FILTER DEVICE, HIGH-FREQUENCY MODULE, AND COMMUNICATION DEVICE

Abstract

The present disclosure provides a filter device that can be used in a high-frequency band, a high-frequency module including the same, and a communication device. A filter device (100) according to the present disclosure comprises a first terminal (P1), a first inductor (L1), a second inductor (L2), a second terminal (P2), and a capacitor (Cg) connected between a first connection point (T1) and the ground. Further, the filter device (100) includes capacitors (C1, C2) connected to at least one of between a second connection point (T2) between the first terminal (P1) and the first inductor (L1) and the ground, or between a third connection point (T3) between the second terminal (P2) and the second inductor (L2) and the ground. The first inductor (L1) and the second inductor (L2) are additively connected to each other.

Description

[Technical field]

[0001] The present disclosure relates to a filter device, a high-frequency module, and a communication device. [Background technology]

[0002] A known filter device is a low-pass filter described in Japanese Utility Model Publication No. 60-35297 (Patent Document 1). This filter device has two inductors connected in series between an input terminal and an output terminal, and the two inductors are magnetically coupled to each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Jpn. Jpn. Published No. 60-35297 Summary of the Invention [Problem to be solved by the invention]

[0004] In the filter device described in Patent Document 1, it is necessary to increase the magnetic field coupling between the inductors in order to obtain desired characteristics. However, in this filter device, it is difficult to generate strong magnetic field coupling between the inductors while ensuring the inductance value required for designing the filter circuit.

[0005] In particular, when using filter devices in communications at high frequencies such as several hundred MHz or several GHz, it is not possible to use magnetic materials with high losses, and parasitic inductance (equivalent series inductance (ESL)) functions as leakage inductance, making it difficult to ensure the necessary coupling coefficient.

[0006] Therefore, an object of the present disclosure is to provide a filter device that can be used in high frequency bands, a high frequency module including the same, and a communication device. [Means for solving the problem]

[0007] A filter device according to an embodiment of the present disclosure includes a first terminal, a first inductor connected to the first terminal, a second inductor connected in series with the first inductor, a second terminal connected to the second inductor, and a first capacitor connected between a first connection point between the first inductor and the second inductor and ground, and a second capacitor connected at least one of between a second connection point between the first terminal and the first inductor and ground and between a third connection point between the second terminal and the second inductor and ground. The first inductor, the second inductor, the first capacitor, and the second capacitor are formed in an insulator having a pair of opposing main surfaces and a side surface connecting the main surfaces. The insulator includes a plurality of first wiring patterns disposed inside the insulator and constituting a part of the first inductor, and a plurality of second wiring patterns disposed so as to at least partially overlap the first wiring patterns when viewed in plan from one of the main surfaces and constituting a part of the second inductor. The first wiring patterns and the second wiring patterns are alternately stacked in the insulator. The first inductor and the second inductor are sum-connected to each other.

[0008] A radio frequency module according to an embodiment of the present disclosure includes the filter device and an electronic component connected to the filter device. Also, a communication device according to an embodiment of the present disclosure includes the radio frequency module. Effect of the Invention

[0009] According to one embodiment of the present disclosure, a second capacitor is provided connected at least one of between a second connection point between the first terminal and the first inductor and ground, and between a third connection point between the second terminal and the second inductor and ground, and the first inductor and the second inductor are sum-connected to each other, thereby ensuring a coupling coefficient necessary for use in high frequency bands. [Brief description of the drawings]

[0010] [Figure 1] 1 is a circuit diagram of a filter device according to a first embodiment. [Diagram 2] FIG. 4 is an equivalent circuit diagram of a filter device for comparison. [Diagram 3] 4 is a graph showing the transmission characteristics of the filter device according to the first embodiment. [Figure 4] 1 is a perspective view of a filter device according to a first embodiment. [Diagram 5]1 is an exploded plan view showing a configuration of a filter device according to a first embodiment. [Figure 6] 4 is a graph showing transmission characteristics versus frequency of the filter device according to the first embodiment. [Figure 7] FIG. 11 is a circuit diagram of a filter device according to a second embodiment. [Figure 8] 11 is a graph showing transmission characteristics versus frequency of a filter device according to a second embodiment. [Figure 9] 10 is a graph showing another transmission characteristic versus frequency of the filter device according to the second embodiment. [Figure 10] FIG. 11 is a circuit diagram of a filter device according to a third embodiment. [Figure 11] 11 is a graph showing transmission characteristics versus frequency of a filter device according to a third embodiment. [Figure 12] FIG. 11 is a circuit diagram of a filter device according to a fourth embodiment. [Figure 13] FIG. 11 is an exploded plan view showing the configuration of a filter device according to a fifth embodiment. [Figure 14] 13 is an exploded plan view showing another configuration of the filter device according to the fifth embodiment. FIG. [Figure 15] 13 is an exploded plan view showing still another configuration of the filter device according to the fifth embodiment. FIG. [Figure 16] FIG. 1 is a schematic diagram showing a communication device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A filter device, a high-frequency module, and a communication device according to the present embodiment will be described below.

[0012] (Embodiment 1) First, a filter device according to a first embodiment will be described with reference to the drawings. Fig. 1 is a circuit diagram of a filter device 100 according to the first embodiment. The filter device 100 is a pass filter used in communications in a high frequency band, such as several hundreds of MHz or several GHz. In particular, the filter device 100 is an LC filter circuit as shown in Fig. 1.

[0013] Specifically, the filter device 100 includes a first terminal P1, a first inductor L1 connected to the first terminal P1, a second inductor L2 connected in series to the first inductor L1, a second terminal P2 connected to the second inductor L2, and a capacitor Cg (first capacitor) connected between a first connection point T1 between the first inductor L1 and the second inductor L2 and ground. The filter device 100 also includes a capacitor C12 (third capacitor) connected in parallel to the first inductor L1 and the second inductor L2 between the first terminal P1 and the second terminal P2. The first inductor L1 and the second inductor L2 are sum-connected to each other. Due to the sum-connection, a negative inductor (-M) remains in the circuit configuration.

[0014] The filter device 100 further includes a capacitor C1 (second capacitor) connected between a second connection point T2 between the first terminal P1 and the first inductor L1 and ground, and a capacitor C2 (second capacitor) connected between a third connection point T3 between the second terminal P2 and the second inductor L2 and ground. The capacitors C1 and C2 are shunt capacitors. In the filter device 100, both the capacitor C1 and the capacitor C2 are provided as shunt capacitors, but a configuration in which either the capacitor C1 or the capacitor C2 is provided as the shunt capacitor may be used.

[0015] In the filter device 100, the degree (number of stages) of the filter is increased by providing a shunt capacitor. It is known that in a general filter device that does not use a negative inductor, the constant of each constituent element decreases as the degree (number of stages) increases. Although it is not known in the case of a filter device using a negative inductor, it has been found that providing a shunt capacitor reduces the magnitude of the negative inductance (-M) generated by magnetic coupling between the first inductor L1 and the second inductor L2, the sum of the first inductor L1 and the lossless inductor (+M), and the sum of the second inductor L2 and the lossless inductor (+M), which are necessary to obtain desired characteristics.

