LC filter

Abstract

The present invention facilitates adjustment of the pass characteristics of an LC filter. A first capacitor electrode (121) is connected to one end of a first via-hole conductor (V1) and is opposed to a first ground electrode (111) in a stacking direction (Z). A second capacitor electrode (122) is connected to one end of a second via-hole conductor (V2) and is opposed to the first ground electrode (111) in a stacking direction (Z). A third capacitor electrode (123) is connected to one end of a third via-hole conductor (V3) and is opposed to the first ground electrode (111) in a stacking direction (Z). A fourth capacitor electrode (124) is connected to one end of a fourth via-hole conductor (V4) and is opposed to the first ground electrode (111) in a stacking direction (Z). The second capacitor electrode (122) is opposed to each of the first capacitor electrode (121), the third capacitor electrode (123), and the fourth capacitor electrode (124) in a direction perpendicular to the stacking direction (Z).

Description

Technical Field

[0001] The present invention relates to an LC filter including a plurality of LC resonators. Background Art

[0002] LC filters comprising multiple LC resonators are known. For example, International Publication No. 2018 / 100923 (Patent Document 1) discloses a bandpass filter in which four LC resonators are arranged in a staggered pattern, each adjacent to at least two other LC resonators. This staggered arrangement of the four LC resonators enhances magnetic coupling between the LC resonators compared to a linear arrangement, thereby widening the passband of the bandpass filter.

[0003] Patent Document 1: International Publication No. 2018 / 100923

[0004] The passband characteristics of an LC filter need to be adjusted according to the communication system in which it is used. For example, the passband can be adjusted by adjusting the frequencies that produce attenuation poles in a frequency band lower than the LC filter's passband (low-frequency side) and a frequency band higher than the passband (high-frequency side).

[0005] However, the bandpass filter with four staggered LC resonators disclosed in Patent Document 1 has no attenuation pole on the low-frequency side in its passband characteristics. Therefore, adjustment of the passband characteristics is limited with this bandpass filter, making it difficult to achieve a desired passband characteristic. Summary of the Invention

[0006] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to facilitate adjustment of the transmission characteristics of an LC filter.

[0007] In an LC filter according to one embodiment of the present invention, a plurality of dielectric layers are stacked in a stacking direction. The LC filter includes a first LC resonator, a second LC resonator, a third LC resonator, a fourth LC resonator, and a first ground electrode. The first LC resonator includes a first via-hole conductor and a first capacitor electrode. The first via-hole conductor extends in the stacking direction. The first capacitor electrode is connected to one end of the first via-hole conductor and faces the first ground electrode in the stacking direction. The second LC resonator includes a second via-hole conductor and a second capacitor electrode. The second via-hole conductor extends in the stacking direction. The second capacitor electrode is connected to one end of the second via-hole conductor and faces the first ground electrode in the stacking direction. The third LC resonator includes a third via-hole conductor and a third capacitor electrode. The third via-hole conductor extends in the stacking direction. The third capacitor electrode is connected to one end of the third via-hole conductor and faces the first ground electrode in the stacking direction. The fourth LC resonator includes a fourth via-hole conductor and a fourth capacitor electrode. The fourth via-hole conductor extends in the stacking direction. The fourth capacitor electrode is connected to one end of the fourth via conductor and faces the first ground electrode in the stacking direction. The second capacitor electrode faces each of the first capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode in a direction perpendicular to the stacking direction.

[0008] According to the LC filter of one embodiment of the present invention, the second capacitor electrode faces each of the first capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode in a direction perpendicular to the stacking direction, thereby facilitating adjustment of the transmission characteristics of the LC filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is an equivalent circuit diagram of a bandpass filter as an example of the LC filter according to the first embodiment.

[0010] Figure 2 yes Figure 1 A three-dimensional diagram of the bandpass filter.

[0011] Figure 3 Looking down from the X-axis Figure 2 Figure 5. A side view of a bandpass filter.

[0012] Figure 4 Looking down from the Z axis Figure 2 Figure 2 is a diagram of the upper surface of a bandpass filter.

[0013] Figure 5 It means narrowing Figure 4 A diagram of an example of the spacing between two capacitor electrodes.

[0014] Figure 6 It means expansion Figure 4A diagram of an example of the spacing between two capacitor electrodes.

[0015] Figure 7 It is shown together Figures 4 to 6 Graph showing the pass characteristics of each bandpass filter.

[0016] Figure 8 It means narrowing Figure 4 FIG. 1 is a diagram showing other examples of the interval between two capacitor electrodes.

[0017] Figure 9 It means expansion Figure 4 FIG. 1 is a diagram showing other examples of the interval between two capacitor electrodes.

[0018] Figure 10 It is shown together Figure 4 、 Figure 8 as well as Figure 9 Graph showing the pass characteristics of each bandpass filter.

[0019] Figure 11 This is a diagram showing a bandpass filter as an example of an LC filter according to a first modification of the first embodiment, viewed from above in the Z-axis direction.

[0020] Figure 12 This is a perspective view of the appearance of a bandpass filter as an example of an LC filter according to a second modification of the first embodiment.

[0021] Figure 13 Looking down from the Y axis Figure 12 Figure 5. A side view of a bandpass filter.

[0022] Figure 14 This is an equivalent circuit diagram of a bandpass filter as an example of an LC filter according to Modification 3 of Embodiment 1.

[0023] Figure 15 yes Figure 14 A three-dimensional diagram of the bandpass filter.

[0024] Figure 16 Looking down from the Y axis Figure 15 Figure 5. A side view of a bandpass filter.

[0025] Figure 17 This is a perspective view of the appearance of a bandpass filter as an example of an LC filter according to Modification 4 of Embodiment 1.

[0026] Figure 18 This is an equivalent circuit diagram of a bandpass filter as an example of the LC filter according to the second embodiment.

[0027] Figure 19 yes Figure 18A three-dimensional diagram of the bandpass filter.

[0028] Figure 20 Looking down from the Y axis Figure 19 Figure 5. A side view of a bandpass filter.

[0029] Figure 21 This is a perspective view of the appearance of a bandpass filter as an example of an LC filter according to a modification of the second embodiment.

[0030] Figure 22 Looking down from the Y axis Figure 21 Figure 5. A side view of a bandpass filter.

[0031] Figure 23 It is shown together Figure 19 The pass characteristics of the bandpass filter and Figure 21 Graph of the pass characteristics of a bandpass filter.

[0032] Figure 24 This is an equivalent circuit diagram of a bandpass filter as an example of the LC filter according to the third embodiment.

[0033] Figure 25 Looking down from the Z axis Figure 24 Diagram of a bandpass filter.

[0034] Figure 26 This is an equivalent circuit diagram of a bandpass filter as an example of the LC filter according to the fourth embodiment.

[0035] Figure 27 Looking down from the Z axis Figure 26 Diagram of a bandpass filter.

[0036] Figure 28 This is an equivalent circuit diagram of a bandpass filter as an example of the LC filter according to the fifth embodiment.

[0037] Figure 29 Looking down from the Z axis Figure 28 Diagram of a bandpass filter. DETAILED DESCRIPTION

[0038] Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and their description will not be repeated in principle.

[0039] [Implementation Method 1]

[0040] Figure 1 FIG. 1 is an equivalent circuit diagram of a bandpass filter 1 as an example of an LC filter according to the first embodiment. Figure 1As shown, bandpass filter 1 includes input / output terminals P1 and P2, LC parallel resonators LC1 to LC4, capacitors C12, C13, C23, C24, and C34. Hereinafter, the wavelength corresponding to the operating frequency of the bandpass filter (e.g., the center frequency of the passband) is denoted as λ. Furthermore, the LC filter of the embodiment may also include an LC series resonator.

[0041] LC parallel resonator LC1 is connected to input / output terminal P1. LC parallel resonator LC4 is connected to input / output terminal P2. Alternatively, LC parallel resonator LC1 may be indirectly connected to input / output terminal P1 via an inductor or capacitor. Similarly, LC parallel resonator LC4 may be indirectly connected to input / output terminal P2 via an inductor or capacitor.

[0042] The LC parallel resonators LC2 and LC3 are arranged between the LC parallel resonators LC1 and LC4. The LC parallel resonators LC1 to LC4 are sequentially coupled according to the strength of magnetic coupling and capacitive coupling described later, thereby forming a four-stage LC filter.

[0043] Capacitor C12 is connected between the LC parallel resonators LC1 and LC2. Capacitor C12 represents capacitive coupling between the LC parallel resonators LC1 and LC2.

[0044] Capacitor C13 is connected between the LC parallel resonators LC1 and LC3. Capacitor C13 represents capacitive coupling between the LC parallel resonators LC1 and LC3.

[0045] Capacitor C23 is connected between the LC parallel resonators LC2 and LC3. Capacitor C23 represents capacitive coupling between the LC parallel resonators LC2 and LC3.

