vias disposed between the dielectric layers. An LC resonant circuit is formed by these inductors and capacitors.

[0024] In the following description, the stacking direction of the laminate 110 is referred to as the "Z-axis direction", the direction perpendicular to the Z-axis direction and along the long side of the laminate 110 is referred to as the "X-axis direction", and the direction along the short side of the laminate 110 is referred to as the "Y-axis direction". In addition, in the following, the positive direction of the Z-axis in each figure is referred to as the upper side, and the negative direction is referred to as the lower side.

[0025] In addition, Figure 1 And the following Figure 4 , Figure 9 , Figure 11In this diagram, the dielectric of the laminate 110 is omitted, and only the wiring pattern, vias, and conductors of the terminals formed inside are shown.

[0026] Figure 2 From Figure 1 View the side perspective of the LC filter 100 from the negative Y-axis direction. (Refer to...) Figure 1 and Figure 2 The laminate 110 has an upper surface 111 and a lower surface 112. On the lower surface 112 of the laminate 110, an input terminal T1, an output terminal T2, and a ground terminal GND are provided. The input terminal T1, output terminal T2, and ground terminal GND are external terminals used to connect the LC filter 100 to external devices, and are flat electrode plates. Specifically, the input terminal T1, output terminal T2, and ground terminal GND are LGA (Land Grid Array) terminals regularly arranged on the lower surface 112 of the laminate 110.

[0027] A planar electrode PG2 is disposed in the dielectric layer near the lower surface 112 of the laminate 110. For example... Figure 2 As shown, the planar electrode PG2 is connected to the ground terminal GND via vias VGA and VGB. Additionally, a planar electrode PG1 is provided on the dielectric layer near the upper surface 111 of the laminate 110. Furthermore, in... Figure 1 In the diagram, the flat plate electrode PG1 is shown by a dashed line.

[0028] Planar electrodes PG1 and PG2 are connected via grounding vias VG11, VG12, and VG13 extending in the stacking direction of the laminate 110. Grounding vias VG11 and VG13 are configured along side 113 (first side) of the laminate 110 in the positive Y-axis direction. Grounding via VG11 is located at a corner in the negative X-axis direction, and grounding via VG13 is located at a corner in the positive X-axis direction. Grounding via VG12 is configured along side 114 (second side) of the laminate 110 in the negative X-axis direction, near the center. Sides 113 and 114 are opposite to each other.

[0029] Multiple plate-shaped electrodes P11 to P15 are disposed in the dielectric layer between plate electrodes PG1 and PG2. These electrodes P11 to P15 are separately disposed from plate electrode PG2, forming a capacitor with plate electrode PG2. Hereinafter, electrodes P11 to P15 are also referred to as "capacitor electrodes". Capacitor electrodes P11 to P15 are separately disposed from each other and capacitively coupled to each other. Inductor vias V11 to V15, which constitute an LC resonant circuit, are respectively connected to capacitor electrodes P11 to P15.

[0030] Input terminal T1 is connected to capacitor electrode P11 via via V11A and wiring electrode P11A. One end of inductor via V11 is connected to capacitor electrode P11, and the other end is connected to wiring electrode PA1. Wiring electrode PA1 is disposed in the dielectric layer between plate electrode PG1 and capacitor electrode P11, connecting inductor via V11 and ground via VG11. That is, the other end of inductor via V11 is connected to the position between plate electrodes PG1 and PG2 in ground via VG11 via wiring electrode PA1. With this structure, inductor via V11 and capacitor electrode P11 form an LC resonant circuit (first resonant circuit RC1) directly connected to ground via VG11.

[0031] Output terminal T2 is connected to capacitor electrode P15 via via V15A and wiring electrode P15A. One end of inductor via V15 is connected to capacitor electrode P15, and the other end is connected to wiring electrode PA2. Wiring electrode PA2 is disposed in the dielectric layer between plate electrode PG1 and capacitor electrode P15, connecting inductor via V15 and ground via VG13. That is, the other end of inductor via V15 is connected to the position between plate electrodes PG1 and PG2 in ground via VG13 via wiring electrode PA2. With this structure, inductor via V15 and capacitor electrode P15 form an LC resonant circuit (fifth resonant circuit RC5) directly connected to ground via VG13.

[0032] An inductor via V12 is positioned at the corner along the negative direction of the X-axis along side 114. The inductor via V12 is connected to the plate electrode PG1 and the capacitor electrode P12, forming an LC resonant circuit (second resonant circuit RC2).

[0033] An inductor via V13 is positioned near the center of the X-axis along side 113. Specifically, the inductor via V13 is positioned between the ground via VG11 and the ground via VG13 along side 113. The inductor via V13 is connected to the planar electrode PG1 and the capacitor electrode P13, forming an LC resonant circuit (the third resonant circuit RC3).