[0016] Here, a comparative filter device that does not include the capacitors C1 and C2, which are shunt capacitors, will be described. Fig. 2 is an equivalent circuit diagram of the comparative filter device 200. In the filter device 200, a first inductor L1 and a second inductor L2 are connected in series between a first terminal P1 and a second terminal P2, similar to the filter device 100. Note that since the circuit shown in Fig. 2 is an equivalent circuit diagram of the filter device 200, a negative inductor (-M) and a lossless inductor (+M) generated by magnetic coupling between the first inductor L1 and the second inductor L2 are also shown.

[0017] Like the filter device 200, the filter device 100 can cancel the parasitic inductance of the capacitor Cg and can reduce the constants of the constituent elements by providing the capacitors C1 and C2, which are shunt capacitors. Therefore, in the filter device 100, by reducing the inductance of the first inductor L1 and the second inductor L2, the parasitic resistance (equivalent series resistance (ESR)) itself can be reduced and the insertion loss can be improved.

[0018] Furthermore, in the filter device 100, a lossless inductor (+M) generated by magnetically coupling the first inductor L1 and the second inductor L2 can reduce parasitic resistance and improve insertion loss. Fig. 3 is a graph showing the transmission characteristics of the filter device 100 according to the first embodiment. In Fig. 3, the horizontal axis represents frequency and the vertical axis represents insertion loss.

[0019] 3 in the filter device 200, which is a comparison example of the filter device 100, the values ​​of the first inductor L1 and the second inductor L2 of the filter device 200 must be small, and the value of the coupling coefficient k must be large. Specifically, in the filter device 200, the first inductor L1 and the second inductor L2 must be approximately 0.31 nH, the capacitor Cg must be approximately 0.54 pF, the capacitor C12 must be approximately 0.31, and the coupling coefficient k must be approximately 0.65. However, when actually manufacturing the filter device 200, it is difficult to obtain the required value of the coupling coefficient k because the values ​​of the first inductor L1 and the second inductor L2 are small.

[0020] On the other hand, in the filter device 100 according to the present embodiment, by providing the capacitors C1 and C2 which are shunt capacitors, it is possible to obtain the transmission characteristics shown in Fig. 3 with the values ​​of the first inductor L1 and the second inductor L2 and the value of the coupling coefficient k which can be actually made. Specifically, in the filter device 100, the first inductor L1 and the second inductor L2 are about 0.38 nH, the capacitor Cg is about 0.30 pF, the capacitor C12 is about 0.24, and the coupling coefficient k is about 0.35. Note that, since the newly provided capacitors C1 and C2 in the filter device 100 are small at about 0.16 pF, it is possible to obtain the transmission characteristics shown in Fig. 3 while keeping the filter device 100 itself compact.

[0021] As will be described later, the filter device 100 is formed as one chip component by laminating a plurality of insulating layers on which electrodes such as coil patterns are formed by photolithography.

[0022] As described above, in the filter device 100, the constants of each element can be reduced by providing the capacitors C1 and C2, which are shunt capacitors. Therefore, the negative inductor (-M) and lossless inductor (+M) required in the filter device 100 can also be reduced, and the coupling coefficient k itself between the first inductor L1 and the second inductor L2 can also be reduced. Therefore, by providing the capacitors C1 and C2, which are shunt capacitors, the filter device 100 can ensure the required coupling coefficient k while ensuring the required inductance value in the high frequency band.

[0023] Next, the structure of the filter device 100 will be described. FIG. 4 is a perspective view of the filter device 100 according to the first embodiment. FIG. 5 is an exploded plan view showing the configuration of the filter device 100 according to the first embodiment. As shown in FIGS. 4 and 5, the filter device 100 is composed of an insulator 3 in which a plurality of insulating layers on which wiring patterns of inductors and capacitors are formed are laminated. The insulating layers are made of materials such as an insulating material mainly composed of borosilicate glass, a dielectric ceramic material such as low-temperature fired ceramic, and an insulating resin such as glass epoxy resin and polyimide resin. In addition, the insulator 3 may have an unclear interface between the plurality of insulating layers due to treatment such as firing and hardening.

[0024] The insulator 3 has a pair of main surfaces facing each other and side surfaces connecting the main surfaces. Wiring patterns of the first inductor L1, the second inductor L2, and the capacitors C1, C2, and Cg are formed on the main surfaces of the insulating layers constituting the insulator 3. The main surface of the pair of main surfaces of the insulator 3 that is mounted on the board is called the bottom surface, and the opposite main surface is called the top surface. When viewed from a plane from one of the main surfaces (top surface), an electrode of the first terminal P1, an electrode of the second terminal P2, and electrodes of ground terminals G1 and G2 for grounding are formed at the four corners of the insulator 3. The respective electrodes are formed on three surfaces of the insulator 3: the side surfaces on the long sides, the side surfaces on the short sides, and the bottom surface.

[0025] In the filter device 100, a wiring pattern 16 (first wiring pattern) constituting a part of the first inductor L1 and a wiring pattern 12 (second wiring pattern) constituting a part of the second inductor L2 are arranged inside the insulator 3. In addition, in the filter device 100, wiring patterns 11 and 13 (the wiring pattern 11 is grounded) constituting a part of the capacitor Cg, a wiring pattern 15 (the wiring pattern 15 is grounded) constituting a part of the capacitor C1 and a wiring pattern arranged on the insulating layers 3d, 3g, and 3j, and a wiring pattern 14 (the wiring pattern 14 is grounded) constituting a part of the capacitor C2 and a wiring pattern arranged on the insulating layers 3b, 3e, and 3h are arranged inside the insulator 3. The capacitor C12 is formed at an overlapping portion between the wiring pattern 16 and the wiring pattern 12. In addition, a strong magnetic field coupling occurs at the overlapping portion between the wiring pattern 16 and the wiring pattern 12.

[0026] Moreover, the wiring patterns 16 and 12 are laminated in the direction between the main surfaces (the up-down direction in FIG. 4) within the insulator 3. Furthermore, the wiring patterns 16 and 12 are laminated alternately within the insulator 3, and the first inductor L1 and the second inductor L2 are additively connected to each other. In this manner, by laminating the wiring patterns 16 and 12, the necessary coupling coefficient k between the first inductor L1 and the second inductor L2 is ensured.

[0027] Note that a state in which inductors are additively connected is a connection state in which, when a current flows from one inductor to the other inductor via a connection point, the magnetic fields generated by the two inductors are oriented in the same direction and reinforce each other, that is, a connection state in which the magnetic flux that links the wiring patterns that make up the inductors is shared. For example, if two inductors are coil-shaped and the openings of the coils overlap when viewed in a plan view, the winding direction from the end of one coil to the connection point of the two coils is the same as the winding direction from the connection point of the two coils to the end of the other coil.

[0028] The configuration of each layer of the filter device 100 will be described with reference to the exploded plan view shown in Fig. 5. The electrode of the first terminal P1, the electrode of the second terminal P2, the electrodes of the ground terminals G1 and G2, and the wiring patterns 11 to 16 are formed on the insulating layers 3a to 3m by photolithography. On the insulating layer 3a shown in Fig. 5, the electrode of the first terminal P1, the electrode of the second terminal P2, and the electrodes of the ground terminals G1 and G2 are formed at the four corners.

