LC filter

Abstract

The LC filter (100) of the present invention comprises: a laminate (110) having a plurality of dielectric layers stacked thereon, planar electrodes (PG1, PG2), capacitor electrodes (P1, P2), inductor vias (V1, V2), and ground vias (VG1, VG2). The planar electrodes are formed on different layers of the laminate. A capacitor is formed between the capacitor electrode and the electrode (PG2). The inductor via (VG1) is connected to the electrode (PG1) and the capacitor electrode (P1), and the inductor via (VG2) is connected to the electrode (PG1) and the capacitor electrode (P2). The ground via connects the planar electrodes to each other. The inductor via (V1) and the capacitor electrode (P1) form a resonant circuit that receives a signal from an input terminal (T1). The inductor via (V2) and the capacitor electrode (P2) form a resonant circuit that transmits a signal to an output terminal (T2).

Description

Technical Field

[0001] The present disclosure relates to LC filters, and more particularly, to a technique for miniaturizing stacked LC filters. Background Art

[0002] Japanese Patent Application Publication No. 2000-165171 (Patent Document 1) discloses an LC filter having multiple resonators composed of inductors and capacitors formed within a multilayer substrate. In the LC filter disclosed in Japanese Patent Application Publication No. 2000-165171 (Patent Document 1), desired filtering characteristics are achieved by magnetically and / or capacitively coupling each resonator stage with adjacent resonators.

[0003] In Japanese Patent Application Laid-Open No. 2000-165171 (Patent Document 1), the laminate forming the LC filter has a cubic shape. A flat-plate first electrode is formed on the upper surface of the laminate, and a flat-plate second electrode is formed on the lower surface. The second electrode is connected to ground potential, and the first and second electrodes are connected via a flat-plate connection electrode formed on the side of the laminate. Each resonator stage is connected to the first electrode.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-165171

[0005] LC filters such as those described above are often used in portable communication devices such as mobile phones and smartphones. Demand for miniaturization and thinness continues to be high in these mobile devices, and this drives the need for miniaturization of the electronic components installed within them.

[0006] In the LC filter described in Japanese Patent Application Laid-Open No. 2000-165171 (Patent Document 1), as described above, each resonator stage, formed within the laminate, is positioned so as to be sandwiched between connecting electrodes formed on the sides of the laminate. To minimize the size of an LC filter with this structure, it is necessary to position each resonator further inward (toward the center) within the laminate to maintain a sufficient distance between the connecting electrodes and the resonators. However, positioning the resonators toward the center can increase the coupling between the resonators, potentially degrading filtering characteristics. Summary of the Invention

[0007] The present disclosure has been made to solve such a problem, and an object thereof is to suppress a decrease in filtering characteristics accompanying miniaturization in a multi-stage multilayer LC filter.

[0008] The LC filter disclosed herein is an LC filter that transmits a signal from an input terminal to an output terminal. The filter comprises: a laminate having multiple dielectric layers, a first and second flat-plate-shaped electrode, a first and second capacitor electrode, a first and second inductor via, and a first and second ground via. The first and second electrodes are formed on different dielectric layers in the laminate. A capacitor is formed between the first and second capacitor electrodes and the second electrode. The first inductor via is connected to the first electrode and the first capacitor electrode, and the second inductor via is connected to the first and second capacitor electrodes. The first and second ground vias connect the first and second electrodes. The first inductor via and the first capacitor electrode form a first resonant circuit that receives a signal from the input terminal. The second inductor via and the second capacitor electrode form a second resonant circuit that transmits a signal to the output terminal.

[0009] In the LC filter disclosed herein, multiple resonant circuits (first and second resonant circuits) are formed between two planar electrodes (first and second electrodes). The first and second electrodes are connected via a connecting electrode in the form of a via. This structure minimizes the increase in coupling between the connecting electrode and each resonant circuit, even when the LC filter is reduced in size. This ensures that the distance between the resonant circuits is maintained, thus minimizing the increase in coupling between the resonant circuits. Consequently, in multi-stage stacked LC filters, the degradation of filtering characteristics associated with miniaturization can be minimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a perspective view of the LC filter according to the first embodiment.

[0011] Figure 2 yes Figure 1 Side perspective view of an LC filter.

[0012] Figure 3 yes Figure 1 Equivalent circuit diagram of the LC filter.

[0013] Figure 4 It is a perspective view of an LC filter of a comparative example.

[0014] Figure 5 It is a diagram for explaining the filtering characteristics of the LC filter according to the first embodiment and the LC filter of the comparative example.

[0015] Figure 6 This is a perspective view of the LC filter according to Modification 1.

[0016] Figure 7It is a perspective view of an LC filter according to Modification 2.

[0017] Figure 8 It is a perspective view of an LC filter according to the second embodiment.

[0018] Figure 9 yes Figure 8 Side perspective view of an LC filter.

[0019] Figure 10 It is used for Figure 8 A diagram illustrating a signal (current) propagating through a first electrode in an LC filter.

[0020] Figure 11 This is a diagram for explaining the filtering characteristics of the LC filter according to the second embodiment.

[0021] Figure 12 This is a perspective view of an LC filter according to Modification 3.

[0022] Figure 13 It is a top view of the LC filter of Modification 4.

[0023] Figure 14 It is a top view of the LC filter of Modification 5.

[0024] Figure 15 It is a top view of the LC filter of Modification Example 6.

[0025] Figure 16 This is an exploded perspective view of the LC filter according to the third embodiment.

[0026] Figure 17 yes Figure 16 Top view of the LC filter.

[0027] Figure 18 yes Figure 16 Equivalent circuit diagram of the LC filter.

[0028] Figure 19 This is a diagram for explaining the filtering characteristics of the LC filter according to the third embodiment. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated.

[0030] [Implementation Method 1]

[0031] (Filter Structure)

[0032] use Figure 1 and Figure 2, the structure of the LC filter 100 according to the first embodiment will be described. Figure 1 1 is a perspective view of the LC filter 100. Figure 2 This is a side perspective view of LC filter 100. LC filter 100 includes a multilayer structure 110 in the shape of a cube or a substantially cube, formed by stacking multiple dielectric layers in a stacking direction. Each dielectric layer of multilayer structure 110 is made of, for example, ceramic. Within multilayer structure 110, multiple wiring patterns and electrodes formed in each dielectric layer, as well as multiple vias formed between dielectric layers, form the inductor and capacitor that form the LC resonant circuit.

[0033] In the following description, the stacking direction of the stacked body 110 is referred to as the "Z-axis direction," the direction perpendicular to the Z-axis direction and along the long side of the stacked body 110 is referred to as the "X-axis direction," and the direction along the short side of the stacked body 110 is referred to as the "Y-axis direction." 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.