[0046] Capacitor C24 is connected between the LC parallel resonators LC2 and LC4. Capacitor C24 represents capacitive coupling between the LC parallel resonators LC2 and LC4.

[0047] Capacitor C34 is connected between the LC parallel resonators LC3 and LC4. Capacitor C34 represents capacitive coupling between the LC parallel resonators LC3 and LC4.

[0048] The LC parallel resonator LC1 (first LC resonator) includes an inductor L1 and a capacitor C1. The inductor L1 and the capacitor C1 are connected in parallel between a ground point and a connection point between the input / output terminal P1 and the capacitor C12.

[0049] The LC parallel resonator LC2 (second LC resonator) includes an inductor L2 and a capacitor C2. The inductor L2 and the capacitor C2 are connected in parallel between the ground point and the connection point of the capacitors C12 and C23.

[0050] The LC parallel resonator LC3 (third LC resonator) includes an inductor L3 and a capacitor C3. The inductor L3 and the capacitor C3 are connected in parallel between the ground point and the connection point of the capacitors C23 and C34.

[0051] The LC parallel resonator LC4 (fourth LC resonator) includes an inductor L4 and a capacitor C4. The inductor L4 and the capacitor C4 are connected in parallel between the ground point and the connection point between the capacitor C34 and the input / output terminal P2.

[0052] Figure 2 yes Figure 1 The appearance of the bandpass filter 1 is shown in FIG. Figure 2 In the figure, the X-axis, Y-axis and Z-axis are orthogonal to each other. Figures 3 to 6 、 Figure 8 、 Figure 9 、 Figures 11 to 13 、 Figures 15 to 17 、 Figures 19 to 22 、 Figure 25 、 Figure 27 as well as Figure 29 The same is true in Chinese.

[0053] Reference Figure 2 The bandpass filter 1 is a laminate having a plurality of dielectric layers stacked in the Z-axis direction (stacking direction). The bandpass filter 1 is, for example, in the shape of a rectangular parallelepiped. The surfaces of the bandpass filter 1 perpendicular to the Z-axis direction are defined as the bottom surface BF and the top surface UF. Among the surfaces parallel to the stacking direction, the surfaces along the YZ plane are defined as side surfaces SF1 and SF3. Among the surfaces along the stacking direction, the surfaces along the ZX plane are defined as side surfaces SF2 and SF4.

[0054] A side surface electrode 105 is arranged on the side surface SF1. The side surface electrode 105 forms the input / output terminal P1. A side surface electrode 106 is arranged on the side surface SF3. The side surface electrode 106 forms the input / output terminal P2.

[0055] Ground terminals 101 and 102 are arranged on the bottom surface BF. Ground terminals 151 and 152 are arranged on the upper surface UF. A side electrode 103 is arranged on the side surface SF2. The side electrode 103 connects the ground terminals 101 and 151. A side electrode 104 is arranged on the side surface SF4. The side electrode 104 connects the ground terminals 102 and 152. The ground terminals 101, 102, 151, and 152 are connected to the Figure 1 corresponding to the grounding point.

[0056] A ground electrode 111 (first ground electrode) and a ground electrode 141 (second ground electrode) are arranged within bandpass filter 1. Ground electrode 111 faces bottom surface BF. Ground electrode 141 faces top surface UF. Capacitor electrodes 121-124, via-hole conductors V1-V4, and planar electrodes 131-134 are arranged between ground electrodes 111 and 141.

[0057] Capacitor electrode 121 (first capacitor electrode) is connected to side electrode 105. Capacitor electrode 121 faces ground electrode 111. Capacitor electrode 121 and ground electrode 111 form capacitor C1. Capacitor electrode 121 and ground electrode 141 are connected via via conductor V1 (first via conductor) extending in the Z-axis direction.

[0058] The via-hole conductor V1 forms an inductor L1. One end of the via-hole conductor V1 is connected to the capacitor electrode 121. The via-hole conductor V1 is an open end that is DC-insulated from the ground electrode 111 by the capacitor electrode 121. The LC parallel resonator LC1 is a λ / 4 resonator. The length of the via-hole conductor V1 is approximately λ / 4.

[0059] Capacitor electrode 122 (second capacitor electrode) faces ground electrode 111. Capacitor electrode 122 and ground electrode 111 form capacitor C2. Capacitor electrode 122 and ground electrode 141 are connected via via conductor V2 (second via conductor) extending in the Z-axis direction. Capacitor electrode 122 faces capacitor electrode 121 in the X-axis direction. Capacitor electrodes 121 and 122 form capacitor C12.

[0060] The via-hole conductor V2 forms an inductor L2. One end of the via-hole conductor V2 is connected to the capacitor electrode 122. The via-hole conductor V2 is open and DC-insulated from the ground electrode 111 by the capacitor electrode 122. The LC parallel resonator LC2 is a λ / 4 resonator. The length of the via-hole conductor V2 is approximately λ / 4.

[0061] Capacitor electrode 123 (third capacitor electrode) faces ground electrode 111. Capacitor electrode 123 and ground electrode 111 form capacitor C3. Capacitor electrode 123 and ground electrode 141 are connected via via conductor V3 (third via conductor) extending in the Z-axis direction. Capacitor electrode 123 faces capacitor electrode 122 in the Y-axis direction. Capacitor electrodes 122 and 123 form capacitor C23. Capacitor electrode 123 faces capacitor electrode 121 in the X-axis direction. Capacitor electrodes 121 and 123 form capacitor C13.

[0062] The via-hole conductor V3 forms an inductor L3. One end of the via-hole conductor V3 is connected to the capacitor electrode 123. One end of the via-hole conductor V3 is an open end that is DC-insulated from the ground electrode 111 by the capacitor electrode 123. The LC parallel resonator LC3 is a λ / 4 resonator. The length of the via-hole conductor V3 is approximately λ / 4.

[0063] Capacitor electrode 124 (fourth capacitor electrode) is connected to side electrode 106. Capacitor electrode 124 faces ground electrode 111. Capacitor electrode 124 and ground electrode 111 form capacitor C4. Capacitor electrode 124 and ground electrode 141 are connected via via conductor V4 (fourth via conductor) extending in the Z-axis direction. Capacitor electrode 124 faces capacitor electrodes 122 and 123 in the X-axis direction. Capacitor electrodes 122 and 124 form capacitor C24. Capacitor electrodes 123 and 124 form capacitor C34.

[0064] Via-hole conductor V4 forms inductor L4. One end of via-hole conductor V4 is connected to capacitor electrode 124. One end of via-hole conductor V4 is an open end that is DC-insulated from ground electrode 111 by capacitor electrode 124. LC parallel resonator LC4 is a λ / 4 resonator. The length of via-hole conductor V4 is approximately λ / 4.

[0065] The planar electrode 131 is connected to the via-hole conductor V1 between its two ends. The planar electrode 132 is connected to the via-hole conductor V2 between its two ends. The planar electrode 133 is connected to the via-hole conductor V3 between its two ends. The planar electrode 134 is connected to the via-hole conductor V4 between its two ends.

[0066] At least a portion of one side of the planar electrode 132 faces at least a portion of one side of each of the planar electrodes 131 and 134 in the Y-axis direction. The planar electrodes 131 and 132 form a capacitor C12. The planar electrodes 132 and 134 form a capacitor C24.

[0067] At least a portion of one side of the planar electrode 133 faces at least a portion of one side of each of the planar electrodes 131 and 134 in the Y-axis direction. The planar electrodes 131 and 133 form a capacitor C13. The planar electrodes 133 and 134 form a capacitor C34.

[0068] In bandpass filter 1, the capacitances of capacitors C12, C13, C24, and C34 can be independently adjusted by changing the shape and arrangement of planar electrodes 131 to 134. As a result, the characteristics of bandpass filter 1 can be brought close to desired characteristics with high accuracy.

[0069] Figure 3 Looking down from the X-axis Figure 2 FIG. 1 is a side view of the bandpass filter 1 SF1. Figure 3 As shown, capacitor electrodes 121 to 124 are arranged on dielectric layer Ly 1 . By forming capacitor electrodes 121 to 124 on the same dielectric layer, the height of bandpass filter 1 can be reduced.

[0070] When manufacturing bandpass filter 1 using ceramic multilayer substrate technology, multiple layers of ceramic sheets having multiple identical wiring conductor patterns and through-conductors formed in the planar direction are stacked and fired to form a stacked assembly. This stacked assembly is then divided in the planar direction to produce individual bandpass filters 1. To adjust the characteristics of bandpass filter 1 according to a particular communication system, a prototype stacked assembly is formed in which the shape and arrangement of the wiring conductor patterns corresponding to capacitor electrodes 121 to 124 are modified in the planar direction. This stacked assembly is then divided to produce multiple prototype bandpass filters 1 with different characteristics. By extracting a bandpass filter 1 that matches the desired characteristics from the prototype bandpass filters 1 and using the same planar electrode pattern as the pattern for mass production, the characteristics of bandpass filter 1 can be adjusted more efficiently.