[0029] The electrodes of the first terminal P1 formed on each layer are electrically connected by electrodes formed on the long side and short side as shown in FIG. 4. The electrodes of the second terminal P2 and the ground terminals G1 and G2 formed on each layer are also electrically connected by electrodes formed on the long side and short side as shown in FIG. 4. Instead of the electrodes formed on the long side and short side, the electrodes of the first terminal P1, the second terminal P2, and the ground terminals G1 and G2 formed on each layer may be electrically connected by connecting the layers with via conductors. In the filter device 100, the first terminal P1 and the second terminal P2 are arranged along one long side of the insulator 3, and the ground terminals G1 and G2 are arranged along the other long side of the insulator 3 as shown in FIG. 4. However, the arrangement of the terminals is not limited to this, and the filter device 100 may have the first terminal P1 and the second terminal P2 arranged along one short side of the insulator 3, and the ground terminals G1, G2 arranged along the other short side of the insulator 3.

[0030] A wiring pattern 11 and a wiring pattern 12 are formed on the insulating layer 3b. The wiring pattern 11 is electrically connected to the electrodes of the ground terminals G1 and G2, and constitutes the ground side electrode of the capacitor Cg. The wiring pattern 12 has a portion formed from the electrode of the second terminal P2 to a connection portion 12a along the long side and short side of the insulating layer 3b, which constitutes a part of the second inductor L2. Moreover, the wiring pattern 12 has a portion 12b extending from the electrode of the second terminal P2 along the short side, which constitutes the electrode on the third connection point T3 side of the capacitor C2.

[0031] On the insulating layer 3c, wiring patterns 13, 14, and 15 are formed. The wiring pattern 13 is formed from the connection portion 13a along the long side of the insulating layer 3c to the connection portion 13b. The connection portion 13a is electrically connected to the connection portion 12a of the insulating layer 3b by a via conductor, and the connection portion 13b is electrically connected to the connection portion 16a of the insulating layer 3d by a via conductor.

[0032] The wiring pattern 13 is also a first connection point T1 that connects the first inductor L1 and the second inductor L2, and constitutes a capacitor Cg between itself and the wiring pattern 11 disposed on the insulating layer 3b or the like. The wiring pattern 14 is formed from the electrode of the ground terminal G2 along the short side, and constitutes the ground side electrode of the capacitor C2. The wiring pattern 15 is formed from the electrode of the ground terminal G1 along the short side, and constitutes the ground side electrode of the capacitor C1.

[0033] A wiring pattern 11 and a wiring pattern 16 are formed on the insulating layer 3d. The wiring pattern 11 is electrically connected to the electrodes of the ground terminals G1 and G2, and constitutes the ground side electrode of the capacitor Cg. The wiring pattern 16 has a portion formed from the electrode of the first terminal P1 to a connection portion 16a along the long and short sides of the insulating layer 3d, which constitutes a part of the first inductor L1. Moreover, the wiring pattern 16 has a portion 16b extending from the electrode of the first terminal P1 along the short side, which constitutes the electrode on the second connection point T2 side of the capacitor C1.

[0034] The subsequent layers are a repetition of insulating layer 3b to insulating layer 3d. Insulating layers 3e and 3h have the same wiring pattern as insulating layer 3b. Insulating layers 3f and 3i have the same wiring pattern as insulating layer 3c. Insulating layers 3g and 3j have the same wiring pattern as insulating layer 3d.

[0035] The insulating layer 3k and the insulating layer 3l are formed with only the electrodes of the first terminal P1, the second terminal P2, and the ground terminals G1 and G2. The insulating layer 3m is formed with the electrodes of the first terminal P1, the second terminal P2, and the ground terminals G1 and G2 at its four corners for electrically connecting with the wiring of a substrate such as a high-frequency module when the filter device 100 is mounted on the substrate. The electrodes formed on the insulating layer 3m have a larger area than the other insulating layers 3a to 3l for electrically connecting with the wiring of the substrate.

[0036] The filter device 100 is formed by stacking a plurality of insulating layers 3a to 3m shown in Fig. 5 and then performing processes such as baking and hardening. An electrode of the first terminal P1, an electrode of the second terminal P2, and electrodes of the ground terminals G1 and G2 shown in Fig. 4 are formed on the side surfaces of the insulator 3 that has been subjected to processes such as baking and hardening.

[0037] In the filter device 100, the wiring pattern 16 and the wiring pattern 12 each have a loop shape of less than one turn when viewed in plan from the top surface side, and are combined with the wiring pattern 16 and the wiring pattern 12 to form a coil pattern of one or more turns within the insulator 3. Therefore, in the filter device 100, the wiring patterns 16 and 12, which are loop-shaped and connected in parallel and have less than one turn, are alternately stacked, thereby reducing the inductance value of the first inductor L1 and the second inductor L2 while ensuring a coupling coefficient k required for use in high frequency bands.

[0038] Furthermore, the wiring patterns 16 are formed on the insulating layers 3d, 3g, and 3j, and are electrically connected to each other by via conductors, thereby being connected in parallel. Also, the wiring patterns 12 are formed on the insulating layers 3b, 3e, and 3h, and are electrically connected to each other by via conductors, thereby being connected in parallel. With this configuration, it is possible to reduce the resistance generated in the first inductor L1 and the second inductor L2, and to obtain an inductor with a high Q value.

[0039] 6 is a graph showing the transmission characteristics versus frequency of filter device 100 according to the first embodiment. In FIG. 6, the horizontal axis represents frequency, and the vertical axis represents loss. Graph B shows the simulation results of return loss on the input side of filter device 100. Graph C shows the simulation results of insertion loss in filter device 100. Graph D shows the simulation results of return loss on the output side of filter device 100.

[0040] It can be seen that the filter device 100 functions as a low-pass filter (LPF) having two attenuation poles at approximately 13.5 GHz and approximately 17.3 GHz as shown in FIG.

[0041] As described above, the filter device 100 according to the first embodiment includes the first terminal P1, the first inductor L1 connected to the first terminal P1, the second inductor L2 connected in series to the first inductor L1, the second terminal P2 connected to the second inductor L2, and the capacitor Cg connected between the first connection point T1 between the first inductor L1 and the second inductor L2 and the ground. The filter device 100 further includes the capacitors C1 and C2 connected at least one of between the second connection point T2 between the first terminal P1 and the first inductor L1 and the ground, and between the third connection point T3 between the second terminal P2 and the second inductor L2 and the ground. The first inductor L1 and the second inductor L2 are sum-connected to each other.

[0042] As a result, the filter device 100 according to the first embodiment can ensure a coupling coefficient required for use in high frequency bands, and a small-sized pass filter that can be used in high frequency bands can be obtained.

[0043] It is also preferable to further include a capacitor C12 connected in parallel to the first inductor L1 and the second inductor L2 between the first terminal P1 and the second terminal P2. This allows the filter device 100 to increase the factors that determine the resonance frequency, thereby reducing the constants of each element, improving design freedom, and reducing the device size.