[0034] An inductor via V14 is positioned at the corner along the side 114 in the positive direction of the X-axis. The inductor via V14 is connected to the plate electrode PG1 and the capacitor electrode P14, forming an LC resonant circuit (the fourth resonant circuit RC4).

[0035] In this way, the LC filter 100 has a structure with multiple resonant circuits adjacent to each other, and the attenuation poles generated by the magnetic coupling and / or capacitive coupling between the adjacent resonant circuits function as bandpass filters. The high-frequency signal supplied to the input terminal T1 is output from the output terminal T2 via the first resonant circuit RC1, the second resonant circuit RC2, the third resonant circuit RC3, the fourth resonant circuit RC4, and the fifth resonant circuit RC5.

[0036] Figure 3 It is used for Figure 1 A top view illustrating the signal (current) transmission path in the planar electrode PG1 of the LC filter 100. (Refer to...) Figure 3 As shown by arrow AR0, the high-frequency signal supplied to input terminal T1 is transmitted from the first resonant circuit RC1 to the adjacent second resonant circuit RC2 via magnetic coupling. The signal transmitted to the second resonant circuit RC2, as shown by arrow AR1, is transmitted to the adjacent third resonant circuit RC3 via the plate electrode PG1, and, as shown by arrow AR2, to the fourth resonant circuit RC4 (arrow AR2) adjacent to the third resonant circuit RC3. Furthermore, the signal transmitted to the fourth resonant circuit RC4, as shown by arrow AR3, is transmitted to the fifth resonant circuit RC5 via magnetic coupling and output from output terminal T2.

[0037] Here, when signals are transmitted between resonant circuits, from the viewpoint of reducing signal loss in the desired passband, it is important to increase the coupling between the resonant circuits to improve the Q value. On the other hand, in the case of a filter device, it is preferable to avoid transmitting non-passband signals as much as possible. That is, from the viewpoint of attenuating non-passband signals, it is also necessary to reduce the coupling between the resonant circuits.

[0038] Therefore, in the LC filter 100 of Embodiment 1, in order to prevent the coupling between resonant circuits from being too high, the resonant circuits connected to the input and output terminals, namely the first resonant circuit RC1 and the fifth resonant circuit RC5, are connected to the grounding vias VG11 and VG13 through wiring electrodes PA1 and PA2. More specifically, as... Figure 1 As shown, unlike other resonant circuits, the inductor vias V11 and V15 in the first resonant circuit RC1 and the fifth resonant circuit RC5 are not directly connected to the plate electrode PG1. Instead, they are connected to the plate electrodes PG1 and PG2 via wiring electrodes PA1 and PA2, and grounding vias VG11 and VG13, respectively. This structure reduces the coupling between the first resonant circuit RC1 and the second resonant circuit RC2, and between the fourth resonant circuit RC4 and the fifth resonant circuit RC5, compared to the case where the first resonant circuit RC1 and the fifth resonant circuit RC5 are directly connected to the plate electrode PG1.

[0039] Furthermore, it is well known that, generally speaking, in multi-stage LC filters, the Q-value of the resonant circuit located in the middle stage contributes significantly to the overall Q-value of the filter device, while the Q-value of the resonant circuit near the ends (input / output terminals) has a relatively smaller impact on the overall Q-value of the filter. Therefore, as described above, by configuring the resonant circuit connected to the input / output terminals and the circuit connected to the ground via, the overall Q-value of the filter can be maintained, and the coupling between the resonant circuits will not be too high.

[0040] Furthermore, in the LC filter 100 of Embodiment 1, such as Figure 3 As shown, when viewing the laminate 110 from the stacking direction (Z-axis direction), the grounding vias VG11, VG12, and VG13 are disposed on both sides of the signal transmission paths (arrows AR1 and AR2) between the inductor vias V12, V13, and V14 in the planar electrode PG1. Specifically, the imaginary line CL1 (first imaginary line) connecting the inductor vias V12 and V13 intersects the imaginary line CL2 (second imaginary line) connecting the grounding vias VG11 and VG12. Similarly, the imaginary line CL3 connecting the inductor vias V13 and V14 intersects the imaginary line CL4 connecting the grounding vias VG12 and VG13.

[0041] Furthermore, in order to achieve symmetry in the characteristics of the filter, it is preferable to arrange the inductor vias and the ground vias symmetrically so that the imaginary lines CL1 and CL2 intersect each other at the midpoint, and the imaginary lines CL3 and CL4 intersect each other at the midpoint.

