Multilayer LC Filter

Abstract

The present invention provides a laminated LC filter that facilitates jump coupling of LC parallel resonators that are distant from each other.　In the present invention, a plurality of LC parallel resonators, in each of which an inductor and a capacitor are connected in parallel, are formed inside a laminated body. The inductor of each of the LC parallel resonators includes a loop inductor composed of a line conductor pattern and at least one pair of via conductors connected to the line conductor pattern. The loop inductors of all of the LC parallel resonators are formed such that, when the laminated body is looked through in the height direction, open via conductors are located close to the center of the laminated body, and short-circuit via conductors are located close to an outer side of the laminated body, in at least one of the width direction and the length direction.

Description

[Technical field]

[0001] The present invention relates to a multilayer LC filter in which a plurality of LC parallel resonators are formed inside a laminate in which a plurality of dielectric layers are stacked. [Background technology]

[0002] Multilayer LC filters are widely used in various electronic devices, and are used to form a variety of filters, such as band-pass filters, low-pass filters, and high-pass filters.

[0003] In general, a filter has poles outside the passband to obtain good passband characteristics. For example, a standard bandpass filter often has poles with the same amount of attenuation on both the lower and higher frequency sides of the passband.

[0004] However, the specifications of electronic devices in which the laminated LC filter is used may require the passband characteristics of the filter to have characteristics different from the standard passband characteristics. For example, in a bandpass filter, the attenuation of the pole on the low frequency side may be required to be greater than the attenuation of the pole on the high frequency side. However, this is only one example, and the present invention is not limited to this example. Various characteristics may be required for the passband characteristics.

[0005] In such a case, for example, specific LC parallel resonators that are separated from each other on the equivalent circuit are cross-coupled by capacitive coupling to obtain a desired passband characteristic.

[0006] A multilayer LC filter that serves as a reference for the present invention is disclosed in Document 1 (Japanese Patent No. 5549744). In this multilayer LC filter, the inductor of the LC parallel resonator is configured as a so-called loop inductor. That is, the inductor is formed as a loop inductor by connecting via conductors formed to penetrate the dielectric layers to both ends of a line-shaped conductor pattern formed between certain layers of the laminate.

[0007] In the multilayer LC filter of Literature 1, dielectric layers having a relatively large size in the planar direction are stacked to form a laminate. In addition, in the multilayer LC filter of Literature 1, a relatively large number of dielectric layers are stacked to form a laminate. Therefore, in the multilayer LC filter of Literature 1, it is easy to provide a new conductor pattern for jump coupling inside the laminate, and it is easy to achieve desired passband characteristics by capacitively coupling specific LC parallel resonators that are distant from each other on the equivalent circuit. In the multilayer LC filter of Literature 1, when viewed through the laminate in the height direction, the loop inductors of each LC parallel resonator are arranged such that, in the length direction, the short-circuiting via conductors connecting the line-like conductor pattern and the ground conductor pattern are arranged toward the center of the laminate, and the open via conductors connecting the line-like conductor pattern and the capacitor conductor pattern are arranged toward the outside of the laminate.

[0008] However, in recent years, with the miniaturization of electronic devices, there is a demand for miniaturization of electronic components, including the multilayer LC filters used. For example, in multilayer LC filters, there is a demand for the size of the dielectric layers in the planar direction to be smaller than before, and for the number of laminated dielectric layers to be reduced compared to before. There is also a demand for forming the required number of LC parallel resonators inside such a laminate without degrading characteristics including the passband characteristics.

[0009] A miniaturized multilayer LC filter is disclosed in Document 2 (WO2007 / 119356A1). In this multilayer LC filter, the inductor of each LC parallel resonator is also formed by a loop inductor having a structure in which via conductors are connected to both ends of a line-shaped conductor pattern formed between certain layers of the laminate.

[0010] In the laminated LC filter of Document 2, the line-like conductor patterns of the loop inductors of the inductors of each LC parallel resonator are arranged in parallel inside the laminate. For example, in the case of a four-stage bandpass filter, the line-like conductor patterns of the loop inductors of the inductors of the first to fourth stages of resonators are arranged in parallel.

[0011] As a result, in the laminated LC filter of Document 2, the planar size of the dielectric layers is made smaller than in the conventional filter, and the number of laminated dielectric layers is reduced compared to the conventional filter, thereby making the laminate smaller. Nevertheless, the required number of LC parallel resonators are formed inside the laminate, and a required circuit is configured. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Patent No. 5549744 [Patent Document 2] WO2007 / 119356A1 publication Summary of the Invention [Problem to be solved by the invention]

[0013] In the laminated LC filter of Reference 2, specific LC parallel resonators that are distant from each other on the equivalent circuit are coupled by capacitive coupling, making it difficult to adjust the passband characteristics.

[0014] That is, for example, when an attempt is made to adjust the passband characteristics by adding a new conductor pattern for cross-coupling and cross-coupling the first-stage LC parallel resonator and the third-stage LC parallel resonator through capacitive coupling, the conductor pattern for cross-coupling is arranged passing near the second-stage LC parallel resonator. As a result, not only is a new cross-coupling between the first-stage LC parallel resonator and the third-stage LC parallel resonator created, but the coupling state between the first-stage LC parallel resonator and the second-stage LC parallel resonator and even the coupling state between the second-stage LC parallel resonator and the third-stage LC parallel resonator change, resulting in a problem that the basic passband characteristics themselves are disrupted. In other words, it is difficult to control the cross-coupling independently. [Means for solving the problem]

[0015] The present invention has been made to solve the above-mentioned problems in the related art, and as a means therefor, a laminated LC filter according to one embodiment of the present invention is a laminated LC filter that transmits a signal from an input terminal to an output terminal, and includes a laminate in which a plurality of dielectric layers are laminated, and a plurality of LC parallel resonators that are arranged on the laminate and electromagnetically coupled to each other, the laminate includes a first line-like conductor pattern formed between the dielectric layers, a second line-like conductor pattern, and a third line-like conductor pattern, a first capacitor conductor pattern formed between the dielectric layers, a second capacitor conductor pattern, a third capacitor conductor pattern, and at least one ground conductor pattern formed between the dielectric layers, and the plurality of LC parallel resonators include the first LC parallel resonator, the second LC parallel resonator, and the third LC parallel resonator. the first LC parallel resonator includes a first line-like conductor pattern, a first open via conductor connecting the first line-like conductor pattern and the first capacitor conductor pattern, and a first short-circuiting via conductor connecting the first line-like conductor pattern and the ground conductor pattern; the second LC parallel resonator includes a second line-like conductor pattern, a second open via conductor connecting the second line-like conductor pattern and the second capacitor conductor pattern, and a second short-circuiting via conductor connecting the second line-like conductor pattern and the ground conductor pattern; the third LC parallel resonator includes a third line-like conductor pattern, a third open via conductor connecting the third line-like conductor pattern and the third capacitor conductor pattern, and a third short-circuiting via conductor connecting the third line-like conductor pattern and the ground conductor pattern; When viewed through the laminate from the stacking direction, the first open via conductor is positioned closer to the second open via conductor than the second short-circuiting via conductor, and closer to the third open via conductor than the third short-circuiting via conductor, and the second open via conductor is positioned closer to the third open via conductor than the third short-circuiting via conductor. Effect of the Invention

[0016] In a laminated LC filter according to one embodiment of the present invention, the first open via conductor is positioned closer to the second open via conductor than the second short-circuiting via conductor and closer to the third open via conductor than the third short-circuiting via conductor, the second open via conductor is positioned closer to the third open via conductor than the third short-circuiting via conductor, and the capacitor conductor patterns and / or open via conductors of the capacitors of each LC parallel resonator are concentrated near the center of the laminate, making it easy to achieve jump-coupling between distant LC parallel resonators on an equivalent circuit by capacitive coupling. [Brief description of the drawings]

[0017] [Figure 1] 1 is an exploded perspective view of a laminated LC filter 100 according to a first preferred embodiment of the present invention. [Diagram 2] 1 is an equivalent circuit diagram of a laminated LC filter 100. FIG. [Diagram 3] 1 is an explanatory diagram (perspective plan view) of a laminated LC filter 100. FIG. [Figure 4] 2 is a graph showing frequency characteristics of the laminated LC filter 100. [Diagram 5] 1 is an exploded perspective view showing a laminated LC filter 110 according to a first modified example of the laminated LC filter 100. FIG. [Figure 6] 11 is an exploded perspective view showing a laminated LC filter 120 according to a second modified example of the laminated LC filter 100. FIG. [Figure 7] 11 is an exploded perspective view showing a laminated LC filter 130 according to a third modified example of the laminated LC filter 100. FIG. [Figure 8] FIG. 11 is an exploded perspective view of a laminated LC filter 200 according to a second embodiment. [Figure 9] 2 is an equivalent circuit diagram of the laminated LC filter 200. FIG. [Figure 10] 1 is an explanatory diagram (perspective plan view) of a laminated LC filter 200. FIG. [Figure 11] 2 is a graph showing frequency characteristics of the laminated LC filter 200. [Figure 12]1 is an exploded perspective view showing a laminated LC filter 210 according to a first modified example of the laminated LC filter 200. FIG. [Figure 13] 13 is an exploded perspective view showing a laminated LC filter 220 according to a second modified example of the laminated LC filter 200. FIG. [Figure 14] 13 is an exploded perspective view showing a laminated LC filter 230 according to a third modified example of the laminated LC filter 200. FIG. [Figure 15] Fig. 15(A) is an explanatory diagram (perspective plan view) of a layered LC filter 300 according to a third embodiment. Fig. 15(B) is an equivalent circuit diagram of the layered LC filter 300. [Figure 16] Fig. 16(A) is an explanatory diagram (perspective plan view) of a layered LC filter 400 according to a third embodiment. Fig. 16(B) is an equivalent circuit diagram of the layered LC filter 400. [Figure 17] FIG. 13 is an exploded perspective view of a laminated LC filter 500 in accordance with a fifth embodiment. [Figure 18] Fig. 18(A) is an exploded perspective view of a main portion of the laminated LC filter 500. Fig. 18(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 500. [Figure 19] Fig. 19(A) is an exploded perspective view of a main part of a laminated LC filter 510 according to a first modified example of the laminated LC filter 500. Fig. 19(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 510. [Figure 20] 20(A-1) and (B-1) are explanatory diagrams of Experiment 1. Figs. 20(A-2) and (B-2) are characteristic diagrams of Experiment 1. [Figure 21] Fig. 21A is an exploded perspective view of a main portion of a laminated LC filter 530 according to a second modified example of the laminated LC filter 500. Fig. 21B is an exploded perspective view of a main portion of a laminated LC filter 540 according to a third modified example of the laminated LC filter 500. [Figure 22] FIG. 13 is an exploded perspective view of a main part of a laminated LC filter 600 according to a sixth embodiment. [Figure 23]Fig. 23(A) is an exploded perspective view of a main portion of the laminated LC filter 600. Fig. 23(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 600. [Figure 24] Fig. 24(A) is an exploded perspective view of a main part of a laminated LC filter 610 according to a first modified example of the laminated LC filter 600. Fig. 24(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 610. [Diagram 25] 20(A-1) and (B-1) are explanatory diagrams of Experiment 2. FIGS. 20(A-2) and (B-2) are characteristic diagrams of Experiment 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] Note that each embodiment is an illustrative example of an embodiment of the present invention, and the present invention is not limited to the contents of the embodiment. In addition, it is possible to combine the contents described in different embodiments and implement them, and the implementation contents in such cases are also included in the present invention. In addition, the drawings are intended to aid in understanding the specification, and may be drawn diagrammatically, and the dimensional ratios of the drawn components or between the components may not match the dimensional ratios of those components described in the specification. In addition, components described in the specification may be omitted in the drawings, or may be drawn with the number of components omitted.

