Filter apparatus

Abstract

To provide a filter apparatus capable of achieving a required attenuation characteristic even when its size is reduced.SOLUTION: A filter apparatus 100 according to the present disclosure comprises: an insulator 3; a first coil element L1; an external electrode 4e; a second coil element L2; an external electrode 4a; an electrode pattern 7a; an electrode pattern 7b; and an external electrode 4d. The insulator 3 has a pair of main surfaces facing each other and a side surface connecting the main surfaces. The first coil element L1 forms a spiral-shaped coil within the insulator 3. The second coil element L2 overlaps at least a part of the first coil element L1 when viewed in a plan view from a side of one of the main surfaces, and forms a helical-shaped coil within the insulator 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a filter device. [Background technology]

[0002] In recent years, with the development of communication technology, it has become necessary for communication terminals to support multiple frequency bands and multiple communication methods. To this end, communication terminals are provided with filter devices such as low-pass filters in which a signal pass band and an attenuation band are set. For example, Japanese Patent No. 7021723 (Patent Document 1) describes a filter device such as a low-pass filter that includes two coil elements connected in series to a signal path and a capacitor connected in shunt to the signal path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7021723 Summary of the Invention [Problem to be solved by the invention]

[0004] However, as the equipment in which the filter device is mounted becomes smaller, the filter device itself must also become smaller. When a filter device is an electronic component constructed within a single insulator, the distance between the two coil elements becomes closer as the device becomes smaller, increasing the impact of magnetic field coupling between the two coil elements. In a filter device, if the impact of magnetic field coupling between the two coil elements becomes too great, the required attenuation characteristics cannot be obtained.

[0005] Therefore, an object of the present disclosure is to provide a filter device that can obtain the required attenuation characteristics even when it is miniaturized. [Means for solving the problem]

[0006] A filter device according to one embodiment of the present disclosure includes an insulator, a first coil element, a first external electrode, a second coil element, a second external electrode, a first electrode pattern, a second electrode pattern, and a third external electrode. The insulator has a pair of opposing main surfaces and a side surface connecting the main surfaces. The first coil element forms a spiral-shaped coil within the insulator. The first external electrode is electrically connected to one end of the first coil element. The second coil element overlaps at least a portion of the first coil element when viewed from one of the main surfaces, forming a helical-shaped coil within the insulator. The second external electrode is electrically connected to one end of the second coil element. The first electrode pattern is electrically connected to the other end of the first coil element and the other end of the second coil element and is formed within the insulator. The second electrode pattern is disposed opposite the first electrode pattern and forms a first capacitor. The third external electrode is electrically connected to the second electrode pattern. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, by providing a first coil element that forms a spiral-shaped coil and a second coil element that forms a helical-shaped coil, the effects of magnetic field coupling between the two coil elements can be suppressed, thereby obtaining the required attenuation characteristics even when the device is miniaturized. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view of a filter device according to a first embodiment. [Figure 2] 1 is an exploded perspective view showing the configuration of a filter device according to a first embodiment. [Figure 3] 1 is a circuit diagram of a filter device according to a first embodiment. [Figure 4] 4 is a graph showing the transmission characteristics of a low-pass filter of the filter device according to the first embodiment. [Figure 5] 4 is a graph showing the transmission characteristics of a high-pass filter of the filter device according to the first embodiment. [Figure 6] FIG. 10 is a perspective view of a filter device according to a second embodiment. [Figure 7] FIG. 10 is an exploded perspective view showing the configuration of a filter device according to a second embodiment. [Figure 8] 10 is a graph showing the transmission characteristics of a low-pass filter of the filter device according to the second embodiment. [Figure 9] 10 is a graph showing the transmission characteristics of a high-pass filter of the filter device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A diplexer will be described in detail below as an example of a filter device according to an embodiment, with reference to the drawings. Note that identical or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, the filter device according to the embodiment is not limited to a diplexer. The filter device according to the embodiment may include at least the configuration of a low-pass filter described below. Furthermore, the low-pass filter described below will be described using a third-order T-type LC filter circuit, but it may also be a fifth-order T-type LC filter circuit or a higher-order T-type LC filter circuit.