[0044] The first inductor L1, the second inductor L2, the capacitor Cg, and the capacitors C1 and C2 are formed in an insulator 3 having a pair of mutually opposing main surfaces and side surfaces connecting the main surfaces. The insulator 3 preferably includes a plurality of wiring patterns 16 arranged inside the insulator 3 and constituting a part of the first inductor L1, and a plurality of wiring patterns 12 arranged to at least partially overlap the wiring patterns 16 when viewed in plan from one of the main surfaces (top surface) and constituting a part of the second inductor L2. This allows the filter device 100 to realize a configuration of additive connection in which the direction of the current flowing through the first inductor L1 and the second inductor L2 is the same, and the generated magnetic field is also in the same direction.

[0045] The wiring pattern 16 and the wiring pattern 12 are preferably laminated in the direction between the principal surfaces within the insulator 3. This enables the filter device 100 to strengthen the magnetic field coupling by arranging the wiring patterns of the first inductor L1 and the second inductor L2 so as to overlap each other.

[0046] The wiring patterns 16 and 12 are preferably stacked alternately within the insulator 5. This allows the filter device 100 to arrange the wiring patterns of the first inductor L1 and the second inductor L2, which are to be magnetically coupled, close to each other in the stacking direction, thereby strengthening the magnetic field coupling.

[0047] The insulator 3 preferably includes an electrode connected to the first terminal P1, an electrode connected to the second terminal P2, and electrodes of the ground terminals G1 and G2. This allows the filter device 100 to effectively arrange the wiring pattern when the insulator 3 is viewed in plan from the top surface side, thereby achieving miniaturization.

[0048] Each of the wiring patterns 16 and 12 has a loop shape of less than one turn when viewed from one of the main surfaces (top surface), and it is preferable that the wiring patterns 16 and 12 are combined in the insulator 3 to form a coil pattern of one turn or more. This allows the filter device 100 to ensure a coupling coefficient k required for use in a high frequency band while reducing the inductance values ​​of the first inductor L1 and the second inductor L2. Furthermore, by combining the wiring patterns 16 and 12 to form a loop shape of one turn or more, it is possible to form a portion that strengthens the magnetic flux generated in the first inductor L1 and the second inductor L2 while connecting the inductors to each other. This allows the first inductor L1 and the second inductor L2 to be additively connected.

[0049] (Embodiment 2) In filter device 100 according to the first embodiment, capacitors C1 and C2 are directly connected to ground as shown in Fig. 1. However, in filter device 100 according to the second embodiment, a configuration in which capacitors C1 and C2 are connected to ground via inductors will be described. Fig. 7 is a circuit diagram of filter device 100A according to the second embodiment. Note that, in filter device 100A shown in Fig. 7, the same components as those in filter device 100 shown in Fig. 1 are denoted by the same reference numerals and detailed description thereof will not be repeated.

[0050] The filter device 100A includes a capacitor C1 (second capacitor) connected to the second connection point T2, and a third inductor L3 connected between the capacitor C1 and ground. The filter device 100A also includes a capacitor C2 (second capacitor) connected between the third connection point T3 and ground. The third inductor L3 may be provided between the capacitor C2 and ground, in addition to between the capacitor C1 and ground. The third inductor L3 is provided between the capacitor C2 and ground, but may not be provided between the capacitor C1 and ground.

[0051] Further, in the filter device 100A, the shunt capacitor is provided for both the capacitor C1 and the capacitor C2, but the shunt capacitor may be provided for either the capacitor C1 or the capacitor C2. In this case, the filter device 100A has a third inductor L3 provided between the provided shunt capacitor (the capacitor C1 or the capacitor C2) and ground.

[0052] Fig. 8 is a graph showing the transmission characteristics versus frequency of the filter device according to the second embodiment. Fig. 8 is a graph showing the transmission characteristics when the third inductor L3 is about 0.33 nH. The parameters of the other elements are set to the same values ​​as the parameters of the elements of the filter device 100 in the graph shown in Fig. 3. In Fig. 8, the horizontal axis represents frequency, the vertical axis represents insertion loss, and graph G1 is a simulation result of the insertion loss in the filter device 100A (L3=about 0.33 nH). Graph F1 is a simulation result of the insertion loss in a filter device without the third inductor L3.

[0053] 9 is a graph showing another transmission characteristic versus frequency of the filter device according to the second embodiment. In FIG. 9, the transmission characteristic is shown when the third inductor L3 is set to about 1.44 nH. The other parameters are the same as those in the simulation of the graph shown in FIG.

[0054] 9, the horizontal axis represents frequency, the vertical axis represents insertion loss, and graph H1 represents a simulation result of the insertion loss in the filter device 100A (L3=approximately 1.44 nH). Graph F1 represents a simulation result of the insertion loss in a filter device without the third inductor L3.

[0055] By providing a third inductor L3 connected in series to the shunt capacitor, the filter device 100A can increase the number of attenuation poles, make the attenuation band wider and deeper, and improve the steepness between the pass band and the attenuation band, as shown in Figures 8 and 9.

[0056] As described above, the filter device 100A according to the second embodiment further includes the third inductor L3 connected in series between the shunt capacitors (capacitors C1 and C2) and the ground. This allows the filter device 100A to form an attenuation pole in the attenuation band due to resonance between the shunt capacitors (capacitors C1 and C2) and the third inductor L3, thereby improving the attenuation characteristics and steepness.

[0057] (Embodiment 3) In the filter device 100 according to the first embodiment, a configuration has been described in which shunt capacitors (capacitors C1 and C2) are provided for one unit including a first inductor L1, a second inductor L2, and a capacitor Cg as shown in Fig. 1. In the filter device according to the third embodiment, a configuration will be described in which a plurality of units including a first inductor L1, a second inductor L2, and a capacitor Cg are connected and shunt capacitors are provided between them.

[0058] Fig. 10 is a circuit diagram of a filter device 100B according to an embodiment 3. In filter device 100B shown in Fig. 10, the same components as those in filter device 100 shown in Fig. 1 are denoted by the same reference characters and detailed description thereof will not be repeated.

[0059] Specifically, the filter device 100B includes a first terminal P1, a first inductor L1 connected to the first terminal P1, a second inductor L2 connected in series with the first inductor L1, a fourth inductor L4 connected in series with the second inductor L2, a fifth inductor L5 connected in series with the fourth inductor L4, and a second terminal P2 connected to the fifth inductor L5. The filter device 100B further includes a capacitor Cg1 (first capacitor) connected between a first connection point T1 between the first inductor L1 and the second inductor L2 and ground, and a capacitor Cg2 (first capacitor) connected between a fourth connection point T4 between the fourth inductor L4 and the fifth inductor L5 and ground. The first inductor L1 and the second inductor L2 are sum-connected to each other, and the fourth inductor L4 and the fifth inductor L5 are sum-connected to each other.

[0060] The filter device 100B has a configuration in which a unit including a first inductor L1, a second inductor L2, and a capacitor Cg1 is connected to a unit including a fourth inductor L4, a fifth inductor L5, and a capacitor Cg2. In other words, the filter device 100B has a configuration in which two circuit units shown in the filter device 100 are cascade-connected. The filter device 100B further includes a capacitor C12 (third capacitor) connected in parallel to the first inductor L1 and the second inductor L2, and a capacitor C45 (third capacitor) connected in parallel to the fourth inductor L4 and the fifth inductor L5.