[0020] [First embodiment: laminated LC filter 100] Figures 1, 2 and 3 show a laminated LC filter 100 according to a first preferred embodiment. Fig. 1 is an exploded perspective view of the laminated LC filter 100. Fig. 2 is an equivalent circuit diagram of the laminated LC filter 100. Fig. 3 is an explanatory diagram (perspective plan view) of the laminated LC filter 100.

[0021] The multilayer LC filter 100 is a band-pass filter. However, the multilayer LC filter of the present invention is not limited to a band-pass filter, and may be a low-pass filter, a high-pass filter, or the like.

[0022] The multilayer LC filter 100 includes a laminate 1.

[0023] The laminate 1 has a height direction Z in which dielectric layers 1a to 1g described later are laminated, a width direction W orthogonal to the height direction Z, and a length direction L orthogonal to both the height direction Z and the width direction W. In the present embodiment, when the length in the width direction W is a and the length in the length direction L is b, a < b, but alternatively, a = b may be used.

[0024] The laminate 1 is composed of dielectric layers 1a to 1g laminated in order from the bottom. In FIG. 1, the thicknesses of the dielectric layers 1a to 1g are shown uniformly, but in actuality, there may be a difference in thickness. In this case, for example, a dielectric layer with a small thickness is composed of one dielectric sheet, and a dielectric layer with a large thickness is composed of a plurality of dielectric sheets. The material of the laminate 1 (dielectric layers 1a to 1g) is arbitrary, and various dielectric materials can be used.

[0025] Hereinafter, each configuration of the dielectric layers 1a to 1g will be described.

[0026] On the lower main surface of the dielectric layer 1a, a first input / output terminal T1, a second input / output terminal T2, two ground terminals Tg, and two dummy terminals Td are formed. The dummy terminal Td is an electrode that is not used for electrical connection when mounting the multilayer LC filter 100 on a substrate or the like, and is used solely to improve the mounting strength. In FIG. 1, for reasons of drawing, the input / output terminals T1, T2, the ground terminals Tg, and the dummy terminals Td are shown separated from the lower main surface of the dielectric layer 1a.

[0027] Via conductors 2a, 2b, 2c, and 2d are formed through the upper and lower main surfaces of the dielectric layer 1a.

[0028] A ground conductor pattern 3 is formed on the upper main surface of the dielectric layer 1a. The ground conductor pattern 3 is connected to two ground terminals Tg by two via conductors 2b and 2c, respectively.

[0029] In addition to the above-mentioned via conductors 2a and 2d, new via conductors 2e, 2f, 2g, and 2h are formed penetrating between the upper and lower main surfaces of the dielectric layer 1b.

[0030] A jump coupling capacitor conductor pattern 4a is formed on the upper main surface of the dielectric layer 1a.

[0031] The above-mentioned via conductors 2a, 2d, 2e, 2f, 2g, and 2h are formed penetrating between the upper and lower main surfaces of the dielectric layer 1c.

[0032] Three capacitor conductor patterns 5a, 5b, and 5c are formed on the upper main surface of the dielectric layer 1c. The capacitor conductor pattern 5a is connected to a first input / output terminal T1 by a via conductor 2a. The capacitor conductor pattern 5c is connected to a second input / output terminal T2 by a via conductor 2d.

[0033] In addition to the above-mentioned via conductors 2e, 2f, 2g, and 2h, new via conductors 2i, 2j, and 2k are formed penetrating between the upper and lower main surfaces of the dielectric layer 1d.

[0034] Coupling capacitor conductor patterns 6a and 6b are formed on the upper main surface of the dielectric layer 1d.

[0035] The above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, and 2k are formed so as to penetrate between the upper and lower main surfaces of the dielectric layer 1e.

[0036] Line-like conductor patterns 7a, 7b, and 7c are formed on the upper main surface of the dielectric layer 1e. One end of the line-like conductor pattern 7a is connected to the ground conductor pattern 3 by a via conductor 2e. The other end of the line-like conductor pattern 7a is connected to the capacitor conductor pattern 5a by a via conductor 2i. One end of the line-like conductor pattern 7b is connected to the ground conductor pattern 3 by a via conductor 2f. The other end of the line-like conductor pattern 7b is connected to the ground conductor pattern 3 by a via conductor 2h. A portion near the center of the line-like conductor pattern 7b is connected to the capacitor conductor pattern 5b by a via conductor 2j. One end of the line-like conductor pattern 7c is connected to the ground conductor pattern 3 by a via conductor 2g. The other end of the line-like conductor pattern 7c is connected to the capacitor conductor pattern 5c by a via conductor 2k.

[0037] The above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, and 2k are formed so as to penetrate between the upper and lower main surfaces of the dielectric layer 1f.

[0038] Line-like conductor patterns 7d, 7e, and 7f are formed on the upper main surface of the dielectric layer 1f. The line-like conductor patterns 7d, 7e, and 7f are formed so as to vertically overlap the above-mentioned line-like conductor patterns 7a, 7b, and 7c, respectively. That is, in the multilayer LC filter 100, the line-like conductor patterns are each formed in two layers in order to improve the Q of the inductor. Note that, in terms of the electric circuit, the line-like conductor patterns 7d, 7e, and 7f may be omitted.

[0039] One end of the line-like conductor pattern 7d is connected to the ground conductor pattern 3 by a via conductor 2e. The other end of the line-like conductor pattern 7d is connected to the capacitor conductor pattern 5a by a via conductor 2i. One end of the line-like conductor pattern 7e is connected to the ground conductor pattern 3 by a via conductor 2f. The other end of the line-like conductor pattern 7e is connected to the ground conductor pattern 3 by a via conductor 2h. A portion near the center of the line-like conductor pattern 7e is connected to the capacitor conductor pattern 5b by a via conductor 2j. One end of the line-like conductor pattern 7f is connected to the ground conductor pattern 3 by a via conductor 2g. The other end of the line-like conductor pattern 7f is connected to the capacitor conductor pattern 5c by a via conductor 2k.

[0040] The dielectric layer 1g is a protective layer, and no via conductors or conductor patterns are formed thereon.

[0041] The materials for the input / output terminals T1, T2, ground terminal Tg, dummy terminal Td, via conductors 2a to 2k, ground conductor pattern 3, jump coupling capacitor conductor pattern 4a, capacitor conductor patterns 5a to 5c, coupling capacitor conductor patterns 6a, 6b, and line-like conductor patterns 7a to 7f are each arbitrary, and various conductive materials can be used.

[0042] The layered LC filter 100 has an equivalent circuit shown in FIG.

[0043] The laminated LC filter 100 includes a first input / output terminal T1 and a second input / output terminal T2. A signal line SL is formed between the first input / output terminal T1 and the second input / output terminal T2.

[0044] In the layered LC filter 100, a capacitor C12 and a capacitor C23 are connected in this order to a signal line SL connecting a first input / output terminal T1 and a second input / output terminal T2. In the layered LC filter 100, a capacitor C13 is connected in parallel with the capacitor C12 and the capacitor C23 between the first input / output terminal T1 and the second input / output terminal T2.

[0045] The layered LC filter 100 includes three LC parallel resonators, namely, first to third LC parallel resonators LC1, LC2, and LC3. The first LC parallel resonator LC1 is configured by connecting an inductor L1 and a capacitor C1 in parallel. The second LC parallel resonator LC2 is configured by connecting an inductor L2 and a capacitor C2 in parallel. The third LC parallel resonator LC3 is configured by connecting an inductor L3 and a capacitor C3 in parallel.

[0046] The first LC parallel resonator LC1 has one end connected to a portion of the signal line SL between the first input / output terminal T1 and the capacitor C12, and the other end connected to the ground terminal Tg. The second LC parallel resonator LC2 has one end connected to a portion of the signal line SL between the capacitor C12 and the capacitor C23, and the other end connected to the ground terminal Tg. The third LC parallel resonator LC3 has one end connected to a portion of the signal line SL between the capacitor C23 and the second input / output terminal T2, and the other end connected to the ground terminal Tg.

[0047] Next, the main coupling relationships among the first to third LC parallel resonators LC1, LC2, and LC3 will be described.

[0048] The first LC parallel resonator LC1 and the second LC parallel resonator LC2 are magnetically coupled by the magnetic coupling between the inductor L1 and the inductor L2. The second LC parallel resonator LC2 and the third LC parallel resonator LC3 are magnetically coupled by the magnetic coupling between the inductor L2 and the inductor L3.

[0049] The first LC parallel resonator LC1 and the second LC parallel resonator LC2 are capacitively coupled by the capacitance of the capacitor C12. The second LC parallel resonator LC2 and the third LC parallel resonator LC3 are capacitively coupled by the capacitance of the capacitor C23. The first LC parallel resonator LC1 and the third LC parallel resonator LC3 are capacitively coupled by the capacitance of the capacitor C13.

[0050] Due to the above-described equivalent circuits and couplings, the layered LC filter 100 has a three-stage bandpass filter configured between the first input / output terminal T1 and the second input / output terminal T2.

[0051] Next, the relationship between the equivalent circuit of the laminated LC filter 100 and its structure will be described.

[0052] The capacitor C1 of the first LC parallel resonator LC1 is formed by the capacitance between the capacitor conductor pattern 5a and the ground conductor pattern 3. The capacitor conductor pattern 5a is connected to the first input / output terminal T1 through the via conductor 2a. The inductor L1 of the first LC parallel resonator LC1 is formed by a loop inductor that starts at the capacitor conductor pattern 5a, passes through the via conductor 2i, the line-like conductor patterns 7a and 7d, and the via conductor 2e, and ends at the ground conductor pattern 3.

[0053] The capacitor C2 of the second LC parallel resonator LC2 is formed by the capacitance between the capacitor conductor pattern 5b and the ground conductor pattern 3. The inductor L2 of the second LC parallel resonator LC2 is formed by a loop inductor that starts at the capacitor conductor pattern 5b, passes through the via conductor 2j and the line-like conductor patterns 7b and 7e, then branches into two paths, passes through the via conductor 2f and the via conductor 2h, and ends at the ground conductor pattern 3.