[0010] (Embodiment 1) [Filter device structure] First, a filter device according to a first embodiment will be described with reference to the drawings. Fig. 1 is a perspective view of a filter device 100 according to the first embodiment. Fig. 2 is an exploded perspective view showing the configuration of the filter device 100 according to the first embodiment. Fig. 3 is a circuit diagram of the filter device 100 according to the first embodiment. Here, in Figs. 1 and 2, the short side direction of the filter device 100 is the X direction, the long side direction is the Y direction, and the height direction is the Z direction.

[0011] The filter device 100 is a diplexer that combines two filter circuits, one of which has a low-pass filter on the low-pass side port and a high-pass filter on the high-pass side port. The filter device 100 is composed of an insulator 3, which is a rectangular parallelepiped chip component and in which multiple insulating substrates (insulator layers) are stacked. The insulating substrates are stacked in the Z direction, with the arrow pointing upward. The insulating substrates are made of materials such as an insulating material containing borosilicate glass as a main component, or insulating resins such as alumina, zirconia, or polyimide resin. Furthermore, the interfaces between the multiple insulating substrates in the insulator 3 may not be clear due to processes such as baking and hardening.

[0012] The insulator 3 has a pair of opposing main surfaces, and the lower main surface in FIG. 1 is the mounting surface, which faces the circuit board. In this embodiment, the lower main surface in FIG. 1 is also referred to as the bottom surface, and the upper main surface in FIG. 1 is also referred to as the top surface. When viewed from above from the top surface of the main surfaces, the insulator 3 has a first region 100a that forms a low-pass filter and a second region 100b that forms a high-pass filter.

[0013] The first region 100a includes a low-pass filter LPF configured with a first coil element L1 and a second coil element L2 connected in series to a signal path connecting the first terminal P1 and the second terminal P2 shown in the circuit diagram of Fig. 3, and a first capacitor C1 connected in shunt to the signal path. As shown in Fig. 1 and Fig. 2, in the first region 100a of the insulator 3, the first coil element L1, the second coil element L2, and the first capacitor C1 are arranged in this order from the top surface side to the bottom surface side of the insulator 3.

[0014] The first coil element L1 forms a spiral-shaped coil within the insulator 3, and includes spiral-shaped first coil patterns 1a and 1b as shown in Fig. 2. The first coil pattern 1a is formed on an insulating substrate 3b, and the first coil pattern 1b is formed on an insulating substrate 3c. One end of the first coil pattern 1a and one end of the first coil pattern 1b are electrically connected via an external electrode 4e (first external electrode). The other end of the first coil pattern 1a and the other end of the first coil pattern 1b are electrically connected via a via conductor 11.

[0015] The first coil element L1 is configured by connecting first coil patterns 1a and 1b of the same shape in parallel. Generally, to increase the inductance of a spiral-shaped coil, a large area is required on the surface of the insulating substrate due to the need to increase the number of turns. Therefore, in the first coil element L1, the first coil patterns 1a and 1b of the same shape are connected in parallel to ensure the necessary inductance within the insulator 3, which has a limited area. In addition, the parallel connection of the first coil patterns 1a and 1b forms a second capacitor C2 connected in parallel to the first coil element L1 shown in the circuit diagram of FIG. 3.

[0016] A second coil element L2 that forms a helical-shaped coil within the insulator 3 is disposed below the first coil element L1. The second coil element L2 includes second coil patterns 2a, 2b, and 2c that form part of the helical-shaped coil, as shown in Fig. 2. The second coil pattern 2a is formed on an insulating substrate 3d, the second coil pattern 2b is formed on an insulating substrate 3e, and the second coil pattern 2c is formed on an insulating substrate 3f.

[0017] One end of the second coil pattern 2a is electrically connected to the other ends of the first coil pattern 1a and the first coil pattern 1b via via conductors 11, connecting the first coil element L1 and the second coil element L2 in series. The other end of the second coil pattern 2a is electrically connected to one end of the second coil pattern 2b via via conductors 12. The other end of the second coil pattern 2b is electrically connected to one end of the second coil pattern 2c via via conductors 13. The other end of the second coil pattern 2c is electrically connected to the external electrode 4a (second external electrode). In this way, the second coil patterns 2a to 2c formed on different insulating substrates 3e to 3f are electrically connected by the via conductors 12 and 13 to form the helical-shaped second coil element L2.

