LC filter

Abstract

An LC filter (1) comprises: a ground electrode (3) and an electrode (2) facing each other with a gap therebetween; a resonator (7) positioned between the ground electrode (3) and the electrode (2); a via conductor (4) connected to the ground electrode (3) and the electrode (2); and a power supply conductor (8) connected to the electrode (2). The resonator (7) includes: an electrode (5) that is disposed apart from the electrode (2) and constitutes a capacitor component together with the electrode (2); and a via conductor (6) that is connected to the electrode (5) and the ground electrode (3) and has an inductor component. The LC filter (1) is supplied with power via the power supply conductor (8).

Description

LC Filter

[0001] This disclosure relates to an LC filter.

[0002] Patent Document 1 discloses a resonator that includes a via electrode portion connected to a shielding conductor on the upper surface, and a strip electrode connected to the via electrode portion and facing a shielding conductor on the lower surface, and is supplied with power through the shielding conductor on the upper surface.

[0003] Japanese Patent Application Laid-Open No. 2018-196082

[0004] In recent years, with the miniaturization and high integration of electronic devices such as smartphones, multiple electronic components mounted on a substrate inside the electronic device may interfere with each other, resulting in characteristic degradation. In order to avoid the occurrence of such characteristic degradation, it is conceivable to arrange a metal shield on the substrate on which the electronic components are mounted. However, for example, in the resonator of Patent Document 1, when a metal shield is arranged adjacent to the upper shielding conductor, a minute current may flow through the metal shield due to the magnetic field generated in the resonator, canceling the magnetic field and causing deterioration of the frequency characteristics.

[0005] An object of the present disclosure is to provide an LC filter capable of suppressing deterioration of frequency characteristics when a metal shield is arranged adjacent to a first electrode.

[0006] The LC filter according to an aspect of the present disclosure includes a ground electrode and a first electrode facing each other with a gap therebetween, a first resonator positioned between the ground electrode and the first electrode, a first conductor connected to the ground electrode and the first electrode, and a second conductor connected to the first electrode, wherein the first resonator includes a second electrode arranged with a gap from the first electrode and constituting a capacitor component together with the first electrode, and a first wiring connected to the second electrode and the ground electrode and having an inductor component, and is supplied with power through the second conductor.

[0007] According to the present disclosure, it is possible to provide an LC filter capable of suppressing deterioration of frequency characteristics when a metal shield is arranged adjacent to a first electrode.

[0008] A perspective view showing an LC filter according to the first embodiment of this disclosure. A perspective view showing the LC filter of Figure 1 with the substrate removed. A side view showing the LC filter of Figure 2. A diagram showing the relationship between the S-parameters and frequency of the LC filter of Figure 1 and the LC filter of the comparative example. A diagram showing the relationship between the S-parameters and frequency of the LC filter of Figure 1. A diagram showing the relationship between the S-parameters and frequency of the LC filter of the comparative example. A side view showing the magnetic field distribution of the LC filter of Figure 1. A plan view showing the current density distribution of the LC filter of Figure 1. A perspective view showing an LC filter according to the second embodiment of this disclosure. A side view showing the LC filter of Figure 9. A perspective view showing the LC filter of the second embodiment from a different angle than Figure 9. A perspective view showing an LC filter according to the third embodiment of this disclosure. A side view showing the LC filter of Figure 12. A perspective view showing the LC filter of the third embodiment from a different angle than Figure 12. A perspective view showing the LC filter of the comparative example. A side view showing the LC filter of Figure 16. A side view showing the magnetic field distribution of the LC filter of Figure 16. A plan view showing the current density distribution of the LC filter of Figure 16. A perspective view showing an LC filter according to the fourth embodiment of this disclosure. A cross-sectional view along the line XX-XX in Figure 19.

[0009] Various aspects of this disclosure will be described below.

[0010] An LC filter according to a first aspect of the present disclosure comprises a ground electrode and a first electrode facing each other with a gap between them; a first resonator located between the ground electrode and the first electrode; a first conductor connected to the ground electrode and the first electrode; and a second conductor connected to the first electrode, wherein the first resonator includes a second electrode positioned with a gap between it and the first electrode and constituting a capacitor component together with the first electrode; and a first wiring connected to the second electrode and the ground electrode and having an inductive component, and is powered via the second conductor.

[0011] An LC filter according to a second aspect of the present disclosure is an LC filter according to a first aspect, comprising a second resonator including a second wiring located between the ground electrode and the first electrode and having an inductive component, and a third electrode connected to the second wiring and constituting a capacitive component together with the first electrode, wherein the third electrode is arranged with a gap between it and the first electrode, one end of the second wiring is connected to the ground electrode, and the other end of the second wiring is connected to the third electrode of the second resonator.