[0054] The capacitor C3 of the third LC parallel resonator LC3 is formed by the capacitance between the capacitor conductor pattern 5c and the ground conductor pattern 3. The inductor L3 of the third LC parallel resonator LC3 is formed by a loop inductor that starts at the capacitor conductor pattern 5c, passes through the via conductor 2k, the line-like conductor patterns 7c and 7f, and the via conductor 2g, and ends at the ground conductor pattern 3. The capacitor conductor pattern 5c is connected to the second input / output terminal T2 by the via conductor 2d.

[0055] The capacitor C12 is formed by the capacitance between the capacitor conductor pattern 5a and the coupling capacitor conductor pattern 6a, which are connected in series, and the capacitance between the coupling capacitor conductor pattern 6a and the capacitor conductor pattern 5b.

[0056] The capacitor C23 is formed by the capacitance between the capacitor conductor pattern 5b and the coupling capacitor conductor pattern 6b, and the capacitance between the coupling capacitor conductor pattern 6b and the capacitor conductor pattern 5c, which are connected in series.

[0057] The capacitor C13 is constituted by a capacitance between the capacitor conductor pattern 5a and the jump coupling capacitor conductor pattern 4a, and a capacitance between the jump coupling capacitor conductor pattern 4a and the capacitor conductor pattern 5c, which are connected in series.

[0058] In the laminated LC filter 100 having the above structure and equivalent circuit, when the laminate 1 is seen through in the height direction Z, in all of the inductor L1 which is the loop inductor of the first LC parallel resonator LC1, the inductor L2 which is the loop inductor of the second LC parallel resonator LC2, and the inductor L3 which is the loop inductor of the third LC parallel resonator LC3, the open via conductors are arranged toward the center in the length direction L of the laminate 1, and the short-circuiting via conductors are arranged toward the outside in the length direction L of the laminate 1. Note that the open via conductors refer to via conductors connected to a capacitor conductor pattern, and the short-circuiting via conductors refer to via conductors connected to a ground conductor pattern.

[0059] As described above, the inductor L1, which is the loop inductor of the first LC parallel resonator LC1, is formed by a loop inductor that starts at the capacitor conductor pattern 5a, passes through the via conductor 2i, the line-like conductor patterns 7a and 7d, and the via conductor 2e, and ends at the ground conductor pattern 3. Among these, the via conductor 2i is the open via conductor of the inductor L1, and the via conductor 2e is the short-circuit via conductor of the inductor L1.

[0060] Inductor L2, which is a loop inductor of the second LC parallel resonator LC2, is formed by a loop inductor that starts at capacitor conductor pattern 5b, passes through via conductor 2j and line-like conductor patterns 7b and 7e, then branches into two paths, passes through via conductor 2f and via conductor 2h, and ends at ground conductor pattern 3. Of these, via conductor 2j is the open via conductor of inductor L2, and via conductors 2f and 2h are short-circuited via conductors of inductor L2.

[0061] The inductor L3, which is a loop inductor of the third LC parallel resonator LC3, is formed by a loop inductor that starts at the capacitor conductor pattern 5c, passes through the via conductor 2k, the line-like conductor patterns 7c and 7f, and the via conductor 2g, and ends at the ground conductor pattern 3. Among these, the via conductor 2k is the open via conductor of the inductor L3, and the via conductor 2g is the short-circuit via conductor of the inductor L1.

[0062] 3 shows the open via conductors and the short-circuit via conductors of the inductors L1 to L3. As can be seen from FIG. 3, in the laminated LC filter 100, in all the inductors L1, L2, and L3 of the first to third LC parallel resonators LC1, LC2, and LC3, the open via conductors are arranged closer to the center in the length direction L, and the short-circuit via conductors are arranged closer to the outside in the length direction L. From another perspective, the open via conductor of the inductor L1 is arranged closer to the open via conductor of the inductor L2 than the short-circuit via conductor of the inductor L2, and is arranged closer to the open via conductor of the inductor L3 than the short-circuit via conductor of the inductor L3, and the open via conductor of the inductor L2 is arranged closer to the open via conductor of the inductor L3 than the short-circuit via conductor of the inductor L3. As a result, the open via conductors are arranged closer to the center of the laminate 1. Furthermore, as a result, in the laminated LC filter 100, the capacitor conductor patterns 5a, 5b, and 5c of the first to third LC parallel resonators LC1, LC2, and LC3 are also disposed toward the center of the laminate 1. This is because the open via conductors are via conductors connected to the capacitor conductor patterns.

[0063] Arranging the capacitor conductor patterns of the LC parallel resonators toward the center of the laminate facilitates cross-coupling (cross-coupling capacitive coupling) between LC parallel resonators that are distant from each other on the equivalent circuit. This is because cross-coupling capacitive coupling is generally achieved by inserting a capacitor between the capacitor conductor patterns of two LC parallel resonators that are to be cross-coupled. More specifically, cross-coupling capacitive coupling can be achieved by providing a cross-coupling capacitor conductor pattern between the capacitor conductor patterns of two LC parallel resonators that are to be cross-coupled.

[0064] In the multilayer LC filter 100, the first LC parallel resonator LC1 and the third LC parallel resonator LC3 are cross-coupled (cross-capacitively coupled) by providing the cross-coupling capacitor conductor pattern 4a, so that the multilayer LC filter 100 is adjusted to have desired frequency characteristics (passband characteristics).

[0065] Fig. 4 shows the frequency characteristics of the laminated LC filter 100. As can be seen from Fig. 4, two-stage attenuation poles can be easily formed on the low-frequency side by arranging each open via conductor of each LC parallel resonator toward the center of the laminate 1. Although two-stage attenuation poles are formed on the low-frequency side in Fig. 4, it is also possible to form two-stage attenuation poles on the high-frequency side by adjusting capacitive coupling and magnetic coupling.

[0066] [First Modification of the First Embodiment: Multilayer LC Filter 110] 5 shows a laminated LC filter 110 according to a first modified example of the first embodiment. Note that FIG. 5 is an exploded perspective view of the laminated LC filter 110.

[0067] The multilayer LC filter 110 according to the first modified example adds a new configuration to the multilayer LC filter 100 described above. Specifically, new via conductors 12a, 12b, and 12c are formed to penetrate between the upper and lower main surfaces of the dielectric layer 1b. In addition, three adjustment capacitor conductor patterns 18a, 18b, and 18c are formed on the upper main surface of the dielectric layer 1b. The adjustment capacitor conductor pattern 18a is connected to the ground conductor pattern 3 by the via conductor 12a. The adjustment capacitor conductor pattern 18b is connected to the ground conductor pattern 3 by the via conductor 12b. The adjustment capacitor conductor pattern 18c is connected to the ground conductor pattern 3 by the via conductor 12c.

[0068] The adjustment capacitor conductor pattern 18a increases the capacitance of the capacitor C1 formed between the capacitor conductor pattern 5a and the ground conductor pattern 3. The adjustment capacitor conductor pattern 18b increases the capacitance of the capacitor C2 formed between the capacitor conductor pattern 5b and the ground conductor pattern 3. The adjustment capacitor conductor pattern 18c increases the capacitance of the capacitor C3 formed between the capacitor conductor pattern 5c and the ground conductor pattern 3.

[0069] In this way, the layered LC filter 110 has the adjustment capacitor conductor patterns 18a, 18b, and 18c formed, and the capacitances of the capacitors C1, C2, and C3 are increased to adjust the frequency characteristics (passband characteristics).

[0070] The adjustment capacitor conductor pattern 18a may be connected to the capacitor conductor pattern 5a instead of to the ground conductor pattern 3. The adjustment capacitor conductor pattern 18b may be connected to the capacitor conductor pattern 5b instead of to the ground conductor pattern 3. The adjustment capacitor conductor pattern 18c may be connected to the capacitor conductor pattern 5c instead of to the ground conductor pattern 3. In such cases, the capacitances of the capacitors C1, C2, and C3 can be increased and the frequency characteristics can be adjusted.

[0071] In the multilayer LC filter 110, the adjustment capacitor conductor patterns 18a, 18b, and 18c are formed in the same interlayer space as the jump coupling capacitor conductor pattern 4a inside the laminate 1. This enables the multilayer LC filter 110 to adjust the frequency characteristics without increasing the size of the laminate 1 in the height direction Z.

[0072] [Second Modification of the First Embodiment: Multilayer LC Filter 120] 6 shows a laminated LC filter 120 according to a second modified example of the first embodiment. Note that FIG. 6 is an exploded perspective view of the laminated LC filter 120.

[0073] The multilayer LC filter 120 according to the second modification has a part of the configuration of the above-mentioned multilayer LC filter 100 modified. Specifically, the linear line conductor patterns 7b, 7e in the configuration of the multilayer LC filter 100 are changed to a T-shape to form line conductor patterns 27b, 27e. Accordingly, in the multilayer LC filter 120, the position at which the via conductor 2j is formed is shifted toward the center of the laminate 1 in the width direction W.

[0074] As a result, in the laminated LC filter 120, the open via conductor of the second LC parallel resonator is closer to the open via conductor of the first LC parallel resonator and the open via conductor of the third LC parallel resonator than in the laminated LC filter 100. Therefore, the cross coupling is stronger. By adjusting the position of the open via conductor of the second LC parallel resonator, it is possible to adjust the cross coupling between the first LC parallel resonator and the second LC parallel resonator and the cross coupling between the second LC parallel resonator and the third LC parallel resonator.

[0075] [Third Modification of the First Embodiment: Multilayer LC Filter 130] 7 shows a laminated LC filter 130 according to a third modified example of the first embodiment. Note that FIG. 7 is an exploded perspective view of the laminated LC filter 130.

[0076] A laminated LC filter 130 according to the third modified example has a structure in which the above-described laminated LC filter 100 is partially modified.

[0077] In the multilayer LC filter 100, the line-like conductor patterns 7a and 7d of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 7b and 7e of the inductor L2 of the second LC parallel resonator LC2 are independent. The line-like conductor patterns 7a and 7d of the inductor L1 of the first LC parallel resonator LC1 are connected to the ground conductor pattern 3 by a via conductor 2e, and the line-like conductor patterns 7b and 7e of the inductor L2 of the second LC parallel resonator LC2 are connected to the ground conductor pattern 3 by a via conductor 2f. In the multilayer LC filter 130, this is changed so that the line-like conductor patterns 37a and 37d of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 37b and 37e of the inductor L2 of the second LC parallel resonator LC2 are connected to each other and then connected to the ground conductor pattern 3 by a single common via conductor 32a.