[0042] With this via configuration, a portion of the signal (current) transmitted from inductor via V12 to inductor via V13 on the flat plate electrode PG1 leaks to ground vias VG11 and VG12, as indicated by arrows AR1A and AR1B. Similarly, a portion of the signal (current) transmitted from inductor via V13 to inductor via V14 leaks to ground vias VG12 and VG13, as indicated by arrows AR2A and AR2B. Consequently, the coupling between the second resonant circuit RC2 and the third resonant circuit RC3, as well as the coupling between the third resonant circuit RC3 and the fourth resonant circuit RC4, is slightly reduced.

[0043] Furthermore, in Embodiment 1, "plate electrode PG1" and "plate electrode PG2" correspond to "first electrode" and "second electrode" in this disclosure, respectively. In Embodiment 1, "grounding vias VG11 to VG13" correspond to "first grounding via" to "third grounding via" in this disclosure, and generally correspond to "connection electrode" in this disclosure. In Embodiment 1, "capacitor electrode P11," "capacitor electrode P12," "capacitor electrode P13," "capacitor electrode P15," and "capacitor electrode P14" correspond to "first capacitor electrode" to "fifth capacitor electrode" in this disclosure, respectively. In Embodiment 1, "inductor via V11," "inductor via V12," "inductor via V13," "inductor via V15," and "inductor via V14" correspond to "first inductor via" to "fifth inductor via" in this disclosure, respectively.

[0044] (Filter characteristics)

[0045] Next, the pass characteristics of the LC filter 100 of Embodiment 1 will be described in comparison with the comparative example.

[0046] Figure 4 This is a perspective view of the comparative example LC filter 100#. In the comparative example LC filter 100#, the first resonant circuit RC1 connected to the input terminal T1 and the fifth resonant circuit RC5 connected to the output terminal T2 are replaced with the first resonant circuit RC1# and the fifth resonant circuit RC5#, respectively, as in the LC filter 100 of Embodiment 1.

[0047] Specifically, in the first resonant circuit RC1# of the comparative example, the wiring electrode PA1 in Embodiment 1 is removed. Furthermore, the inductor via V11# is connected to the plate electrode PG1 and the capacitor electrode P11. Similarly, in the fifth resonant circuit RC5#, the wiring electrode PA2 in Embodiment 1 is removed, and the inductor via V15# is connected to the plate electrode PG1 and the capacitor electrode P15. That is, the first resonant circuit RC1# and the fifth resonant circuit RC5# are structured to be directly connected to the plate electrode PG1.

[0048] Figure 5 This is a diagram used to illustrate the pass-through characteristics of the LC filter 100 in Embodiment 1 and the LC filter 100# in the comparative example. Figure 5 In the diagram, the horizontal axis represents the frequency, and the vertical axis represents the insertion loss from input terminal T1 to output terminal T2. Figure 5In the diagram, solid lines LN10 and LN10A represent the LC filter 100 of Embodiment 1, while dashed lines LN11 and LN11A represent the LC filter 100# of the comparative example. Furthermore, solid lines LN10A and dashed lines LN11A are magnified graphs of the vertical axis of solid lines LN10 and dashed lines LN11 (right-axis scale). The passband of this LC filter is specified as 4400MHz to 5000MHz.

[0049] Reference Figure 5 Regarding the insertion loss in the passband, as shown by the solid line LN10A and the dashed line LN11A, from the peak value perspective, the insertion loss of the LC filter 100 in Embodiment 1 is greater than that of the LC filter 100# in the Comparative Example. This is because in Embodiment 1, as described above, the coupling is reduced by forming a structure where the first resonant circuit RC1 and the fifth resonant circuit RC5 are directly connected to the ground via. However, for a bandwidth where the insertion loss is less than 3dB, both can achieve almost the same level of bandwidth.

[0050] Regarding the attenuation characteristics, for the lower frequency side of the passband, the attenuation in the comparative example is approximately 25 dB, while in Embodiment 1, an attenuation of approximately 60 dB can be achieved. Furthermore, for the higher frequency side of the passband, the attenuation is almost the same, but Embodiment 1 achieves a steeper attenuation.

[0051] In this way, in the LC filter 100 of Embodiment 1, by forming a structure in which the resonant circuit connected to the input and output terminals is directly connected to the grounding via, it is possible to suppress the increase of filter loss in the passband and improve the attenuation characteristics in the non-passband.

[0052] (Modified Example)

[0053] In Embodiment 1, an example of an LC filter structure having a five-stage resonant circuit was described. In the following Variations 1 to 3, examples of LC filters with resonant circuits having different numbers of stages are described.