[0071] The planar electrodes 131 to 134 are arranged on the dielectric layer Ly 2 . By forming the planar electrodes 131 to 134 on the same dielectric layer, the height of the bandpass filter 1 can be reduced.

[0072] Figure 4 Looking down from the Z axis Figure 2 Figure 1 shows the upper surface UF of the bandpass filter 1. Figure 4 In order to emphasize the characteristic arrangement of the capacitor electrodes 121 to 124 , the planar electrodes 131 to 134 are not shown.

[0073] like Figure 4 As shown, via-hole conductors V2 and V3 are located on either side of a virtual line VL1 connecting via-hole conductors V1 and V4. That is, via-hole conductors V1 and V4 are located on virtual line VL1, while via-hole conductors V2 and V3 are not. Via-hole conductor V2 is located on one side of virtual line VL1, and via-hole conductor V3 is located on the other side. When viewing bandpass filter 1 from above in the Y-axis direction, via-hole conductors V2 and V3 are sandwiched between via-hole conductors V1 and V4.

[0074] Generally speaking, each LC resonator couples to other LC resonators through magnetic and capacitive coupling. The strength of these couplings is determined by the shape and position of each LC resonator. The LC resonators are sequentially coupled based on the strength of the combined magnetic and capacitive coupling, forming an LC filter.

[0075] For example, in Embodiment 1, magnetic coupling is superior to capacitive coupling. The distance between via-hole conductors V1 and V2 is shorter than the distance between via-hole conductors V1 and V3. Therefore, the magnetic coupling between LC parallel resonators LC1 and LC2 is stronger than the magnetic coupling between LC parallel resonators LC1 and LC3.

[0076] The distance between via-hole conductors V4 and V3 is shorter than the distance between via-hole conductors V4 and V2. Therefore, the magnetic coupling between LC parallel resonators LC4 and LC3 is stronger than the magnetic coupling between LC parallel resonators LC4 and LC2. As a result, starting from the input / output terminal P1 side, the LC parallel resonators LC1, LC parallel resonator LC2, LC parallel resonator LC3, and LC4 are coupled in this order, forming a four-stage LC filter.

[0077] Capacitor electrodes 122 and 123 are arranged between capacitor electrodes 121 and 124 in the X-axis direction. Capacitor electrodes 122 and 123 are arranged side by side in the Y-axis direction. Capacitor electrode 121 is adjacent to capacitor electrodes 122 and 123. Capacitor electrode 124 is adjacent to capacitor electrodes 122 and 123. In other words, capacitor electrodes 121 to 124 are arranged in a staggered manner (zigzag pattern). As a result, Figure 1 LC parallel resonators LC1 to LC4 are arranged alternately. Compared to a linear arrangement, the magnetic coupling between the LC parallel resonators is enhanced. This facilitates signal transmission between the inductors and expands the passband of bandpass filter 1.

[0078] Capacitor electrode 122 has outer periphery F21 (first outer periphery) and outer periphery F23 (third outer periphery) facing capacitor electrodes 121 and 124 in the X-axis direction, respectively. Capacitor electrode 122 has outer periphery F22 (second outer periphery) facing capacitor electrode 123 in the Y-axis direction.

[0079] Capacitor electrode 121 has an outer peripheral portion F11 (fourth outer peripheral portion) that opposes outer peripheral portion F21. Capacitor electrode 123 has an outer peripheral portion F32 (fifth outer peripheral portion) that opposes outer peripheral portion F22. Capacitor electrode 124 has an outer peripheral portion F41 (sixth outer peripheral portion) that opposes outer peripheral portion F23. Capacitor electrode 123 has outer peripheral portions F31 and F33 that oppose outer peripheral portions F11 and F41, respectively.

[0080] The outer peripheries F21 to F23 are parallel to the outer periphery F11, the outer periphery F32, and the outer periphery F41, respectively. The outer peripheries F31 and F33 are parallel to the outer peripheries F11 and F41, respectively.

[0081] By arranging capacitor electrodes 121-124 so that their opposing outer portions are parallel, the two opposing outer portions can be brought closer to a single capacitor. This facilitates adjusting the capacitive coupling between LC resonators. Furthermore, in the LC filter of the embodiment, the two opposing outer portions do not need to be parallel; for example, one of the two opposing outer portions may have a wavy or sawtooth shape.

[0082] The interval W1 is the interval between the capacitor electrodes 121 and 122 in the X-axis direction. The interval W2 is the interval between the capacitor electrodes 121 and 123 in the X-axis direction. The interval W3 is the interval between the capacitor electrodes 122 and 124 in the X-axis direction. The interval W4 is the interval between the capacitor electrodes 123 and 124 in the X-axis direction. Figures 5 to 10 , the case where the passband of the bandpass filter 1 can be adjusted by changing the intervals W1 to W4 will be described. Figures 5 to 10 In order to emphasize the change in the distance between the two capacitor electrodes, electrodes other than the capacitor electrodes 121 to 124 and the via-hole conductors V1 to V4 are not shown.

[0083] Figure 5 It means narrowing Figure 4 FIG is a diagram showing an example of the interval W2 between the capacitor electrodes 121 and 123, and the interval W3 between the capacitor electrodes 122 and 124. Figure 5 middle, Figure 1 The capacitance values of capacitors C13 and C24 are Figure 4 It also increased compared to the previous period.

[0084] Reference Figure 4 as well as Figure 5 ,exist Figure 5 In FIG. 1 , the distance between the capacitor electrodes 121 and 123 is narrowed from W2 to W21 (< W2 ), and the distance between the capacitor electrodes 122 and 124 is narrowed from W3 to W31 (< W3 ).

[0085] Figure 6 It means expansion Figure 4 FIG is a diagram showing an example of the interval W2 between the capacitor electrodes 121 and 123, and the interval W3 between the capacitor electrodes 122 and 124. Figure 6 middle, Figure 1 The capacitance values of capacitors C13 and C24 are Figure 4 It is also reduced in comparison.

[0086] Reference Figure 4 as well as Figure 6 ,exist Figure 6 In FIG. 1 , the distance between capacitor electrodes 121 and 123 is expanded from W2 to W22 (> W2 ), and the distance between capacitor electrodes 122 and 124 is expanded from W3 to W32 (> W3 ).

[0087] Figure 7 It is shown together Figures 4 to 6 The graphs of the pass characteristics IL1 to IL3 of the bandpass filters 1 are shown. The pass characteristics of a bandpass filter refer to the frequency characteristics of the insertion loss of the bandpass filter. The insertion loss is maximum at the frequency where the attenuation peak occurs.

[0088] Reference Figure 7 , as shown by characteristic IL1, in Figure 4 On the low-frequency side of the passband of the bandpass filter 1, an attenuation pole is generated at frequency f11. On the high-frequency side of the passband, an attenuation pole is generated at frequency f21. The center frequency of the passband of the bandpass filter 1 is f1.

[0089] As shown by characteristic IL2, Figure 5 An attenuation pole is generated at a frequency f12 (< f11) on the low-frequency side of the passband of the bandpass filter 1. An attenuation pole is generated at a frequency f22 (< f21) on the high-frequency side of the passband. Figure 5 The center frequency of the passband of bandpass filter 1 is f2 (< f1). Regarding the attenuation peak on the low-frequency side, the attenuation at frequency f12 of characteristic IL2 is greater than the attenuation at frequency f11 of characteristic IL1. Regarding the attenuation peak on the high-frequency side, the attenuation at frequency f22 of characteristic IL12 is less than the attenuation at frequency f21 of characteristic IL1.

[0090] As shown by characteristic IL3, Figure 6 On the low-frequency side of the passband of bandpass filter 1, an attenuation pole occurs at frequency f13 (> f11). On the high-frequency side of this passband, an attenuation pole occurs at frequency f23 (> f21). The center frequency of the passband of bandpass filter 1 is f3 (> f1). Regarding the attenuation pole on the low-frequency side, the attenuation at frequency f13 of characteristic IL3 is smaller than the attenuation at frequency f11 of characteristic IL1. Regarding the attenuation pole on the high-frequency side, the attenuation at frequency f23 of characteristic IL3 is larger than the attenuation at frequency f21 of characteristic IL1.

[0091] like Figure 7 As shown, by Figure 1 By increasing the capacitance of capacitors C13 and C24, the pass characteristics of the bandpass filter 1 can be slid toward the lower frequency side. As a result, the center frequency of the bandpass filter 1 can be lowered. Figure 1 By reducing the capacitance of capacitors C13 and C24, the pass characteristics of the bandpass filter 1 can be shifted toward higher frequencies. As a result, the center frequency of the bandpass filter 1 can be increased.