[0078] In the multilayer LC filter 100, the line-like conductor patterns 7b and 7e of the inductor L2 of the second LC parallel resonator LC2 and the line-like conductor patterns 7c and 7f of the inductor L3 of the third LC parallel resonator LC3 are independent of each other. The line-like conductor patterns 7b and 7e of the inductor L2 of the second LC parallel resonator LC2 are connected to the ground conductor pattern 3 by the via conductor 2h, and the line-like conductor patterns 7c and 7f of the inductor L3 of the third LC parallel resonator LC3 are connected to the ground conductor pattern 3 by the via conductor 2g. In the multilayer LC filter 130, this is changed so that the line-like conductor patterns 37b and 37e of the inductor L2 of the second LC parallel resonator LC2 and the line-like conductor patterns 37c and 37f of the inductor L3 of the third LC parallel resonator LC3 are connected to each other and then connected to the ground conductor pattern 3 by one common via conductor 32b.

[0079] In the multilayer LC filter 130, the line-like conductor patterns 37a, 37d of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 37b, 37e of the inductor L2 of the second LC parallel resonator LC2 are connected to the ground conductor pattern 3 by one common via conductor 32a, thereby strengthening the magnetic coupling between the first LC parallel resonator LC1 and the second LC parallel resonator LC2. In the multilayer LC filter 130, the line-like conductor patterns 37b, 37e of the inductor L2 of the second LC parallel resonator LC2 and the line-like conductor patterns 37c, 37f of the inductor L3 of the third LC parallel resonator LC3 are connected to the ground conductor pattern 3 by one common via conductor 32b, thereby strengthening the magnetic coupling between the second LC parallel resonator LC2 and the third LC parallel resonator LC3.

[0080] In this way, by commonizing the line-like conductor patterns of the inductors of two adjacent LC parallel resonators on the equivalent circuit and connecting them to the ground conductor pattern 3 by one common via conductor, it is possible to strengthen the magnetic coupling between the two LC parallel resonators.

[0081] [Second embodiment: laminated LC filter 200] Figures 8, 9, and 10 show a laminated LC filter 200 according to the second embodiment. Fig. 8 is an exploded perspective view of the laminated LC filter 200. Fig. 9 is an equivalent circuit diagram of the laminated LC filter 200. Fig. 10 is an explanatory diagram (perspective plan view) of the laminated LC filter 200.

[0082] The laminated LC filter 200 is a bandpass filter.

[0083] The laminated LC filter 200 includes a laminate 1 .

[0084] The laminate 1 is made up of dielectric layers 1a to 1i laminated in this order from the bottom up. The configuration of each of the dielectric layers 1a to 1g will be described below.

[0085] A first input / output terminal T1, a second input / output terminal T2, two ground terminals Tg, and two dummy terminals Td are formed on the lower main surface of the dielectric layer 1a.

[0086] Via conductors 2a, 2b, 2c, and 2d are formed penetrating between the upper and lower main surfaces of the dielectric layer 1a.

[0087] A ground conductor pattern 3 is formed on the upper main surface of the dielectric layer 1a. The ground conductor pattern 3 is connected to two ground terminals Tg by two via conductors 2b and 2c, respectively.

[0088] In addition to the above-mentioned via conductors 2a and 2d, new via conductors 2e, 2f, 2g, and 2h are formed penetrating between the upper and lower main surfaces of the dielectric layer 1b.

[0089] A jump coupling capacitor conductor pattern 4a is formed on the upper main surface of the dielectric layer 1a. Also, a coupling capacitor conductor pattern 6a is formed on the upper main surface of the dielectric layer 1a.

[0090] The above-mentioned via conductors 2a, 2d, 2e, 2f, 2g, and 2h are formed penetrating between the upper and lower main surfaces of the dielectric layer 1c.

[0091] Four capacitor conductor patterns 5a, 5b, 5c, and 5d are formed on the upper main surface of the dielectric layer 1c. The capacitor conductor pattern 5a is connected to a first input / output terminal T1 through a via conductor 2a. The capacitor conductor pattern 5d is connected to a second input / output terminal T2 through a via conductor 2d.

[0092] In addition to the above-mentioned via conductors 2e, 2f, 2g, and 2h, new via conductors 2i, 2j, 2k, 2l, 2m, and 2n are formed penetrating between the upper and lower main surfaces of the dielectric layer 1d.

[0093] Coupling capacitor conductor patterns 6b and 6c are formed on the upper main surface of the dielectric layer 1d, and jump coupling capacitor conductor patterns 4b, 4c, 4d and 4e are formed on the upper main surface of the dielectric layer 1d.

[0094] The coupling capacitor conductor pattern 6b is connected to the capacitor conductor pattern 5a by a via conductor 2m. The coupling capacitor conductor pattern 6c is connected to the capacitor conductor pattern 5d by a via conductor 2n.

[0095] In addition to the above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, 2k, and 2l, new via conductors 2o, 2p, 2q, and 2r are formed penetrating between the upper and lower main surfaces of the dielectric layer 1e.

[0096] A line-like conductor pattern 7a is formed on the upper main surface of the dielectric layer 1e. One end of the line-like conductor pattern 7a is connected to the jump coupling capacitor conductor pattern 4c by a via conductor 2p. The other end of the line-like conductor pattern 7a is connected to the jump coupling capacitor conductor pattern 4e by a via conductor 2r.

[0097] The above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, 2k, 2l, 2o, and 2q are formed penetrating between the upper and lower main surfaces of the dielectric layer 1f.

[0098] A line-like conductor pattern 7b is formed on the upper main surface of the dielectric layer 1f. One end of the line-like conductor pattern 7b is connected to the jump coupling capacitor conductor pattern 4b by a via conductor 2o. The other end of the line-like conductor pattern 7b is connected to the jump coupling capacitor conductor pattern 4d by a via conductor 2q.

[0099] The above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, 2k, and 2l are formed to penetrate between the upper and lower main surfaces of the dielectric layer 1g.

[0100] Line-like conductor patterns 7c, 7d, 7e, and 7f are formed on the upper main surface of the dielectric layer 1g. One end of the line-like conductor pattern 7c is connected to the ground conductor pattern 3 by a via conductor 2e. The other end of the line-like conductor pattern 7c is connected to the capacitor conductor pattern 5a by a via conductor 2i. One end of the line-like conductor pattern 7d is connected to the ground conductor pattern 3 by a via conductor 2f. The other end of the line-like conductor pattern 7d is connected to the capacitor conductor pattern 5b by a via conductor 2j. One end of the line-like conductor pattern 7e is connected to the ground conductor pattern 3 by a via conductor 2h. The other end of the line-like conductor pattern 7e is connected to the capacitor conductor pattern 5c by a via conductor 2k. One end of the line-like conductor pattern 7f is connected to the ground conductor pattern 3 by a via conductor 2g. The other end of the line-like conductor pattern 7f is connected to the capacitor conductor pattern 5d by a via conductor 2l.

[0101] The above-mentioned via conductors 2e, 2f, 2g, 2h, 2i, 2j, 2k, and 2l are formed so as to penetrate between the upper and lower main surfaces of the dielectric layer 1h.

[0102] Line-like conductor patterns 7g, 7h, 7i, and 7j are formed on the upper main surface of the dielectric layer 1g. One end of the line-like conductor pattern 7g is connected to the ground conductor pattern 3 by a via conductor 2e. The other end of the line-like conductor pattern 7g is connected to the capacitor conductor pattern 5a by a via conductor 2i. One end of the line-like conductor pattern 7h is connected to the ground conductor pattern 3 by a via conductor 2f. The other end of the line-like conductor pattern 7h is connected to the capacitor conductor pattern 5b by a via conductor 2j. One end of the line-like conductor pattern 7i is connected to the ground conductor pattern 3 by a via conductor 2h. The other end of the line-like conductor pattern 7i is connected to the capacitor conductor pattern 5c by a via conductor 2k. One end of the line-like conductor pattern 7j is connected to the ground conductor pattern 3 by a via conductor 2g. The other end of the line-like conductor pattern 7j is connected to the capacitor conductor pattern 5d by a via conductor 2l.

[0103] The dielectric layer 1h is a protective layer, and no via conductors or conductor patterns are formed thereon.

[0104] The layered LC filter 200 has an equivalent circuit shown in FIG.

[0105] The laminated LC filter 200 includes a first input / output terminal T1 and a second input / output terminal T2. A signal line SL is formed between the first input / output terminal T1 and the second input / output terminal T2.

[0106] In the layered LC filter 200, a capacitor C12, a capacitor C23, and a capacitor C34 are connected in this order to a signal line SL connecting the first input / output terminal T1 and the second input / output terminal T2. In the layered LC filter 200, a capacitor C14 is connected between a first LC parallel resonator LC1 and a fourth LC parallel resonator LC4, which will be described next. A capacitor C13 is connected between the first LC parallel resonator LC1 and the third LC parallel resonator LC3. A capacitor C14 is connected between the second LC parallel resonator LC2 and the fourth LC parallel resonator LC4.

[0107] The layered LC filter 100 includes first to fourth LC parallel resonators LC1, LC2, LC3, and LC4. The first LC parallel resonator LC1 is formed by connecting an inductor L1 and a capacitor C1 in parallel. The second LC parallel resonator LC2 is formed by connecting an inductor L2 and a capacitor C2 in parallel. The third LC parallel resonator LC3 is formed by connecting an inductor L3 and a capacitor C3 in parallel. The fourth LC parallel resonator LC4 is formed by connecting an inductor L4 and a capacitor C4 in parallel.

[0108] The first LC parallel resonator LC1 has one end connected to a portion of the signal line SL between the first input / output terminal T1 and the capacitor C12, and the other end connected to a ground terminal Tg. The second LC parallel resonator LC2 has one end connected to a portion of the signal line SL between the capacitor C12 and the capacitor C23, and the other end connected to the ground terminal Tg. The third LC parallel resonator LC3 has one end connected to a portion of the signal line SL between the capacitor C23 and the capacitor C34, and the other end connected to the ground terminal Tg. The fourth LC parallel resonator LC4 has one end connected to a portion of the signal line SL between the capacitor C34 and the second input / output terminal T2, and the other end connected to the ground terminal Tg.

[0109] Next, the main coupling relationships among the first to third LC parallel resonators LC1, LC2, and LC3 will be described.

[0110] The first LC parallel resonator LC1 and the second LC parallel resonator LC2 are magnetically coupled by the magnetic coupling between the inductor L1 and the inductor L2. The third LC parallel resonator LC3 and the fourth LC parallel resonator LC4 are magnetically coupled by the magnetic coupling between the inductor L3 and the inductor L4.

[0111] The first LC parallel resonator LC1 and the second LC parallel resonator LC2 are capacitively coupled by the capacitance of the capacitor C12. The second LC parallel resonator LC2 and the third LC parallel resonator LC3 are capacitively coupled by the capacitance of the capacitor C23. The third LC parallel resonator LC3 and the fourth LC parallel resonator LC4 are capacitively coupled by the capacitance of the capacitor C34.

[0112] The first LC parallel resonator LC1 and the fourth LC parallel resonator LC4 are cross-capacitively coupled by the capacitance of the capacitor C14. The first LC parallel resonator LC1 and the third LC parallel resonator LC3 are cross-capacitively coupled by the capacitance of the capacitor C13. The second LC parallel resonator LC1 and the fourth LC parallel resonator LC4 are cross-capacitively coupled by the capacitance of the capacitor C23.