[0034] In addition, Figure 1 and the following Figure 4 、 Figures 6 to 8 、 Figure 12 In FIG. 1 , the dielectric of the laminate 110 is omitted, and only the wiring pattern, via holes, and terminal conductors formed inside are shown.

[0035] Reference Figure 1 and Figure 2 The LC filter 100 includes a laminate 110 , an input terminal T1 , an output terminal T2 , inductor vias V1 to V4 , ground vias VG1 to VG4 , and capacitor electrodes P1 to P4 .

[0036] The laminate 110 has an upper surface 111 and a lower surface 112. The external terminals (input terminal T1, output terminal T2, and ground terminal GND) for connecting the LC filter 100 to external devices are flat-plate electrodes, and are LGA (Land Grid Array) terminals regularly arranged on the lower surface 112 of the laminate 110.

[0037] A plate electrode PG2 is formed on the dielectric layer near the lower surface 112 of the stacked body 110. Figure 2 As shown, the plate electrode PG2 is connected to the ground terminal GND on the lower surface 112 via the via holes VGA and VGB. In addition, the plate electrode PG1 is formed on the dielectric layer close to the upper surface 111 of the laminate 110. Figure 1 In FIG, the plate electrode PG1 is shown by a dotted line.

[0038] When viewing the stack 110 from the stacking direction (Z-axis), ground vias VG1 to VG4 are arranged at the four corners of the stack 110. Specifically, ground vias VG1 and VG3 are arranged in the order of ground via VG1 and ground via VG3 along the side surface 113 of the stack 110 in the X-axis direction. Furthermore, ground vias VG2 and VG4 are arranged in the order of ground via VG2 and ground via VG4 along the side surface 114 of the stack 110 in the X-axis direction. Ground vias VG1 to VG4 connect the plate electrode PG1 and the plate electrode PG2, respectively.

[0039] Plate-shaped capacitor electrodes P1 to P4 are formed in the dielectric layer between plate electrode PG1 and plate electrode PG2. Capacitor electrodes P1 to P4 are spaced apart from plate electrode PG2 and form capacitors with plate electrode PG2.

[0040] When viewing the laminate 110 from the stacking direction, capacitor electrodes P2 and P3 are spaced apart from each other along the Y-axis near the center in the X-axis direction. Capacitor electrodes P2 and P3 are connected to inductor vias V2 and V3, respectively, each of which has one end connected to plate electrode PG1. Inductor via V2 is located between ground via VG2 and ground via VG4 along a side surface 114 of the laminate 110. Inductor via V3 is located between ground via VG1 and ground via VG3 along a side surface 113 of the laminate 110. An LC resonant circuit (second resonant circuit RC2) is formed by inductor via V2 and capacitor electrode P2. An LC resonant circuit (third resonant circuit RC3) is formed by inductor via V3 and capacitor electrode P3.

[0041] When the stacked body 110 is viewed from the stacking direction, capacitor electrodes P1 and P4 are spaced apart from each other along the X axis near the center in the Y axis direction. Capacitor electrodes P1 and P4 are disposed so that portions of capacitor electrodes P2 and P3 are formed between them.

[0042] Capacitor electrode P1 is connected to input terminal T1 formed on lower surface 112 of laminate 110 via via V1A. Furthermore, one end of inductor via V1 is connected to capacitor electrode P1. The other end of inductor via V1 is connected to plate electrode PG1. An LC resonant circuit (first resonant circuit RC1) is formed by inductor via V1 and capacitor electrode P1.

[0043] Capacitor electrode P4 is connected to output terminal T2 formed on lower surface 112 of laminate 110 via via V4A. Furthermore, one end of inductor via V4 is connected to capacitor electrode P4. The other end of inductor via V4 is connected to plate electrode PG1. An LC resonant circuit (fourth resonant circuit RC4) is formed by inductor via V4 and capacitor electrode P4.

[0044] Thus, LC filter 100 has a structure with multiple adjacent resonant circuits. The attenuation poles created by magnetic and / or capacitive coupling between adjacent resonant circuits function as a bandpass filter. A high-frequency signal supplied to input terminal T1 is output from output terminal T2 via first resonant circuit RC1, second resonant circuit RC2, third resonant circuit RC3, and fourth resonant circuit RC4.

[0045] Figure 3 yes Figure 1 The equivalent circuit diagram of the LC filter 100 is shown in FIG. Figure 3 The connected parts indicated by dotted lines correspond to Figure 1 The plate electrodes PG1, PG2 and capacitor electrodes P1~P4.

[0046] Input terminal T1 is connected to capacitor electrode P1. Capacitor C1 is formed between capacitor electrode P1 and plate electrode PG2 connected to ground terminal GND. Inductor L1 is connected between capacitor electrode P1 and plate electrode PG1. Inductor L1 corresponds to inductor via V1.

[0047] An inductor L2 is connected between the plate electrode PG1 and the capacitor electrode P2. The inductor L2 corresponds to the inductor via V2. A capacitor C2 is formed between the capacitor electrode P2 and the plate electrode PG2.

[0048] An inductor L3 is connected between the plate electrode PG1 and the capacitor electrode P3. The inductor L3 corresponds to the inductor via V3. A capacitor C3 is formed between the capacitor electrode P3 and the plate electrode PG2.

[0049] Output terminal T2 is connected to capacitor electrode P4. Capacitor C4 is formed between capacitor electrode P4 and plate electrode PG2. Inductor L4 is connected between capacitor electrode P4 and plate electrode PG1. Inductor L4 corresponds to inductor via V4.

[0050] An inductor LG is connected between the plate electrode PG1 and the plate electrode PG2 . The inductor LG corresponds to the ground vias VG1 to VG4 connected in parallel.

[0051] Capacitor C12 is formed between capacitor electrode P1 and capacitor electrode P2. Capacitor C13 is formed between capacitor electrode P1 and capacitor electrode P3. Capacitor C14 is formed between capacitor electrode P1 and capacitor electrode P4. Capacitor C23 is formed between capacitor electrode P2 and capacitor electrode P3. Capacitor C34 is formed between capacitor electrode P3 and capacitor electrode P4.