[0054] (a) Variation Example 1

[0055] Figure 6 This is a top view of the LC filter 100A of Modified Example 1. The LC filter 100A has a four-stage resonant circuit. More specifically, the LC filter 100A includes: a first resonant circuit RC1A containing an inductor via V21 and a wiring electrode PA21; a second resonant circuit RC2A containing an inductor via V22; a third resonant circuit RC3A containing an inductor via V23; and a fourth resonant circuit RC4A containing an inductor via V24 and a wiring electrode PA22. Furthermore, although in Figure 6Although not shown in the figure, capacitor electrodes are connected to each inductor via, similar to the LC filter 100 in Embodiment 1.

[0056] When viewed from the stacking direction, the inductor vias V22 and V23 are located at the corner of one diagonal of the rectangular planar electrode PG1. Additionally, the grounding vias VG21 and VG22 are located at the corner of the other diagonal of the planar electrode PG1. In other words, the grounding via VG21 and the inductor via V23 are arranged along the side surface 113 of the stack 110. Furthermore, the grounding via VG22 and the inductor via V22 are arranged along the side surface 114 of the stack 110. The inductor vias V22 and V23, and the grounding vias VG21 and VG22 are arranged such that the imaginary line connecting the inductor vias V22 and V23 intersects the imaginary line connecting the grounding vias VG21 and VG22.

[0057] An inductor via V21 is positioned between the ground via VG21 and the inductor via V22. One end of the inductor via V21 is connected to the input terminal via a capacitor electrode. The other end of the inductor via V21 is connected to the middle position of the ground via VG21 (between the planar electrodes PG1 and PG2) via a wiring electrode PA21. That is, the first resonant circuit RC1A is directly connected to the ground via.

[0058] Inductor via V24 is positioned between ground via VG22 and inductor via V23. One end of inductor via V24 is connected to the output terminal via a capacitor electrode. The other end of inductor via V24 is connected to the middle position of ground via VG22 (between plate electrodes PG1 and PG2) via wiring electrode PA22. That is, the fourth resonant circuit RC4A is directly connected to the ground via.

[0059] The high-frequency signal supplied to the input terminal, as shown by arrow AR20, is transmitted from the first resonant circuit RC1A to the second resonant circuit RC2A via magnetic coupling. The signal transmitted to the second resonant circuit RC2A, as shown by arrow AR21, is transmitted to the third resonant circuit RC3A via the plate electrode PG1, and, as shown by arrow AR22, is transmitted to the fourth resonant circuit RC4A via magnetic coupling, and is output from the output terminal.

[0060] In the LC filter 100A, the first resonant circuit RC1A connected to the input terminal and the fourth resonant circuit RC4A connected to the output terminal are directly connected to ground vias. Furthermore, ground vias VG21 and VG22 are arranged on both sides of the signal (current) transmission path from the second resonant circuit RC2A to the third resonant circuit RC3A in the plate electrode PG1. By adopting this structure, in the LC filter 100A of Modified Example 1, similar to Embodiment 1, the decrease in the overall Q value of the filter is suppressed, and the coupling between the resonant circuits is reduced. Therefore, the decrease in the insertion loss of the filter can be suppressed, and the attenuation characteristics can be improved.

[0061] Furthermore, the "grounding vias VG21 and VG22" in Modification 1 correspond to the "first grounding via" and "second grounding via" in this disclosure, respectively, and generally correspond to the "connection electrode" in this disclosure. The "inductance vias V21 to V24" in Modification 1 correspond to the "first inductance via" to "fourth inductance via" in this disclosure, respectively.

[0062] (b) Variation Example 2

[0063] Figure 7 This is a top view of the LC filter 100B of Modified Example 2. The LC filter 100B has a structure that includes a six-stage resonant circuit by further adding another stage of resonant circuit to the structure of the LC filter 100 of Embodiment 1.

[0064] More specifically, the LC filter 100B includes: a first resonant circuit RC1B containing an inductor via V31 and a wiring electrode PA31; a second resonant circuit RC2B containing an inductor via V32; a third resonant circuit RC3B containing an inductor via V33; a fourth resonant circuit RC4B containing an inductor via V34; a fifth resonant circuit RC5B containing an inductor via V35; and a sixth resonant circuit RC6B containing an inductor via V36 and a wiring electrode PA32. Furthermore, although in Figure 7 Although not shown in the diagram, capacitor electrodes are connected to each inductor via.

[0065] When viewed from the stacking direction, the grounding vias VG31 and VG33, and the inductor vias V33 and V35 are arranged along the side surface 113 of the stack 110 in the positive X-axis direction in the order of grounding via VG31, inductor via V33, grounding via VG33, and inductor via V35. Furthermore, the grounding vias VG32 and VG34, and the inductor vias V32 and V34 are arranged along the side surface 114 of the stack 110 in the positive X-axis direction in the order of inductor via V32, grounding via VG32, inductor via V34, and grounding via VG34.