[0061] The filter device 100B includes, as shunt capacitors, a capacitor C1 (second capacitor) connected to the second connection point T2, a capacitor C2 (second capacitor) connected to the third connection point T3, and a capacitor C3 (second capacitor) connected to the fifth connection point T5. Note that the filter device 100B is not limited to the case where shunt capacitors are provided at all of the second connection point T2, the third connection point T3, and the fifth connection point T5, and a shunt capacitor may be provided at at least one of the second connection point T2, the third connection point T3, and the fifth connection point T5.

[0062] Furthermore, in the filter device 100B, the third inductor L3 described in the second embodiment may be connected in series between the shunt capacitors (capacitors C1, C2, C3) and the ground.

[0063] Fig. 11 is a graph showing the transmission characteristics versus frequency of the filter device according to embodiment 3. In Fig. 11, a simulation of the filter device 100B is performed with the first inductor L1 and the fourth inductor L4 = approximately 0.325 nH, the second inductor L2 and the third inductor L3 = approximately 0.326 nH, the capacitors Cg1 and Cg2 = approximately 0.071 pF, the capacitors C12 and C45 = approximately 0.171 pF, the capacitors C1 and C3 = approximately 0.012 pF, the capacitor C2 = approximately 0.371 pF, and the coupling coefficient k = 0.348.

[0064] 11, the horizontal axis represents frequency, the vertical axis represents insertion loss, and graph I1 represents a simulation result of the insertion loss in the filter device 100B. Graph F1 represents a simulation result of the insertion loss in a filter device that does not include the fourth inductor L4 and the fifth inductor L5.

[0065] In the filter device 100B, as shown in FIG. 10, a plurality of units each including a first inductor L1, a second inductor L2, and a capacitor Cg are connected together, thereby making it possible to improve the steepness of the attenuation band as shown in FIG.

[0066] As described above, in the filter device 100B according to the third embodiment, a configuration including the first inductor L1, the second inductor L2, and the capacitor Cg is regarded as one unit, and a plurality of units are connected together, so that the attenuation characteristics can be improved.

[0067] (Embodiment 4) In the filter device 100 according to the first embodiment, a filter device of an unbalanced circuit (one line grounded) has been described as shown in Fig. 1. In the filter device according to the fourth embodiment, a filter device of a balanced circuit will be described. Fig. 12 is a circuit diagram of a filter device 100C according to the fourth embodiment.

[0068] Specifically, the filter device 100C includes a first balanced terminal P1a, a first balanced inductor L1a connected to the first balanced terminal P1a, a second balanced inductor L2a connected in series with the first balanced inductor L1a, and a second balanced terminal P2a connected to the second balanced inductor L2a.Furthermore, the filter device 100C includes a third balanced terminal P3a, a third balanced inductor L3a connected to the third balanced terminal P3a, a fourth balanced inductor L4a connected in series with the third balanced inductor L3a, and a fourth balanced terminal P4a connected to the fourth balanced inductor L4a.

[0069] The filter device 100C includes a capacitor Cg (first capacitor) connected between a first connection point T1a between the first balanced inductor L1a and the second balanced inductor L2a and a second connection point T2a between the third balanced inductor L3a and the fourth balanced inductor L4a. The filter device 100C further includes a capacitor C1a (second capacitor) connected between a third connection point T3a between the first balanced terminal P1a and the first balanced inductor L1a and a fourth connection point T4a between the third balanced terminal P3a and the third balanced inductor L3a, a fifth connection point T5a between the second balanced terminal P2a and the second balanced inductor L2a, and a sixth connection point T6a between the fourth balanced terminal P4a and the fourth balanced inductor L4a. The capacitors C1a and C2a are shunt capacitors. In the filter device 100C, a shunt capacitor is provided for both the capacitor C1a and the capacitor C2a, but a shunt capacitor may be provided for either the capacitor C1a or the capacitor C2a.

[0070] The filter device 100C may include a capacitor C12a (third capacitor) connected in parallel to the first balanced inductor L1a and the second balanced inductor L2a between the first balanced terminal P1a and the second balanced terminal P2a, and a capacitor C34a (third capacitor) connected in parallel to the third balanced inductor L3a and the fourth balanced inductor L4a between the third balanced terminal P3a and the fourth balanced terminal P4a. The first balanced inductor L1a and the second balanced inductor L2a are sum-connected to each other, and the third balanced inductor L3a and the fourth balanced inductor L4a are sum-connected to each other. Due to the sum-connection, a negative inductor (-M) remains in the circuit configuration. In the filter device 100C, the first balanced inductor L1a and the second balanced inductor L2a are sum-connected to each other, and the third balanced inductor L3a and the fourth balanced inductor L4a are sum-connected to each other, but a configuration in which either one of them is sum-connected may be used.

[0071] The transmission characteristics of the filter device 100C according to the fourth embodiment can be made the same as those of the filter device 100 shown in FIG. 3 by adjusting the parameter values ​​of each element.

[0072] (Embodiment 5) In the filter device 100 according to the first embodiment, the first inductor L1, the second inductor L2, and the capacitors C1, C2, Cg, and C12 are formed in the insulator 3 in a structure as shown in Fig. 4 and Fig. 5. In particular, the capacitor Cg (first capacitor) has a structure in which the wiring pattern 13 connecting the first inductor L1 and the second inductor L2 serves as one electrode, and the wiring pattern 11 connecting between the ground terminals G1 and G2 serves as the other electrode. However, the filter device is not limited to the structures of the first inductor L1, the second inductor L2, and the capacitor Cg as shown in Fig. 4 and Fig. 5, and may have a structure in which the first inductor L1, the second inductor L2, and the capacitor Cg are arranged in different regions inside the insulator 3.

[0073] Fig. 13 is an exploded plan view showing the configuration of a filter device 100D according to the first embodiment. In the filter device 100D, the electrode of the first terminal P1, the electrode of the second terminal P2, the ground terminal G, the electrode of the non-connect terminal N, and the wiring patterns 21 to 25 are each formed on the insulating layers 3A to 3F by photolithography. The insulating layer 3A shown in Fig. 13 has electrodes formed at its four corners. Specifically, the electrode of the first terminal P1 and the electrode of the second terminal P2 are arranged along one short side of the insulating layer 3A, and the electrode of the ground terminal G and the electrode of the non-connect terminal N are arranged along the other short side of the insulating layer 3A.

[0074] The electrodes of the first terminal P1 formed on each layer are electrically connected by electrodes formed on the long side and short side. The electrodes of the second terminal P2, the ground terminal G, and the non-connect terminal N formed on each layer are also electrically connected by electrodes formed on the long side and short side. Instead of the electrodes formed on the long side and short side, the layers may be connected by via conductors to electrically connect the electrodes of the first terminal P1, the second terminal P2, the ground terminal G, and the non-connect terminal N formed on each layer.

[0075] A wiring pattern 51, a wiring pattern 21, and a wiring pattern 61 are formed on the insulating layer 3B. The wiring pattern 51 is electrically connected to the electrode of the ground terminal G, and constitutes an electrode of a capacitor Cg (first capacitor) arranged on the left side of the insulating layer in the figure. The wiring pattern 21 is a wire for electrically connecting the wiring pattern 51 and a first inductor L1 arranged in the center of the insulating layer in the figure, and is formed from the wiring pattern 51 to a connection portion 21a. The wiring pattern 61 is electrically connected to the electrode of the first terminal P1, and constitutes an electrode on the first terminal P1 side of a capacitor C12 (third capacitor) arranged on the right side of the insulating layer in the figure.