[0113] Due to the above-described equivalent circuits and couplings, the layered LC filter 200 has a four-stage bandpass filter configured between the first input / output terminal T1 and the second input / output terminal T2.

[0114] Next, the relationship between the equivalent circuit of the laminated LC filter 200 and the structure will be described.

[0115] The capacitor C1 of the first LC parallel resonator LC1 is formed by the capacitance between the capacitor conductor pattern 5a and the ground conductor pattern 3. The capacitor conductor pattern 5a is connected to the first input / output terminal T1 through the via conductor 2a. The inductor L1 of the first LC parallel resonator LC1 is formed by a loop inductor that starts at the capacitor conductor pattern 5a, passes through the via conductor 2i, the line-like conductor patterns 7c and 7d, and the via conductor 2e, and ends at the ground conductor pattern 3.

[0116] The capacitor C2 of the second LC parallel resonator LC2 is formed by the capacitance between the capacitor conductor pattern 5b and the ground conductor pattern 3. The inductor L2 of the second LC parallel resonator LC2 is formed by a loop inductor that starts at the capacitor conductor pattern 5b, passes through the via conductor 2j, the line-like conductor patterns 7d and 7h, and the via conductor 2f, and ends at the ground conductor pattern 3.

[0117] The capacitor C3 of the third LC parallel resonator LC3 is formed by the capacitance between the capacitor conductor pattern 5c and the ground conductor pattern 3. The inductor L3 of the third LC parallel resonator LC3 is formed by a loop inductor that starts at the capacitor conductor pattern 5c, passes through the via conductor 2k, the line-like conductor patterns 7e and 7i, and the via conductor 2h, and ends at the ground conductor pattern 3.

[0118] The capacitor C4 of the fourth LC parallel resonator LC4 is formed by the capacitance between the capacitor conductor pattern 5d and the ground conductor pattern 3. The inductor L4 of the fourth LC parallel resonator LC4 is formed by a loop inductor that starts at the capacitor conductor pattern 5d, passes through the via conductor 2l, the line-like conductor patterns 7f and 7j, and the via conductor 2g, and ends at the ground conductor pattern 3. The capacitor conductor pattern 5d is connected to the second input / output terminal T2 by the via conductor 2d.

[0119] The capacitor C12 is formed by the capacitance between the coupling capacitor conductor pattern 6b and the capacitor conductor pattern 5b. The coupling capacitor conductor pattern 6b is connected to the capacitor conductor pattern 5a by a via conductor 2m.

[0120] The capacitor C23 is formed by the capacitance between the capacitor conductor pattern 5b and the coupling capacitor conductor pattern 6a, and the capacitance between the coupling capacitor conductor pattern 6a and the capacitor conductor pattern 5c, which are connected in series.

[0121] The capacitor C34 is formed by the capacitance between the capacitor conductor pattern 5b and the coupling capacitor conductor pattern 6c. The coupling capacitor conductor pattern 6c is connected to the capacitor conductor pattern 5d by a via conductor 2n.

[0122] The capacitor C14 is constituted by the capacitance between the capacitor conductor pattern 5a and the jump coupling capacitor conductor pattern 4a, which are connected in series, and the capacitance between the jump coupling capacitor conductor pattern 4a and the capacitor conductor pattern 5d.

[0123] The capacitor C13 is composed of the capacitance between the capacitor conductor pattern 5a and the jump coupling capacitor conductor pattern 4b, which are connected in series, and the capacitance between the jump coupling capacitor conductor pattern 4d and the capacitor conductor pattern 5c. The jump coupling capacitor conductor pattern 4b and the jump coupling capacitor conductor pattern 4d are connected via a via conductor 2o, a line-like conductor pattern 7b, and a via conductor 2q.

[0124] The capacitor C24 is composed of the capacitance between the capacitor conductor pattern 5b and the jump coupling capacitor conductor pattern 4c, which are connected in series, and the capacitance between the jump coupling capacitor conductor pattern 4e and the capacitor conductor pattern 5d. The jump coupling capacitor conductor pattern 4c and the jump coupling capacitor conductor pattern 4e are connected via a via conductor 2p, a line-like conductor pattern 7a, and a via conductor 2r.

[0125] Fig. 10 shows the open via conductors and short-circuiting via conductors of the inductors L1 to L4. As can be seen from Fig. 10, in the laminated LC filter 200, in all of the inductors L1, L2, L3, and L4 of the first to fourth LC parallel resonators LC1, LC2, LC3, and LC4, the open via conductors are arranged closer to the center in the length direction L, and the short-circuiting via conductors are arranged closer to the outside in the length direction L. As a result, all of the open via conductors are arranged closer to the center of the laminate 1.

[0126] In the multilayer LC filter 200, all open via conductors are disposed toward the center of the laminate 1, which facilitates cross-coupling (cross-capacitive coupling) between LC parallel resonators that are separated from each other on the equivalent circuit. Specifically, it is possible to easily form the cross-capacitive coupling of the capacitors C14, C13, and C24.

[0127] Fig. 11 shows the frequency characteristics of the laminated LC filter 200. As can be seen from Fig. 11, three stages of attenuation poles can be easily formed on the low-frequency side by arranging the open via conductors of each LC parallel resonator toward the center of the laminate 1. Although three stages of attenuation poles are formed on the low-frequency side in Fig. 11, it is also possible to form three stages of attenuation poles on the high-frequency side by adjusting capacitive coupling and magnetic coupling.

[0128] [First Modification of the Second Embodiment: Multilayer LC Filter 210] 12 shows a laminated LC filter 210 according to a first modified example of the second embodiment. Note that FIG. 12 is an exploded perspective view of the laminated LC filter 210.

[0129] The multilayer LC filter 210 according to the first modification adds a new configuration to the multilayer LC filter 200 described above. Specifically, new via conductors 42a, 42b, 42c, and 42d are formed penetrating between the upper and lower main surfaces of the dielectric layer 1b. Four adjustment capacitor conductor patterns 48a, 48b, 48c, and 48d are formed on the upper main surface of the dielectric layer 1b. The adjustment capacitor conductor pattern 48a is connected to the ground conductor pattern 3 by the via conductor 42a. The adjustment capacitor conductor pattern 48b is connected to the ground conductor pattern 3 by the via conductor 42b. The adjustment capacitor conductor pattern 48c is connected to the ground conductor pattern 3 by the via conductor 42c. The adjustment capacitor conductor pattern 48d is connected to the ground conductor pattern 3 by the via conductor 42d.

[0130] The adjustment capacitor conductor pattern 48a increases the capacitance of the capacitor C1 formed between the capacitor conductor pattern 5a and the ground conductor pattern 3. The adjustment capacitor conductor pattern 48b increases the capacitance of the capacitor C2 formed between the capacitor conductor pattern 5b and the ground conductor pattern 3. The adjustment capacitor conductor pattern 48c increases the capacitance of the capacitor C3 formed between the capacitor conductor pattern 5c and the ground conductor pattern 3. The adjustment capacitor conductor pattern 48d increases the capacitance of the capacitor C4 formed between the capacitor conductor pattern 5c and the ground conductor pattern 3.

[0131] In this way, the layered LC filter 210 has the adjustment capacitor conductor patterns 48a, 48b, 48c, and 48d formed, and the capacitances of the capacitors C1, C2, C3, and C4 are increased to adjust the frequency characteristics (passband characteristics).

[0132] [Second Modification of the Second Embodiment: Multilayer LC Filter 220] 13 shows a laminated LC filter 220 according to a second modified example of the second embodiment. Note that FIG. 13 is an exploded perspective view of the laminated LC filter 220.

[0133] A layered LC filter 220 according to the third modified example has a structure in which the above-described layered LC filter 200 has been partially modified.

[0134] In the multilayer LC filter 200, the line-like conductor patterns 7c and 7g of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 7d and 7h of the inductor L2 of the second LC parallel resonator LC2 are independent. The line-like conductor patterns 7c and 7g of the inductor L1 of the first LC parallel resonator LC1 are connected to the ground conductor pattern 3 by the via conductor 2e, and the line-like conductor patterns 7d and 7h of the inductor L2 of the second LC parallel resonator LC2 are connected to the ground conductor pattern 3 by the via conductor 2f. In the multilayer LC filter 220, this is changed so that the line-like conductor patterns 57c and 57g of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 57d and 57h of the inductor L2 of the second LC parallel resonator LC2 are connected to each other and then connected to the ground conductor pattern 3 by one common via conductor 52a.

[0135] In the multilayer LC filter 200, the line-like conductor patterns 7e and 7i of the inductor L3 of the third LC parallel resonator LC3 and the line-like conductor patterns 7f and 7j of the inductor L3 of the fourth LC parallel resonator LC3 are independent of each other. The line-like conductor patterns 7e and 7i of the inductor L3 of the third LC parallel resonator LC3 are connected to the ground conductor pattern 3 by the via conductor 2h, and the line-like conductor patterns 7f and 7j of the inductor L4 of the fourth LC parallel resonator LC4 are connected to the ground conductor pattern 3 by the via conductor 2g. In the multilayer LC filter 220, this is changed so that the line-like conductor patterns 57e and 57i of the inductor L3 of the third LC parallel resonator LC3 and the line-like conductor patterns 57f and 57j of the inductor L4 of the fourth LC parallel resonator LC4 are connected to each other and then connected to the ground conductor pattern 3 by one common via conductor 52b.

[0136] In the multilayer LC filter 220, the line-like conductor patterns 57c and 57g of the inductor L1 of the first LC parallel resonator LC1 and the line-like conductor patterns 57d and 57h of the inductor L2 of the second LC parallel resonator LC2 are connected to the ground conductor pattern 3 by one common via conductor 52a, thereby strengthening the magnetic coupling between the first LC parallel resonator LC1 and the second LC parallel resonator LC2. In the multilayer LC filter 220, the line-like conductor patterns 57e and 57i of the inductor L3 of the third LC parallel resonator LC3 and the line-like conductor patterns 57f and 57j of the inductor L4 of the fourth LC parallel resonator LC4 are connected to the ground conductor pattern 3 by one common via conductor 52b, thereby strengthening the magnetic coupling between the third LC parallel resonator LC3 and the fourth LC parallel resonator LC4.

[0137] [Third Modification of the Second Embodiment: Multilayer LC Filter 230] 14 shows a laminated LC filter 230 according to a third modified example of the second embodiment. FIG. 14 is an exploded perspective view of the laminated LC filter 230.

[0138] A layered LC filter 230 according to the third modified example has a structure in which the above-described layered LC filter 200 has been partially modified.