[0052] Furthermore, the "plate electrode PG1" and "plate electrode PG2" in Embodiment 1 correspond to the "first electrode" and "second electrode," respectively, in this disclosure. The "ground vias VG1 to VG4" in Embodiment 1 correspond to the "first to fourth ground vias," respectively, in this disclosure, and generally correspond to the "connecting electrode," respectively, in this disclosure. The "capacitor electrode P2" and "capacitor electrode P3" in Embodiment 1 correspond to the "first capacitor electrode" and "second capacitor electrode," respectively, in this disclosure. The "inductor via V2" and "inductor via V3" in Embodiment 1 correspond to the "first inductor via" and "second inductor via," respectively, in this disclosure.

[0053] (Filtering characteristics)

[0054] Next, the transmission characteristics of the LC filter 100 according to the first embodiment will be described in comparison with the case of a comparative example.

[0055] Figure 4 This is a perspective view of an LC filter 100# of a comparative example. In the LC filter 100# of the comparative example, instead of the ground vias VG1 to VG4 in the LC filter 100 of the first embodiment, the plate electrode PG1 and the plate electrode PG2 are connected via flat side electrodes PGA and PGB formed on the side surfaces of the laminate 110. Figure 4 In FIG. 1 , descriptions of elements common to those of the LC filter 100 are not repeated.

[0056] Reference Figure 4 In LC filter 100#, a flat plate-shaped side electrode PGA is formed on side surface 113 of the stack, and a flat plate-shaped side electrode PGB is formed on side surface 114. The side electrodes PGA and PGB are connected to the end surfaces of the plate electrodes PG1 and PG2.

[0057] In the structure in which the plate electrodes PG1 and PG2 are connected via the side electrodes PGA and PGB as in the LC filter 100# of the comparative example, the resonant circuit (particularly, Figure 4The second resonant circuit RC2 and the third resonant circuit RC3 in the multilayer structure are easily coupled to the side electrodes PGA and PGB, which are coupled to ground potential. This increases the signal leakage from the resonant circuit to ground potential, thereby increasing filter loss. In particular, as the size of the filter device is reduced, the distance between the side electrodes PGA and PGB and the resonant circuit is further shortened. Therefore, to minimize the increase in loss, it is necessary to place the resonant circuit near the center of the stack to ensure a sufficient distance between the side electrodes and the resonant circuit.

[0058] It is known that in LC filters, the attenuation characteristics in the non-passband can be improved by providing multiple resonant circuits within a laminate. However, as mentioned above, arranging the resonant circuits near the center of the laminate increases the coupling between the resonant circuits, which in turn reduces the attenuation characteristics for signals in the non-passband.

[0059] In the LC filter 100 of embodiment 1, the connection electrode for connecting the planar electrodes PG1 and PG2 is formed by a via hole rather than a side electrode. By adopting such a structure, the coupling between the connection electrode and the resonant circuit can be reduced, and further, the coupling between the resonant circuits can also be reduced. In addition, the inventors have discovered that by changing the connection electrode from a large-area side electrode to a via hole, although the resistance component of the connection electrode itself increases slightly, the loss improvement effect associated with reducing the coupling between the connection electrode and the resonant circuit is greater than the increase in loss associated with the change to the via hole. By adopting a structure in which the connection electrode is formed by a via hole as in embodiment 1, the filter loss can be improved compared to the LC filter 100# of the comparative example, and the attenuation characteristics in the non-passband can be improved.

[0060] Figure 5 1 is a diagram for explaining the filtering characteristics of the LC filter 100 in the first embodiment and the LC filter 100# in the comparative example. Figure 5 In the figure, the horizontal axis shows the frequency, and the vertical axis shows the insertion loss and the reflection loss. Figure 5 In the figure, solid lines LN10, LN10A, and LN20 represent LC filter 100 according to Embodiment 1, while dashed lines LN11, LN11A, and LN21 represent LC filter 100# according to the comparative example. Solid lines LN10 and LN10X and dashed lines LN11 and LN11A represent insertion loss, while solid lines LN20 and dashed lines LN21 represent return loss. Furthermore, solid lines LN10A and dashed lines LN11A represent enlarged vertical axes (right-axis scales) representing solid lines LN10 and dashed lines LN11, respectively. The passband specification for this LC filter is 4400 MHz to 5000 MHz.

[0061] Reference Figure 5Regarding insertion loss, LC filter 100 of Embodiment 1 is lower than LC filter 100# of Comparative Example throughout the entire passband. Furthermore, regarding return loss, LC filter 100 of Embodiment 1 also has a loss equal to or lower than that of LC filter 100# of Comparative Example within the passband.

[0062] Regarding the attenuation characteristics, the attenuation of the first embodiment is greater than that of the comparative example on the low-frequency side of the passband. Furthermore, the first embodiment can achieve steeper attenuation than that of the comparative example on the high-frequency side of the passband.

[0063] As described above, in the LC filter 100 of the first embodiment, by connecting the plate electrode PG1, which is commonly connected to the inductor vias of each resonant circuit, and the plate electrode PG2, which is connected to the ground terminal GND, via vias, it is possible to suppress the degradation of filtering characteristics associated with the miniaturization of the filter device. Furthermore, the degree of freedom in the arrangement of the resonant circuits within the laminate can be increased.

[0064] (Variation)

[0065] In the first embodiment, an example of the configuration of the LC filter having four-stage resonant circuits has been described. However, the number of resonant circuits constituting the LC filter is not limited to four.

[0066] For example, Figure 6 As shown in the LC filter 100A of the first modification, a two-stage resonant circuit may be used. The LC filter 100A has a configuration in which the second resonant circuit RC2 and the third resonant circuit RC3 of the LC filter 100 of the first embodiment are deleted.

[0067] Or, as Figure 7 As shown in the LC filter 100B of the second modification example, the resonant circuit may be a three-stage structure. Figure 6 In LC filter 100A of Modification 1, a second resonant circuit RC2B is disposed between first resonant circuit RC1 and fourth resonant circuit RC4. Second resonant circuit RC2B is formed by capacitor electrode P2B and inductor via V2B connected between capacitor electrode P2B and plate electrode PG1. Inductor via V2B is disposed along the X-axis between inductor via V1 and inductor via V4.

[0068] In the LC filters 100A and 100B of the modified examples, the plate electrode PG1 and the plate electrode PG2 are also connected via the ground vias VG1 to VG4 . This can suppress the degradation of the filter characteristics accompanying the miniaturization of the filter device.

[0069] In addition, although not shown in the drawings, the LC filter may also have a structure having five or more stages of resonance circuits.

[0070] Furthermore, the "capacitor electrode P1" and "capacitor electrode P4" in Modifications 1 and 2 correspond to the "first capacitor electrode" and "second capacitor electrode," respectively, in this disclosure. The "inductor via V1" and "inductor via V4" in Modifications 1 and 2 correspond to the "first inductor via" and "second inductor via," respectively, in this disclosure.