[0092] Figure 8 It means narrowing Figure 4 FIG is a diagram showing an example of the interval W1 between the capacitor electrodes 121 and 122, and the interval W4 between the capacitor electrodes 123 and 124. Figure 8 middle, Figure 1 The capacitance values of capacitors C12 and C34 are Figure 4 It also increased compared to the previous period.

[0093] Reference Figure 4 as well as Figure 8 ,exist Figure 8 In FIG. 1 , the distance between the capacitor electrodes 121 and 122 is narrowed from W1 to W11 (< W1 ), and the distance between the capacitor electrodes 123 and 124 is narrowed from W4 to W41 (< W4 ).

[0094] Figure 9 It means expansion Figure 4 FIG is a diagram showing an example of the interval W1 between the capacitor electrodes 121 and 122, and the interval W4 between the capacitor electrodes 123 and 124. Figure 9 middle, Figure 1 The capacitance values of capacitors C12 and C34 are Figure 4 It is also reduced in comparison.

[0095] Reference Figure 4 as well as Figure 9 ,exist Figure 9 , the distance between capacitor electrodes 121 and 122 is expanded from W1 to W12 (> W1), and the distance between capacitor electrodes 123 and 124 is expanded from W4 to W42 (> W4).

[0096] Figure 10 It is shown together Figure 4 、 Figure 8 as well as Figure 9 Graphs showing the pass characteristics IL4 to IL6 of the respective bandpass filters 1 are shown.

[0097] Reference Figure 10 , as shown by characteristic IL4, in Figure 4 An attenuation pole is generated at a frequency f14 on the low-frequency side of the passband of the bandpass filter 1. An attenuation pole is generated at a frequency f24 on the high-frequency side of the passband.

[0098] As shown by characteristic IL5, Figure 8 An attenuation pole occurs at a frequency f15 (≈ f14) on the low-frequency side of the passband of the bandpass filter 1. An attenuation pole occurs at a frequency f25 (< f24) on the high-frequency side of the passband.

[0099] As shown by characteristic IL6, Figure 9An attenuation pole occurs at a frequency f16 (≈ f14) on the low-frequency side of the passband of the bandpass filter 1. An attenuation pole occurs at a frequency f26 (> f21) on the high-frequency side of the passband.

[0100] like Figure 10 As shown, by Figure 1 By increasing the capacitance of capacitors C12 and C34, the frequency of the attenuation pole on the high-frequency side of the bandpass filter 1 can be reduced. As a result, the bandwidth of the passband of the bandpass filter 1 can be narrowed. Figure 1 By reducing the capacitance of capacitors C12 and C34, the frequency at which an attenuation pole is generated on the high-frequency side of the bandpass filter 1 can be increased. As a result, the bandwidth of the passband of the bandpass filter 1 can be widened.

[0101] [Variation 1 of Embodiment 1]

[0102] In the first embodiment, a configuration in which the distances between adjacent via-hole conductors vary is described. In the first modification of the first embodiment, a configuration in which the distances between adjacent via-hole conductors are equal is described.

[0103] Figure 11 This is a diagram showing a bandpass filter 1A as an example of an LC filter according to a first modification of the first embodiment, viewed from the Z-axis direction. The bandpass filter 1A is configured by Figure 4 The configuration of the bandpass filter 1 is such that the capacitor electrodes 121 and 124 are replaced with capacitor electrodes 121A and 124A, and the positions of the via-hole conductors V2 and V3 are moved.

[0104] like Figure 11 As shown, via-hole conductors V1 to V4 are arranged in a diamond shape. The distance between via-hole conductors V1 and V2 is equal to the distance between via-hole conductors V1 and V3. Therefore, the magnetic coupling between via-hole conductors V1 and V2 is equal to the magnetic coupling between via-hole conductors V1 and V3. The distance between via-hole conductors V4 and V3 is equal to the distance between via-hole conductors V4 and V2. Therefore, the magnetic coupling between via-hole conductors V4 and V3 is equal to the magnetic coupling between via-hole conductors V4 and V2. Furthermore, the distance between via-hole conductors V1 and V2 is equal to the distance between via-hole conductors V2 and V4.

[0105] The capacitor electrode 121A (first capacitor electrode) faces the capacitor electrodes 122 and 123 in the X-axis direction. The portion of the capacitor electrode 121A facing the capacitor electrode 122 is longer than the portion of the capacitor electrode 121A facing the capacitor electrode 123. Figure 1 The capacitance value of capacitor C12 is larger than the capacitance value of capacitor C13.

[0106] The capacitor electrode 124A (fourth capacitor electrode) faces the capacitor electrodes 122 and 123 in the X-axis direction. The portion of the capacitor electrode 124A facing the capacitor electrode 123 is longer than the portion of the capacitor electrode 124A facing the capacitor electrode 122. Figure 1 The capacitance value of capacitor C34 is larger than the capacitance value of capacitor C24.

[0107] [Variation 2 of Embodiment 1]

[0108] In the first embodiment, a configuration was described in which electrodes forming input and output terminals are arranged on the side surfaces (outer peripheral surfaces) of an LC filter formed as a laminate. The input and output terminals may also be formed on surfaces other than the outer peripheral surfaces of the laminate. In a second variation of the first embodiment, a configuration is described in which the input and output terminals forming the bandpass filter are formed as LGA (Land Grid Array) terminals regularly arranged on the bottom surface of the laminate.

[0109] Figure 12 This is a perspective view of the appearance of a bandpass filter 1B as an example of an LC filter according to a second modification of the first embodiment. Figure 13 Looking down from the Y axis Figure 12 The side view SF2 of the bandpass filter 1B is shown. The bandpass filter 1B is constructed by Figure 2 The side electrodes 105 and 106, the ground electrode 111, and the capacitor electrodes 121 and 124 of the bandpass filter 1 are replaced with LGA terminals 105B and 106B, the ground electrode 111B, and the capacitor electrodes 121B and 124B, and via-hole conductors V5 and V6 are added. Other than these, the configuration is the same and will not be repeated.

[0110] like Figure 12 as well as Figure 13 As shown, the LGA terminal 105B and the capacitor electrode 121B are connected via a via-hole conductor V5 , and the LGA terminal 106B and the capacitor electrode 124B are connected via a via-hole conductor V6 .

[0111] [Variation 3 of Embodiment 1]

[0112] In the first embodiment, a configuration in which one end of the inductor of the LC resonator included in the LC filter is open is described. In a third variation of the first embodiment, a configuration in which both ends of the inductor are open is described.

[0113] Figure 14 This is an equivalent circuit diagram of a bandpass filter 1C as an example of an LC filter according to a third modification of the first embodiment. Figure 14 The equivalent circuit diagrams shown are for Figure 1 The LC parallel resonators LC1 to LC4 in the equivalent circuit diagram shown are configured by adding capacitors C10, C20, C30, and C40. Other than these, the components are the same and their description will not be repeated.

[0114] like Figure 14 As shown, capacitor C10 is connected between inductor L1 and ground. Capacitor C20 is connected between inductor L2 and ground. Capacitor C30 is connected between inductor L3 and ground. Capacitor C40 is connected between inductor L4 and ground.

[0115] Figure 15 yes Figure 14 A three-dimensional diagram of the appearance of the bandpass filter 1C. Figure 16 Looking down from the Y axis Figure 15 The side view of the bandpass filter 1C is shown in FIG. SF2. The bandpass filter 1C is configured to Figure 1 The configuration of the bandpass filter 1 is the same as that in which capacitor electrodes 161 to 164 and a ground electrode 141 are added, and via-hole conductors V1 to V4 are replaced with V1C to V4C, respectively.

[0116] like Figure 15 as well as Figure 16 As shown, the capacitor electrode 161 (fifth capacitor electrode) faces the ground electrode 141. The capacitor electrode 161 and the ground electrode 141 form a capacitor C10.

[0117] The via-hole conductor V1C (first via-hole conductor) forms the inductor L1. One end of the via-hole conductor V1C is connected to the capacitor electrode 121. One end of the via-hole conductor V1C is an open end that is DC-insulated from the ground electrode 111 by the capacitor electrode 121. The other end of the via-hole conductor V1C is connected to the capacitor electrode 161. The other end of the via-hole conductor V1C is an open end that is DC-insulated from the ground electrode 141 by the capacitor electrode 161. Since both ends of the via-hole conductor V1C are open, Figure 10 In FIG, the LC parallel resonator LC1 is a λ / 2 resonator, and the length of the via-hole conductor V1C is substantially equal to λ / 2.

[0118] The capacitor electrode 162 (sixth capacitor electrode) faces the ground electrode 141. The capacitor electrode 162 and the ground electrode 141 form a capacitor C20.