[0066] The first resonant circuit RC1B is a structure in which the wiring electrode PA31 is directly connected to the middle position of the grounding via VG31. The sixth resonant circuit RC6B is a structure in which the wiring electrode PA32 is directly connected to the middle position of the grounding via VG34.

[0067] High-frequency signals supplied to the input terminals, such as Figure 7 As indicated by arrows AR30 to AR34, the signal is transmitted in the order of the first resonant circuit RC1B, the second resonant circuit RC2B, the third resonant circuit RC3B, the fourth resonant circuit RC4B, the fifth resonant circuit RC5B, and the sixth resonant circuit RC6B, and output from the output terminal. Grounding vias VG31 to VG34 are located on both sides of the signal transmission path (arrows AR31 to AR33) in the plate electrode PG1.

[0068] In the LC filter 100B, the first resonant circuit RC1B connected to the input terminal and the sixth resonant circuit RC6B connected to the output terminal are directly connected to ground vias. Furthermore, in the planar electrode PG1, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. By adopting this structure, in the LC filter 100B of Modified Example 2, the decrease in the overall Q value of the filter is suppressed, and the coupling between the resonant circuits is reduced. Therefore, the decrease in the insertion loss of the filter can be suppressed, and the attenuation characteristics can be improved.

[0069] Furthermore, in Modification 2, the "grounding vias VG31 to VG33" correspond to the "first grounding via" to the "third grounding via" in this disclosure, respectively. In Modification 2, the "grounding vias VG31 to VG34" generally correspond to the "connecting electrode" in this disclosure. In Modification 2, the "inductor vias V31," "inductor via V32," "inductor via V33," "inductor via V36," and "inductor via V34" correspond to the "first inductor via" to the "fifth inductor via" in this disclosure, respectively.

[0070] (c) Variation 3

[0071] Figure 8 This is a top view of the LC filter 100C of Modified Example 3. The LC filter 100C has a structure that includes a seven-stage resonant circuit, by further adding another stage of resonant circuit to the structure of the LC filter 100B of Modified Example 2.

[0072] More specifically, the LC filter 100C includes: a first resonant circuit RC1C containing an inductor via V41 and a wiring electrode PA41; a second resonant circuit RC2C containing an inductor via V42; a third resonant circuit RC3C containing an inductor via V43; a fourth resonant circuit RC4C containing an inductor via V44; a fifth resonant circuit RC5C containing an inductor via V45; a sixth resonant circuit RC6C containing an inductor via V46; and a seventh resonant circuit RC7C containing an inductor via V47 and a wiring electrode PA42. Furthermore, although in Figure 8 Although not shown in the diagram, each inductor via is connected to the capacitor electrode.

[0073] When viewed from above in the stacking direction, the grounding vias VG41, VG43, and VG45, and the inductor vias V43 and V45 are arranged along the side surface 113 of the stack 110 in the positive X-axis direction, in the order of grounding via VG41, inductor via V43, grounding via VG43, inductor via V45, and grounding via VG45. Similarly, the grounding vias VG42 and VG44, and the inductor vias V42, V44, and V46 are arranged along the side surface 114 of the stack 110 in the positive X-axis direction, in the order of inductor via V42, grounding via VG42, inductor via V44, grounding via VG44, and inductor via V46.

[0074] The first resonant circuit RC1C is a structure in which the wiring electrode PA41 is directly connected to the middle position of the grounding via VG41. Additionally, the seventh resonant circuit RC7C is a structure in which the wiring electrode PA42 is directly connected to the middle position of the grounding via VG45.

[0075] High-frequency signals supplied to the input terminals, such as Figure 8 As indicated by arrows AR40 to AR45, the signal is transmitted in the following order: first resonant circuit RC1C, second resonant circuit RC2C, third resonant circuit RC3C, fourth resonant circuit RC4C, fifth resonant circuit RC5C, sixth resonant circuit RC6C, and seventh resonant circuit RC7C, and output from the output terminal. Grounding vias VG41 to VG45 are positioned on both sides of the signal transmission path (arrows AR41 to AR44) in the planar electrode PG1.

[0076] In the LC filter 100C, the first resonant circuit RC1C connected to the input terminal and the seventh resonant circuit RC7C connected to the output terminal are directly connected to ground vias. Furthermore, in the planar electrode PG1, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. With this structure, in the LC filter 100C of Modified Example 3, the decrease in the overall Q value of the filter is suppressed, and the coupling between the resonant circuits is reduced. Therefore, the decrease in the insertion loss of the filter can be suppressed, and the attenuation characteristics can be improved.

[0077] Furthermore, in Modification 3, the "grounding vias VG41 to VG43" correspond to the "first grounding via" to the "third grounding via" in this disclosure, respectively. In Modification 3, the "grounding vias VG41 to VG45" generally correspond to the "connecting electrode" in this disclosure. In Modification 3, the "inductance vias V41," "inductance via V42," "inductance via V46," and "inductance via V47" correspond to the "first inductance via" to the "fourth inductance via" in this disclosure, respectively.