[0012] An LC filter according to a third aspect of the present disclosure is an LC filter according to a second aspect, comprising a third resonator including a third wiring located between the ground electrode and the first electrode and having an inductive component, and a fourth electrode connected to the third wiring and constituting a capacitive component together with the first electrode, wherein the fourth electrode is positioned with a gap between it and the first electrode, one end of the third wiring is connected to the ground electrode, and the other end of the third wiring is connected to the fourth electrode of the second resonator.

[0013] A fourth aspect of the present disclosure is an LC filter in any of the first to third aspects, comprising: a substrate having a first main surface and a second main surface facing each other, on which the ground electrode, the first resonator, the first conductor, and the second conductor are arranged; and a ground terminal connected to the ground electrode and located on the second main surface, wherein the ground electrode faces the second main surface of the substrate, and the distance between the second main surface of the substrate and the ground electrode is shorter than the distance between the second main surface of the substrate and the first electrode.

[0014] A fifth aspect of the present disclosure is an LC filter in the fourth aspect, wherein the substrate has sides different from the first main surface and the second main surface, the second conductor includes a power supply terminal, and the power supply terminal is located on the side of the substrate.

[0015] An LC filter according to a sixth aspect of the present disclosure is an LC filter according to a fifth aspect, wherein the second conductor includes a power supply terminal and a seventh conductor, the power supply terminal is located on the second main surface, and the seventh conductor is located inside the substrate and connected to the power supply terminal and the first electrode.

[0016] An LC filter according to a seventh aspect of the present disclosure is an LC filter according to a second or third aspect, further comprising a fifth electrode disposed between the second electrode and the ground electrode, and between the third electrode and the ground electrode, wherein the fifth electrode is disposed opposite to the second and third electrodes with a gap between them.

[0017] An LC filter according to an eighth aspect of the present disclosure is an LC filter according to an LC filter according to a third aspect, comprising: a fifth electrode disposed between the second electrode and the ground electrode and between the third electrode and the ground electrode; and a sixth electrode disposed between the third electrode and the ground electrode and between the fourth electrode and the ground electrode, wherein the fifth electrode is disposed opposite to the second electrode and the third electrode with a gap between them, and the sixth electrode is disposed opposite to the third electrode and the fourth electrode with a gap between them.

[0018] Various aspects of this disclosure will be described below with reference to the accompanying drawings. The following description is essentially illustrative and does not limit the applications or uses of this disclosure. The accompanying drawings are schematic, and the dimensional proportions, etc., of the illustrated configuration may differ from those of the actual product. In the following description, terms such as "approximately" or "about" mean that the values ​​or shapes, etc., that follow these terms include an acceptable margin of error as determined by a person skilled in the art.

[0019] (First Embodiment) The LC filter 1 of the first embodiment of the present disclosure, as shown in Figures 1 to 3, comprises an electrode 2, a ground electrode 3, a via conductor 4, a resonator 7, and a power supply conductor 8. In this embodiment, the LC filter 1 comprises a ground terminal 9 and a substrate 10, and the electrode 2, the ground electrode 3, the via conductor 4, the resonator 7, and a part of the power supply conductor 8 are located inside the substrate 10. The substrate 10 is constructed, for example, by stacking a plurality of dielectric layers and has a substantially rectangular parallelepiped shape. In this embodiment, the thickness direction of the substrate is defined as the Z direction, the direction intersecting the Z direction is defined as the X direction, and the direction intersecting the X and Z directions is defined as the Y direction. The ground terminal 9 is formed on one of the surfaces located at both ends of the substrate 10 in the Z direction.

[0020] Electrode 2 is an example of the first electrode. In this embodiment, electrode 2 is located inside the substrate 10 and has a substantially rectangular plate shape extending along the Y direction, as shown in Figures 2 and 3, but is not limited to this.

[0021] The ground electrode 3 is a high-frequency grounded electrode. As shown in Figure 3, the electrode 2 and the ground electrode 3 face each other with a gap 200 in the Z direction. In this embodiment, they are located inside the substrate 10. The ground electrode 3 may be formed on one of the surfaces located at both ends of the substrate 10 in the Z direction. In this embodiment, the ground electrode 3 has a substantially rectangular plate shape, but is not limited to this. The ground electrode 3 has two notches 31 provided at both ends in the X direction and substantially in the center in the Y direction. Inside each notch 31, a power supply terminal 81, which will be described later, is located with a gap between it and the ground terminal 9.

[0022] As shown in Figure 3, the ground terminal 9 is connected to the ground electrode 3 via a via conductor 91. The ground electrode 3 is connected to the ground terminal 9 and is high-frequency grounded via the ground terminal 9. The ground terminal 9 has a substantially flat shape, but is not limited to this.