[0139] Specifically, in the laminated LC filter 200, to form the jump coupling capacitor C13, the jump coupling capacitor conductor pattern 4b is formed opposite the capacitor conductor pattern 5a, the jump coupling capacitor conductor pattern 4d is formed opposite the capacitor conductor pattern 5c, and the jump coupling capacitor conductor pattern 4b and the jump coupling capacitor conductor pattern 4d are connected by a path passing through the via conductor 2o, the line-like conductor pattern 7b, and the via conductor 2q. Also, to form the jump coupling capacitor C24, the jump coupling capacitor conductor pattern 4c is formed opposite the capacitor conductor pattern 5b, the jump coupling capacitor conductor pattern 4e is formed opposite the capacitor conductor pattern 5d, and the jump coupling capacitor conductor pattern 4c and the jump coupling capacitor conductor pattern 4e are connected by a path passing through the via conductor 2p, the line-like conductor pattern 7a, and the via conductor 2r.

[0140] In the laminated LC filter 230, the jump coupling capacitor conductor patterns 4b, 4c, 4d, and 4e, the line-like conductor patterns 7a and 7b, and the via conductors 2o, 2p, 2q, and 2r are deleted, and instead, one rectangular jump coupling capacitor conductor pattern 64a is provided opposite each of the capacitor conductor patterns 5a, 5b, 5c, and 5d.

[0141] In the laminated LC filter 230, the jump coupling capacitor C13 is constituted by the capacitance between the capacitor conductor pattern 5a and the jump coupling capacitor conductor pattern 64a, which are connected in series, and the capacitance between the jump coupling capacitor conductor pattern 64a and the capacitor conductor pattern 5c. The jump coupling capacitor C24 is constituted by the capacitance between the capacitor conductor pattern 5b and the jump coupling capacitor conductor pattern 64a, which are connected in series, and the capacitance between the jump coupling capacitor conductor pattern 64a and the capacitor conductor pattern 5d.

[0142] Thus, the cross-coupling capacitor conductor patterns can take a variety of forms.

[0143] [Third embodiment: laminated LC filter 300] 15(A) and (B) show a laminated LC filter 300 according to the third embodiment. Fig. 15(A) is an explanatory diagram (perspective plan view) of the laminated LC filter 300. Fig. 15(B) is an equivalent circuit diagram of the laminated LC filter 300.

[0144] The laminated LC filter 300 is a five-stage bandpass filter in which five LC parallel resonators LC1 to LC5 are formed in a laminate 1.

[0145] Fig. 15(A) shows the open via conductors and short-circuiting via conductors of the inductors L1 to L5 of the resonators LC1 to LC5. As can be seen from Fig. 15(A), in the multilayer LC filter 300, in all of the inductors L1 to L5 of the LC parallel resonators LC1 to LC5, the open via conductors are arranged closer to the center in the length direction L, and the short-circuiting via conductors are arranged closer to the outside in the length direction L. As a result, all of the open via conductors are arranged closer to the center of the laminate 1.

[0146] 15(B), the multilayer LC filter 300 has three jump coupling capacitors C14, C15, and C25 formed in the laminate 1. In the multilayer LC filter 300, all of the open via conductors of the inductors L1 to L5 are disposed toward the center of the laminate 1, so that the jump coupling capacitors C14, C15, and C25 can be easily formed.

[0147] [Fourth embodiment: laminated LC filter 400] 16(A) and (B) show a laminated LC filter 400 according to the fourth embodiment. Fig. 16(A) is an explanatory diagram (perspective plan view) of the laminated LC filter 400. Fig. 16(B) is an equivalent circuit diagram of the laminated LC filter 400.

[0148] The laminated LC filter 400 is a six-stage bandpass filter in which six LC parallel resonators LC1 to LC6 are formed in a laminate 1.

[0149] Fig. 16(A) shows the open via conductors and short-circuiting via conductors of the inductors L1 to L6 of the resonators LC1 to LC6. As can be seen from Fig. 16(A), in the multilayer LC filter 400, in all of the inductors L1 to L6 of the LC parallel resonators LC1 to LC6, the open via conductors are arranged closer to the center in the length direction L, and the short-circuiting via conductors are arranged closer to the outside in the length direction L. As a result, all of the open via conductors are arranged closer to the center of the laminate 1.

[0150] 16(B), the multilayer LC filter 400 has five jump coupling capacitors C15, C16, C24, C26, and C35 formed in the laminate 1. In the multilayer LC filter 400, all of the open via conductors of the inductors L1 to L6 are disposed toward the center of the laminate 1, so that the jump coupling capacitors C15, C16, C24, C26, and C35 can be easily formed.

[0151] [Fifth embodiment: laminated LC filter 500] 17, 18(A) and 18(B) show a laminated LC filter 500 according to the fifth embodiment. FIG. 17 is an exploded perspective view of the laminated LC filter 500. FIG. 18(A) is an exploded perspective view of a main part of the laminated LC filter 500. FIG. 18(A) shows the laminated LC filter 500 with only the configuration necessary for explanation left and omitting dielectric layers 1a-1i and the like. FIG. 18(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 500 showing the positional relationship between a shield conductor pattern 58 (described later) and line-like conductor patterns 7c-7j.

[0152] The laminated LC filter 500 according to the fifth embodiment adds a new configuration to the laminated LC filter 200 according to the second embodiment shown in Fig. 8. Specifically, the laminated LC filter 500 adds a dielectric layer 51a, a shielding conductor pattern 58, and shielding via conductors 62a and 62b to the laminated LC filter 200.

[0153] In the laminated LC filter 500, a new dielectric layer 51a is added between the dielectric layer 1h and the dielectric layer 1i of the laminate 1.

[0154] A rectangular shielding conductor pattern 58 is formed on the upper main surface of the dielectric layer 51a. However, the shape of the shielding conductor pattern 58 is arbitrary and is not limited to a rectangle.

[0155] Shielding via conductors 62a, 62b are formed penetrating the dielectric layers 1b-1h and the dielectric layer 51a. The shielding conductor pattern 58 is directly connected to the grounding conductor pattern 3 by the shielding via conductors 62a, 62b. Note that, although the number of shielding via conductors is two in the present embodiment, the number of shielding via conductors is arbitrary and may be one, or may be three or more.

[0156] As shown in FIG. 18(B), in the laminated LC filter 500, when the laminate 1 is seen through in the height direction, the shielding conductor pattern 58 covers the line-like conductor patterns 7c to 7j.

[0157] As a result, the multilayer LC filter 500 suppresses fluctuations in characteristics even when metal is in proximity. In other words, if the shield conductor pattern 58 is not provided, for example, when metal is in proximity above the laminate 1, the magnetic field generated by the inductors of the LC parallel resonators of the multilayer LC filter is affected, causing fluctuations in the strength of the magnetic coupling between the two LC parallel resonators. This causes fluctuations in the overall characteristics of the multilayer LC filter. Therefore, by providing the shield conductor pattern 58, the multilayer LC filter 500 reduces fluctuations in characteristics even when metal is in proximity around the laminate 1.

[0158] More specifically, the multilayer LC filter 500 uses the shield conductor pattern 58 to prevent the magnetic field of the inductor of each LC parallel resonator from leaking to the periphery of the laminate 1. Therefore, the multilayer LC filter 500 exhibits small fluctuations in characteristics even when metal is placed close to the periphery of the laminate 1. This effect will be described in Experiment 1 below.

[0159] The equivalent circuit of the layered LC filter 500 is the same as the equivalent circuit of the layered LC filter 200 shown in FIG.

[0160] [First Modification of Fifth Embodiment: Multilayer LC Filter 510] 19(A) and (B) show a laminated LC filter 510 according to a first modified example of the fifth embodiment. Fig. 19(A) is an exploded perspective view of a main part of the laminated LC filter 510. Fig. 19(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 510 showing the positional relationship between the shield conductor pattern 58 and the line-like conductor patterns 77c to 77j.

[0161] The multilayer LC filter 510 according to the first modification is an improvement over the multilayer LC filter 500 according to the fifth embodiment. That is, compared to the multilayer LC filter 500, the multilayer LC filter 510 is more suppressed in terms of fluctuations in characteristics when a metal is placed in close proximity to the periphery of the laminate 1.

[0162] 18(B), when seen through in the planar direction, the multilayer LC filter 500 has room for improvement because the gap G between the line-like conductor patterns 7c-7j and the shield conductor pattern 58 is small and the magnetic field generated by the line-like conductor patterns 7c-7j still leaks to the periphery of the laminate 1. Thus, the multilayer LC filter 510 moves the line-like conductor patterns toward the center of the laminate 1 to further suppress leakage of the magnetic field to the periphery of the laminate 1 and further suppress fluctuations in characteristics.

[0163] 19(A) and 19(B), when the laminate 1 is seen through in the height direction, the laminate LC filter 510 has the open via conductors 2i, 2j, 2k, and 2l each shifted to the vicinity of the center of the laminate 1. Meanwhile, the short-circuiting via conductors 2e, 2f, 2g, and 2h each disposed near the periphery of the laminate 1. As a result, in the laminate LC filter 510, the line-like conductor patterns 77c to 77j are each disposed radially from the vicinity of the center of the laminate 1 toward the vicinity of the periphery.

[0164] In the laminated LC filter 510, the short-circuiting via conductors 2e to 2h are not moved to the center of the laminate 1 because it is necessary to secure a distance between them and the shielding via conductors 62a, 62b. That is, if the short-circuiting via conductors 2e to 2h are arranged close to the shielding via conductors 62a, 62b, which are at ground potential, a stray capacitance is generated between them, which may cause fluctuations in the characteristics of each LC parallel resonator, which is not preferable.

[0165] The laminated LC filter 510, in which the line-like conductor patterns 77c to 77j are arranged radially from near the center of the laminate 1 toward near the periphery, further suppresses leakage of the magnetic field to the outside of the laminate 1 compared to the laminated LC filter 500, and is less susceptible to fluctuations in characteristics even when a metal is brought into proximity to the laminate 1.

[0166] [Experiment 1] In order to confirm that providing a shielding conductor pattern 58 is effective in suppressing the fluctuation in characteristics when metal is in close proximity, Experiment 1 shown in Figures 20(A-1), (A-2), (B-1), and (B-2) was conducted.

[0167] First, a multilayer LC filter 510 was prepared. A multilayer LC filter 520 was also prepared, in which the shielding conductor pattern 58 and the shielding via conductors 62a and 62b were omitted from the multilayer LC filter 510.

[0168] 20(A-1), the laminated LC filter 510 was mounted on a substrate, and three different characteristics were measured: when there was no metal (metal plate) adjacent to the upper part of the laminated LC filter 510, when there was a metal adjacent to a distant position F, and when there was a metal adjacent to a nearby position N. The measurement results of the characteristics are shown in FIG.

[0169] 20(B-1), the laminated LC filter 520 was mounted on a substrate, and three different characteristics were measured: when there was no metal (metal plate) adjacent to the upper part of the laminated LC filter 520, when there was a metal adjacent to a distant position F, and when there was a metal adjacent to a nearby position N. The measurement results of the characteristics are shown in FIG. 20(B-2).