[0078] In the above-described Embodiment 1 and its variations, examples of LC filters with four to seven resonant circuits were described, but the same structure can also be applied to LC filters with more stages.

[0079] [Implementation Method 2]

[0080] In Embodiment 2, an example of an LC filter structure in which the inductor via and the ground via are configured differently will be described.

[0081] Figure 9 This is a perspective view of the LC filter 100D according to Embodiment 2. Additionally, Figure 10 This is a side perspective view of the LC filter 100D as seen from the side 114 of the stack 110. The LC filter 100D has a structure that includes a four-stage resonant circuit, similar to the modified example 1 in Embodiment 1 described above.

[0082] Reference Figure 9 and Figure 10 The LC filter 100D includes planar electrodes PG1 and PG2, input terminal T1 and output terminal T2, inductor vias V51 to V54, ground vias VG51 to VG54, capacitor electrodes P51 to P54, and wiring electrodes PA51 and PA52 disposed on the laminate 110.

[0083] Similar to the LC filter 100 in Embodiment 1, a planar electrode PG1 is provided on the dielectric layer near the upper surface 111 of the laminate 110, and a planar electrode PG2 is provided on the dielectric layer near the lower surface 112. The planar electrode PG2 is connected to the ground terminal GND provided on the lower surface 112 via vias VGA and VGB.

[0084] Viewed from above in the stacking direction (Z-axis direction) of the laminate 110, grounding vias VG51 to VG54 are respectively disposed at the four corners of the laminate 110. Specifically, grounding vias VG51 and VG53 are disposed along the side surface 113 of the laminate 110 in the X-axis direction in the order of grounding via VG51 and grounding via VG53. Furthermore, grounding vias VG52 and VG54 are disposed along the side surface 114 of the laminate 110 in the X-axis direction in the order of grounding via VG52 and grounding via VG54. Grounding vias VG51 to VG54 are respectively connected to the planar electrode PG1 and the planar electrode PG2.

[0085] A plate-shaped capacitor electrode P51 to P54 is disposed in the dielectric layer between the plate electrode PG1 and the plate electrode PG2. The capacitor electrode P51 to P54 are disposed separately from the plate electrode PG2, forming a capacitor with the plate electrode PG2.

[0086] Viewed from the stacking direction, the capacitor electrodes P52 and P53 are arranged separately along the Y-axis near the center in the X-axis direction. Inductor vias V52 and V53, each with one end connected to the plate electrode PG1, are connected to the capacitor electrodes P52 and P53, respectively. The inductor via V52 is positioned along the side 114 of the stack 110 between the ground via VG52 and VG54. The inductor via V53 is positioned along the side 113 of the stack 110 between the ground via VG51 and VG53. An LC resonant circuit (second resonant circuit RC2D) is formed through the inductor via V52 and the capacitor electrode P52. An LC resonant circuit (third resonant circuit RC3D) is formed through the inductor via V53 and the capacitor electrode P53.

[0087] When viewed from above in the stacking direction, capacitor electrodes P51 and P54 are arranged separately from each other along the X-axis near the center in the Y-axis direction. A portion of capacitor electrodes P52 and P53 is disposed between capacitor electrodes P51 and P54.

[0088] The capacitor electrode P51 is connected to the input terminal T1, which is disposed on the lower surface 112 of the laminate 110, via the via V51A. Additionally, one end of the inductor via V51 is connected to the capacitor electrode P51, and the other end is connected to the wiring electrode PA51. The wiring electrode PA51 is disposed in the dielectric layer between the planar electrodes PG1 and PG2. The inductor via V51 is connected to the middle position of the ground via VG51 (between the planar electrodes PG1 and PG2) via the wiring electrode PA51. The inductor via V51, the wiring electrode PA51, and the capacitor electrode P51 together form an LC resonant circuit (first resonant circuit RC1D) directly connected to the ground via.

[0089] The capacitor electrode P54 is connected to the output terminal T2 disposed on the lower surface 112 of the laminate 110 via the via V54A. Additionally, one end of the inductor via V54 is connected to the capacitor electrode P54, and the other end is connected to the wiring electrode PA52. The wiring electrode PA52 is disposed in the dielectric layer between the planar electrodes PG1 and PG2. The inductor via V54, through the wiring electrode PA52, is connected to the middle position of the ground via VG53 (the position between the planar electrodes PG1 and PG2). The inductor via V54, the wiring electrode PA52, and the capacitor electrode P54 together form an LC resonant circuit (fourth resonant circuit RC4D) directly connected to the ground via.