[0023] The via conductor 4 is an example of a first conductor and is connected to the electrode 2 and the ground electrode 3. In other words, the electrode 2 and the ground electrode 3 are connected via the via conductor 4. Of the two ends of the via conductor 4 in the Z direction, one end is connected to the electrode 2 and the other end is connected to the ground electrode 3. A portion of the current caused by the voltage input to the electrode 2 flows to the ground electrode through the via conductor 4. In this embodiment, the LC filter 1 comprises two via conductors 4. Each via conductor 4 is connected to both ends of the electrode 2 in the Y direction and to the ground electrode 3, respectively. Each via conductor 4 is a through via having a substantially columnar shape, but is not limited thereto. The via conductor 4 may be configured, for example, by combining multiple vias and wiring. Each via conductor 4 may be connected to the portion of the electrode 2 other than both ends in the Y direction and to the ground electrode 3. Each via conductor 4 is formed in a substantially columnar shape, but is not limited thereto.

[0024] The resonator 7 is an example of a first resonator and includes an electrode 5 and a via conductor 6, and is located between electrode 2 and ground electrode 3.

[0025] Electrode 5 is an example of a second electrode and is positioned with a gap between it and electrode 2 in the Z direction. In this embodiment, electrode 5 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 5 is positioned opposite electrode 2 in the Z direction and together with electrode 2 constitutes a capacitor component. When viewed along the Z direction, electrode 5 is positioned such that at least a portion of it overlaps with electrode 2.

[0026] The via conductor 6 is an example of the first wiring and has an inductive component. Of the two ends of the via conductor 6 in the Z direction, one end is connected to electrode 5 and the other end is connected to ground electrode 3. In this embodiment, the via conductor 6 has a substantially columnar shape, but is not limited thereto.

[0027] The resonator 7, together with the electrode 2, forms an LC resonant circuit. In this embodiment, as shown in Figure 3, the electrodes 2, 5, via conductor 6, and ground electrode 3 are arranged in that order from top to bottom in the Z-axis direction.

[0028] The power supply conductor 8 is an example of a second conductor and is connected to the electrode 2. The power supply conductor 8 is configured to supply the input voltage input from outside the LC filter 1 to the electrode 2. In other words, the input voltage is supplied to the electrode 2 via the power supply conductor 8. In this embodiment, the power supply conductor 8 includes a power supply terminal 81, a power supply via 82, and a power supply electrode 83.

[0029] The power supply terminal 81 is located on one of the surfaces of the substrate 10 located at both ends in the Z direction. For example, the power supply terminal 81 is formed on the same plane as the ground terminal 9. In this embodiment, the power supply terminal 81 has a substantially flat shape, but is not limited to this. The power supply conductor 8 does not have to include the power supply terminal 81.

[0030] The power supply via 82 is an example of a seventh conductor and is connected to the power supply terminal 81 and the power supply electrode 83. In this embodiment, the power supply via 82 has a substantially columnar shape, but is not limited to this.

[0031] The power supply electrode 83 is, for example, a substantially rectangular plate shape extending in the X direction, and supplies the input voltage input to the power supply conductor 8 to the electrode 2. In this embodiment, the power supply conductor 8 has two power supply electrodes 83, each located on either side of the electrode 2 in the X direction. Of the two ends of each power supply electrode 83 in the X direction, one end is connected to the electrode 2, and the other end is connected to a power supply via 82.

[0032] The substrate 10 is, for example, a dielectric substrate and has main surfaces 101 and 102 facing each other in the Z direction. Main surface 101 is an example of a first main surface, and main surface 102 is an example of a second main surface. The substrate 10 has a side surface 103 that is different from the main surfaces 101 and 102. Side surface 103 extends substantially perpendicular to the main surfaces 101 and 102. In this embodiment, the electrode 2, the ground electrode 3, and the electrode 5 face the main surfaces 101 and 102. As shown in Figure 3, the main surface 101 is located closer to the electrode 2 in the Z direction than the main surface 102, and the main surface 102 is located closer to the ground electrode 3 in the Z direction than the main surface 101. That is, the linear distance L1 between the electrode 2 and the main surface 101 is shorter than the linear distance L2 between the electrode 2 and the main surface 102, and the linear distance L3 between the ground electrode 3 and the main surface 102 is shorter than the linear distance L4 between the ground electrode 3 and the main surface 101. The substrate 10 is not limited to a dielectric substrate, but may also be a multilayer substrate. If the substrate 10 is a multilayer substrate, the electrodes 2, ground electrode 3, and electrode 5 may be configured to be located in each layer of the substrate 10, respectively.

[0033] The frequency characteristics of LC filter 1 will be explained using a comparative example.