[0170] 20(A-1) and 20(B-1), the characteristics of the laminated LC filter 520, which does not include the shield conductor pattern 58, vary greatly when metal is brought into close proximity. In contrast, the characteristics of the laminated LC filter 510, which includes the shield conductor pattern 58, vary only slightly even when metal is brought into close proximity. From the above, it has been confirmed that providing the shield conductor pattern 58 is effective in suppressing the variation in characteristics when metal is brought into close proximity.

[0171] [Second Modification of Fifth Embodiment: Multilayer LC Filter 530] [Third Modification of Fifth Embodiment: Multilayer LC Filter 540] Fig. 21(A) shows a laminated LC filter 530 which is a second modified example of the fifth embodiment. Fig. 21(B) shows a laminated LC filter 540 which is a third modified example of the fifth embodiment. Fig. 21(A) is a perspective view of a main portion of the laminated LC filter 530. Fig. 21(B) is a perspective view of a main portion of the laminated LC filter 540.

[0172] The laminated LC filters 530 and 540 are obtained by modifying the configuration of the laminated LC filter 510 of the first modified example of the fifth embodiment shown in FIGS. 19(A) and 19(B), respectively.

[0173] Specifically, in the multilayer LC filter 510, the shield conductor pattern 58 is directly connected to the ground conductor pattern 3 by the shield via conductors 62a and 62b. In the multilayer LC filter 530 which is the second modified example, the shield conductor pattern 58 is connected to the short-circuiting via 2f side of the line-like conductor pattern 77h by the shield via conductor 62f, and is connected to the short-circuiting via 2h side of the line-like conductor pattern 77i by the shield via conductor 62h. In other words, in the multilayer LC filter 530, the shield conductor pattern 58 is not directly connected to the ground conductor pattern 3 by the shield via conductor, but is indirectly connected to the ground conductor pattern 3 via the shield via conductors 62f and 62h and the short-circuiting via conductors 2f and 2h.

[0174] The laminated LC filter 540, which is the third modified example, further adds a configuration to the laminated LC filter 530, which is the second modified example. That is, the shield conductor pattern 58 is further connected to the short-circuiting via 2e side of the line-like conductor pattern 77g by a shielding via conductor 62e, and is connected to the short-circuiting via 2g side of the line-like conductor pattern 77j by a shielding via conductor 62g. That is, in the laminated LC filter 540, the shield conductor pattern 58 is not directly connected to the ground conductor pattern 3 by the shielding via conductor, but is indirectly connected to the ground conductor pattern 3 via the shielding via conductors 62e, 62f, 62g, and 62h and the short-circuiting via conductors 2e, 2f, 2g, and 2h.

[0175] In this way, the shield conductor pattern 58 may be indirectly connected to the ground conductor pattern 3 via another component, rather than being directly connected to the ground conductor pattern 3 by the shielding via conductor. This method is effective when the internal volume of the laminate 1 is limited and the shield conductor pattern 58 cannot be directly connected to the ground conductor pattern 3 by the shielding via conductor.

[0176] However, if the shield conductor pattern 58 is indirectly connected to the ground conductor pattern 3 via other components rather than directly connected to the ground conductor pattern 3 via a shielding via conductor, the characteristics may vary. For example, in the multilayer LC filter 530, the inductor L2 of the LC parallel resonator LC2, which is composed of the short-circuiting via conductor 2e, the line-like conductor patterns 77d and 77h, and the open via conductor 2j, and the inductor L3 of the LC parallel resonator LC3, which is composed of the short-circuiting via conductor 2h, the line-like conductor patterns 77e and 77i, and the open via conductor 2k, are connected to each other via the shielding via conductor 62f, the shielding conductor pattern 58, and the shielding via conductor 62h, and the magnetic coupling between the inductor L2 and the inductor L3 may be strengthened, resulting in a variation in the characteristics. Therefore, if possible, it is preferable to directly connect the shield conductor pattern 58 and the ground conductor pattern 3 via a shielding via conductor.

[0177] [Sixth embodiment: laminated LC filter 600] 22, 23(A) and 23(B) show a laminated LC filter 600 according to a sixth embodiment. Fig. 22 is an exploded perspective view of a main portion of the laminated LC filter 600. Fig. 23(A) is also an exploded perspective view of a main portion of the laminated LC filter 600. Fig. 23(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 600 showing the positional relationship between the shield conductor pattern 58 and the line-like conductor patterns 87c to 87j.

[0178] The layered LC filter 600 according to the sixth embodiment is a further improvement of the layered LC filter 500 according to the fifth embodiment shown in FIGS.

[0179] In the laminated LC filter 500 according to the fifth embodiment, the line-like conductor pattern 7c constituting the inductor L1 of the LC parallel resonator LC1, the line-like conductor pattern 7d constituting the inductor L2 of the LC parallel resonator LC2, the line-like conductor pattern 7e constituting the inductor L3 of the LC parallel resonator LC3, and the line-like conductor pattern 7f constituting the inductor L4 of the LC parallel resonator LC4 are all formed between the same layers of the laminate 1, and the line-like conductor pattern 7g constituting the inductor L1 of the LC parallel resonator LC1, the line-like conductor pattern 7h constituting the inductor L2 of the LC parallel resonator LC2, the line-like conductor pattern 7i constituting the inductor L3 of the LC parallel resonator LC3, and the line-like conductor pattern 7j constituting the inductor L4 of the LC parallel resonator LC4 are all formed between the same layers of the laminate 1. Therefore, with the laminated LC filter 500, when two laminated LC filters 500 are mounted close to each other on a substrate or the like, there is a problem in that unnecessary magnetic coupling may occur between the laminated LC filters 500, which may cause fluctuations in the characteristics of both the laminated LC filters 500.

[0180] In view of this, in the laminated LC filter 600 according to the sixth embodiment, as shown in Fig. 22, two dielectric layers 61a and 61b are added between the dielectric layer 1h and the dielectric layer 51a. Then, a line-like conductor pattern 87c constituting the inductor L1 of the LC parallel resonator LC1 and a line-like conductor pattern 87f constituting the inductor L4 of the LC parallel resonator LC4 are formed on the existing dielectric layer 1g. Also, a line-like conductor pattern 87g constituting the inductor L1 of the LC parallel resonator LC1 and a line-like conductor pattern 87j constituting the inductor L4 of the LC parallel resonator LC4 are formed on the existing dielectric layer 1h. Then, a line-like conductor pattern 87d constituting the inductor L2 of the LC parallel resonator LC2 and a line-like conductor pattern 87e constituting the inductor L3 of the LC parallel resonator LC3 are formed on the added dielectric layer 61a. Furthermore, on the added dielectric layer 61b, a line-like conductor pattern 87h constituting the inductor L2 of the LC parallel resonator LC2, and a line-like conductor pattern 87i constituting the inductor L3 of the LC parallel resonator LC3 are formed.

[0181] As a result, if two laminated LC filters 600 are mounted in the same direction on a substrate or the like, even if they are mounted close to each other, unwanted magnetic coupling between the laminated LC filters 600 is suppressed, and fluctuations in characteristics are suppressed. This effect will be described later in Experiment 2.

[0182] [First Modification of the Sixth Embodiment: Multilayer LC Filter 610] 24(A) and (B) show a laminated LC filter 610 according to a first modified example of the sixth embodiment. Fig. 24(A) is an exploded perspective view of a main part of the laminated LC filter 610. Fig. 24(B) is an explanatory diagram (perspective plan view) of the laminated LC filter 610 showing the positional relationship between the shield conductor pattern 58 and the line-like conductor patterns 97c to 97j.

[0183] The multilayer LC filter 610 according to the first modified example is an improvement over the multilayer LC filter 600 according to the sixth embodiment. That is, compared to the multilayer LC filter 600, the multilayer LC filter 610 further suppresses the fluctuation in characteristics when a metal is placed in the vicinity of the laminate 1.

[0184] The layered LC filter 610 aims to achieve the same effects as the layered LC filter 510 according to the first modified example of the fifth embodiment shown in FIGS.

[0185] 24(A) and 24(B), when the laminate 1 is seen through in the height direction, the laminate LC filter 610 has the open via conductors 2i, 2j, 2k, and 2l each shifted to the vicinity of the center of the laminate 1. Meanwhile, the short-circuiting via conductors 2e, 2f, 2g, and 2h each disposed near the periphery of the laminate 1. As a result, in the laminate LC filter 610, the line-like conductor patterns 97c to 97j are each disposed radially from the vicinity of the center of the laminate 1 toward the vicinity of the periphery.

[0186] Compared to the laminated LC filter 600, the laminated LC filter 610 suppresses leakage of a magnetic field to the outside of the laminate 1, and the characteristics are less likely to vary even if a metal is brought into close proximity to the laminate 1. The reason for this has been described in the explanation of the laminated LC filter 510 of the first modified example of the fifth embodiment, so a description thereof will be omitted here.

[0187] [Experiment 2] In order to confirm the effectiveness of the sixth embodiment, Experiment 2 shown in FIGS. 25(A-1), (A-2), (B-1), and (B-2) was carried out.

[0188] First, four laminated LC filters 610 of Modification 1 were prepared. Then, the characteristics of each of the laminated LC filters 610 alone were measured.

[0189] Next, as shown in Fig. 25(A-1), the two laminated LC filters 610 were mounted on the substrate with an interval of 100 μm between them, aligned in the same direction, and mounted on the substrate. The characteristics of the laminated LC filters 610 at this time are shown in Fig. 25(A-2).

[0190] Furthermore, as shown in Fig. 25(B-1), two laminated LC filters 610 were mounted on a substrate with a gap of 100 μm between them, with their orientations reversed. The characteristics of the laminated LC filters 610 at this time are shown in Fig. 25(B-2).

[0191] 25(B-1) and 25(B-2), the variation in characteristics is smaller when two laminated LC filters 610 are mounted in close proximity to each other in an aligned manner than when they are mounted in opposite directions. This is believed to be due to the effect of suppressing the occurrence of unnecessary magnetic coupling between the two laminated LC filters 610 by forming the line-like conductor patterns of the different LC parallel resonators on different layers of the laminate 1.

[0192] As in the laminated LC filters 600 and 610 of the sixth embodiment, the line-like conductor patterns of different LC parallel resonators are formed on different layers of the laminate 1, and the two laminated LC filters are mounted in an aligned manner with the same direction, thereby making it possible to suppress variation in characteristics even when the two laminated LC filters are mounted in close proximity.

[0193] The first to sixth embodiments have been described above. However, the present invention is not limited to the above-described contents, and various modifications can be made in accordance with the spirit of the invention.

[0194] For example, in the above embodiment, the open via conductors were positioned toward the center of the laminate in the length direction, and the short-circuit via conductors were positioned toward the outside of the laminate, but instead, the open via conductors may be positioned toward the center of the laminate in both the length direction and the width direction, and the short-circuit via conductors may be positioned toward the outside of the laminate.