[0071] [Implementation Method 2]

[0072] In the second embodiment, an example of the structure of an LC filter in which inductor vias and ground vias are arranged differently will be described.

[0073] (Filter Structure)

[0074] Figure 8 : is a perspective view of an LC filter 100C according to Embodiment 2. Figure 9 This is a side perspective view of the LC filter 100C when viewed from the side surface 114 of the laminate 110. The LC filter 100C has a structure including a five-stage resonant circuit.

[0075] Reference Figure 8 and Figure 9 The LC filter 100C includes plate electrodes PG1 and PG2 formed on the laminate 110 , an input terminal T1 and an output terminal T2 , inductor vias V11 to V15 , ground vias VG11 to VG13 , capacitor electrodes P11 to P15 , and wiring electrodes PA1 and PA2 .

[0076] Similar to LC filter 100 of Embodiment 1, plate electrode PG1 is formed on the dielectric layer near upper surface 111 of laminate 110, and plate electrode PG2 is formed on the dielectric layer near lower surface 112. Plate electrode PG2 is connected to ground terminal GND formed on lower surface 112 via vias VGA and VGB.

[0077] Plate electrode PG1 and plate electrode PG2 are connected via ground vias VG11, VG12, and VG13 extending in the stacking direction of stacked body 110. Ground vias VG11 and VG13 are arranged along side surface 113 (first side surface) of stacked body 110 in the positive Y-axis direction. Ground via VG11 is arranged at a corner in the negative X-axis direction, and ground via VG13 is arranged at a corner in the positive X-axis direction. In stacked body 110, ground via VG12 is arranged approximately near the center in the X-axis direction along side surface 114 (second side surface) opposite side surface 113.

[0078] Capacitor electrodes P11-P15 are formed in the dielectric layer between plate electrodes PG1 and PG2. Capacitor electrodes P11-P15 are spaced apart from plate electrode PG2, forming capacitors with plate electrode PG2. Furthermore, capacitor electrodes P11-P15 are spaced apart from each other and capacitively coupled to each other. Inductor vias V11-V15 are connected to capacitor electrodes P11-P15, respectively, to form an LC resonant circuit.

[0079] 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 formed in the dielectric layer between plate electrode PG1 and capacitor electrode P11, connecting inductor via V11 to ground via VG11. Specifically, the other end of inductor via V11 is connected to a point in ground via VG11 between plate electrode PG1 and plate electrode PG2 via wiring electrode PA1. With this structure, inductor via V11 and capacitor electrode P11 form an LC resonant circuit (first resonant circuit RC1C) directly connected to the ground via.

[0080] 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 formed in the dielectric layer between plate electrode PG1 and capacitor electrode P15, connecting inductor via V15 to ground via VG13. Specifically, the other end of inductor via V15 is connected to a position in ground via VG13 between plate electrode PG1 and plate electrode PG2 via wiring electrode PA2. With this structure, inductor via V15 and capacitor electrode P15 form an LC resonant circuit (fifth resonant circuit RC5C) directly connected to the ground via.

[0081] The inductor via V12 is arranged at a corner in the negative direction of the X-axis along the side surface 114. The inductor via V12 is connected to the plate electrode PG1 and the capacitor electrode P12 to form an LC resonant circuit (second resonant circuit RC2C).

[0082] Inductor via V13 is positioned near the center of the circuit along side surface 113 in the X-axis direction. Specifically, inductor via V13 is positioned between ground via VG11 and ground via VG13 along side surface 113. Inductor via V13 is connected to plate electrode PG1 and capacitor electrode P13, forming an LC resonant circuit (third resonant circuit RC3C).

[0083] The inductor via V14 is arranged at a corner in the positive direction of the X axis along the side surface 114. The inductor via V14 is connected to the plate electrode PG1 and the capacitor electrode P14 to form an LC resonant circuit (fourth resonant circuit RC4C).

[0084] As described above, LC filter 100C has a structure with five adjacent resonant circuits. It functions as a bandpass filter by utilizing the attenuation poles created by magnetic and / or capacitive coupling between adjacent resonant circuits. A high-frequency signal supplied to input terminal T1 passes through first resonant circuit RC1C, second resonant circuit RC2C, third resonant circuit RC3C, fourth resonant circuit RC4C, and fifth resonant circuit RC5C, and is output from output terminal T2.

[0085] Figure 10 It is used for Figure 8 This is a top view for explaining the signal (current) transmission path in the plate electrode PG1 of the LC filter 100C. Figure 10 The high-frequency signal supplied to input terminal T1 is transmitted through magnetic coupling from the first resonant circuit RC1C formed by inductor via V11, capacitor electrode P11, and wiring electrode PA1 to the adjacent second resonant circuit RC2C (inductor via V12 + capacitor electrode P12) (arrow AR0). The signal transmitted to the second resonant circuit RC2C is then transmitted through plate electrode PG1 to the adjacent third resonant circuit RC3C (inductor via V13 + capacitor electrode P13) (arrow AR1), and further to the fourth resonant circuit RC4C (inductor via V14 + capacitor electrode P14) adjacent to the third resonant circuit RC3C (arrow AR2). Furthermore, the signal from the fourth resonant circuit RC4C is transmitted through magnetic coupling to the fifth resonant circuit RC5C formed by inductor via V15, capacitor electrode P15, and wiring electrode PA2, and is output from output terminal T2.

[0086] Here, from the perspective of reducing the loss of signals in the desired passband when transmitting signals between resonant circuits, it is important to increase the coupling between resonant circuits to improve the Q value. On the other hand, in the case of filter devices, it is preferable to minimize the transmission of non-passband signals. In other words, from the perspective of attenuating non-passband signals, it is also necessary to reduce the coupling between resonant circuits.

[0087] Therefore, in the LC filter 100C of the second embodiment, in order to prevent the coupling between the resonant circuits from becoming too strong, the resonant circuits (the first resonant circuit RC1C and the fifth resonant circuit RC5C) connected to the input and output terminals are connected to the ground vias using the wiring electrodes PA1 and PA2. Figure 8As shown, unlike other resonant circuits, inductor vias V11 and V15 in the first resonant circuit RC1C and the fifth resonant circuit RC5C are not directly connected to the plate electrode PG1. Instead, they are connected to the plate electrodes PG1 and PG2 through wiring electrodes PA1 and PA2, respectively, via ground vias VG11 and VG13. This structure allows the coupling between the first resonant circuit RC1C and the second resonant circuit RC2C, and between the fourth resonant circuit RC4C and the fifth resonant circuit RC5C, to be weaker than the coupling between the second resonant circuit RC2C and the third resonant circuit RC3C, and between the third resonant circuit RC3C and the fourth resonant circuit RC4C.