[0076] A wiring pattern 52, a wiring pattern 22, and a wiring pattern 62 are formed on the insulating layer 3C. The wiring pattern 52 is electrically connected to the electrode of the non-connect terminal N, and constitutes an electrode of the capacitor Cg. The wiring pattern 22 constitutes a part of the first inductor L1, and is formed from the connection portion 22a to the connection portion 22b, forming a U-shaped pattern. The connection portion 22a is electrically connected to the connection portion 21a of the insulating layer 3B by a via conductor. When the filter device 100D is mounted on a substrate, a part of the wiring pattern 22 also functions as an electrode that constitutes a capacitor C1 (second capacitor) between the wiring pattern 22 and the ground wiring of the substrate. The wiring pattern 62 is electrically connected to the electrode of the second terminal P2, and constitutes an electrode on the second terminal P2 side of the capacitor C12.

[0077] The insulating layer 3D is provided with a wiring pattern 53, a wiring pattern 23, and a wiring pattern 63. The wiring pattern 53 is electrically connected to the electrode of the ground terminal G, and constitutes an electrode of the capacitor Cg. The wiring pattern 23 constitutes a part of the first inductor L1, and is formed from the connection portion 23a to the wiring pattern 63, forming a rectangular pattern. The connection portion 23a is electrically connected to the connection portion 22b of the insulating layer 3C by a via conductor. The wiring pattern 63 is electrically connected to the electrode of the first terminal P1, and constitutes an electrode on the first terminal P1 side of the capacitor C12.

[0078] A wiring pattern 54, a wiring pattern 24, and a wiring pattern 64 are formed on the insulating layer 3E. The wiring pattern 54 is electrically connected to the electrode of the non-connect terminal N, and constitutes an electrode of the capacitor Cg. The wiring pattern 24 constitutes a part of the second inductor L2, and is formed from the connection portion 24a to the wiring pattern 64, forming a rectangular pattern. The connection portion 24a is electrically connected to the connection portion 23a of the insulating layer 3D by a via conductor. The wiring pattern 64 is electrically connected to the electrode of the second terminal P2, and constitutes an electrode on the second terminal P2 side of the capacitor C12.

[0079] The insulating layer 3F is provided with a wiring pattern 55, a wiring pattern 25, a wiring pattern 26, and a wiring pattern 65. The wiring pattern 55 is electrically connected to the electrode of the ground terminal G, and constitutes an electrode of the capacitor Cg. The wiring pattern 25 constitutes a part of the second inductor L2, and is formed from the connection portion 25a to the connection portion 25b, forming a U-shaped pattern. The connection portion 25a is electrically connected to the connection portion 24a of the insulating layer 3E by a via conductor. The wiring pattern 26 is a wiring for electrically connecting the wiring pattern 55 and the second inductor L2, and is formed from the wiring pattern 55 to the connection portion 25b. The wiring pattern 65 is electrically connected to the electrode of the first terminal P1, and constitutes an electrode on the first terminal P1 side of the capacitor C12.

[0080] 13 are laminated and then subjected to treatment such as baking and hardening. An electrode for the first terminal P1, an electrode for the second terminal P2, an electrode for the ground terminal G, and an electrode for the non-connect terminal N are formed on the side surfaces of the insulator 3 that has been subjected to treatment such as baking and hardening.

[0081] In the filter device 100D, the first inductor L1 and the second inductor L2 are disposed in different regions inside the insulator 3, and therefore wiring patterns 21 and 26 are provided to electrically connect the first inductor L1 and the second inductor L2 to the capacitor Cg. The first inductor L1 and the second inductor L2 function as a transformer by being magnetically coupled. When the first inductor L1 and the second inductor L2 are simply connected to function as a transformer, the coupling coefficient k is approximately 0.53. The coupling coefficient k was obtained by performing a simulation for a configuration in which the coil outer diameter is 270 μm, the wiring pattern width is 30 μm, and the first inductor L1 and the second inductor L2 are each turned 1.5 times.

[0082] On the other hand, in the filter device 100D, the first inductor L1 and the second inductor L2 are connected via the capacitor Cg, and therefore the coupling coefficient k is reduced due to the parasitic inductances of the wiring patterns 51 to 55, the electrode of the ground terminal G, the electrode of the non-connect terminal N, etc. Specifically, when a similar simulation is performed on the filter device 100D, the coupling coefficient k is approximately 0.32, which is approximately 0.2 lower than in a configuration in which the first inductor L1 and the second inductor L2 are simply connected.

[0083] Therefore, a filter device having a structure in which the first inductor L1 and the second inductor L2 are connected without the capacitor Cg will be described. Fig. 14 is an exploded plan view showing another configuration of a filter device according to embodiment 5. In a filter device 100E shown in Fig. 14, the electrode of the first terminal P1, the electrode of the second terminal P2, the ground terminal G, the electrode of the non-connect terminal N, and the wiring patterns 21-25 are each formed on insulating layers 3A-3F by photolithography. Electrodes are formed at the four corners of the insulating layer 3A shown in Fig. 14. In the filter device 100E shown in Fig. 14, the same components as those of the filter device 100D shown in Fig. 13 are denoted by the same reference numerals and detailed description thereof will not be repeated.

[0084] On the insulating layer 3B, there are formed a wiring pattern 51, a wiring pattern 21, and a wiring pattern 61. In the wiring pattern 21, a connection portion 21b is formed between the wiring pattern 51 and the connection portion 21a.

[0085] On the insulating layer 3C, a wiring pattern 52, a wiring pattern 22, and a wiring pattern 62 are formed. Furthermore, a connection portion 22c is formed between the connection portion 22a and the wiring pattern 52. The connection portion 22a is electrically connected to the connection portion 21a of the insulating layer 3B by a via conductor, and the connection portion 22c is electrically connected to the connection portion 21b of the insulating layer 3B by a via conductor.

[0086] On the insulating layer 3D, a wiring pattern 53, a wiring pattern 23, and a wiring pattern 63 are formed. Furthermore, a connection portion 23b is formed between the wiring pattern 53 and the wiring pattern 23. Note that the connection portion 23a is electrically connected to the connection portion 22b of the insulating layer 3C by a via conductor, and the connection portion 23b is electrically connected to the connection portion 23b of the insulating layer 3C by a via conductor.

[0087] On the insulating layer 3E, a wiring pattern 54, a wiring pattern 24, and a wiring pattern 64 are formed. Furthermore, a connection portion 24b is formed between the wiring pattern 54 and the wiring pattern 24. Note that the connection portion 24a is electrically connected to the connection portion 23a of the insulating layer 3D by a via conductor, and the connection portion 24b is electrically connected to the connection portion 23b of the insulating layer 3D by a via conductor.

[0088] On the insulating layer 3F, a wiring pattern 55, a wiring pattern 25, a wiring pattern 27, and a wiring pattern 65 are formed. Furthermore, a connection portion 27a is formed between the wiring pattern 55 and the wiring pattern 25. The wiring pattern 27 is a wiring for electrically connecting the connection portion 27a and the connection portion 25b. The connection portion 25a is electrically connected to the connection portion 24a of the insulating layer 3E by a via conductor, and the connection portion 27a is electrically connected to the connection portion 24b of the insulating layer 3E by a via conductor.

