JP2024042638A - Filter device and high frequency front end circuit with it - Google Patents

Abstract

[Problem] In a laminated filter device including multiple stages of resonators, the degree of coupling between the resonators is increased while suppressing an increase in the size of the device. [Solution] A filter device (100) includes a main body (110), an input terminal (T1), an output terminal (T2), a ground terminal (GND), and resonators (RC2, RC3). The resonators (RC2, RC3) are disposed in the main body (110) and transmit a signal from the input terminal (T1) to the output terminal (T2) by electromagnetically coupling with each other. Each of the resonators (RC2, RC3) includes a first path connected from a node (N2B, N3B) to the ground terminal (GND) via a capacitor (C2, C3), and a second path connected from the node (N2B, N3B) to the ground terminal (GND) without passing through the capacitor (C2, C3). The second path of the resonator (RC2) and the second path of the resonator (RC3) are partially shared. The filter device 100 further includes a third path L23A connected to a node N2B of the resonator RC2 and a node N3B of the resonator RC3.

Description

The present disclosure relates to a filter device and a high-frequency front-end circuit including the same, and more particularly to a structure for improving filter characteristics of a filter device configured with a plurality of resonators.

International Publication No. 2022/071191 (Patent Document 1) discloses a stacked filter device including multiple stages of resonators. In such a filter device, filter characteristics can be adjusted depending on the degree of coupling between the resonators.

International Publication No. 2022/071191 Specification

Increasing the degree of coupling between resonators may be achieved, for example, by adjusting the inductance value of an inductor that constitutes the target resonator. When adjusting the inductance value by increasing it, it is necessary to lengthen the electrodes or vias that constitute the inductor. However, in this case, the overall size of the device becomes large, so that it may not be possible to achieve the desired product size in products that require miniaturization and low profile.

Conversely, when adjusting the inductance value to a smaller value, it is necessary to increase the capacitance value of the capacitor that constitutes the resonator in order to achieve the desired resonant frequency. In this case, it may not be possible to secure the electrode area that constitutes the capacitor, or the impedance of the resonator may decrease, resulting in a situation where the desired filter characteristics cannot be obtained.

The present disclosure has been made to solve such problems, and the purpose is to suppress an increase in the device size while increasing the distance between the resonators in a stacked filter device including multiple stages of resonators. The goal is to increase the degree of connectivity.

A filter device according to a first aspect of the present disclosure includes a main body, an input terminal, an output terminal, a ground terminal, a first resonator, and a second resonator. The first resonator and the second resonator are arranged in the main body and transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. Each of the first resonator and the second resonator has a first path connected from a first node to a ground terminal via a capacitor, and a second path connected from the first node to a ground terminal without a capacitor. including the route. A part of the second path of the first resonator and the second path of the second resonator are shared. The filter device further includes a third path connected to the first node of the first resonator and the first node of the second resonator.

A filter device according to a second aspect of the present disclosure includes an input terminal, an output terminal, a ground terminal, a first resonator, and a second resonator. The first resonator and the second resonator transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. The first resonator includes a first capacitor connected between a first node and a ground terminal, a first inductor having one end connected to the first node, and a first inductor connected to the other end of the first inductor. 2 inductors, and a common inductor connected between the other end of the second inductor and a ground terminal. The second resonator includes a second capacitor connected between the second node and the ground terminal, a third inductor having one end connected to the second node, and a common inductor connected to the other end of the third inductor. and a fourth inductor connected therebetween. The filter device further includes a fifth inductor connected between the other end of the first inductor and the other end of the third inductor.

The filter device according to the third aspect of the present disclosure includes a main body, an input terminal, an output terminal, a ground terminal, a fifth resonator, and a sixth resonator. The fifth resonator and the sixth resonator are disposed in the main body and transmit a signal from the input terminal to the output terminal by electromagnetically coupling with each other. The fifth resonator includes a third capacitor connected between the third node and the input terminal, a sixth inductor having one end connected to the third node, a seventh inductor connected to the other end of the sixth inductor, and a common inductor connected between the other end of the seventh inductor and the ground terminal. The sixth resonator includes a fourth capacitor connected between the fourth node and the ground terminal, an eighth inductor having one end connected to the fourth node, and a ninth inductor connected between the other end of the eighth inductor and the common inductor. The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor.