[0034] Figure 4 shows the frequency characteristics of LC filter 1 measured under the condition that electrode 2 is sufficiently far from the metal shield. In Figure 4, the relationship between the S-parameters and frequency of LC filter 1 is shown by a solid line, and the relationship between the S-parameters and frequency of the comparative example LC filter 100 is shown by a dashed line. As shown in Figure 4, it was found that LC filter 1 exhibits approximately the same frequency characteristics as filter 100.

[0035] Here, the LC filter 100 will be described using Figures 15 and 16. The comparative example LC filter 100 differs from the LC filter 1 in that it includes a resonator 170 with electrodes 150 and via conductors 160. In the LC filter 100, electrode 150 is located closer to the ground electrode 3 than electrode 2 in the Z direction and together with the ground electrode 3 forms a capacitor component. The via conductor 160 is connected to electrode 2 and electrode 150. In the LC filter 100, as shown in Figure 16, the electrodes 2, via conductor 160, electrode 150, and ground electrode 3 are arranged in that order from top to bottom in the Z direction.

[0036] Figure 5 shows the frequency characteristics of LC filter 1 with a metal shield adjacent to electrode 2 and without a metal shield adjacent to electrode 2. Figure 6 shows the frequency characteristics of LC filter 100 with a metal shield adjacent to electrode 2 and without a metal shield adjacent to electrode 2. In Figures 5 and 6, a metal shield is placed 0.1 mm away from electrode 2 along the Z direction. The relationship between S-parameters and frequency when a metal shield adjacent to electrode 2 is placed is shown by a solid line, and the relationship between S-parameters and frequency when a metal shield adjacent to electrode 2 is not placed is shown by a dashed line.

[0037] As shown in Figure 5, it was found that the LC filter 1 has an attenuation pole (M01) at 6.78 GHz when the metal shield is adjacent, and an attenuation pole (M02) at 6.79 GHz when the adjacent metal shield is absent. In other words, it was found that by bringing the metal shield close to the electrode 2, the attenuation pole of the LC filter 1 shifted to a higher frequency of 10 MHz.

[0038] As shown in Figure 6, it was found that the LC filter 100 has an attenuation pole (M01) at 7.00 GHz when the metal shield is adjacent, and an attenuation pole (M02) at 6.95 GHz when the adjacent metal shield is absent. In other words, it was found that by bringing the metal shield close to electrode 2, the attenuation pole of the LC filter 100 shifted to a higher frequency of 50 MHz.

[0039] The results shown in Figures 5 and 6 indicate that when a metal shield is placed adjacent to electrode 2, LC filter 1 can suppress the frequency shift of the attenuation pole more effectively than LC filter 100.

[0040] Figure 7 is a cross-sectional view showing the magnetic field distribution of the LC filter 1. The cross-sectional view in Figure 7 is a cross-sectional view along the line I-I in Figure 2. As shown in Figure 7, in the LC filter 1, the magnetic field strength between electrode 5 and electrode 2 is low. This is thought to be because electrode 5 is positioned with a gap between it and electrode 2, and together with electrode 2, they form a capacitor component.

[0041] Figure 17 shows the magnetic field distribution of the LC filter 100. The cross-sectional view in Figure 17 is a cross-sectional view along the line II-II in Figure 15. As shown in Figure 17, in the LC filter 100, the magnetic field strength is high around the via conductor 160 between electrode 150 and electrode 2. This is thought to be because a magnetic flux is generated when current flows through the via conductor 160 included in the resonator 170 of the LC filter 100.

[0042] When a metal shield approaches electrode 2 along the Z direction, the magnetic field near electrode 2 is affected by the metal shield. Therefore, LC filter 100, which has a higher magnetic field strength around electrode 2, is more susceptible to the effects of approaching metal shields than LC filter 1, and its frequency characteristics are more easily altered. As a result, LC filter 100 exhibits a larger frequency shift at the attenuation pole compared to LC filter 1.

[0043] Figure 8 is a plan view showing the current density distribution of LC filter 1 when viewed from above in the Z direction in Figure 3 along the Z direction. Figure 18 is a plan view showing the current density distribution of LC filter 100 when viewed from above in the Z direction in Figure 16 along the Z direction. Comparing Figures 8 and 18, the current density around the electrode 2 of LC filter 1 shown in Figure 8 is lower than that around the electrode 2 of LC filter 100 shown in Figure 18. From the comparison of Figures 8 and 18, it can be seen that LC filter 100 experiences a larger attenuation pole frequency shift compared to LC filter 1.