[0018] A first capacitor C1 is disposed below the second coil element L2. The first capacitor C1 includes an electrode pattern 7a (first electrode pattern) shown in Fig. 2 and an electrode pattern 7b (second electrode pattern) disposed opposite the electrode pattern 7a. The electrode pattern 7a is formed on an insulating substrate 3g, and the electrode pattern 7b is formed on an insulating substrate 3h.

[0019] The electrode pattern 7a is electrically connected to the second coil pattern 2a through via conductors 14. The second coil pattern 2a is further electrically connected to the first coil pattern 1a through via conductors 11, so that the electrode pattern 7a is electrically connected to the first coil element L1 and the second coil element L2. The electrode pattern 7b is electrically connected to the external electrode 4d (third external electrode).

[0020] In addition to the electrode pattern 7a, an electrode pattern 8a is formed on the insulating substrate 3g. The electrode pattern 8a is electrically connected to the external electrode 4a and is disposed opposite the electrode pattern 8b formed on the insulating substrate 3h. The electrode pattern 8b is disposed opposite not only the electrode pattern 8a but also the electrode pattern 7a. Therefore, the electrode patterns 8a and 8b form a third capacitor C3 shown in the circuit diagram of FIG. 3. In the circuit diagram of FIG. 3, the first terminal P1 corresponds to the external electrode 4e (first external electrode), the second terminal P2 corresponds to the external electrode 4a (second external electrode), and GND corresponds to the external electrode 4d (third external electrode).

[0021] The second region 100b includes a high-pass filter HPF configured with a fourth capacitor C4, a third coil element L3, a fourth coil element L4, and a fifth capacitor C5 connected in series to a signal path connecting the first terminal P1 and the third terminal P3 shown in the circuit diagram of Fig. 3, and a fifth coil element L5 connected in shunt to the signal path. As shown in Figs. 1 and 2, the fourth capacitor C4, the third coil element L3, the fourth coil element L4, the fifth capacitor C5, and the fifth coil element L5 are arranged within the insulator 3 in the second region 100b of the insulator 3.

[0022] The fourth capacitor C4 includes an electrode pattern 9a (fourth electrode pattern) shown in FIG. 2 and an electrode pattern 9b (third electrode pattern) disposed opposite the electrode pattern 9a. The electrode pattern 9a is formed on an insulating substrate 3g, and the electrode pattern 9b is formed on an insulating substrate 3h. The electrode pattern 9a is electrically connected to the third coil pattern 5a through a via conductor 15. The electrode pattern 9b is electrically connected to an external electrode 4e (first external electrode).

[0023] The third coil element L3 includes a third coil pattern 5a and a third coil pattern 5b that form part of a helical coil as shown in Fig. 2. The third coil pattern 5a is formed on an insulating substrate 3b, and the third coil pattern 5b is formed on an insulating substrate 3c.

[0024] One end of the third coil pattern 5a is electrically connected to the electrode pattern 9a through the via conductor 15, connecting the fourth capacitor C4 and the third coil element L3 in series. The other end of the third coil pattern 5a is electrically connected to one end of the third coil pattern 5b through the via conductor 16. In this way, the third coil patterns 5a and 5b formed on the different insulating substrates 3b and 3c are electrically connected by the via conductor 16 to form the helical-shaped third coil element L3.

[0025] The fourth coil element L4 includes fourth coil patterns 6a, 6b, 6c, 6d, and 6e that form part of a helical-shaped coil as shown in Fig. 2. The fourth coil pattern 6a is formed on the insulating substrate 3b, the fourth coil pattern 6b is formed on the insulating substrate 3c, the fourth coil pattern 6c is formed on the insulating substrate 3d, the fourth coil pattern 6d is formed on the insulating substrate 3e, and the fourth coil pattern 6e is formed on the insulating substrate 3f.