A filter device according to a fourth aspect of the present disclosure includes a main body, an input terminal, an output terminal, a ground terminal, a fifth resonator, and a seventh resonator. The fifth resonator and the seventh resonator are arranged in the main body and transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. The fifth resonator includes a third capacitor connected between the third node and the input terminal, a sixth inductor having one end connected to the third node, and a sixth inductor connected to the other end of the sixth inductor. 7 inductor, and a common inductor connected between the other end of the seventh inductor and a ground terminal. The seventh resonator includes a sixth capacitor connected between the fourth node and the output terminal, an eighth inductor having one end connected to the fourth node, and the other end of the eighth inductor and a common inductor. and a ninth inductor connected therebetween. The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor.

In the filter device according to the present disclosure, in each of the two resonators, the paths (second paths) connected to the ground terminal without a capacitor are connected by the third path. With such a configuration, it is possible to increase the degree of coupling between resonators while suppressing an increase in device size.

1 is a block diagram of a communication device having a high-frequency front-end circuit to which a filter device according to a first embodiment is applied. FIG. 3 is an equivalent circuit diagram of the filter device according to the first embodiment. 1 is an external perspective view of a filter device according to a first embodiment; FIG. FIG. 4 is an exploded perspective view showing an example of the laminated structure of the filter device shown in FIG. 3; 7 is a diagram illustrating Comparative Example 1 corresponding to the second to third stage filters of the filter device of Embodiment 1. FIG. FIG. 3 is a diagram for explaining the degree of coupling in the second and third stage filters of the filter device of the first embodiment. FIG. 3 is a diagram for explaining the relationship between the resonant frequency and the degree of coupling between resonators in the filter devices of Embodiment 1 and Comparative Example 1. FIG. 3 is a diagram for explaining filter characteristics in the filter device of Embodiment 1. FIG. FIG. 3 is a schematic diagram of the second and third stage filters in the filter device of the first embodiment. FIG. 3 is a schematic diagram of the second and third stage filters in the filter device of Modification 1. FIG. FIG. 3 is a schematic diagram of the second and third stage filters in the filter device of Modification 2. FIG. FIG. 7 is a schematic diagram of the second and third stage filters in the filter device of Modification 3. FIG. 3 is an equivalent circuit diagram of a filter device according to a second embodiment. 3 is an equivalent circuit diagram of a filter device of Comparative Example 2. FIG. 15 is a diagram obtained by converting the equivalent circuit of FIG. 14. FIG. 7 is a diagram for explaining filter characteristics in a filter device according to a second embodiment. FIG. FIG. 7 is an equivalent circuit diagram of a filter device according to a third embodiment.

Embodiments of the present disclosure will be described in detail below with reference to the drawings. In addition, the same reference numerals are attached to the same or corresponding parts in the drawings, and the description thereof will not be repeated.

[Embodiment 1]
(Basic configuration of communication device)
FIG. 1 is a block diagram of a communication device 10 having a high frequency front end circuit 20 to which the filter device of the first embodiment is applied. The communication device 10 is, for example, a mobile terminal such as a smartphone, or a mobile phone base station.

Referring to FIG. 1, communication device 10 includes an antenna 12, a high frequency front end circuit 20, a mixer 30, a local oscillator 32, a D/A converter (DAC) 40, and an RF circuit 50. The high frequency front end circuit 20 also includes band pass filters 22 and 28, an amplifier 24, and an attenuator 26. Note that in FIG. 1, a case will be described in which the high frequency front end circuit 20 includes a transmitting circuit that transmits a high frequency signal from the antenna 12; however, the high frequency front end circuit 20 is a receiving circuit that receives a high frequency signal via the antenna 12. May contain.

The communication device 10 up-converts the transmission signal transmitted from the RF circuit 50 into a high-frequency signal and radiates it from the antenna 12. A modulated digital signal, which is a transmission signal output from the RF circuit 50, is converted into an analog signal by the D/A converter 40. The mixer 30 mixes the transmission signal, which has been converted from a digital signal to an analog signal by the D/A converter 40, with an oscillation signal from the local oscillator 32, and up-converts it into a high-frequency signal. The bandpass filter 28 removes unnecessary waves generated by upconversion and extracts only the transmission signal in a desired frequency band. Attenuator 26 adjusts the strength of the transmitted signal. Amplifier 24 amplifies the power of the transmission signal that has passed through attenuator 26 to a predetermined level. The bandpass filter 22 removes unnecessary waves generated during the amplification process and passes only signal components in a frequency band defined by communication standards. The transmission signal that has passed through the bandpass filter 22 is radiated from the antenna 12.

As the bandpass filters 22 and 28 in the communication device 10 as described above, a filter device compatible with the present disclosure can be adopted.