[0119] The via-hole conductor V2C (second via-hole conductor) forms the inductor L2. One end of the via-hole conductor V2C is connected to the capacitor electrode 122. One end of the via-hole conductor V2C is an open end that is DC-insulated from the ground electrode 111 by the capacitor electrode 122. The other end of the via-hole conductor V2C is connected to the capacitor electrode 162. The other end of the via-hole conductor V2C is an open end that is DC-insulated from the ground electrode 141 by the capacitor electrode 162. Since both ends of the via-hole conductor V2C are open, Figure 10 In FIG, the LC parallel resonator LC2 is a λ / 2 resonator, and the length of the via-hole conductor V2C is substantially equal to λ / 2.

[0120] The capacitor electrode 163 (seventh capacitor electrode) faces the ground electrode 141. The capacitor electrode 163 and the ground electrode 141 form a capacitor C30.

[0121] The via-hole conductor V3C (third via-hole conductor) forms the inductor L3. One end of the via-hole conductor V3C is connected to the capacitor electrode 123. One end of the via-hole conductor V3C is an open end that is DC-insulated from the ground electrode 111 by the capacitor electrode 123. The other end of the via-hole conductor V3C is connected to the capacitor electrode 163. The other end of the via-hole conductor V3C is an open end that is DC-insulated from the ground electrode 141 by the capacitor electrode 163. Since both ends of the via-hole conductor V3C are open, Figure 10 In FIG, the LC parallel resonator LC3 is a λ / 2 resonator. The length of the via-hole conductor V3C is approximately equal to λ / 2.

[0122] The capacitor electrode 164 (eighth capacitor electrode) faces the ground electrode 141. The capacitor electrode 164 and the ground electrode 141 form a capacitor C40.

[0123] Via-hole conductor V4C (fourth via-hole conductor) forms inductor L4. One end of via-hole conductor V4C is connected to capacitor electrode 124. One end of via-hole conductor V4C is an open end, isolated from ground electrode 111 by capacitor electrode 124. The other end of via-hole conductor V4C is connected to capacitor electrode 164. The other end of via-hole conductor V4C is an open end, isolated from ground electrode 141 by capacitor electrode 164. Because both ends of via-hole conductor V4C are open, LC parallel resonator LC4 is a λ / 2 resonator. The length of via-hole conductor V4C is approximately equal to λ / 2.

[0124] [Variation 4 of Embodiment 1]

[0125] In Embodiment 1, a planar electrode for adjusting capacitive coupling between LC resonators is connected between both ends of a via-hole conductor forming an inductor. However, the LC filter of the embodiment may not include this planar electrode.

[0126] Figure 17 This is a perspective view of the appearance of a bandpass filter 1D as an example of an LC filter according to a fourth modification of the first embodiment. The bandpass filter 1D is constructed from Figure 1 The configuration of the bandpass filter 1 is obtained by removing the planar electrodes 131 to 134. Other than these, the configuration is the same and therefore description thereof will not be repeated.

[0127] As described above, according to the LC filters of the first embodiment and modifications 1 to 4, it is possible to facilitate adjustment of the transmission characteristics of the LC filter.

[0128] In the first embodiment, a configuration in which a plurality of LC resonators are connected to a common ground electrode is described. In the second embodiment, a configuration in which a plurality of LC resonators are connected to different ground electrodes is described.

[0129] [Implementation Method 2]

[0130] Figure 18 This is an equivalent circuit diagram of a bandpass filter 2 as an example of an LC filter according to the second embodiment. Figure 18 The equivalent circuit diagram shown is for Figure 1 The equivalent circuit diagram shown is a configuration in which a capacitor C14 is added.

[0131] like Figure 18 As shown, capacitor C14 is connected between the LC parallel resonators LC1 and LC4. Capacitor C14 represents the capacitive coupling of the LC parallel resonators LC1 and LC4.

[0132] Figure 19 yes Figure 18 A three-dimensional diagram of the appearance of the bandpass filter 2. Figure 20 Looking down from the Y axis Figure 19 The side view of the bandpass filter 2 SF22. The equivalent circuit diagram of the bandpass filter 2 is the same as Figure 1 The equivalent circuit diagram shown is the same.

[0133] Reference Figure 19 as well as Figure 20The bandpass filter 2 is a laminated body having a plurality of dielectric layers stacked in the Z-axis direction (stacking direction). The bandpass filter 2 is, for example, in the shape of a rectangular parallelepiped. The surfaces of the bandpass filter 2 perpendicular to the Z-axis direction are defined as the bottom surface BF2 and the top surface UF2. Among the surfaces parallel to the stacking direction, the surfaces along the YZ plane are defined as the side surfaces SF21 and SF23. Among the surfaces along the stacking direction, the surfaces along the ZX plane are defined as the side surfaces SF22 and SF24.

[0134] A side surface electrode 205 is arranged on the side surface SF21. The side surface electrode 205 forms the input / output terminal P1. A side surface electrode 206 is arranged on the side surface SF23. The side surface electrode 206 forms the input / output terminal P2.

[0135] A side electrode 203 is arranged on the side surface SF22. A side electrode 204 is arranged on the side surface SF24. The side electrodes 203 and 204 are arranged on the side surface SF24. Figure 18 corresponding to the grounding point.

[0136] A ground electrode 211 (first ground electrode) and ground electrodes 241 to 244 are arranged within the bandpass filter 2. Ground electrode 211 faces bottom surface BF2. Ground electrodes 241 to 244 face top surface UF2. Ground electrode 241 is connected to side electrodes 203 and 204. Ground electrode 242 is connected to side electrode 204. Ground electrode 243 is connected to side electrode 203. Ground electrode 244 is connected to side electrodes 203 and 204. Capacitor electrodes 221 to 224 and 250, via-hole conductors V21 to V24, planar electrodes 231 to 234 and 260, and line electrodes 271 and 272 are arranged between ground electrodes 211 and 241 to 244.

[0137] The capacitor electrode 221 (first capacitor electrode) faces the ground electrode 211. The capacitor electrode 221 and the ground electrode 211 form a capacitor C1. The capacitor electrode 221 and the ground electrode 241 are connected by a via-hole conductor V21 (first via-hole conductor) extending in the Z-axis direction.

[0138] Via-hole conductor V21 forms inductor L1. One end of via-hole conductor V21 is connected to capacitor electrode 221. One end of via-hole conductor V21 is an open end, DC-insulated from ground electrode 211 by capacitor electrode 221. LC parallel resonator LC1 is a λ / 4 resonator. The length of via-hole conductor V21 is approximately λ / 4.

[0139] Capacitor electrode 222 (second capacitor electrode) faces ground electrode 211. Capacitor electrode 222 and ground electrode 211 form capacitor C2. Capacitor electrode 222 and ground electrode 242 are connected via via conductor V22 (second via conductor) extending in the Z-axis direction. Capacitor electrode 222 faces capacitor electrode 221 in the X-axis direction. Capacitor electrodes 221 and 222 form capacitor C12.

[0140] Via-hole conductor V22 forms inductor L2. One end of via-hole conductor V22 is connected to capacitor electrode 222. One end of via-hole conductor V22 is an open end, DC-insulated from ground electrode 211 by capacitor electrode 222. LC parallel resonator LC2 is a λ / 4 resonator. The length of via-hole conductor V22 is approximately λ / 4.

[0141] Capacitor electrode 223 (third capacitor electrode) faces ground electrode 211. Capacitor electrode 223 and ground electrode 211 form capacitor C3. Capacitor electrode 223 and ground electrode 243 are connected via via conductor V23 (third via conductor) extending in the Z-axis direction. Capacitor electrode 223 faces capacitor electrode 222 in the Y-axis direction. Capacitor electrodes 222 and 223 form capacitor C23. Capacitor electrode 223 faces capacitor electrode 221 in the X-axis direction. Capacitor electrodes 221 and 223 form capacitor C13.

[0142] Via-hole conductor V23 forms inductor L3. One end of via-hole conductor V23 is connected to capacitor electrode 223. One end of via-hole conductor V23 is an open end, DC-insulated from ground electrode 211 by capacitor electrode 223. LC parallel resonator LC3 is a λ / 4 resonator. The length of via-hole conductor V23 is approximately λ / 4.

[0143] Capacitor electrode 224 (fourth capacitor electrode) faces ground electrode 211. Capacitor electrode 224 and ground electrode 211 form capacitor C4. Capacitor electrode 224 and ground electrode 244 are connected via via conductor V24 (fourth via conductor) extending in the Z-axis direction. Capacitor electrode 224 faces capacitor electrodes 222 and 223 in the X-axis direction. Capacitor electrodes 222 and 224 form capacitor C24. Capacitor electrodes 223 and 224 form capacitor C34.

[0144] Via-hole conductor V24 forms inductor L4. One end of via-hole conductor V24 is connected to capacitor electrode 224. One end of via-hole conductor V24 is an open end, DC-insulated from ground electrode 211 by capacitor electrode 224. LC parallel resonator LC4 is a λ / 4 resonator. The length of via-hole conductor V24 is approximately λ / 4.