[0088] Furthermore, it is generally known that in a multi-stage LC filter, the Q value of the resonant circuits located in the middle stages contributes significantly to the overall Q value of the filter, while the Q value of the resonant circuits near the ends (input / output terminals) has a relatively small impact on the overall Q value of the filter. Therefore, by connecting the resonant circuits connected to the input / output terminals to the ground vias as described above, the overall Q value of the filter can be maintained while preventing excessive coupling between the resonant circuits.

[0089] In addition, in the LC filter 100C of the second embodiment, as shown in FIG. Figure 10 As shown, when looking down at the laminate 110 from the stacking direction (Z-axis direction), ground vias VG11, VG12, and VG13 are arranged on both sides of the signal transmission path (arrows AR1 and AR2) between the inductor vias V12, V13, and V14 in the plate electrode PG1. Specifically, an imaginary line CL1 (a first imaginary line) connecting the inductor vias V12 and V13 intersects an imaginary line CL2 (a second imaginary line) connecting the ground vias VG11 and VG12. Similarly, an imaginary line CL3 connecting the inductor vias V13 and V14 intersects an imaginary line CL4 connecting the ground vias VG12 and VG13.

[0090] Furthermore, to achieve symmetry in filter characteristics, the inductor vias and the ground vias are preferably arranged symmetrically so that the imaginary lines CL1 and CL2 intersect at their midpoints, and the imaginary lines CL3 and CL4 intersect at their midpoints.

[0091] With this arrangement of vias, a portion of the signal (current) transmitted from inductor via V12 to inductor via V13 on plate electrode PG1 leaks into 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 into ground vias VG12 and VG13, as indicated by arrows AR2A and AR2B. Consequently, the coupling between second resonant circuit RC2C and third resonant circuit RC3C, as well as the coupling between third resonant circuit RC3C and fourth resonant circuit RC4C, is slightly reduced.

[0092] Furthermore, the "plate electrode PG1" and "plate electrode PG2" in Embodiment 2 correspond to the "first electrode" and "second electrode," respectively, in the present disclosure. The "ground vias VG11 to VG13" in Embodiment 2 correspond to the "first ground via" to "third ground via" in the present disclosure, respectively, and generally correspond to the "connecting electrode" in the present disclosure. The "capacitor electrode P12," "capacitor electrode P13," and "capacitor electrode P14" in Embodiment 2 correspond to the "first capacitor electrode" to "third capacitor electrode," respectively, in the present disclosure. The "inductor via V12," "inductor via V13," and "inductor via V14" in Embodiment 2 correspond to the "first inductor via" to "third inductor via," respectively, in the present disclosure.

[0093] (Filtering characteristics)

[0094] Next, use Figure 11 The filtering characteristics of the LC filter 100C according to the second embodiment will be described. Figure 11 In FIG. 5 , the horizontal axis shows the frequency, and the vertical axis shows the insertion loss (solid line LN30 ) and the reflection loss (dashed line LN31 ).

[0095] Reference Figure 11 In the passband (4400MHz to 5000MHz), the insertion loss is less than 5dB and the return loss is less than 20dB. In addition, regarding the attenuation characteristics in the non-passband near the passband, the attenuation is more than 40dB on both the low-frequency side and the high-frequency side compared to the passband, which can achieve a better performance than Figure 5 The LC filter 100 of the first embodiment shown has higher attenuation characteristics.

[0096] As described above, even in the configuration of LC filter 100C according to Embodiment 2, by connecting plate electrode PG1 and plate electrode PG2 via a via, it is possible to suppress the degradation of filtering characteristics associated with miniaturization of the filter device. Furthermore, by directly connecting the resonant circuit connected to the input / output terminal to the ground via, it is possible to suppress increases in filter loss in the passband and further improve attenuation characteristics in the non-passband.

[0097] (Variation)

[0098] (a) Modification 3

[0099] and Figure 11 The resonant circuits (first resonant circuit RC1C and fifth resonant circuit RC5C) directly connected to the ground vias in the LC filter 100C of the second embodiment are not necessarily required. In the third modification, a configuration without such resonant circuits in the LC filter 100C will be described.

[0100] Figure 12 This is a perspective view of an LC filter 100D according to Modification 3. LC filter 100D eliminates the inductor vias V11 and V15 and capacitor electrodes P11 and P15 of LC filter 100C according to Embodiment 2. Input terminal T1 is connected to capacitor electrode P12, which is connected to inductor via V12, via via V11A and wiring electrode P11B. Output terminal T2 is connected to capacitor electrode P14, which is connected to inductor via V14, via via V15A and wiring electrode P15B.

[0101] In LC filter 100D, the resonant circuit formed by inductor via V12 and capacitor electrode P12 is the first resonant circuit RC1D, the resonant circuit formed by inductor via V13 and capacitor electrode P13 is the second resonant circuit RC2D, and the resonant circuit formed by inductor via V14 and capacitor electrode P14 is the third resonant circuit RC3D. In other words, LC filter 100D is a filter device having three resonant circuits. A high-frequency signal supplied to input terminal T1 is output from output terminal T2 via the first resonant circuit RC1D, the second resonant circuit RC2D, and the third resonant circuit RC3D.

[0102] In the LC filter 100D of Modification 3, the plate electrode PG1 and the plate electrode PG2 are also connected by a ground via. Furthermore, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. This structure can suppress the degradation of filtering characteristics associated with the miniaturization of the filter device.

[0103] In addition, the "plate electrode PG1" and "plate electrode PG2" in Modification Example 3 correspond to the "first electrode" and "second electrode" in the present disclosure, respectively. The "ground vias VG11 to VG13" in Modification Example 3 correspond to the "first ground via" to "third ground via" in the present disclosure, respectively, and generally correspond to the "connecting electrode" in the present disclosure. The "capacitor electrode P12," "capacitor electrode P13," and "capacitor electrode P14" in Modification Example 3 correspond to the "first capacitor electrode" to "third capacitor electrode" in the present disclosure, respectively. The "inductor via V12," "inductor via V13," and "inductor via V14" in Modification Example 3 correspond to the "first inductor via" to "third inductor via" in the present disclosure, respectively.

[0104] (b) Modification 4

[0105] In Modification 4, an example in which the resonant circuit has two stages will be described. Figure 13 This is a top view of an LC filter 100E according to Modification 4. LC filter 100E is a two-stage resonant circuit structure derived from LC filter 100D shown in Modification 3. More specifically, LC filter 100E includes a first resonant circuit RC1E including inductor vias V21 and a second resonant circuit RC2E including inductor vias V22. Each of inductor vias V21 and V22 has one end connected to plate electrode PG1 and the other end connected to a capacitor electrode (not shown), similar to Modification 3.