[0044] LC filter 1 can achieve the following effects:

[0045] The LC filter 1 includes a ground electrode 3 and an electrode 2 (an example of a first electrode) that face each other with a gap therebetween, a resonator 7 (an example of a first resonator) positioned between the ground electrode 3 and the electrode 2, a via conductor 4 (an example of a first conductor) connected to the ground electrode 3 and the electrode 2, and a power supply conductor 8 connected to the electrode 2. The resonator 7 is arranged with a gap from the electrode 2 and includes an electrode 5 (an example of a second electrode) that forms a capacitor component together with the electrode 2, and a via conductor 6 (an example of a first wiring) connected to the electrode 5 and the ground electrode 3 and having an inductor component. The LC filter 1 is powered through the power supply conductor 8 (an example of a second conductor). With such a configuration, an LC filter 1 capable of suppressing deterioration of frequency characteristics when a metal shield is arranged adjacent to the electrode 2 can be realized.

[0046] The LC filter 1 has a main surface 101 (an example of a first main surface) and a main surface 102 (an example of a second main surface) that face each other, and includes a substrate 10 on which the ground electrode 3, the resonator 7, the via conductor 4, and the via conductor 6 are arranged, and a ground terminal 9 connected to the ground electrode 3 and arranged on the main surface 102. The ground electrode 3 faces the main surface 102 of the substrate 10. The distance between the main surface 102 of the substrate 10 and the ground electrode 3 is shorter than the distance between the main surface 102 of the substrate 10 and the electrode 2. With such a configuration, an LC filter capable of high-frequency grounding can be realized.

[0047] The LC filter 1 can be configured as follows.

[0048] The LC filter 1 may not include the ground terminal 9 and the substrate 10. In this case, the ground electrode 3 is grounded at high frequency without passing through the ground terminal 9. With such a configuration, the LC filter can be made smaller than when there is a ground terminal 9.

[0049] In a plan view, the electrode 2 may not overlap with the ground electrode 3.

[0050] Electrode 2 may be located on the main surface 101, and ground electrode 3 may be located on the main surface 102. If ground electrode 3 is located on the main surface 102, ground electrode 3 may be omitted, in which case the LC filter can be made more compact.

[0051] The power supply conductor 8 does not necessarily have to include the power supply terminal 81, and the input voltage may be supplied to the power supply via 82.

[0052] The power supply conductor 8 does not necessarily have to include the power supply via 82, and the input voltage may be supplied to the power supply electrode 83.

[0053] The power supply conductor 8 does not necessarily have to include the power supply electrode 83, and the power supply via 82 and the electrode 2 may be directly connected.

[0054] The power supply terminal 81 may be located on the main surface 102 of the substrate 10. In this case, the power supply via 82 (an example of a seventh conductor) is located inside the substrate 10 and connected to the power supply terminal 81 and the electrode 2 (an example of a first electrode). With this configuration, the input voltage can be supplied to the electrode 2 via the power supply terminal 81 on the main surface 102 of the substrate 10.

[0055] The power supply terminal 81 may be located on a side surface 103 (see Figure 1) of the substrate 10, different from the main surfaces 101 and 102. With this configuration, the input voltage can be supplied to the electrode 2 via the power supply terminal 81 on the side surface 103 of the substrate 10. Thus, in the LC filter 1, the power supply terminal 81 can be located on the main surface 102 or the side surface 103. In other words, an LC filter with a high degree of design flexibility can be realized.

[0056] (Second Embodiment) The LC filter 11 of the second embodiment of this disclosure differs from the LC filter 1 of the first embodiment in that it includes two resonators 171 and 172 and an electrode 21, as shown in Figures 9 to 12. Hereinafter, the same reference numerals are used for parts that are the same as in the first embodiment and their descriptions are omitted.

[0057] Resonator 171 is an example of a first resonator and includes an electrode 151 and a via conductor 161. Resonator 172 is an example of a second resonator and includes an electrode 152 and a via conductor 162. Resonators 171 and 172 are located between the electrode 2 and the ground electrode 3 in the Y direction, similar to the resonator 7 of the LC filter 1 in the first embodiment, and are arranged with a gap between them and the electrode 2 in the Y direction and connected to the ground electrode 3. In this embodiment, resonators 171 and 172 are arranged side by side in the X direction, but are not limited to this and may be arranged side by side in the Y direction, for example.

[0058] Electrode 151 is an example of a second electrode and is positioned with a gap between it and electrode 2 in the Y direction. In this embodiment, electrode 151 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 151 faces electrode 2 in the Y direction and together with electrode 2 constitutes a capacitor component. When viewed along the Y direction, electrode 151 is positioned such that at least a portion of it overlaps with electrode 2.

[0059] Electrode 152 is an example of a third electrode and is positioned with a gap between it and electrode 2 in the Y direction. In this embodiment, electrode 152 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 152 faces electrode 2 in the Y direction and together with electrode 2 constitutes a capacitor component. When viewed along the Y direction, electrode 152 is positioned such that at least a portion of it overlaps with electrode 2.