[0145] The capacitor electrode 250 faces the capacitor electrodes 222 and 223 in the Z-axis direction. The capacitor electrodes 222, 223, and 250 form a capacitor C23.

[0146] The planar electrode 231 is connected to the via-hole conductor V21 between its two ends. The planar electrode 232 is connected to the via-hole conductor V22 between its two ends. The planar electrode 233 is connected to the via-hole conductor V23 between its two ends. The planar electrode 234 is connected to the via-hole conductor V24 between its two ends.

[0147] The planar electrode 232 faces the planar electrodes 231 and 234 in the Y-axis direction. The planar electrodes 231 and 232 form a capacitor C12. The planar electrodes 232 and 234 form a capacitor C24.

[0148] The planar electrode 233 faces the planar electrodes 231 and 234 in the Y-axis direction. The planar electrodes 231 and 233 form a capacitor C13. The planar electrodes 233 and 234 form a capacitor C34.

[0149] The planar electrode 260 faces the planar electrodes 231 and 234 in the Z-axis direction. The planar electrodes 231, 234, and 260 form a capacitor C14.

[0150] The line electrode 271 connects the side electrode 205 to the via-hole conductor V21 between the planar electrode 231 and the ground electrode 241. The line electrode 272 connects the side electrode 206 to the via-hole conductor V24 between the planar electrode 234 and the ground electrode 244.

[0151] Figure 21 1 is a perspective view of the appearance of a bandpass filter 2A as an example of an LC filter according to a modification of the second embodiment. Figure 22 Looking down from the Y axis Figure 21 The side view of the bandpass filter 2A is shown in FIG. 22. The bandpass filter 2A is constructed as follows: Figure 19 In bandpass filter 2A, electrodes other than line electrodes 271 and 272 are arranged so that electrodes closer to upper surface UF2 are closer to bottom surface BF2, and electrodes closer to bottom surface BF2 are arranged closer to upper surface UF2. In other words, bandpass filter 2A is constructed by reversing the arrangement of electrodes other than line electrodes 271 and 272 in bandpass filter 2 in the vertical direction (Z-axis direction). Other details are the same, so description will not be repeated.

[0152] The line electrode 271 connects the side electrode 205 to the via-hole conductor V21 between the planar electrode 231 and the capacitor electrode 221 . The line electrode 272 connects the side electrode 206 to the via-hole conductor V24 between the planar electrode 234 and the capacitor electrode 224 .

[0153] Figure 23 It is shown together Figure 19 The pass characteristic IL20 of the bandpass filter 2, and Figure 21 Refer to the figure of the pass characteristic IL21 of the bandpass filter 2A. Figure 23 As shown in the passband characteristic IL20, an attenuation pole occurs at a frequency f41 on the low-frequency side of the passband of the bandpass filter 2. An attenuation pole occurs at a frequency f42 on the high-frequency side of the passband.

[0154] As shown in the passband characteristic IL21, an attenuation pole occurs at frequency f51 (< f41) on the low-frequency side of the passband of the bandpass filter 2A, and an attenuation pole occurs at frequency f52 (< f42) on the high-frequency side of the passband.

[0155] The difference between frequencies f41 and f51 is greater than the difference between frequencies f42 and f52. The attenuation d21 at frequency f51 of characteristic IL21 is greater than the attenuation d11 at frequency f41 of characteristic IL20. The attenuation d22 at frequency f52 of characteristic IL21 is greater than the attenuation d12 at frequency f42 of characteristic IL20. The difference between attenuations d21 and d11 is greater than the difference between attenuations d22 and d12. By configuring bandpass filter 2 as bandpass filter 2A, it is possible to change the attenuation characteristics on the low-frequency side while roughly maintaining the attenuation characteristics on the high-frequency side.

[0156] As described above, according to the LC filters of the second embodiment and the modified example, it is possible to facilitate adjustment of the transmission characteristics of the LC filter.

[0157] In Embodiments 1 and 2, the LC filter includes four LC resonators. However, the number of LC resonators included in the LC filter of the embodiments is not limited to four. Hereinafter, Embodiments 3 and 4 describe configurations including five LC resonators, and Embodiment 5 describes a configuration including seven LC resonators.

[0158] [Implementation Method 3]

[0159] Figure 24 : is an equivalent circuit diagram of a bandpass filter 3 as an example of an LC filter according to the third embodiment. Figure 24 In the equivalent circuit diagram shown in Figure 1The equivalent circuit diagram shown here removes capacitor C24 and adds LC parallel resonator LC5 and capacitors C14, C25, C35, and C45. In other words, the five LC resonators are coupled in sequence to form a five-stage LC filter. Other than these, the circuit is identical and will not be described again.

[0160] like Figure 24 As shown, the LC parallel resonator LC5 is connected to the input / output terminal P2.

[0161] Capacitor C14 is connected between the LC parallel resonators LC1 and LC4. Capacitor C14 represents the capacitive coupling between the LC parallel resonators LC1 and LC4.

[0162] Capacitor C25 is connected between the LC parallel resonators LC2 and LC5. Capacitor C25 represents the capacitive coupling between the LC parallel resonators LC2 and LC5.

[0163] Capacitor C35 is connected between the LC parallel resonators LC3 and LC5. Capacitor C35 represents the capacitive coupling between the LC parallel resonators LC3 and LC5.

[0164] Capacitor C45 is connected between the LC parallel resonators LC4 and LC5. Capacitor C45 represents the capacitive coupling between the LC parallel resonators LC4 and LC5.

[0165] The LC parallel resonator LC5 includes an inductor L5 and a capacitor C5. The inductor L5 and the capacitor C5 are connected in parallel between the ground point and the connection point between the capacitor C45 and the input / output terminal P2.

[0166] Figure 25 Looking down from the Z axis Figure 24 Figure 3 of the bandpass filter. Figure 25 In order to emphasize the characteristics of the bandpass filter 3, the composition is shown. Figure 24 The main electrodes of the LC parallel resonator LC1 to LC5. Figure 25 As shown, the bandpass filter 3 includes a ground electrode 311 , via-hole conductors V31 to V35 , and capacitor electrodes 321 to 325 .

[0167] Capacitor electrodes 321 to 325 face ground electrode 311 in the Z-axis direction and form capacitors C1 to C5 together with ground electrode 311. Capacitor electrodes 322 to 324 are arranged between capacitor electrodes 321 and 325 in the X-axis direction. Capacitor electrode 323 is arranged between capacitor electrodes 322 and 324 in the Y-axis direction.

[0168] Capacitor electrode 321 (first capacitor electrode) faces capacitor electrode 322 (second capacitor electrode), capacitor electrode 323 (third capacitor electrode), and capacitor electrode 324 in the X-axis direction. Capacitor electrodes 321 and 322 form capacitor C12. Capacitor electrodes 321 and 323 form capacitor C13. Capacitor electrodes 321 and 324 form capacitor C14.

[0169] Capacitor electrode 322 faces capacitor electrode 323 in the Y-axis direction. Capacitor electrodes 322 and 323 form capacitor C23. Capacitor electrode 323 faces capacitor electrode 324 in the Y-axis direction. Capacitor electrodes 323 and 324 form capacitor C34.

[0170] Capacitor electrode 325 (fourth capacitor electrode) faces capacitor electrodes 322 to 324 in the X-axis direction. Capacitor electrodes 322 and 325 form capacitor C25. Capacitor electrodes 323 and 325 form capacitor C35. Capacitor electrodes 324 and 325 form capacitor C45.

[0171] One end of the via-hole conductor V31 (first via-hole conductor) is connected to the capacitor electrode 321 (first capacitor electrode). The via-hole conductor V31 forms the inductor L1.

[0172] One end of the via-hole conductor V32 (second via-hole conductor) is connected to the capacitor electrode 322 (second capacitor electrode). The via-hole conductor V32 forms the inductor L2.

[0173] One end of the via-hole conductor V33 (third via-hole conductor) is connected to the capacitor electrode 323 (third capacitor electrode). The via-hole conductor V33 forms the inductor L3.

[0174] One end of the via-hole conductor V34 is connected to the capacitor electrode 324. The via-hole conductor V34 forms the inductor L4.

[0175] One end of the via-hole conductor V35 (fourth via-hole conductor) is connected to the capacitor electrode 325 (fourth capacitor electrode). The via-hole conductor V35 forms the inductor L5.

[0176] For example, in Embodiment 3, magnetic coupling is superior to capacitive coupling. The distance between via-hole conductors V31 and V32 is shorter than the distance between via-hole conductors V31 and V33. Therefore, the magnetic coupling between LC parallel resonators LC1 and LC2 is stronger than the magnetic coupling between LC parallel resonators LC1 and LC3.