[0106] When viewing the laminate 110 from the stacking direction, inductor vias V21 and V22 are located at the corners of one diagonal line of the rectangular plate electrode PG1. Furthermore, ground vias VG21 and VG22 are located at the corners of the other diagonal line of the plate electrode PG1. In other words, ground via VG21 and inductor via V22 are located along a side surface 113 of the laminate 110. Furthermore, inductor via V21 and ground via VG22 are located along a side surface 114 of the laminate 110. Inductor vias V12 and V22 and ground vias VG21 and VG22 are located so that an imaginary line connecting inductor vias V21 and V22 intersects an imaginary line connecting ground vias VG21 and VG22.

[0107] The high-frequency signal supplied to the input terminal T1 is transferred from the first resonance circuit RC1E to the second resonance circuit RC2E through the plate electrode PG1 (arrow AR21 ), and is output from the output terminal T2 .

[0108] In LC filter 100E of Modification 4, plate electrode PG1 and plate electrode PG2 are connected via a ground via. Furthermore, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. This structure can suppress the degradation of filtering characteristics associated with miniaturization of the filter device.

[0109] Furthermore, the "ground vias VG21" and "ground vias VG22" in Modification 4 correspond to the "first ground via" and "second ground via" in this disclosure, respectively, and generally correspond to the "connection electrode" in this disclosure. The "inductor vias V21" and "inductor vias V22" in Modification 4 correspond to the "first inductor via" and "second inductor via" in this disclosure, respectively.

[0110] (c) Modification 5

[0111] Figure 14 1 is a plan view of an LC filter 100F according to Modification 5. The LC filter 100F has a structure including four resonant circuits, in which a first-stage resonant circuit is added to the structure of the LC filter 100D according to Modification 3.

[0112] More specifically, the LC filter 100F includes a first resonant circuit RC1F including the inductor via V31, a second resonant circuit RC2F including the inductor via V32, a third resonant circuit RC3F including the inductor via V33, and a fourth resonant circuit RC4F including the inductor via V34. Figure 14 Although not shown in the figure, capacitor electrodes are connected to the respective inductor vias.

[0113] When the laminate 110 is viewed from the stacking direction, the ground vias VG31 and VG33 and the inductor vias V32 and V34 are arranged in the order of ground via VG31, inductor via V32, ground via VG33, and inductor via V34 along the side surface 113 of the laminate 110 in the positive direction of the X-axis. Furthermore, the ground vias VG32, VG34 and the inductor vias V31 and V33 are arranged in the order of inductor via V31, ground via VG32, inductor via V33, and ground via VG34 along the side surface 114 of the laminate 110 in the positive direction of the X-axis.

[0114] The high frequency signal supplied to the input terminal T1 is as Figure 14As indicated by arrows AR31 to AR33 in FIG1 , the signal propagates in the order of the first resonant circuit RC1F, the second resonant circuit RC2F, the third resonant circuit RC3F, and the fourth resonant circuit RC4F, and is output from the output terminal T2. Ground vias VG31 to VG34 are arranged on both sides of the signal propagation path (arrows AR31 to AR33) in the plate electrode PG1.

[0115] In LC filter 100F of Modification 5, plate electrode PG1 and plate electrode PG2 are connected via a ground via. Furthermore, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. This structure can suppress the degradation of filtering characteristics associated with miniaturization of the filter device.

[0116] Furthermore, the "ground vias VG31 to VG33" in Modification 5 correspond to the "first ground via" to the "third ground via" in this disclosure, respectively. Furthermore, the "ground vias VG31 to VG34" in Modification 5 generally correspond to the "connection electrode" in this disclosure. The "inductor vias V31 to V33" in Modification 5 correspond to the "first inductor via" to the "third inductor via" in this disclosure, respectively.

[0117] (d) Modification 6

[0118] Figure 15 1 is a plan view of an LC filter 100G according to Modification 6. The LC filter 100G has a structure including five resonant circuits, in which a single resonant circuit is added to the structure of the LC filter 100F according to Modification 5.

[0119] More specifically, the LC filter 100G includes a first resonant circuit RC1G including the inductor via V41, a second resonant circuit RC2G including the inductor via V42, a third resonant circuit RC3G including the inductor via V43, a fourth resonant circuit RC4G including the inductor via V44, and a fifth resonant circuit RC5G including the inductor via V45. Figure 15 Although not shown in the figure, capacitor electrodes are connected to the respective inductor vias.

[0120] When the laminate 110 is viewed from the stacking direction, the ground vias VG41, VG43, and VG45 and the inductor vias V42 and V44 are arranged in the order of ground via VG41, inductor via V42, ground via VG43, inductor via V44, and ground via VG45 along the side surface 113 of the laminate 110 in the positive direction of the X-axis. Furthermore, the ground vias VG42, VG44, and inductor vias V41, V43, and V45 are arranged in the order of inductor via V41, ground via VG42, inductor via V43, ground via VG44, and inductor via V45 along the side surface 114 of the laminate 110 in the positive direction of the X-axis.

[0121] The high frequency signal supplied to the input terminal T1 is as Figure 15 As indicated by arrows AR41 to AR44 in FIG1 , the signal is transmitted in the order of the first resonant circuit RC1G, the second resonant circuit RC2G, the third resonant circuit RC3G, the fourth resonant circuit RC4G, and the fifth resonant circuit RC5G, and is output from the output terminal T2. Ground vias VG41 to VG45 are arranged on both sides of the signal transmission path (arrows AR41 to AR44) in the plate electrode PG1.

[0122] In the LC filter 100G of Modification 6, the plate electrode PG1 and the plate electrode PG2 are connected by a ground via. Furthermore, ground vias are arranged on both sides of the signal transmission path between adjacent resonant circuits. This structure can suppress the degradation of filtering characteristics associated with miniaturization of the filter device.

[0123] Furthermore, the "ground vias VG41 to VG43" in Modification 6 correspond to the "first ground via" to the "third ground via" in this disclosure, respectively. The "ground vias VG41 to VG45" in Modification 6 generally correspond to the "connection electrode" in this disclosure. The "inductor vias V41 to V43" in Modification 6 correspond to the "first inductor via" to the "third inductor via" in this disclosure, respectively.