(Configuration of filter device)
Next, the detailed configuration of the filter device 100 according to the first embodiment will be described using FIGS. 2 to 4.

Figure 2 is an equivalent circuit diagram of the filter device 100. Referring to Figure 2, the filter device 100 has an input terminal T1, an output terminal T2, and resonators RC1 to RC4. Each of the resonators RC1 to RC4 is an LC parallel resonator in which an inductor and a capacitor are connected in parallel.

Resonator RC1 includes inductors L1 and L5 connected in series between input terminal T1 and ground terminal GND, and capacitor C1 connected in parallel to inductors L1 and L5. A connection node N1A between the inductor L1 and the capacitor C1 is connected to the input terminal T1.

The resonator RC2 includes inductors L2A, L2B, L23B, and L5 connected in series, and a capacitor C2 connected in parallel to the inductors L2A, L2B, L23B, and L5. A connection node N2A between the inductor L2A and the capacitor C2 is connected to the connection node N1A (i.e., the input terminal T1) of the resonator RC1 via the capacitor C12.

The resonator RC3 includes inductors L3A, L3B, L23B, and L5 connected in series, and a capacitor C3 connected in parallel to the inductors L3A, L3B, L23B, and L5. A connection node N3A between the inductor L3A and the capacitor C3 is connected to a connection node N4A (ie, output terminal T2) of the resonator RC4 via a capacitor C34. Further, the connection node N3A is also connected to the connection node N2A of the resonator RC2 via the capacitor C23. Further, an inductor L23A is connected between a connection node N3B between the inductor L3A and the inductor L3B and a connection node N2B between the inductor L2A and the inductor L2B in the resonator RC2.

Resonator RC4 includes inductors L4 and L5 connected in series between output terminal T2 and ground terminal GND, and capacitor C4 connected in parallel to inductors L4 and L5. A connection node N4A between the inductor L4 and the capacitor C4 is connected to the output terminal T2. Furthermore, the connection node N4A is connected to the connection node N1A (ie, the input terminal T1) of the resonator RC1 via the capacitor C14.

As described above, the inductor L5 is shared by the resonators RC1 to RC4. Furthermore, the inductor L23B is shared by the resonators RC2 and RC3.

Each resonator is coupled by magnetic coupling. In this way, the filter device 100 has a configuration in which four stages of resonators magnetically coupled to each other are arranged between the input terminal T1 and the output terminal T2. By adjusting the resonant frequency of each resonator, the filter device 100 functions as a bandpass filter that passes signals in a desired frequency band.

Connection nodes N2B and N3B in FIG. 2 are examples of "first nodes" in the present disclosure. In this case, in the resonator RC2, the path from the connection node N2B to the ground terminal GND via the inductor L2A and capacitor C2 corresponds to the "first path" in the present disclosure. Furthermore, the path from the connection node N2B to the ground terminal GND via the inductors L2B, L23B, and L5 corresponds to the "second path" in the present disclosure. Similarly, in resonator RC3, the path from connection node N3B to ground terminal GND via inductor L3A and capacitor C3 corresponds to the "first path" in the present disclosure. Further, the path from the connection node N3B to the ground terminal GND via the inductors L3B, L23B, and L5 corresponds to the "second path" in the present disclosure. The inductor L23A that connects the connection node N2B and the connection node N3B corresponds to the "third path" in the present disclosure.

Note that the capacitor C12 connected to the resonator RC1 and the resonator RC2 may be connected between the connection node N1A and the connection node N2B in FIG. 2. Further, the capacitor C34 connected to the resonator RC3 and the resonator RC4 may be connected between the connection node N3B and the connection node N4A in FIG. 2.

FIG. 3 is an external perspective view of the filter device 100, and FIG. 4 is an exploded perspective view showing an example of the laminated structure of the filter device 100.

Referring to FIGS. 3 and 4, filter device 100 includes a rectangular parallelepiped or substantially rectangular parallelepiped main body 110 in which a plurality of dielectric layers LY1 to LY10 are laminated in the lamination direction. The dielectric layers LY1 to LY10 are made of ceramic such as low temperature co-fired ceramics (LTCC) or resin, for example. Inside the main body 110, an inductor and a capacitor of the LC parallel resonator are configured by a plurality of electrodes provided on each dielectric layer and a plurality of vias provided between the dielectric layers. Note that in this specification, "via" refers to a conductor provided in a dielectric layer to connect electrodes provided in different dielectric layers. Vias are formed, for example, by conductive paste, plating, and/or metal pins.