[0026] One end of the fourth coil pattern 6a is electrically connected to the other end of the third coil pattern 5b via a via conductor 17, connecting the third coil element L3 and the fourth coil element L4 in series. The other end of the fourth coil pattern 6a is electrically connected to one end of the fourth coil pattern 6b via a via conductor 18. The other end of the fourth coil pattern 6b is electrically connected to one ends of the fourth coil patterns 6c and 6d via a via conductor 19. The other ends of the fourth coil patterns 6c and 6d are electrically connected to one end of the fourth coil pattern 6e via a via conductor 20. In this way, the fourth coil patterns 6a to 6e formed on different insulating substrates 3b to 3f are electrically connected by the via conductors 18 to 20 to form the helical-shaped fourth coil element L4.

[0027] The fifth capacitor C5 includes an electrode pattern 10a (sixth electrode pattern) shown in Fig. 2 and an electrode pattern 10b (fifth electrode pattern) disposed opposite to the electrode pattern 10a. The electrode pattern 10a is formed on an insulating substrate 3g, and the electrode pattern 10b is formed on an insulating substrate 3h.

[0028] The electrode pattern 10a is electrically connected to the external electrode 4c (fifth external electrode). The electrode pattern 10b is electrically connected to the other end of the fourth coil pattern 6e through a via conductor 21, and connects the fifth capacitor C5 and the fourth coil element L4 in series.

[0029] The fifth coil element L5 includes a fifth coil pattern 5c and a fifth coil pattern 5d that form part of a helical coil as shown in Fig. 2. The fifth coil pattern 5c is formed on an insulating substrate 3d, and the fifth coil pattern 5d is formed on an insulating substrate 3e.

[0030] One ends of the fifth coil pattern 5c and the fifth coil pattern 5d are electrically connected to the third coil pattern 5b through via conductors 17. The third coil pattern 5b is further electrically connected to the fourth coil pattern 6a through via conductors 17. Therefore, the fifth coil element L5 is electrically connected to the third coil element L3 and the fourth coil element L4. The other ends of the fifth coil pattern 5c and the fifth coil pattern 5d are electrically connected to the external electrode 4f (fourth external electrode).

[0031] An electrode pattern 9a is formed on the insulating substrate 3g. The electrode pattern 9a is disposed so as to face not only the electrode pattern 9b but also the electrode pattern 10b. Therefore, the electrode patterns 9a and 10b form a sixth capacitor C6 shown in the circuit diagram of Fig. 3. In the circuit diagram of Fig. 3, the third terminal P3 corresponds to the external electrode 4c (fifth external electrode), and GND corresponds to the external electrode 4f (fourth external electrode).

[0032] The coil patterns and electrode patterns shown in Fig. 2 are each formed on insulating substrates 3a to 3i by a printing method. Electrode patterns that form part of external electrodes 4a to 4f are formed on insulating substrate 3a and insulating substrate 3i. The filter device 100 is formed by stacking the multiple insulating substrates 3a to 3i shown in Fig. 2 and then subjecting them to treatments such as baking and hardening. The external electrodes 4a to 4f are formed on the side surfaces of the insulator 3 that has been subjected to treatments such as baking and hardening.

[0033] [Characteristics of the filter device] As shown in FIGS. 1 and 2, the filter device 100 includes a low-pass filter LPF in which a first coil element L1 constituting a spiral-shaped coil and a second coil element L2 constituting a helical-shaped coil are connected in series, and a first capacitor C1 is connected in shunt. To reduce the size of the filter device 100, the first coil element L1 and the second coil element L2 need to be stacked vertically (Z direction), which shortens the distance between the two coil elements. However, if the influence of magnetic field coupling between the two coil elements becomes too great in the filter device, the required attenuation characteristics may not be achieved. Therefore, in the filter device 100, by configuring the first coil element L1 as a spiral-shaped coil, the influence of magnetic field coupling between the two coil elements can be reduced compared to when two helical-shaped coils are stacked vertically.

[0034] Unlike helical coils, which have coil wiring wound in a spiral shape, spiral coils have coil wiring wound on the same plane. As a result, the magnetic field strength generated in the direction perpendicular to the plane on which the coil wiring is wound is weaker in spiral coils than in helical coils. As a result, when one of the coils is a spiral coil, the magnetic field coupling between the coil elements is weaker than when two helical coils are stacked vertically.