[0177] The distance between via-hole conductors V34 and V35 is shorter than the distance between via-hole conductors V33 and V35. Therefore, the magnetic coupling between LC parallel resonators LC4 and LC5 is stronger than the magnetic coupling between LC parallel resonators LC3 and LC5. As a result, starting from the input / output terminal P1 side, the LC parallel resonators LC1, LC2, LC3, LC4, and LC5 are coupled in this order, forming a five-stage LC filter.

[0178] As described above, according to the LC filter of the third embodiment, it is possible to facilitate adjustment of the transmission characteristics of the LC filter.

[0179] [Implementation 4]

[0180] Figure 26 : is an equivalent circuit diagram of a bandpass filter 4 as an example of an LC filter according to the fourth embodiment. Figure 26 In the equivalent circuit diagram shown in Figure 24 The equivalent circuit diagram shown here removes capacitors C14 and C25 and adds capacitor C24. In other words, five LC resonators are coupled in sequence to form a five-stage LC filter. Other than these, the circuit is identical and will not be described again.

[0181] like Figure 26 As shown, capacitor C24 is connected between the LC parallel resonators LC2 and LC4. Capacitor C24 represents the capacitive coupling of the LC parallel resonators LC2 and LC4.

[0182] Figure 27 Looking down from the Z axis Figure 26 Figure 4 of the bandpass filter. Figure 27 In order to emphasize the characteristics of the bandpass filter 4, the composition is shown. Figure 26 The main electrodes of the LC parallel resonator LC1 to LC5. Figure 27 As shown, the bandpass filter 4 includes a ground electrode 411 , via-hole conductors V41 to V45 , and capacitor electrodes 421 to 425 .

[0183] Capacitor electrodes 421 to 425 face ground electrode 411 in the Z-axis direction and form capacitors C1 to C5 together with ground electrode 411. Capacitor electrodes 422 and 424 are arranged between capacitor electrodes 421 and 425 in the X-axis direction. Capacitor electrode 423 is arranged between capacitor electrodes 421 and 425 in the X-axis direction.

[0184] Capacitor electrode 421 (first capacitor electrode) faces capacitor electrode 422 (second capacitor electrode) and capacitor electrode 423 (third capacitor electrode) in the X-axis direction. Capacitor electrodes 421 and 422 form capacitor C12. Capacitor electrodes 421 and 423 form capacitor C13.

[0185] Capacitor electrode 422 faces capacitor electrode 423 in the Y-axis direction. Capacitor electrodes 422 and 423 form capacitor C23. Capacitor electrode 422 faces capacitor electrode 424 (fourth capacitor electrode) in the X-axis direction. Capacitor electrodes 422 and 424 form capacitor C24. Capacitor electrode 423 faces capacitor electrode 424 in the Y-axis direction. Capacitor electrodes 423 and 424 form capacitor C34.

[0186] The capacitor electrode 425 faces the capacitor electrodes 423 and 424 in the X-axis direction. The capacitor electrodes 423 and 425 form a capacitor C35. The capacitor electrodes 424 and 425 form a capacitor C45.

[0187] One end of the via-hole conductor V41 (first via-hole conductor) is connected to the capacitor electrode 421 (first capacitor electrode). The via-hole conductor V41 forms the inductor L1.

[0188] One end of the via-hole conductor V42 (second via-hole conductor) is connected to the capacitor electrode 422 (second capacitor electrode). The via-hole conductor V42 forms the inductor L2.

[0189] One end of the via-hole conductor V43 (third via-hole conductor) is connected to the capacitor electrode 423 (third capacitor electrode). The via-hole conductor V43 forms the inductor L3.

[0190] One end of the via-hole conductor V44 (fourth via-hole conductor) is connected to the capacitor electrode 424. The via-hole conductor V44 forms the inductor L4.

[0191] One end of the via-hole conductor V45 is connected to the capacitor electrode 425. The via-hole conductor V45 forms the inductor L5.

[0192] For example, in Embodiment 4, magnetic coupling is superior to capacitive coupling. The distance between via-hole conductors V41 and V42 is shorter than the distance between via-hole conductors V41 and V43. Therefore, the magnetic coupling between LC parallel resonators LC1 and LC2 is stronger than the magnetic coupling between LC parallel resonators LC1 and LC3.

[0193] The distance between via-hole conductors V44 and V45 is shorter than the distance between via-hole conductors V43 and V45. Therefore, the magnetic coupling between LC parallel resonators LC4 and LC5 is stronger than the magnetic coupling between LC parallel resonators LC3 and LC5. As a result, starting from the input / output terminal P1 side, the LC parallel resonators LC1, LC2, LC3, LC4, and LC5 are coupled in this order, forming a five-stage LC filter.

[0194] As described above, according to the LC filter of the fourth embodiment, it is possible to facilitate adjustment of the transmission characteristics of the LC filter.

[0195] [Implementation 5]

[0196] Figure 28 : is an equivalent circuit diagram of a bandpass filter 5 as an example of an LC filter according to the fifth embodiment. Figure 28 In the equivalent circuit diagram shown in Figure 1 The equivalent circuit diagram shown here adds LC parallel resonators LC5-LC7 and capacitors C45, C46, C56, C57, and C67. In other words, seven LC resonators are coupled in sequence to form a seven-stage LC filter. Other than these, the circuit is identical and will not be described again.

[0197] like Figure 28 As shown, the LC parallel resonators LC5 and LC6 are arranged between the LC parallel resonators LC4 and LC7.

[0198] Capacitor C45 is connected between the LC parallel resonators LC4 and LC5. Capacitor C45 represents the capacitive coupling between the LC parallel resonators LC4 and LC5.

[0199] Capacitor C46 is connected between the LC parallel resonators LC4 and LC6. Capacitor C46 represents the capacitive coupling between the LC parallel resonators LC4 and LC6.

[0200] Capacitor C56 is connected between the LC parallel resonators LC5 and LC6. Capacitor C56 represents the capacitive coupling between the LC parallel resonators LC5 and LC6.

[0201] Capacitor C57 is connected between the LC parallel resonators LC5 and LC7. Capacitor C57 represents the capacitive coupling between the LC parallel resonators LC5 and LC7.

[0202] Capacitor C67 is connected between the LC parallel resonators LC6 and LC7. Capacitor C67 represents the capacitive coupling between the LC parallel resonators LC6 and LC7.

[0203] The LC parallel resonator LC5 includes an inductor L5 and a capacitor C5. The inductor L5 and the capacitor C5 are connected in parallel between the ground point and the connection point of the capacitors C45 and C56.

[0204] The LC parallel resonator LC6 includes an inductor L6 and a capacitor C6. The inductor L6 and the capacitor C6 are connected in parallel between the ground point and the connection point of the capacitors C56 and C67.

[0205] The LC parallel resonator LC7 includes an inductor L7 and a capacitor C7. The inductor L7 and the capacitor C7 are connected in parallel between the ground point and the connection point between the capacitor C67 and the input / output terminal P2.

[0206] Figure 29 Looking down from the Z axis Figure 28 Figure 5 of the bandpass filter. Figure 29 In order to emphasize the characteristics of the bandpass filter 5, the structure is shown. Figure 28 The main electrodes of the LC parallel resonator LC1 to LC7. Figure 29 As shown, the bandpass filter 5 includes a ground electrode 511 (first ground electrode), via-hole conductors V51 to V57 , and capacitor electrodes 521 to 527 .

[0207] Capacitor electrodes 521 to 527 are positioned opposite ground electrode 511 in the Z-axis direction and, together with ground electrode 511, form capacitors C1 to C7. Capacitor electrodes 522 and 523 are positioned between capacitor electrodes 521 and 524 in the X-axis direction. Capacitor electrodes 522 and 523 are arranged side by side in the Y-axis direction. Capacitor electrodes 525 and 526 are positioned between capacitor electrodes 524 and 527 in the X-axis direction. Capacitor electrodes 525 and 526 are arranged side by side in the Y-axis direction.

[0208] Capacitor electrode 521 (first capacitor electrode) faces capacitor electrode 522 (second capacitor electrode) and capacitor electrode 523 (third capacitor electrode) in the X-axis direction. Capacitor electrodes 521 and 522 form capacitor C12. Capacitor electrodes 521 and 523 form capacitor C13. Capacitor electrode 523 faces capacitor electrode 522 in the Y-axis direction. Capacitor electrodes 522 and 523 form capacitor C23. Capacitor electrode 524 (fourth capacitor electrode) faces capacitor electrodes 522 and 523 in the X-axis direction. Capacitor electrodes 522 and 524 form capacitor C24. Capacitor electrodes 523 and 524 form capacitor C34.