In the following description, the stacking direction of the dielectric layers LY1 to LY10 in the main body 110 will be referred to as the "Z-axis direction", and the direction perpendicular to the Z-axis direction and along the long side of the main body 110 will be referred to as the "X-axis direction". ”, and the direction along the short side of the main body 110 is defined as the “Y-axis direction”. Furthermore, hereinafter, the positive direction of the Z-axis in each figure may be referred to as the upper side, and the negative direction may be referred to as the lower side.

A directional mark DM for specifying the direction of the filter device 100 is arranged on the upper surface 111 (dielectric layer LY1) of the main body 110. External terminals (input terminal T1, output terminal T2, and ground terminal GND) for connecting the filter device 100 and external equipment are arranged on the lower surface 112 (dielectric layer LY10) of the main body 110. Each of the input terminal T1, the output terminal T2, and the ground terminal GND is a flat electrode, and is an LGA (Land Grid Array) terminal regularly arranged on the lower surface 112 of the main body 110.

As described in FIG. 2, the filter device 100 includes resonators RC1 to RC4, which are four stages of LC parallel resonators. More specifically, the resonator RC1 includes vias V10, V11, and V12, a capacitor electrode PC1, and plate electrodes PL10A, PL10B, PL11A, and PL11B. Resonator RC2 includes via V20, capacitor electrode PC2A, and plate electrodes PL23A and PL23B. Resonator RC3 includes via V30, capacitor electrode PC3A, and plate electrodes PL23A and PL23B. Resonator RC4 includes vias V40, V41, V42, capacitor electrode PC4, and plate electrodes PL40A, PL40B, PL41A, PL41B.

Input terminal T1 is connected to capacitor electrode PC1 arranged on dielectric layer LY8 by via V10. Capacitor electrode PC1 is a substantially rectangular electrode extending in the X-axis direction. Capacitor electrode PC1 is connected by via V11 to flat plate electrode PL10A disposed on dielectric layer LY5 and flat plate electrode PL10B disposed on dielectric layer LY4.

The flat plate electrodes PL10A and PL10B are band-shaped electrodes whose winding axis is in the Z-axis direction, and have substantially the same shape as each other. A via V11 is connected to one end of the flat plate electrodes PL10A and PL10B. The other ends of the plate electrodes PL10A and PL10B are connected by vias V12 to the plate electrode PL11A arranged on the dielectric layer LY3 and the plate electrode PL11B arranged on the dielectric layer LY2.

The flat plate electrodes PL11A and PL11B are band-shaped electrodes whose winding axis is in the Z-axis direction, and have substantially the same shape as each other. A via V12 is connected to one end of the flat plate electrodes PL11A and PL11B. The other ends of the flat electrodes PL11A and PL11B are connected to a ground electrode PG disposed on the dielectric layer LY9 and a ground terminal GND disposed on the lower surface 112 of the dielectric layer LY10 by vias VG1.

Further, in the dielectric layer LY8, a substantially rectangular capacitor electrode PC2B is arranged adjacent to the capacitor electrode PC1 in the positive direction of the Y axis. Capacitor electrode PC1 and capacitor electrode PC2B are capacitively coupled to each other. Capacitor electrode PC2B is connected to ground terminal GND arranged in dielectric layer LY10 by via VG2. Further, the capacitor electrode PC2B is also connected to the ground electrode PG arranged in the dielectric layer LY9 through a plurality of vias VG5. The ground electrode PG is connected to a ground terminal GND arranged in the dielectric layer LY10 by a via VG4.

Inductor L1 in FIG. 2 is configured by vias V10, V11, V12 and flat plate electrodes PL10A, PL10B, PL11A, PL11B. Inductor L5 in FIG. 2 is configured by via VG1. Further, capacitor C1 in FIG. 2 is configured by capacitor electrodes PC1 and PC2B. That is, a resonator RC1 is configured by vias V10, V11, V12, VG1, flat plate electrodes PL10A, PL10B, PL11A, PL11B, and capacitor electrodes PC1, PC2B.

The capacitor electrode PC1 partially overlaps with the substantially L-shaped capacitor electrode PC2A disposed on the adjacent dielectric layer LY7 when viewed in plan from the stacking direction. The capacitor C12 in FIG. 2 is configured by the capacitor electrodes PC1 and PC2A. The capacitor electrode PC2A also partially overlaps with the capacitor electrode PC2B arranged on the dielectric layer LY8 when viewed in plan from the stacking direction. Capacitor C2 in FIG. 2 is configured by capacitor electrodes PC2A and PC2B.