[0090] In this manner, the LC filter 100D has a structure with multiple resonant circuits adjacent to each other, and the attenuation poles generated by the magnetic coupling and / or capacitive coupling between adjacent resonant circuits function as bandpass filters. The high-frequency signal supplied to the input terminal T1 is output from the output terminal T2 via the first resonant circuit RC1D, the second resonant circuit RC2D, the third resonant circuit RC3D, and the fourth resonant circuit RC4D.

[0091] In the LC filter 100D, the multi-stage resonant circuit has a structure where the first resonant circuit RC1D and the fourth resonant circuit RC4D, which are connected to the input and output terminals, are directly connected to ground vias. Furthermore, in the planar electrode PG1, the imaginary line connecting the inductor vias V52 and V53 intersects with the imaginary line connecting the ground vias VG51 and VG54, or the imaginary line connecting the ground vias VG52 and VG53. With this structure, as explained in Embodiment 1, the decrease in the overall Q value of the filter is suppressed, and the coupling between the individual resonant circuits is reduced. Therefore, the decrease in the filter's insertion loss can be suppressed, and the attenuation characteristics can be improved.

[0092] Furthermore, in Embodiment 2, the "grounding vias VG51 to VG54" correspond to the "first grounding via," "second grounding via," "fifth grounding via," and "sixth grounding via" in this disclosure, respectively, and generally correspond to the "connection electrode" in this disclosure. In Embodiment 2, the "capacitor electrodes P51 to P54" correspond to the "first capacitor electrode" to the "fourth capacitor electrode" in this disclosure, respectively. In Embodiment 2, the "inductor vias V51 to V54" correspond to the "first inductor via" to the "fourth inductor via" in this disclosure, respectively.

[0093] [Implementation Method 3]

[0094] In Embodiment 3, other configuration examples of the connection between the plate electrode PG1 and the plate electrode PG2 will be described.

[0095] Figure 11 This is a perspective view of the LC filter 100E according to Embodiment 3. In the LC filter 100E, instead of the grounding via in the LC filter 100D of Embodiment 2, plate electrodes PG1 and PG2 are connected via plate-shaped electrodes provided on the side of the laminate 110. Furthermore, in Figure 11 In the middle, without repetition with Figure 10 Explanation of the repetitive elements of the LC filter 100D.

[0096] Reference Figure 11 In the LC filter 100E, a plate-shaped side electrode PGA is provided on the side 113 of the laminate, and a plate-shaped side electrode PGB is provided on the side 114. The side electrodes PGA and PGB are connected to the end faces of the plate electrodes PG1 and PG2.

[0097] Furthermore, the inductor via V51, connected to the input terminal T1, is connected to the side electrode PGA via wiring electrode PA51A. Similarly, the inductor via V54, connected to the output terminal T2, is connected to the side electrode PGA via wiring electrode PA52A. Wiring electrodes PA51A and PA52A are respectively disposed in the dielectric layer between the plate electrodes PG1 and PG2, and connected at the position between the plate electrodes PG1 and PG2 of the side electrode PGA. Thus, the inductor via V51, capacitor electrode P51, and wiring electrode PA51A form an LC resonant circuit (first resonant circuit RC1E) directly connected to the ground via. Additionally, the inductor via V54, capacitor electrode P54, and wiring electrode PA54A form an LC resonant circuit (fourth resonant circuit RC4E) directly connected to the ground via. Furthermore, one or both of the wiring electrodes PA51A and PA52A can be used instead of the side electrode PGA connected to the side electrode PGB.

[0098] The high-frequency signal supplied to the input terminal T1 is transmitted through the second resonant circuit RC2E formed by the first resonant circuit RC1E, the inductor via V52 and the capacitor electrode P52, the third resonant circuit RC3E formed by the inductor via V53 and the capacitor electrode P53, and the fourth resonant circuit RC4E, and is output from the output terminal T2.

[0099] In a multi-stage LC filter 100E, which has a structure where the side electrodes PGA and PGB are connected to the planar electrodes PG1 and PG2 instead of a ground via, the first resonant circuit RC1E and the fourth resonant circuit RC4E, which are connected to the input and output terminals, are directly connected to the ground via. Therefore, in the LC filter 100E, by suppressing the decrease in the overall Q value of the filter and reducing the coupling between the resonant circuits, the reduction in the filter's insertion loss can also be suppressed, and the attenuation characteristics can be improved.

[0100] In Embodiment 3, “side electrode PGA, PGB” generally corresponds to “connection electrode” in this disclosure.

[0101] The embodiments disclosed herein should be considered illustrative rather than restrictive in all respects. The scope of this disclosure is defined not by the description of the embodiments above but by the claims, and is intended to include all modifications equivalent to and within the scope of the claims.