[0195] A laminated LC filter according to one embodiment of the present invention is as described in the section "Means for Solving the Problems."

[0196] In the multilayer LC filter, it is also preferable to form a jump-coupling capacitor conductor pattern that capacitively jump-couples at least one LC parallel resonator and at least one other LC parallel resonator that is spaced apart on the equivalent circuit. In this case, the multilayer LC filter can be adjusted to have desired frequency characteristics by the jump-coupling.

[0197] It is also preferable that in at least one LC parallel resonator, an adjustment capacitor conductor pattern for adjusting the capacitance of the capacitor is formed between the dielectric layers of the capacitor conductor pattern and the ground conductor pattern that constitute the capacitor of the LC parallel resonator, and the adjustment capacitor conductor pattern is connected to either the capacitor conductor pattern or the ground conductor pattern by a via conductor. In this case, the capacitance of the capacitor of the LC parallel resonator can be easily adjusted, and the laminated LC filter can be adjusted to have desired frequency characteristics.

[0198] It is also preferable to form a jump coupling capacitor conductor pattern between the same dielectric layers as the dielectric layers on which the adjustment capacitor conductor pattern is formed, for capacitively jump-coupling at least one LC parallel resonator and at least one other LC parallel resonator located apart on the equivalent circuit. In this case, the jump coupling capacitor conductor pattern can be formed without increasing the height of the laminate 1.

[0199] It is also preferable that the short-circuiting via conductor of at least one LC parallel resonator is connected to the short-circuiting via conductor of at least one other LC parallel resonator, and that the connection point is connected to the ground conductor pattern through a common short-circuiting via conductor, which can strengthen the magnetic coupling between the two LC parallel resonators and adjust the multilayer LC filter to have desired frequency characteristics.

[0200] It is also preferable that the laminate has a mounting side principal surface and a non-mounting side principal surface, a shielding conductor pattern is formed between the first line-like conductor pattern, the second line-like conductor pattern, and the third line-like conductor pattern and the non-mounting side principal surface of the laminate, and the shielding conductor pattern layer is connected to the ground conductor pattern through a shielding via conductor. In this case, even if a metal is close to the periphery of the laminate, the fluctuation of characteristics is suppressed.

[0201] In this case, it is also preferable that the shielding conductor pattern is directly connected to the ground conductor pattern through a shielding via conductor, which can reduce the variation in the characteristics of the multilayer LC filter caused by the provision of the shielding conductor pattern.

[0202] It is also preferable that, when the laminate is seen through in the height direction, the first open via conductor, the second open via conductor, and the third open via conductor are each arranged near the center of the laminate, the first short-circuiting via conductor, the second short-circuiting via conductor, and the third short-circuiting via conductor are each arranged near the periphery of the laminate, and the first line-like conductor pattern, the second line-like conductor pattern, and the third line-like conductor pattern are each arranged radially from the center to the periphery. In this case, even if a metal is close to the laminate, the characteristics are less likely to fluctuate.

[0203] It is also preferable that the multiple LC parallel resonators further include a fourth LC parallel resonator, the fourth LC parallel resonator including a fourth line-like conductor pattern, a fourth capacitor conductor pattern, a fourth open via conductor connecting the fourth line-like conductor pattern and the fourth capacitor conductor pattern, and a fourth short-circuiting via conductor connecting the fourth line-like conductor pattern and the ground conductor pattern, and that when the laminate is seen through in the height direction, the first open via conductor, the second open via conductor, the third open via conductor and the fourth open via conductor are each arranged in the vicinity of a center of the laminate, the first short-circuiting via conductor, the second short-circuiting via conductor, the third short-circuiting via conductor and the fourth short-circuiting via conductor are each arranged in the vicinity of a periphery of the laminate, and the first line-like conductor pattern, the second line-like conductor pattern, the third line-like conductor pattern and the fourth line-like conductor pattern are each arranged radially from the vicinity of the center to the vicinity of the periphery. In this case as well, even if a metal is placed in close proximity to the laminate, the characteristics are less likely to fluctuate.

[0204] It is also preferable that the first line-like conductor pattern and the second line-like conductor pattern are disposed between different layers of the laminate. In this case, if the two multilayer LC filters are mounted in the same direction and aligned on a substrate or the like, even if the two filters are mounted close to each other, unwanted magnetic coupling between the multilayer LC filters is suppressed, and fluctuations in characteristics are suppressed.

[0205] It is also preferable that the multiple LC parallel resonators further include a fourth LC parallel resonator including a fourth line-like conductor pattern, a fourth capacitor conductor pattern, a fourth open via conductor connecting the fourth line-like conductor pattern and the fourth capacitor conductor pattern, and a fourth short-circuiting via conductor connecting the fourth line-like conductor pattern and the ground conductor pattern, wherein the first line-like conductor pattern and the fourth line-like conductor pattern are arranged between the same layers of the laminate, the second line-like conductor pattern and the third line-like conductor pattern are arranged between the same layers of the laminate, and the first line-like conductor pattern and the fourth line-like conductor pattern, and the second line-like conductor pattern and the third line-like conductor pattern are arranged between different layers of the laminate. In this case, too, if the two multilayer LC filters are mounted in the same direction and aligned on a substrate or the like, even if they are mounted in close proximity to each other, unwanted magnetic coupling between the multilayer LC filters is suppressed, and fluctuations in characteristics are suppressed. [Explanation of symbols]

[0206] 1. Laminate 1a to 1i, 51a, 61a, 61b... Dielectric layers 2a~2r...Via conductor 3. Ground conductor pattern 4a to 4e: Capacitor conductor patterns for jump coupling 5a to 5d Capacitor conductor patterns 6a to 6c: Coupling capacitor conductor patterns 7a~7j, 77a~77j, 87a~87j, 97a~97j... Line-shaped conductor pattern 58 Shield conductor pattern 62a, 62b, 62e, 62f, 62g, 62h... Shielding via conductor

Claims

1. A laminated LC filter that transmits a signal from an input terminal to an output terminal, a laminate in which a plurality of dielectric layers are laminated; a plurality of LC parallel resonators disposed on the laminate and electromagnetically coupled to each other; The laminate comprises: a first line-like conductor pattern, a second line-like conductor pattern, and a third line-like conductor pattern formed between the dielectric layers; a first capacitor conductor pattern, a second capacitor conductor pattern, and a third capacitor conductor pattern formed between the dielectric layers; at least one ground conductor pattern formed between the dielectric layers; the plurality of LC parallel resonators include a first LC parallel resonator, a second LC parallel resonator, and a third LC parallel resonator; the first LC parallel resonator includes a first line-like conductor pattern, a first open via conductor connecting the first line-like conductor pattern and the first capacitor conductor pattern, and a first short-circuiting via conductor connecting the first line-like conductor pattern and the ground conductor pattern, the second LC parallel resonator includes a second line-like conductor pattern, a second open via conductor connecting the second line-like conductor pattern and the second capacitor conductor pattern, and a second short-circuiting via conductor connecting the second line-like conductor pattern and the ground conductor pattern, the third LC parallel resonator includes a third line-like conductor pattern, a third open via conductor connecting the third line-like conductor pattern and the third capacitor conductor pattern, and a third short-circuiting via conductor connecting the third line-like conductor pattern and the ground conductor pattern, When the laminate is seen through from the lamination direction, the first open via conductor is disposed at a position closer to the second open via conductor than the second short-circuiting via conductor and closer to the third open via conductor than the third short-circuiting via conductor; the second open via conductor is disposed at a position closer to the third open via conductor than the third short-circuiting via conductor is, In at least one of the LC parallel resonators, an adjustment capacitor conductor pattern for adjusting a capacitance of the capacitor is formed in an interlayer of the dielectric layer between the capacitor conductor pattern and the ground conductor pattern, the adjustment capacitor conductor pattern adjusting a capacitance of the capacitor; the adjusting capacitor conductor pattern is directly connected to either the capacitor conductor pattern or the ground conductor pattern by a via conductor; Between the dielectric layers, which are the same as the between the dielectric layers on which the adjusting capacitor conductor pattern is formed, a jump coupling capacitor conductor pattern is formed to capacitively couple at least one of the LC parallel resonators to at least one other LC parallel resonator that is spaced apart on an equivalent circuit; Multilayer LC filter.

2. the short-circuiting via conductor of at least one of the LC parallel resonators is connected to the short-circuiting via conductor of at least one other of the LC parallel resonators, and the connection point and the ground conductor pattern are connected by a common short-circuiting via conductor; 2. The laminated LC filter according to claim 1.

3. the laminate has a mounting side principal surface and a non-mounting side principal surface, a shielding conductor pattern is formed between the first line-like conductor pattern, the second line-like conductor pattern, and the third line-like conductor pattern and the non-mounting main surface, and between the laminate layers; the shield conductor pattern is connected to the ground conductor pattern via a shielding via conductor; 3. The laminated LC filter according to claim 1.

4. the shield conductor pattern is directly connected to the ground conductor pattern through the shielding via conductor; 4. The laminated LC filter according to claim 3.

5. When the laminate is viewed in the height direction, the first open via conductor, the second open via conductor, and the third open via conductor are each disposed near a center of the laminate; the first short-circuiting via conductor, the second short-circuiting via conductor, and the third short-circuiting via conductor are each disposed near a periphery of the laminate; the first line-like conductor pattern, the second line-like conductor pattern, and the third line-like conductor pattern are each radially disposed from the vicinity of the center toward the vicinity of the periphery.

5. The laminated LC filter according to claim 1.

6. the plurality of LC parallel resonators further includes a fourth LC parallel resonator, the fourth LC parallel resonator includes a fourth line-like conductor pattern, a fourth capacitor conductor pattern, a fourth open via conductor connecting the fourth line-like conductor pattern and the fourth capacitor conductor pattern, and a fourth short-circuiting via conductor connecting the fourth line-like conductor pattern and the ground conductor pattern, When the laminate is viewed in the height direction, the first open via conductor, the second open via conductor, the third open via conductor, and the fourth open via conductor are each disposed near the center of the laminate; the first short-circuiting via conductor, the second short-circuiting via conductor, the third short-circuiting via conductor, and the fourth short-circuiting via conductor are each disposed near the periphery of the laminate; the first line-like conductor pattern, the second line-like conductor pattern, the third line-like conductor pattern, and the fourth line-like conductor pattern are each radially disposed from the vicinity of the center toward the vicinity of the periphery.

6. The laminated LC filter according to claim 5.

7. the first line-like conductor pattern and the second line-like conductor pattern are disposed between different layers of the laminate; 7. The laminated LC filter according to claim 1.

8. the first line-like conductor pattern and the fourth line-like conductor pattern are disposed between the same layers of the laminate, the second line-like conductor pattern and the third line-like conductor pattern are disposed between the same layers of the laminate, the first line-like conductor pattern and the fourth line-like conductor pattern, and the second line-like conductor pattern and the third line-like conductor pattern are disposed between different layers of the laminate; 7. The laminated LC filter according to claim 6.

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