[0124] [Implementation Method 3]

[0125] In the third embodiment, an example of the structure of an LC filter having characteristics intermediate between those of the LC filter of the first embodiment and the LC filter of the second embodiment will be described.

[0126] Figure 16 This is an exploded perspective view of an LC filter 100H according to the third embodiment. Figure 16The LC filter 100H is formed from a stacked body 110 composed of multiple dielectric layers LY1 to LY8, and has a generally cubical shape. Directional markings DM are attached to the upper surface 111 (first layer LY1) of the stacked body 110. Input terminals T1, output terminals T2, and ground terminals GND for connecting to external devices are located on the lower surface 112 (eighth layer LY8) of the stacked body 110.

[0127] LC filter 100H, like LC filter 100 of Embodiment 1 and LC filter 100F of Modification 5, has four resonant circuits. More specifically, it includes a first resonant circuit RC1H formed by inductor via V51 and capacitor electrode P51, a second resonant circuit RC2H formed by inductor via V52 and capacitor electrode P52, a third resonant circuit RC3H formed by inductor via V53 and capacitor electrode P53, and a fourth resonant circuit RC4H formed by inductor via V54 and capacitor electrode P54.

[0128] The capacitor electrode P51 of the first resonance circuit RC1H and the capacitor electrode P54 of the fourth resonance circuit RC4H are formed on the sixth layer LY6. The capacitor electrodes P51 and P54 form capacitors with the plate electrode PG2A formed on the fifth layer LY5.

[0129] Capacitor electrode P51 is connected to input terminal T1 via vias V5A and V5B. Capacitor electrode P51 is connected to plate electrode PG1A formed on second layer LY2 via inductor via V51. Capacitor electrode P54 is connected to output terminal T2 via vias V5C and V5D. Capacitor electrode P54 is connected to plate electrode PG1A via inductor via V54.

[0130] Capacitor electrodes P51 and P54 are formed into a roughly C-shape, with one end connected to an inductor via and the other end connected to a via for connecting to external terminals (input terminal T1 and output terminal T2). By forming capacitor electrodes P51 and P54 into this shape and providing a connection path between the via connected to the external terminal and the inductor via, impedance can be improved.

[0131] Capacitor electrode P52 of the second resonant circuit RC2H and capacitor electrode P53 of the third resonant circuit RC3H are formed on the fourth layer LY4. Capacitor electrodes P52 and P53 form capacitors with plate electrode PG2A formed on the fifth layer LY5. Capacitor electrode P52 is connected to plate electrode PG1A via inductor via V52. Capacitor electrode P53 is connected to plate electrode PG1A via inductor via V53.

[0132] Thus, the four resonant circuits RC1H to RC4H are commonly connected to the plate electrode PG1A formed on the second layer LY2. The plate electrode PG1A is connected to the plate electrode PG2A on the fifth layer LY5 via four ground vias VG51 to VG54. The plate electrode PG2A is connected to the ground terminal GND formed on the eighth layer LY8 via vias VG5A and VG5B.

[0133] Capacitor electrodes P5A and P5B are formed on the third layer LY3. Capacitor electrode P5A is connected to the inductor via V51 of the first resonant circuit RC1H. Furthermore, capacitor electrode P5A faces capacitor electrode P52 of the second resonant circuit RC2H formed on the fourth layer LY4. Therefore, capacitor electrode P5A and capacitor electrode P52 form capacitive coupling between the first resonant circuit RC1H and the second resonant circuit RC2H.

[0134] Capacitor electrode P5B is connected to inductor via V54 of the fourth resonant circuit RC4H. Furthermore, capacitor electrode P5B faces capacitor electrode P53 of the third resonant circuit RC3H formed on the fourth layer LY4. Therefore, capacitor electrode P5B and capacitor electrode P53 form capacitive coupling between the third resonant circuit RC3H and the fourth resonant circuit RC4H.

[0135] A capacitor electrode P5C is formed on the seventh layer LY7 . The capacitor electrode P5C faces the capacitor electrodes P51 and P54 of the sixth layer LY6 , thereby forming capacitive coupling between the first resonant circuit RC1H and the fourth resonant circuit RC4H.

[0136] Figure 17 Looking down from the stacking direction Figure 16 A top view of the second layer LY2 of the stacked body 110. Figure 17 As described above, inductor vias V51 to V54 and ground vias VG51 to VG54 are connected to the plate electrode PG1A formed on the second layer LY2 of the LC filter 100H. Along the side surface 113 of the laminate 110, inductor via V51, ground via VG52, ground via VG53, and inductor via V54 are arranged in this order in the X-axis direction. Furthermore, along the side surface 114 of the laminate 110, ground via VG51, inductor via V52, inductor via V53, and ground via VG54 are arranged in this order in the X-axis direction.

[0137] The high frequency signal supplied to the input terminal T1 is as Figure 17As indicated by arrows AR51 through AR53 in FIG, the signal propagates through the first resonant circuit RC1H, the second resonant circuit RC2H, the third resonant circuit RC3H, and the fourth resonant circuit RC4H in this order, and is output from output terminal T2. Ground vias VG51 and VG52 are located on both sides of the transmission path (arrow AR51) from inductor via V51 to inductor via V52, and ground vias VG53 and VG54 are located on both sides of the transmission path (arrow AR53) from inductor via V53 to inductor via V54. Therefore, when the signal propagates along the transmission paths indicated by arrows AR51 and AR53, a portion of the signal leaks into ground vias VG51 through VG54. This slightly weakens the coupling between the first resonant circuit RC1H and the second resonant circuit RC2H, and between the third resonant circuit RC3H and the fourth resonant circuit RC4H.

[0138] On the other hand, inductor vias V52 and V53 are arranged adjacent to each other along side surface 114, and no ground via is arranged at a position intersecting the signal transmission path (arrow AR52) from inductor via V52 to inductor via V53. Consequently, the coupling between the second resonant circuit RC2H and the third resonant circuit RC3H becomes greater than the coupling between the first resonant circuit RC1H and the second resonant circuit RC2H, and greater than the coupling between the third resonant circuit RC3H and the fourth resonant circuit RC4H. In other words, while the coupling between the resonant circuits is weaker than that of LC filter 100 of Embodiment 1, it is stronger than that of LC filter 100F of Comparative Example 5. Consequently, LC filter 100H of Embodiment 3 exhibits a transmission characteristic intermediate between LC filter 100 and LC filter 100F.

[0139] Figure 18 yes Figure 16 The equivalent circuit diagram of the LC filter 100H is shown in FIG. Figure 18 The equivalent circuit of Figure 3 The equivalent circuit diagram is similar to that of , but does not include the capacitive coupling between the first resonant circuit RC1H and the third resonant circuit RC3H, the capacitive coupling between the second resonant circuit RC2H and the third resonant circuit RC3H, and the capacitive coupling between the second resonant circuit RC2H and the third resonant circuit RC3H.