[0089] 14 are laminated and then subjected to treatment such as baking and hardening. An electrode for the first terminal P1, an electrode for the second terminal P2, an electrode for the ground terminal G, and an electrode for the non-connect terminal N are formed on the side surfaces of the insulator 3 that has been subjected to treatment such as baking and hardening.

[0090] In the filter device 100E, the first inductor L1 and the second inductor L2, and the capacitor Cg are disposed in different regions inside the insulator 3, and therefore the wiring pattern 21 is provided to electrically connect the first inductor L1 and the second inductor L2, and the capacitor Cg. However, in the filter device 100E, the wiring pattern 25 of the second inductor L2 is not directly connected to the capacitor Cg, but is connected to the wiring pattern 21 through a via conductor. Therefore, in the filter device 100E, the first inductor L1 and the second inductor L2 are not connected through the capacitor Cg, and the second inductor L2 is connected to the first inductor L1 by the wiring pattern 21 and then connected to the capacitor Cg. Therefore, in the filter device 100E, no parasitic inductance is generated in the wiring patterns 51 to 55, the electrode of the ground terminal G, the electrode of the non-connect terminal N, and the like, and therefore a decrease in the coupling coefficient k can be suppressed. Specifically, when a similar simulation was performed on the filter device 100E, the coupling coefficient k was about 0.41, which is reduced by about 0.1 compared to the configuration in which the first inductor L1 and the second inductor L2 are simply connected. In other words, the coupling coefficient k of the filter device 100E can be improved by about 10% compared to the filter device 100D.

[0091] 13 and 14, in the filter devices 100D and 100E, the first terminal P1 and the second terminal P2 are arranged along one short side of the insulator 3, and the ground terminal G1 and the non-connect terminal N are arranged along the other short side of the insulator 3. However, the arrangement of the terminals is not limited to this, and in the filter devices 100D and 100E, the first terminal P1 and the second terminal P2 may be arranged along one long side of the insulator 3, and the ground terminal G1 and the non-connect terminal N may be arranged along the other long side of the insulator 3. Also, in the filter devices 100D and 100E, the non-connect terminal N may be the ground terminal G.

[0092] In the filter devices 100D and 100E, it has been described that a part of the wiring pattern 22 also functions as an electrode constituting a capacitor C1 (second capacitor) between the filter devices 100D and 100E and the ground wiring of the substrate when the filter devices 100D and 100E are mounted on the substrate. However, the present invention is not limited to this, and the capacitors C1 and C2 may be provided in the structures shown in the filter devices 100D and 100E. FIG. 15 is an exploded plan view showing still another configuration of the filter device according to the fifth embodiment. In the filter device 100F shown in FIG. 15, the electrode of the first terminal P1, the electrode of the second terminal P2, the ground terminal G, the electrode of the non-connect terminal N, and the wiring patterns 21 to 25 are formed on the insulating layers 3A to 3F by a photolithography method. In the filter device 100F shown in FIG. 15, the same components as those in the filter device 100D shown in FIG. 13 and the filter device 100E shown in FIG. 14 are denoted by the same reference numerals and will not be described in detail again.

[0093] On the insulating layer 3C, a wiring pattern 52, a wiring pattern 22, and a wiring pattern 62 are formed. The wiring pattern 52 is electrically connected to an electrode of the ground terminal G, and constitutes an electrode of a capacitor Cg (first capacitor) disposed on the left side of the insulating layer in the figure. Furthermore, the wiring pattern 52 is connected to a wiring pattern 52a that functions as one electrode of a capacitor C1 (second capacitor), and a wiring pattern 52b that functions as one electrode of a capacitor C2 (second capacitor).

[0094] The insulating layer 3D is formed with a wiring pattern 53, a wiring pattern 23, and a wiring pattern 63. The wiring pattern 23 constitutes a part of the first inductor L1, and is formed from a connection portion 23a to the wiring pattern 63 to form a rectangular pattern. Furthermore, the wiring pattern 23 is connected to a wiring pattern 23c that functions as the other electrode of the capacitor C1.

[0095] On the insulating layer 3E, a wiring pattern 54, a wiring pattern 24, and a wiring pattern 64 are formed. The wiring pattern 24 constitutes a part of the second inductor L2, and is formed from the connection portion 24a to the wiring pattern 64 to form a rectangular pattern. Furthermore, a wiring pattern 24c that functions as the other electrode of the capacitor C2 is connected to the wiring pattern 24.

[0096] 15 are laminated and then subjected to treatment such as baking and hardening. An electrode for the first terminal P1, an electrode for the second terminal P2, an electrode for the ground terminal G, and an electrode for the non-connect terminal N are formed on the side surfaces of the insulator 3 that has been subjected to treatment such as baking and hardening.

[0097] The filter device 100E has electrodes (wiring pattern 23c and wiring pattern 52a, and wiring pattern 24c and wiring pattern 52b) corresponding to capacitors C1 and C2 (second capacitors) in the circuit diagram shown in Fig. 1. Therefore, the filter device 100E is provided with both capacitors C1 and C2 as shunt capacitors. Of course, the filter device 100E may be configured to provide either capacitor C1 or capacitor C2 as a shunt capacitor.

[0098] The filter devices 100D to 100E have a common effect. As shown in FIG. 13, the wiring pattern 23 formed on the insulating layer 3D is connected to the wiring pattern 63 constituting the electrode of the capacitor C12. As shown in FIG. 13, the wiring pattern 24 formed on the insulating layer 3E is connected to the wiring pattern 64 constituting the electrode of the capacitor C12. Furthermore, the wiring patterns 23 and 24 overlap when viewed from the top surface side, and therefore can be regarded as a part of the electrode of the capacitor C12. Therefore, the area of ​​the wiring patterns 63 and 64 can be reduced by reducing the capacitance formed by the wiring patterns 63 and 64 by the capacitance formed by the wiring patterns 23 and 24. That is, in the filter device 100D, the wiring patterns 63 and 64 for forming the capacitor C12 can be reduced. The same effect is achieved for the filter devices 100E and 100F.

[0099] Furthermore, the distance from the wiring pattern 64 constituting the electrode of the capacitor C12 on the insulating layer 3E to the electrode of the first terminal P1 formed on the insulating layer 3A is substantially the same as the distance from the wiring pattern 63 constituting the electrode of the capacitor C12 on the insulating layer 3D to the electrode of the second terminal P2 formed on the insulating layer 3A. Therefore, in the filter device 100D, the parasitic inductance generated from the first terminal P1 to the second connection point T2 in the circuit diagram shown in Fig. 1 is substantially the same as the parasitic inductance generated from the second terminal P2 to the third connection point T3, making it easier to design the transformer coil. The same effect is achieved for the filter devices 100E and 100F.

[0100] (Modification) The filter devices 100, 100A to 100C described above are mounted on a high-frequency module, or directly provided in a communication device. Fig. 16 is a schematic diagram showing a communication device. A communication device 300 shown in Fig. 16 is capable of communication in a band including several hundreds of MHz and several GHz. For this reason, the communication device 300 is provided with a high-frequency module 150 that processes signals transmitted and received by an antenna, and the high-frequency module 150 is mounted on a substrate 310. The communication device 300 is, for example, a mobile phone, a smartphone, or a tablet.