[0035] Fig. 4 is a graph showing the transmission characteristics of the low-pass filter of the filter device 100 according to the embodiment 1. Fig. 5 is a graph showing the transmission characteristics of the high-pass filter of the filter device 100 according to the embodiment 1. In Fig. 4 and Fig. 5, the horizontal axis represents frequency and the vertical axis represents loss.

[0036] In Fig. 4, graph A shows the simulation results of the return loss on the input side of the low-pass filter of the filter device 100. Graph B shows the simulation results of the insertion loss in the low-pass filter of the filter device 100. Graph B in Fig. 4 shows that the filter device 100 functions as a low-pass filter (LPF) with two attenuation poles at approximately 1.9 GHz and 2.7 GHz. Graph B also shows that the mark m1 has a small insertion loss of -0.443 dB at a frequency of 0.96 GHz, while the mark m2 has a large insertion loss of -33.487 dB at a frequency of 1.71 GHz.

[0037] 5, graph C shows the simulation results of the return loss on the input side of the high-pass filter of the filter device 100. Graph D shows the simulation results of the insertion loss in the high-pass filter of the filter device 100. In graph D, the insertion loss at a frequency of 0.96 GHz for mark m3 is large at -32.703 dB, while the insertion loss at a frequency of 1.71 GHz for mark m4 is small at -0.423 dB. This shows that the filter device 100 functions as a high-pass filter HPF that passes a signal with a frequency of 1.71 GHz.

[0038] In the filter device 100, when the influence of magnetic field coupling between the first coil element L1 and the second coil element L2 increases, the attenuation between the two attenuation poles shown in graph B of Fig. 4 increases. However, as shown in graph B of Fig. 4, the attenuation between the two attenuation poles does not increase, which shows that the influence of magnetic field coupling between the two coil elements is suppressed by changing the first coil element L1 from a helical-shaped coil to a spiral-shaped coil.

[0039] From the viewpoint of suppressing the influence of magnetic field coupling between the two coil elements, it is preferable that the axis of the spiral shape of the first coil element L1 does not overlap with the axis of the helical shape of the second coil element L2 when viewed in a plan view from the top surface side of the insulator 3. Here, the axis of the spiral shape of the first coil element L1 is the central axis of the coil wiring wound in a spiral shape, and the axis of the helical shape of the second coil element L2 is the central axis of the coil wiring wound in a helical shape.

[0040] Furthermore, when the filter device 100 is configured as a diplexer, it is preferable that the inductance of the first coil element L1 be larger than the inductance of the second coil element L2, so that the attenuation pole of the low-pass filter LPF does not appear in the pass band of the high-pass filter HPF. Note that, because the first coil element L1 is a spiral-shaped coil, the coil wiring must be made longer to increase the inductance. However, if the coil wiring of the first coil element L1 is made longer, the area occupied by the first coil element L1 on the plane on which the first coil element L1 is formed (the XY plane in FIG. 1) increases, so the width of the coil wiring must be made narrower than the width of the coil wiring of the second coil element L2.

[0041] In the filter device 100, the first spiral coil element L1 is arranged on the side of the first terminal P1, which is the input side, as described above, but the second helical coil element L2 may also be arranged on the side of the first terminal P1. Note that by arranging the first spiral coil element L1 with a large insertion loss on the side of the first terminal P1 and then arranging the second helical coil element L2 with a high Q value in the subsequent stage, the transmission characteristics of the low-pass filter are further improved.

[0042] 1 and 2 , in the filter device 100, the first coil element L1, the second coil element L2, and the first capacitor C1 are arranged in the first region 100a of the insulator 3 in this order from the top to the bottom of the insulator 3. When configuring a diplexer with a high-pass filter in the second region 100b of the insulator 3 as in the filter device 100, it is preferable to arrange the first coil element L1, the second coil element L2, and the first capacitor C1 in the above order due to constraints such as the need to form the coil patterns of the coil elements of the low-pass filter and the high-pass filter on the same insulating substrate. However, if this constraint does not need to be taken into consideration, it is not necessary to arrange the first coil element L1, the second coil element L2, and the first capacitor C1 in this order from the top to the bottom of the insulator 3, and they may be arranged in a different order.