[0102] Explanation of reference numerals in the attached figures

[0103] 100, 100A~100E…Filters, 110…Laminator, 111…Top surface, 112…Bottom surface, 113, 114…Side surfaces, GND…Ground terminal, P11~P15, P51~P54…Capacitor electrodes, P11A, P15A, PA1, PA2, PA21, PA22, PA31, PA32, PA41, PA42, PA51, PA51A, PA52, PA52A, PA54A…Wiring electrodes, PG1, PG2…Plate electrodes, PGA, PGB…Side electrodes, RC1, RC1A~RC1E, RC1#, RC2, RC2A~RC2E, R C3, RC3A~RC3E, RC4, RC4A~RC4E, RC5, RC5B, RC5C, RC5#, RC6B, RC6C, RC7C… resonant circuit, T1… input terminal, T2… output terminal, V11~V15, V21~V24, V31~V36, V41~V47, V51~V54, V11#, V15#… inductor vias, V11A, V15A, V51A, V54A, VGA, VGB… vias, VG11~VG13, VG21, VG22, VG31~VG34, VG41~VG45, VG51~VG54… grounding vias.

Claims

1. An LC filter comprising: an input terminal; an output terminal; a laminate including a plurality of dielectric layers; a first electrode and a second electrode disposed in mutually different dielectric layers in the laminate; a connection electrode connected to the first electrode and the second electrode; a first capacitor electrode, a second capacitor electrode, a third capacitor electrode, and a fourth capacitor electrode opposed to the second electrode; a first inductor via connected to the first capacitor electrode; a second inductor via connected to the second capacitor electrode; a third inductor via connected to the third capacitor electrode; a fourth inductor via connected to the fourth capacitor electrode; and a first wiring electrode and a second wiring electrode connected to the connection electrode; the first wiring electrode and the second wiring electrode each being a flat plate-shaped electrode disposed in a dielectric layer between the first electrode and the second electrode in the laminate; one end of the first inductor via being connected to the input terminal via the first capacitor electrode, the other end of the first inductor via being connected to the first wiring electrode, the second inductor via being connected between the first electrode and the second capacitor electrode, the third inductor via being connected between the first electrode and the third capacitor electrode, one end of the fourth inductor via being connected to the output terminal via the fourth capacitor electrode, and the other end of the fourth inductor via being connected to the second wiring electrode.

2. The LC filter according to claim 1, further comprising a ground terminal, the first electrode and the second electrode being connected to the ground terminal, the laminate being disposed in a rectangular parallelepiped having a first side surface and a second side surface opposed to each other, the connection electrode including a first ground via and a second ground via extending in a stacking direction of the laminate, when viewed from the stacking direction of the laminate, the first ground via and the third inductor via being disposed along the first side surface, and the second ground via and the second inductor via being disposed along the second side surface.

3. The LC filter according to claim 2, wherein, when viewed from the stacking direction of the laminate, a first imaginary line linking the second inductor via and the third inductor via intersects a second imaginary line linking the first ground via and the second ground via.

4. The LC filter according to claim 3, wherein the second imaginary line intersects the first imaginary line at a midpoint of the first imaginary line.

5. The LC filter according to claim 4, wherein the second imaginary line intersects the first imaginary line at a midpoint of the second imaginary line, further comprising: a fifth capacitor electrode opposed to the second electrode; and a fifth inductor via disposed along the second side surface and connected to the first electrode and the fifth capacitor electrode, when viewed from the stacking direction of the laminate, the fifth inductor via being disposed between the second inductor via and the second ground via.

6. The LC filter according to claim 5, wherein the fifth inductor via is disposed between the second inductor via and the second ground via. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 6. The LC filter of any one of claims 2-5, wherein, ​ ​ ​ ​ The connection electrode further has a third ground via hole disposed along the first side surface and connecting the first electrode and the second electrode, The second ground via hole is disposed between the second inductor via hole and the fifth inductor via hole, The third inductor via hole is disposed between the first ground via hole and the third ground via hole.

7. The LC filter according to claim 2, wherein further has a fifth ground via hole and a sixth ground via hole connecting the first electrode and the second electrode, when viewed from the stacking direction of the laminate, the third inductor via hole is disposed between the first ground via hole and the fifth ground via hole along the first side surface, the second inductor via hole is disposed between the second ground via hole and the sixth ground via hole along the second side surface.

8. The LC filter according to claim 1, wherein the laminate has a rectangular parallelepiped shape having a first side surface and a second side surface facing each other, the connection electrode is a flat electrode disposed on the first side surface and the second side surface.

9. The LC filter according to any one of claims 1 to 5, wherein the laminate is formed of ceramic.

10. The LC filter according to any one of claims 1 to 5, wherein the LC filter is a band-pass filter.

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