[0209] Capacitor electrode 524 faces capacitor electrodes 525 and 526 in the X-axis direction. Capacitor electrodes 524 and 525 form capacitor C45. Capacitor electrodes 524 and 526 form capacitor C46. Capacitor electrode 525 faces capacitor electrode 526 in the Y-axis direction. Capacitor electrodes 525 and 526 form capacitor C56. Capacitor electrode 527 faces capacitor electrodes 525 and 526 in the X-axis direction. Capacitor electrodes 525 and 527 form capacitor C57. Capacitor electrodes 526 and 527 form capacitor C67.

[0210] One end of the via-hole conductor V51 (first via-hole conductor) is connected to the capacitor electrode 521 (first capacitor electrode). The via-hole conductor V51 forms the inductor L1.

[0211] One end of the via-hole conductor V52 (second via-hole conductor) is connected to the capacitor electrode 522 (second capacitor electrode). The via-hole conductor V52 forms the inductor L2.

[0212] One end of the via-hole conductor V53 (third via-hole conductor) is connected to the capacitor electrode 523 (third capacitor electrode). The via-hole conductor V53 forms the inductor L3.

[0213] One end of the via-hole conductor V54 (fourth via-hole conductor) is connected to the capacitor electrode 524 (fourth capacitor electrode). The via-hole conductor V54 forms the inductor L4.

[0214] One end of the via-hole conductor V55 is connected to the capacitor electrode 525. The via-hole conductor V55 forms the inductor L5.

[0215] One end of the via-hole conductor V56 is connected to the capacitor electrode 526. The via-hole conductor V56 forms the inductor L6.

[0216] One end of the via-hole conductor V57 is connected to the capacitor electrode 527. The via-hole conductor V57 forms the inductor L7.

[0217] The via-hole conductors V52 and V53 are arranged on both sides of a virtual line VL51 connecting the via-hole conductors V51 and V54 . The via-hole conductors V55 and V56 are arranged on both sides of a virtual line VL52 connecting the via-hole conductors V54 and V57 .

[0218] For example, in Embodiment 5, magnetic coupling is prioritized over capacitive coupling. The distance between via-hole conductors V51 and V52 is shorter than the distance between via-hole conductors V51 and V53. Consequently, the magnetic coupling between LC parallel resonators LC1 and LC2 is stronger than the magnetic coupling between LC parallel resonators LC1 and LC3.

[0219] The distance between the via-hole conductors V54 and V53 is shorter than the distance between the via-hole conductors V54 and V52. Therefore, the magnetic coupling between the LC parallel resonators LC4 and LC3 is stronger than the magnetic coupling between the LC parallel resonators LC4 and LC2.

[0220] The distance between the via-hole conductors V54 and V55 is shorter than the distance between the via-hole conductors V54 and V56. Therefore, the magnetic coupling between the LC parallel resonators LC4 and LC5 is stronger than the magnetic coupling between the LC parallel resonators LC4 and LC6.

[0221] The distance between via-hole conductors V57 and V56 is shorter than the distance between via-hole conductors V57 and V55. Therefore, the magnetic coupling between LC parallel resonators LC7 and LC6 is stronger than the magnetic coupling between LC parallel resonators LC7 and LC5. As a result, starting from the input / output terminal P1 side, the LC parallel resonators LC1, LC2, LC3, LC4, LC5, LC6, and LC7 are coupled in this order, forming a seven-stage LC filter.

[0222] As described above, according to the LC filter of the fifth embodiment, it is possible to facilitate adjustment of the transmission characteristics of the LC filter.

[0223] The various embodiments disclosed herein are intended to be implemented in appropriate combinations within the scope of non-inconsistency. The embodiments disclosed herein should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated not by the above description but by the claims, and includes all modifications within the meaning and scope of the claims.

[0224] Explanation of Reference Numerals: 1 to 5, 1A to 1D…bandpass filter, 101, 102, 151, 152…ground terminal, 103 to 106, 203 to 206…side electrodes, 105B, 106B…LGA terminal, 111, 111B, 141, 211, 241 to 244, 311, 411, 511…ground electrode, 121 to 124, 121A, 121B, 124A, 124B, 161 to 164, 221 to 224, 250, 321 to 325, 421 to 425, 521 to 527…capacitor electrode, 131 to 134, 231 to 234, 260…planar electrode, 271, 272…line electrode, BF, BF2 ...bottom surface, C1-C7, C10, C12, C13, C14, C20, C23-C25, C30, C34, C35, C40, C45, C46, C56, C57, C67...capacitors, F11, F21, F22, F23, F31, F32, F41...peripheral portion, L1-L7...inductor, LC1-LC7...LC parallel resonator, Ly1, Ly2...dielectric layer, P1, P2...input and output terminals, SF1-SF4, SF21-SF24...side surface, UF, UF2...top surface, V1-V6, V1C-V4C, V21-V24, V31-V35, V41-V45, V51-V57...via conductors.

Claims

1. An LC filter comprising a plurality of dielectric layers stacked in a stacking direction, the LC filter comprising: a first LC resonator; a second LC resonator; a third LC resonator; a fourth LC resonator; and a first ground electrode, The first LC resonator includes: A first via conductor extending along the stacking direction; and A first capacitor electrode is connected to one end of the first via conductor and faces the first ground electrode in the stacking direction. The second LC resonator includes: A second via conductor extends along the stacking direction; and a second capacitor electrode connected to one end of the second via-hole conductor and facing the first ground electrode in the stacking direction; The third LC resonator includes: A third via conductor extends along the stacking direction; and a third capacitor electrode connected to one end of the third via-hole conductor and facing the first ground electrode in the stacking direction; The fourth LC resonator includes: a fourth via conductor extending along the stacking direction; and a fourth capacitor electrode connected to one end of the fourth via conductor and facing the first ground electrode in the stacking direction; The second capacitor electrode is opposed to each of the first capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode in a direction perpendicular to the stacking direction. The third capacitor electrode faces the first capacitor electrode in a first direction perpendicular to the stacking direction, and faces the second capacitor electrode in a second direction perpendicular to both the stacking direction and the first direction.

2. The LC filter according to claim 1, wherein The third capacitor electrode faces the fourth capacitor electrode in the first direction.

3. The LC filter according to claim 1 or 2, wherein: The second capacitor electrode has a first peripheral portion, a second peripheral portion, and a third peripheral portion respectively facing the first capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode in a direction perpendicular to the stacking direction. The first capacitor electrode has a fourth peripheral portion facing the first peripheral portion. The third capacitor electrode has a fifth outer peripheral portion facing the second outer peripheral portion. The fourth capacitor electrode has a sixth peripheral portion facing the third peripheral portion. The first outer peripheral portion, the second outer peripheral portion, and the third outer peripheral portion are parallel to the fourth outer peripheral portion, the fifth outer peripheral portion, and the sixth outer peripheral portion, respectively.

4. The LC filter according to claim 1 or 2, wherein: The plurality of dielectric layers include a dielectric layer in which the first capacitor electrode, the second capacitor electrode, the third capacitor electrode, and the fourth capacitor electrode are arranged.

5. The LC filter according to claim 1 or 2, wherein: When viewed in plan from the stacking direction, the second via-hole conductor and the third via-hole conductor are respectively arranged on both sides of a virtual line connecting the first via-hole conductor and the fourth via-hole conductor.

6. The LC filter according to claim 4, wherein The LC filter further includes a second ground electrode connected to the other end of the first via-hole conductor, the other end of the second via-hole conductor, the other end of the third via-hole conductor, and the other end of the fourth via-hole conductor.

7. The LC filter according to claim 5, wherein The LC filter further includes a second ground electrode connected to the other end of the first via-hole conductor, the other end of the second via-hole conductor, the other end of the third via-hole conductor, and the other end of the fourth via-hole conductor.

8. The LC filter according to claim 4, wherein The LC filter further includes a second ground electrode. The first LC resonator further includes a fifth capacitor electrode connected to the other end of the first via-hole conductor and facing the second ground electrode in the stacking direction. The second LC resonator further includes a sixth capacitor electrode connected to the other end of the second via-hole conductor and facing the second ground electrode in the stacking direction. The third LC resonator further includes a seventh capacitor electrode connected to the other end of the third via-hole conductor and facing the second ground electrode in the stacking direction. The fourth LC resonator further includes an eighth capacitor electrode connected to the other end of the fourth via-hole conductor and facing the second ground electrode in the stacking direction.

9. The LC filter according to claim 5, wherein The LC filter further includes a second ground electrode. The first LC resonator further includes a fifth capacitor electrode connected to the other end of the first via-hole conductor and facing the second ground electrode in the stacking direction. The second LC resonator further includes a sixth capacitor electrode connected to the other end of the second via-hole conductor and facing the second ground electrode in the stacking direction. The third LC resonator further includes a seventh capacitor electrode connected to the other end of the third via-hole conductor and facing the second ground electrode in the stacking direction. The fourth LC resonator further includes an eighth capacitor electrode connected to the other end of the fourth via-hole conductor and facing the second ground electrode in the stacking direction.

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