[0101] The high frequency module 150 includes electronic components such as a filter device 100, a switch 110, and an amplifier 120. In addition to a substrate 310 on which the high frequency module 150 is mounted, the communication device 300 is also provided with a power supply circuit 320 and the like.

[0102] Furthermore, the filter devices 100, 100A to 100C described above have been described as (low pass filters) LPFs, but they can also be applied to band stop filters (BSFs) in the same manner.

[0103] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0104] 3 insulator, 11-16 wiring patterns, 100, 100A, 100B, 200 filter device, 150 high frequency module, 300 communication device, C1-C3, C12, C45, Cg, Cg1-Cg2 capacitors, G1, G2 ground terminal, L1 first inductor, L2 second inductor, L3 third inductor, L4 fourth inductor, L5 fifth inductor, P1 first terminal, P2 second terminal, T1 first connection point, T2 second connection point, T3 third connection point, T4 fourth connection point, T5 fifth connection point.

Claims

1. A first terminal; a first inductor connected to the first terminal; a second inductor connected in series with the first inductor; a second terminal connected to the second inductor; a first capacitor connected between a first connection point between the first inductor and the second inductor and a ground; a second capacitor connected at least one of between a second connection point between the first terminal and the first inductor and a ground and between a third connection point between the second terminal and the second inductor and a ground, the first inductor, the second inductor, the first capacitor, and the second capacitor are formed in an insulator having a pair of main surfaces facing each other and a side surface connecting the main surfaces; The insulator is a plurality of first wiring patterns disposed inside the insulator and constituting a part of the first inductor; a plurality of second wiring patterns that are arranged to at least partially overlap the first wiring pattern when viewed in a plan view from one of the main surfaces and that constitute a part of the second inductor, the first wiring pattern and the second wiring pattern are alternately laminated in the insulator, The first inductor and the second inductor are summarily connected to each other in a filter device.

2. The filter device according to claim 1 , wherein a direction of a magnetic field generated in the first inductor and a direction of a magnetic field generated in the second inductor are the same.

3. 3. The filter device according to claim 1, further comprising a third capacitor connected in parallel to the first inductor and the second inductor between the first terminal and the second terminal.

4. 3. The filter device according to claim 1, further comprising a third inductor connected in series between the second capacitor and ground.

5. 3. The filter device according to claim 1, wherein the first wiring pattern and the second wiring pattern are laminated in the insulator in a direction between the main surfaces.

6. 3. The filter device according to claim 1, wherein the insulator includes a first electrode connected to the first terminal, a second electrode connected to the second terminal, and a ground electrode.

7. each of the first wiring pattern and the second wiring pattern has a loop shape of less than one revolution when viewed in plan from one of the main surfaces; 3. The filter device according to claim 1, wherein the first wiring pattern and the second wiring pattern are combined within the insulator to form a coil pattern having one or more turns.

8. the first inductor, the second inductor, the first capacitor, the second capacitor, and the third capacitor are formed in the insulator having a pair of main surfaces facing each other and a side surface connecting the main surfaces; The insulator is a plurality of first wiring patterns disposed inside the insulator and constituting a part of the first inductor; a plurality of second wiring patterns that are arranged to at least partially overlap the first wiring pattern when viewed from one of the main surfaces and that constitute a part of the second inductor; a plurality of third wiring patterns connecting the first wiring pattern and the second wiring pattern; a first electrode connected to the first terminal, a second electrode connected to the second terminal, and a ground electrode; The first capacitor is a third electrode is a portion of the first wiring pattern and a portion of the second wiring pattern that is disposed outside a portion of a wiring pattern that becomes a coil pattern, a fourth electrode is a wiring pattern connected to the ground electrode, and the third electrode and the fourth electrode are arranged to overlap each other when viewed in a plan view from one of the main surfaces, The second capacitor is the third wiring pattern is a fifth electrode, a wiring pattern connecting the ground electrodes is a sixth electrode, and the fifth electrode and the sixth electrode are arranged to overlap each other when viewed in a plan view from one of the main surfaces; The third capacitor is 4. The filter device according to claim 3, wherein a portion of the first wiring pattern having a wider wiring width than the others is defined as a seventh electrode, a portion of the second wiring pattern having a wider wiring width than the others is defined as an eighth electrode, and the seventh electrode and the eighth electrode are arranged to overlap when viewed in a plan view from one side of the main surface.

9. 9. The filter device according to claim 8, wherein the first capacitor is arranged on one side of the insulator when viewed in a planar view from one of the main surfaces, and the second capacitor is arranged on one side of the insulator different from the first capacitor.

10. 9. The filter device according to claim 8, wherein the first wiring patterns, the second wiring patterns, and the third wiring patterns are connected in parallel by via conductors disposed between layers.

11. The insulator has a rectangular shape when viewed in plan from one of the main surfaces, 9. The filter device according to claim 8, wherein the ground electrodes include a first ground electrode and a second ground electrode, the first ground electrode and the second ground electrode being disposed along a long side of the insulator.

12. 3 . The filter device according to claim 1 , wherein a configuration including the first inductor, the second inductor, and the first capacitor is regarded as one unit, and a plurality of units are connected together.

13. A first balanced terminal; a first balanced inductor connected to the first balanced terminal; a second balanced inductor connected in series with the first balanced inductor; a second balanced terminal connected to the second balanced inductor; A third balanced terminal; a third balanced inductor connected to the third balanced terminal; a fourth balanced inductor connected in series with the third balanced inductor; a fourth balanced terminal connected to the fourth balanced inductor; a first capacitor connected between a first connection point between the first balanced inductor and the second balanced inductor and a second connection point between the third balanced inductor and the fourth balanced inductor; a second capacitor connected at least one of between a third connection point between the first balanced terminal and the first balanced inductor, a fourth connection point between the third balanced terminal and the third balanced inductor, a fifth connection point between the second balanced terminal and the second balanced inductor, and a sixth connection point between the fourth balanced terminal and the fourth balanced inductor; the first balanced inductor, the second balanced inductor, the third balanced inductor, the fourth balanced inductor, the first capacitor, and the second capacitor are formed in an insulator having a pair of main surfaces facing each other and a side surface connecting the main surfaces, The insulator is a plurality of first wiring patterns disposed inside the insulator and constituting a part of the first balanced inductor; a plurality of second wiring patterns that are arranged to at least partially overlap the first wiring patterns when viewed from one of the principal surfaces and that constitute a part of the second balanced inductor; a plurality of third wiring patterns disposed inside the insulator and constituting a part of the third balanced inductor; a plurality of fourth wiring patterns that are arranged to at least partially overlap the third wiring pattern when viewed in a plan view from one of the principal surfaces and that constitute a part of the fourth balanced inductor, the first wiring pattern and the second wiring pattern are alternately laminated within the insulator, and the third wiring pattern and the fourth wiring pattern are alternately laminated within the insulator, A filter device in which at least one of the first balanced inductor and the second balanced inductor and the third balanced inductor and the fourth balanced inductor is sum-connected to each other.

14. The filter device according to claim 1 or 2; and an electronic component connected to the filter device.

15. A communication device comprising the high frequency module according to claim 14.

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