[0043] (Embodiment 2) In the filter device 100 according to the first embodiment, the first coil element L1 of the first coil element L1 and the second coil element L2 that constitute the low-pass filter is configured as a spiral-shaped coil. When the first coil element L1 is configured as a spiral-shaped coil, the area occupied by the first coil element L1 on the surface on which the first coil element L1 is formed (the XY plane in FIG. 1) becomes large. Therefore, when miniaturizing the filter device, it is considered that the inductance required for the design cannot be achieved by the spiral-shaped coil alone. Therefore, in the filter device according to the second embodiment, the first coil element L1 is configured to include a helical-shaped coil in addition to a spiral-shaped coil.

[0044] A filter device according to a second embodiment will be described with reference to the drawings. Fig. 6 is a perspective view of a filter device 100A according to the second embodiment. Fig. 7 is an exploded perspective view showing the configuration of the filter device 100A according to the second embodiment. In the filter device 100A shown in Figs. 6 and 7, the same components as those in the filter device 100 shown in Figs. 1 and 2 are designated by the same reference numerals, and detailed description thereof will not be repeated.

[0045] The filter device 100A is a diplexer that combines two filter circuits, one of which has a low-pass filter at its low-pass port and the other a high-pass filter at its high-pass port. When viewed from above from the top surface of the main surface, the insulator 3 has a first region 100a that constitutes a low-pass filter and a second region 100b that constitutes a high-pass filter.

[0046] As shown in FIGS. 6 and 7, in the first region 100a of the insulator 3, a first coil element L1, a second coil element L2, and a first capacitor C1 are arranged in this order from the top surface side to the bottom surface side of the insulator 3.

[0047] The first coil element L1 includes a first portion that forms a spiral-shaped coil within the insulator 3, and also includes a second portion that forms a helical-shaped coil. The first portion of the first coil element L1 includes a spiral-shaped first coil pattern 1a and a first coil pattern 1b, as shown in FIG. 7. The first coil pattern 1a is formed on an insulating substrate 3b, and the first coil pattern 1b is formed on an insulating substrate 3c. One end of the first coil pattern 1a and one end of the first coil pattern 1b are electrically connected via an external electrode 4e (first external electrode). The other end of the first coil pattern 1a and the other end of the first coil pattern 1b are electrically connected via a via conductor 11.

[0048] The second portion of the first coil element L1 includes a helical-shaped first coil pattern 1c as shown in Fig. 7. The first coil pattern 1c is formed on an insulating substrate 3d, and one end of the first coil pattern 1c is electrically connected to the other end of the first coil pattern 1a and the other end of the first coil pattern 1b through via conductors 11. The other end of the first coil pattern 1c is electrically connected to one end of a second coil pattern 2a of the second coil element L2, which is also formed on the insulating substrate 3d.

[0049] The first coil pattern 1c and the second coil pattern 2a are formed on the same insulating substrate 3d. The first coil pattern 1c (the second portion of the first coil element L1) is preferably located closer to the second region 100b than the second coil element L2. This allows the second coil element L2 to reduce the influence of the magnetic field from the coil elements of the high-pass filter, improving the transmission characteristics of the low-pass filter. Of course, if the influence of the magnetic field from the coil elements of the high-pass filter is small, the second coil element L2 may be located closer to the second region 100b than the second portion of the first coil element L1.

[0050] Furthermore, by forming the first coil pattern 1c and the second coil pattern 2a on the same insulating substrate 3d, the axis of the spiral shape (first portion) of the first coil element L1 and the axis of the helical shape of the second coil element L2 can be more offset when viewed from the top surface side. Note that the first coil pattern 1c does not need to be formed on the same insulating substrate 3d as the second coil pattern 2a, and may be formed on a different insulating substrate.

[0051] Furthermore, the other end of the first coil pattern 1c is electrically connected to the electrode pattern 7a through the via conductor 14. The other end of the first coil pattern 1c is further electrically connected to one end of the second coil pattern 2a, so that the electrode pattern 7a is electrically connected to the first coil element L1 and the second coil element L2.