[0060] The via conductor 161 is an example of the first wiring and has an inductive component. Of the two ends of the via conductor 161 in the Z direction, one end is connected to the electrode 151 and the other end is connected to the ground electrode 3. In this embodiment, the via conductor 161 has a substantially columnar shape, but is not limited thereto.

[0061] The via conductor 162 is an example of the first wiring and has an inductive component. Of the two ends of the via conductor 162 in the Z direction, one end is connected to electrode 152 and the other end is connected to ground electrode 3. In this embodiment, the via conductor 162 has a substantially columnar shape, but is not limited thereto.

[0062] The LC filter 11 in this embodiment includes an electrode 21 positioned between electrode 151 and ground electrode 3, and between electrode 152 and ground electrode 3. Electrode 21 is an example of a fifth electrode and, as shown in Figures 10 and 11, has a substantially rectangular plate shape extending along the X direction, but is not limited to this. Electrode 21 is positioned opposite electrodes 151 and 152, spaced apart in the Y direction. Electrode 21 and electrode 151, and electrode 21 and electrode 152, each constitute a capacitor component. In this embodiment, the LC filter 11 includes two electrodes 21, but is not limited to this; it may include one or more electrodes 21.

[0063] The LC filter 11 can achieve the following effects.

[0064] The LC filter 11 comprises a ground electrode 3 and an electrode 2 facing each other with a gap between them, resonators 171 and 172 located between the ground electrode 3 and the electrode 2, a via conductor 4 connected to the ground electrode 3 and the electrode 2, and a power supply conductor 8 connected to the electrode 2. The resonator 171 includes an electrode 151 positioned with a gap between it and the electrode 2 and constituting a capacitive component together with the electrode 2, and a via conductor 161 connected to the electrode 151 and the ground electrode 3 and having an inductive component. The resonator 172 includes an electrode 152 positioned with a gap between it and the electrode 2 and constituting a capacitive component together with the electrode 2, and a via conductor 162 connected to the electrode 152 and the ground electrode 3 and having an inductive component. The filter 11 is powered via the power supply conductor 8. With this configuration, the LC filter 11 can be configured as an LC filter having two attenuation poles while suppressing degradation of the frequency characteristics when a metal shield is in close proximity.

[0065] The LC filter 11 includes an electrode 21 positioned between electrode 151 and ground electrode 3, and between electrode 152 and ground electrode 3. The electrode 21 is positioned opposite electrodes 151 and 152 with a gap between them. This configuration makes it possible to couple the capacitances of resonators 171 and 172.

[0066] (Third Embodiment) The LC filter 111 of the third embodiment of this disclosure differs from the LC filter 1 of the first embodiment in that it comprises three resonators 171, 172, and 173 and electrodes 201 and 202, as shown in Figures 12 to 14. Hereinafter, the same reference numerals are used for parts that are the same as in the first embodiment and their descriptions are omitted.

[0067] Resonator 171 is an example of a first resonator and includes an electrode 151 and a via conductor 161. Resonator 172 is an example of a second resonator and includes an electrode 152 and a via conductor 162. Resonator 173 is an example of a second resonator and includes an electrode 153 and a via conductor 163. Resonators 171, 172, and 173 are located between the electrode 2 and the ground electrode 3 in the Y direction, similar to the resonator 7 of the LC filter 1 in the first embodiment, and are arranged with a gap between them and the electrode 2 in the Y direction and connected to the ground electrode 3. In this embodiment, resonators 171, 172, and 173 are arranged in this order in the X direction, with resonators 171 and 172 adjacent to each other and resonators 172 and 173 adjacent to each other, but are not limited to this.

[0068] Electrode 151 is an example of a second electrode and is positioned with a gap between it and electrode 2 in the Y direction. In this embodiment, electrode 151 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 151 faces electrode 2 in the Y direction and together with electrode 2 constitutes a capacitor component. When viewed along the Y direction, electrode 151 is positioned such that at least a portion of it overlaps with electrode 2.

[0069] Electrode 152 is an example of a third electrode and is positioned with a gap between it and electrode 2 in the Y direction. In this embodiment, electrode 152 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 152 faces electrode 2 in the Y direction and together with electrode 2 constitutes a capacitor component. When viewed along the Y direction, electrode 152 is positioned such that at least a portion of it overlaps with electrode 2.

[0070] Electrode 153 is an example of a fourth electrode and is positioned with a gap between it and electrode 2 in the Y direction. In this embodiment, electrode 153 has a substantially plate shape that is smaller than electrode 2, but is not limited to this. Electrode 153 faces electrode 2 in the Y direction and together with electrode 2 constitutes a capacitor component. When viewed along the Y direction, electrode 153 is positioned such that at least a portion of it overlaps with electrode 2.