[0140] In the LC filter 100H, with Figure 3 Similarly, the inductor vias V51 to V54 (corresponding to Figure 18 The inductors L1 to L4 of FIG. 1 are connected to a common plate electrode PG1A, which is connected to the common plate electrode PG1A via ground vias VG51 to VG54 (generally corresponding to Figure 18 The inductor LG) is connected to the plate electrode PG2A connected to the ground terminal GND.

[0141] In LC filter 100H according to Embodiment 3, the connection electrodes for connecting plate electrodes PG1A and PG2A are also formed of vias rather than side electrodes. This reduces coupling between the connection electrodes and the resonant circuit, improving filter loss. Furthermore, since coupling between resonant circuits can be partially reduced during signal transmission through plate electrode PG1A, attenuation characteristics in the non-passband can be improved.

[0142] Next, use Figure 19 The filtering characteristics of the LC filter 100H according to the third embodiment will be described. Figure 19 In FIG. 4 , the horizontal axis shows the frequency, and the vertical axis shows the insertion loss (solid line LN40 ) and the reflection loss (dashed line LN41 ).

[0143] Reference Figure 19 In the passband (8000MHz to 9000MHz), the insertion loss is less than 5dB and the return loss is less than 15dB. In addition, the attenuation characteristics in the non-passband near the passband, especially on the high-frequency side of the passband, can achieve attenuation of more than 30dB.

[0144] In this manner, even in the structure of LC filter 100H according to Embodiment 3, plate electrode PG1A and plate electrode PG2A are connected by vias, and ground vias are arranged on both sides of a portion of the signal transmission path between adjacent resonant circuits. This structure can suppress the degradation of filtering characteristics associated with miniaturization of the filter device.

[0145] Furthermore, the "plate electrode PG1A" and "plate electrode PG2A" in Embodiment 3 correspond to the "first electrode" and "second electrode" in the present disclosure, respectively. The "ground via VG51" and "ground via VG52" in Embodiment 3 correspond to the "first ground via" and "second ground via" in the present disclosure, respectively. The "ground vias VG51 to VG54" in Embodiment 3 generally correspond to the "connecting electrode" in the present disclosure. The "capacitor electrode P51" and "capacitor electrode P52" in Embodiment 3 correspond to the "first capacitor electrode" and "second capacitor electrode" in the present disclosure, respectively. The "inductor via V51" and "inductor via V52" in Embodiment 3 correspond to the "first inductor via" and "second inductor via" in the present disclosure, respectively. The "side surface 114" and "side surface 113" in Embodiment 3 correspond to the "first side surface" and "second side surface" in the present disclosure, respectively.

[0146] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present disclosure is indicated by the claims rather than the above description of the embodiments, and is intended to encompass all modifications within the scope and meaning equivalent to the claims.

[0147] Description of Reference Numerals

[0148] 100, 100A to 100H, 100#…filter; 110…laminate; C1 to C4, C12 to C14, C23, C34…capacitor; DM…directional marker; GND…ground terminal; L1 to L4, LG…inductor; LY1 to LY8…dielectric layer; P1 to P4, P2B, P11 to P15, P51 to P54, P5A to P5C…capacitor electrodes; P11A, P11B, P15A, P15B, PA1, PA2…wiring electrodes; PG1, PG1A, PG2, PG2A…plate electrodes; PGA, PGB…side electrodes; RC1, RC1C to RC1H, RC2, RC2B to RC2H, RC3 , RC3C, RC3D, RC3F, RC3G, RC3H, RC4, RC4C, RC4F, RC4G, RC4H, RC5C, RC5G…resonance circuit; T1…input terminal; T2…output terminal; V1A, V4A, V11A, V15A, V5A~V5D, VG5A, VG5B…vias; V1~V4, V2B, V11~V15, V21, V22, V31~V34, V41~V45, V51~V54…inductor vias; VG1~VG4, VG11~VG13, VG21, VG22, VG31~VG34, VG41~VG45, VG51~VG54…ground vias.

Claims

1. An LC filter for transmitting a signal from an input terminal to an output terminal, comprising: a laminated body having a plurality of dielectric layers laminated thereon; a first electrode and a second electrode in a flat plate shape, formed in different dielectric layers in the laminate; A first capacitor electrode and a second capacitor electrode, forming a capacitor with the second electrode; a first inductor via connected to the first electrode and the first capacitor electrode; a second inductor via connected to the first electrode and the second capacitor electrode; as well as The first grounding via and the second grounding via connect the first electrode and the second electrode. The first inductor via and the first capacitor electrode form a first resonant circuit that receives a signal from the input terminal. The second inductor via and the second capacitor electrode form a second resonant circuit that transmits a signal to the output terminal. The stacked body is formed into a cube having a first side surface and a second side surface facing each other. When viewed from the stacking direction of the stacked body, The first ground via and the second inductor via are arranged along the first side surface. The first inductor via and the second ground via are arranged along the second side surface.

2. The LC filter according to claim 1, wherein When the laminate is viewed in a planar direction from the stacking direction, a first imaginary line connecting the first inductor via and the second inductor via intersects a second imaginary line connecting the first ground via and the second ground via.

3. The LC filter according to claim 2, wherein The second imaginary line intersects the first imaginary line at a midpoint of the first imaginary line.

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

5. The LC filter according to any one of claims 1 to 4, wherein Also features: a third capacitor electrode, forming a capacitor with the second electrode; a third ground via connecting the first electrode and the second electrode; as well as The third inductor via is connected to the first electrode and the third capacitor electrode. When viewed from the stacking direction of the stacked body, The second ground via is arranged along the second side surface between the first inductor via and the third inductor via. The second inductor via is arranged along the first side surface between the first ground via and the third ground via. The third inductor via and the third capacitor electrode form a third resonant circuit. The second resonant circuit transmits a signal to the output terminal via the third resonant circuit.

6. The LC filter according to claim 1, wherein It also includes a third ground via hole and a fourth ground via hole, connecting the first electrode and the second electrode, The second inductor via is arranged along the first side surface between the first ground via and the third ground via. The first inductor via is arranged along the second side surface between the second ground via and the fourth ground via.

7. The LC filter according to any one of claims 1 to 4, wherein The laminated body is formed of ceramics.

8. The LC filter according to any one of claims 1 to 4, wherein The LC filter functions as a bandpass filter that passes a signal in a specific frequency band.

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