[0052] In this way, the first coil element L1 includes not only the spiral-shaped first portion (first coil pattern 1a and first coil pattern 1b) but also the helical-shaped second portion (first coil pattern 1c), thereby ensuring the inductance required for the design even when the filter device 100A is miniaturized.

[0053] Fig. 8 is a graph showing the transmission characteristics of the low-pass filter of the filter device 100A according to the embodiment 2. Fig. 9 is a graph showing the transmission characteristics of the high-pass filter of the filter device 100A according to the embodiment 2. In Fig. 8 and Fig. 9, the horizontal axis represents frequency, and the vertical axis represents loss.

[0054] In Fig. 8, graph E shows the simulation results of the return loss on the input side of the low-pass filter of the filter device 100A. Graph F shows the simulation results of the insertion loss in the low-pass filter of the filter device 100A. Graph F in Fig. 8 shows that the filter device 100A functions as a low-pass filter (LPF) with two attenuation poles at approximately 1.8 GHz and 2.6 GHz. Also, in graph F, the insertion loss at the mark m5 is small at -0.428 dB at a frequency of 0.96 GHz, while the insertion loss at the mark m6 is large at -36.858 dB at a frequency of 1.71 GHz.

[0055] In the filter device 100A, the first coil element L1 includes a second helical portion (first coil pattern 1c) in addition to a first spiral portion (first coil pattern 1a and first coil pattern 1b). As a result, the inductance of the first coil element L1 in the filter device 100A is made larger than that of the filter device 100, and the insertion loss at a frequency of 0.96 GHz is improved from −0.443 dB (FIG. 4) to −0.428 dB (FIG. 8).

[0056] 9, graph G shows the simulation results of the return loss on the input side of the high-pass filter of the filter device 100A. Graph H shows the simulation results of the insertion loss in the high-pass filter of the filter device 100A. In graph H, the insertion loss at mark m7 is large at -33.139 dB at a frequency of 0.96 GHz, while the insertion loss at mark m8 is small at -0.417 dB at a frequency of 1.71 GHz. This shows that the filter device 100A functions as a high-pass filter (HPF) that passes a signal with a frequency of 1.71 GHz.

[0057] (Aspect) (1) A filter device according to the present disclosure includes: an insulator having a pair of opposing main surfaces and a side surface connecting the main surfaces; a first coil element that forms a spiral coil within the insulator; a first external electrode electrically connected to one end of the first coil element; a second coil element that overlaps at least a portion of the first coil element when viewed from one of the main surfaces and forms a helical coil within the insulator; a second external electrode electrically connected to one end of the second coil element; a first electrode pattern formed within the insulator and electrically connected to the other end of the first coil element and the other end of the second coil element; a second electrode pattern disposed opposite the first electrode pattern and constituting a first capacitor; and a third external electrode electrically connected to the second electrode pattern.

[0058] As a result, the filter device of the present disclosure comprises a first coil element that forms a spiral-shaped coil and a second coil element that forms a helical-shaped coil, thereby suppressing the effects of magnetic field coupling between the two coil elements and thereby achieving the required attenuation characteristics even when miniaturized.

[0059] (2) In the filter device described in (1), the inductance of the first coil element is greater than the inductance of the second coil element.

[0060] (3) In the filter device according to (1) or (2), When viewed from one of the main surfaces, the axis of the spiral shape of the first coil element and the axis of the helical shape of the second coil element do not overlap.

[0061] (4) In the filter device according to any one of (1) to (3), The first coil element includes a first portion constituting a spiral-shaped coil, and further includes a second portion constituting a helical-shaped coil.

[0062] (5) In the filter device according to (4), the insulator is formed by laminating a plurality of insulating substrates, the first portion of the first coil element and the second coil element are formed on different insulating substrates; The second portion of the first coil element and a part of the second coil element are formed on the same insulating substrate.

[0063] (6) In the filter device according to any one of (1) to (5), The first coil element, the second coil element, and the first capacitor are arranged in this order from one surface side to the other surface side of the main surfaces.