[0071] The via conductor 161 is an example of the first wiring and has an inductive component. Of the two ends of the via conductor 161 in the Z direction, one end is connected to the electrode 151 and the other end is connected to the ground electrode 3. In this embodiment, the via conductor 161 has a substantially columnar shape, but is not limited thereto.

[0072] The via conductor 162 is an example of a second wiring and has an inductive component. Of the two ends of the via conductor 162 in the Z direction, one end is connected to electrode 152 and the other end is connected to ground electrode 3. In this embodiment, the via conductor 162 has a substantially columnar shape, but is not limited thereto.

[0073] The via conductor 163 is an example of a third wiring and has an inductive component. Of the two ends of the via conductor 163 in the Z direction, one end is connected to electrode 153 and the other end is connected to ground electrode 3. In this embodiment, the via conductor 163 has a substantially columnar shape, but is not limited thereto.

[0074] The LC filter 111 in this embodiment includes an electrode 201 positioned between electrode 151 and ground electrode 3, and between electrode 152 and ground electrode 3. Electrode 201 is an example of a fifth electrode and, as shown in Figures 13 and 14, has a substantially rectangular plate shape extending along the X direction, but is not limited to this. Electrode 201 is positioned opposite electrodes 151 and 152, spaced apart in the Y direction. Electrodes 201 and 151, and electrodes 201 and 152, each constitute a capacitor component. In this embodiment, the LC filter 111 includes one electrode 201, but is not limited to this; it may include one or more electrodes 201.

[0075] The LC filter 111 in this embodiment includes an electrode 202 positioned between electrode 152 and ground electrode 3, and between electrode 153 and ground electrode 3. Electrode 202 is an example of a sixth electrode and, as shown in Figures 13 and 14, has a substantially rectangular plate shape extending along the X direction, but is not limited to this. Electrode 202 is positioned opposite electrodes 152 and 153, spaced apart in the Y direction. Electrode 202 and electrode 152, and electrode 202 and electrode 153, each constitute a capacitor component. In this embodiment, the LC filter 111 includes one electrode 202, but is not limited to this; it may include one or more electrodes 202.

[0076] The LC filter 111 can provide the following effects.

[0077] The LC filter 111 comprises a ground electrode 3 and an electrode 2 facing each other with a gap between them, resonators 171, 172, and 173 located between the ground electrode 3 and the electrode 2, a via conductor 4 connected to the ground electrode 3 and the electrode 2, and a power supply conductor 8 connected to the electrode 2. The resonator 171 includes an electrode 151 positioned with a gap between it and the electrode 2 and constituting a capacitive component together with the electrode 2, and a via conductor 161 connected to the electrode 151 and the ground electrode 3 and having an inductive component. The resonator 172 includes an electrode 152 positioned with a gap between it and the electrode 2 and constituting a capacitive component together with the electrode 2, and a via conductor 162 connected to the electrode 152 and the ground electrode 3 and having an inductive component. The resonator 173 includes an electrode 153 positioned with a gap between it and the electrode 2 and constituting a capacitive component together with the electrode 2, and a via conductor 163 connected to the electrode 153 and the ground electrode 3 and having an inductive component. The filter 111 is powered via the power supply conductor 8. With this configuration, the LC filter 111 can be configured as an LC filter having three attenuation poles, while suppressing the degradation of its frequency characteristics when a metal shield is in close proximity.

[0078] The LC filter 111 includes an electrode 201 positioned between electrode 151 and ground electrode 3, and between electrode 152 and ground electrode 3, and an electrode 202 positioned between electrode 152 and ground electrode 3, and between electrode 153 and ground electrode 3. Electrode 201 is positioned opposite electrodes 151 and 152 with a gap between them, and electrode 202 is positioned opposite electrodes 152 and 153 with a gap between them. This configuration makes it possible to couple the capacitances of resonators 171, 172, and 173.

[0079] (Fourth Embodiment) The LC filter 1111 of the fourth embodiment of this disclosure differs from the LC filter 1 of the first embodiment in that it includes one via conductor 4, as shown in Figures 19 and 20. Hereinafter, the same reference numerals are used for parts that are the same as in the first embodiment and their descriptions are omitted. In Figure 19, the substrate 10 is omitted.

[0080] The via conductor 4 of the LC filter 1111 is located at one of the two ends of the electrode 2 in the Y direction when viewed along the Z direction, and the entire via conductor 4 overlaps with the electrode 2. The via conductor 6 of the LC filter 1111 is located at the end of the electrode 5 in the Y direction that is farther from the via conductor 4 when viewed along the Z direction, and the entire via conductor 6 overlaps with both the electrode 2 and the electrode 5. In the cross-section shown in Figure 20, the power supply via 82 is located between the via conductor 4 and the via conductor 6. Each of the electrode 2 and the electrode 5 has a substantially rectangular plate shape, and is positioned such that the Y direction is the longitudinal direction and the X direction is the short direction when viewed along the Z direction.

[0081] The LC filter 1111 of the fourth embodiment can be more easily miniaturized in the Y direction than the LC filter 1 of the first embodiment, while having substantially the same resonant frequency and Q value. For example, in the LC filter 1, the dimension of the electrode 2 in the Y direction is "1.75 mm", whereas in the LC filter 1111, the dimension of the electrode 2 in the Y direction is "1.03 mm".

[0082] The LC filter 1111 of the fourth embodiment can lower the resonant frequency compared to the LC filter 1 of the first embodiment. In the LC filter 1111, the electrode 2 and the ground electrode 3 are connected in series with a single via conductor 4, and the distance between the via conductor 4 and the via conductor 6 can be made larger than in the LC filter 1. As a result, the inductance can be made higher than in the LC filter 1.

[0083] The embodiments and variations of this disclosure can be combined with each other, or with each other, or with each other. Features included in the embodiments and variations of this disclosure can also be combined with each other.

[0084] The content of this disclosure is subject to change in its constituent details, and changes in the combination and order of elements in each aspect can be achieved without deviating from the scope and intent of the requested disclosure.

[0085] 1, 11, 111 LC filter 2, 21, 201, 202 Electrodes 3 Ground electrode 31 Notch 4, 6, 91, 161, 162, 163 Via conductors 5, 151, 152, 153 Electrodes 7, 171, 172, 173 Resonator 8 Feed conductor 81 Feed terminal 82 Feed via 83 Feed electrode 9 Ground terminal 10 Substrate 101, 102 Main surface 103 Side surface 200 Gap

Claims

1. An LC filter comprising: a ground electrode and a first electrode facing each other with a gap between them; a first resonator located between the ground electrode and the first electrode; a first conductor connected to the ground electrode and the first electrode; and a second conductor connected to the first electrode, wherein the first resonator includes a second electrode positioned with a gap between it and the first electrode and together with the first electrode to constitute a capacitor component; and a first wiring connected to the second electrode and the ground electrode and having an inductive component, and power is supplied via the second conductor.

2. The LC filter according to claim 1, comprising a second resonator including a second wiring located between the ground electrode and the first electrode and having an inductive component, and a third electrode connected to the second wiring and constituting a capacitive component together with the first electrode, wherein the third electrode is arranged with a gap between it and the first electrode, one end of the second wiring is connected to the ground electrode, and the other end of the second wiring is connected to the third electrode of the second resonator.

3. The LC filter according to claim 2, comprising a third resonator including a third wiring having an inductive component and located between the ground electrode and the first electrode, and a fourth electrode connected to the third wiring and constituting a capacitive component together with the first electrode, wherein the fourth electrode is arranged with a gap between it and the first electrode, one end of the third wiring is connected to the ground electrode, and the other end of the third wiring is connected to the fourth electrode of the second resonator.

4. An LC filter according to any one of claims 1 to 3, comprising: a substrate having a first main surface and a second main surface facing each other, on which the ground electrode, the first resonator, the first conductor and the second conductor are arranged; and a ground terminal connected to the ground electrode and located on the second main surface, wherein the ground electrode faces the second main surface of the substrate, and the distance between the second main surface of the substrate and the ground electrode is shorter than the distance between the second main surface of the substrate and the first electrode.

5. The LC filter according to claim 4, wherein the substrate has sides different from the first main surface and the second main surface, the second conductor includes a power supply terminal, and the power supply terminal is located on the side of the substrate.

6. The LC filter according to claim 5, wherein the second conductor includes the power supply terminal and the seventh conductor, the power supply terminal is located on the second main surface, and the seventh conductor is located inside the substrate and connected to the power supply terminal and the first electrode.

7. The LC filter according to claim 2 or 3, further comprising a fifth electrode positioned between the second electrode and the ground electrode, and between the third electrode and the ground electrode, wherein the fifth electrode is positioned opposite the second electrode and the third electrode with a gap between them.

8. An LC filter according to claim 3, comprising: a fifth electrode disposed between the second electrode and the ground electrode and between the third electrode and the ground electrode; and a sixth electrode disposed between the third electrode and the ground electrode and between the fourth electrode and the ground electrode, wherein the fifth electrode is disposed opposite to the second electrode and the third electrode with a gap between them, and the sixth electrode is disposed opposite to the third electrode and the fourth electrode with a gap between them.

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