[0064] (7) In the filter device according to any one of (1) to (3), the insulator, when viewed in plan from one of the main surfaces, has a first region that includes the first coil element, the second coil element, and the first capacitor and configures a low-pass filter, and a second region that configures a high-pass filter, The second region is a third electrode pattern electrically connected to the first external electrode; a fourth electrode pattern disposed opposite the third electrode pattern and constituting a second capacitor; a third coil element, one end of which is electrically connected to the fourth electrode pattern and which forms a helical coil within the insulator; a fourth coil element, one end of which is electrically connected to the other end of the third coil element and which forms a helical coil within the insulator; a fourth external electrode electrically connected to the other end of the fourth coil element; a fifth coil element, one end of which is electrically connected to the other end of the third coil element and which forms a helical coil within the insulator; a fifth electrode pattern formed within the insulator and electrically connected to the other end of the fifth coil element; a sixth electrode pattern that is disposed opposite the fifth electrode pattern and that constitutes a third capacitor; and a fifth external electrode electrically connected to the sixth electrode pattern.

[0065] (8) In the filter device according to (7), the first coil element further includes a second portion constituting a helical coil in addition to a first portion constituting a spiral coil, The second portion is provided at a position closer to the second region than the second coil element.

[0066] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0067] 3 Insulator, 3a to 3i Insulating substrate, 4a to 4f External electrodes, 100, 100A Filter device, C1 First capacitor, C2 Second capacitor, C3 Third capacitor, C4 Fourth capacitor, C5 Fifth capacitor, C6 Sixth capacitor, L1 First coil element, L2 Second coil element, L3 Third coil element, L4 Fourth coil element, L5 Fifth coil element.

Claims

1. an insulator having a pair of opposing main surfaces and a side surface connecting the main surfaces; a first coil element that forms a spiral coil within the insulator; a first external electrode electrically connected to one end of the first coil element; a second coil element that overlaps at least a portion of the first coil element when viewed from one of the main surfaces and forms a helical coil within the insulator; a second external electrode electrically connected to one end of the second coil element; a first electrode pattern formed within the insulator and electrically connected to the other end of the first coil element and the other end of the second coil element; a second electrode pattern disposed opposite the first electrode pattern and constituting a first capacitor; a third external electrode electrically connected to the second electrode pattern.

2. The filter device according to claim 1 , wherein the inductance of the first coil element is greater than the inductance of the second coil element.

3. 2. The filter device according to claim 1, wherein, when viewed in a plan view from one of the main surfaces, the axis of the spiral shape of the first coil element does not overlap with the axis of the helical shape of the second coil element.

4. 2. The filter device according to claim 1, wherein the first coil element further includes a second portion constituting a helical coil in addition to a first portion constituting a spiral coil.

5. the insulator is formed by laminating a plurality of insulating substrates, the first portion of the first coil element and the second coil element are formed on different insulating substrates, The filter device according to claim 4 , wherein the second portion of the first coil element and a part of the second coil element are formed on the same insulating substrate.

6. A filter device as described in any one of claims 1 to 5, wherein the first coil element, the second coil element, and the first capacitor are arranged in order from one side of the main surface to the other side.

7. the insulator has, when viewed in plan from one of the main surfaces, a first region that includes the first coil element, the second coil element, and the first capacitor and configures a low-pass filter, and a second region that configures a high-pass filter, The second region is a third electrode pattern electrically connected to the first external electrode; a fourth electrode pattern disposed opposite the third electrode pattern and constituting a second capacitor; a third coil element, one end of which is electrically connected to the fourth electrode pattern and which forms a helical coil within the insulator; a fourth coil element, one end of which is electrically connected to the other end of the third coil element and which forms a helical coil within the insulator; a fourth external electrode electrically connected to the other end of the fourth coil element; a fifth coil element, one end of which is electrically connected to the other end of the third coil element and which forms a helical coil within the insulator; a fifth electrode pattern formed within the insulator and electrically connected to the other end of the fifth coil element; a sixth electrode pattern disposed opposite the fifth electrode pattern and constituting a third capacitor; 4. The filter device according to claim 1, further comprising: a fifth external electrode electrically connected to the sixth electrode pattern.

8. the first coil element further includes a second portion constituting a helical coil in addition to a first portion constituting a spiral coil, The filter device according to claim 7 , wherein the second portion is provided at a position closer to the second region than the second coil element.

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