Further, the capacitor electrode PC2A is connected to a flat plate electrode PL23A disposed on the dielectric layer LY3 and a flat plate electrode PL23B disposed on the dielectric layer LY2 through a via V20. Each of the flat plate electrodes PL23A and PL23B has a substantially Y-shape with three ends, a first end connected to a via V20, and a second end connected to a via V30. , a via VG1 is connected to the third end.

The via V20 constitutes the inductor L2A in FIG. 2. The inductor L2B in FIG. 2 is configured by the connection point of each path from the first end, second end, and third end of the flat plate electrodes PL23A and PL23B, and the path between the first end. . Further, the inductor L23B in FIG. 2 is configured by the path from the above connection point to the third end.

That is, the resonator RC2 in FIG. 2 is configured by the vias V20, VG1, the flat electrodes PL23A, PL23B, and the capacitor electrodes PC2A, PC2B.

A via V30 connected to the second ends of the flat electrodes PL23A and PL23B is connected to a capacitor electrode PC3A arranged on the dielectric layer LY7. Capacitor electrode PC3A has a substantially L-shape similarly to capacitor electrode PC2A. When viewed in plan from the stacking direction, capacitor electrode PC3A partially overlaps each of capacitor electrodes PC3B and PC4 arranged on dielectric layer LY8. Each of the capacitor electrodes PC3B and PC4 is a substantially rectangular electrode extending in the X-axis direction, and is arranged adjacent to each other in the Y-axis direction. Capacitor electrode PC3B and capacitor electrode PC4 are capacitively coupled to each other.

Capacitor electrode PC4 is connected to output terminal T2 arranged on lower surface 112 of dielectric layer LY10 by via V40. Capacitor electrode PC3B is connected to ground terminal GND arranged in dielectric layer LY10 by via VG3. Further, the capacitor electrode PC3B is also connected to the ground electrode PG arranged in the dielectric layer LY9 through a plurality of vias VG6.

Capacitor C3 in FIG. 2 is configured by capacitor electrodes PC3A and PC3B. Capacitor C34 in FIG. 2 is configured by capacitor electrodes PC3A and PC4. Via V30 constitutes inductor L3A in FIG. 2. An inductor L3B is configured by a path between the connection point of the flat plate electrodes PL23A and PL23B and the second end. Further, as described above, the inductor L23B in FIG. 2 is configured by the path between the connection point and the third end of the flat plate electrodes PL23A and PL23B, and the inductor L5 in FIG. 2 is configured by the via VG1.

That is, the resonator RC3 in FIG. 2 is configured by the vias V30, VG1, the flat electrodes PL23A, PL23B, and the capacitor electrodes PC3A, PC3B.

Capacitor electrode PC4 is connected to flat plate electrode PL40A disposed on dielectric layer LY5 and flat plate electrode PL40B disposed on dielectric layer LY4 through via V41.

The flat plate electrodes PL40A and PL40B are band-shaped electrodes whose winding axis is in the Z-axis direction, and have substantially the same shape as each other. A via V41 is connected to one end of the flat plate electrodes PL40A and PL40B. The other ends of the plate electrodes PL40A and PL40B are connected by vias V42 to the plate electrode PL41A arranged on the dielectric layer LY3 and the plate electrode PL41B arranged on the dielectric layer LY2.

The flat plate electrodes PL41A and PL41B are band-shaped electrodes whose winding axis is in the Z-axis direction, and have substantially the same shape as each other. A via V42 is connected to one end of the flat plate electrodes PL41A and PL41B. The other ends of the plate electrodes PL41A and PL41B are connected to a ground electrode PG disposed on the dielectric layer LY9 and a ground terminal GND disposed on the lower surface 112 of the dielectric layer LY10 via a via VG1.

Inductor L4 in FIG. 2 is configured by vias V40, V41, V42 and flat plate electrodes PL40A, PL40B, PL41A, PL41B. Inductor L5 in FIG. 2 is configured by via VG1. Further, capacitor C4 in FIG. 2 is configured by capacitor electrodes PC3B and PC4. That is, a resonator RC4 is configured by vias V40, V41, V42, VG1, flat plate electrodes PL40A, PL40B, PL41A, PL41B, and capacitor electrodes PC3B, PC4.

Each of the capacitor electrodes PC2A and PC3A arranged on the dielectric layer LY7 partially overlaps with the capacitor electrode PC23 arranged on the dielectric layer LY7 and having a substantially rectangular shape when viewed in plan from the stacking direction. . Capacitor C23 in FIG. 2 is configured by capacitor electrodes PC2A, PC3A, and PC23.

Each of the capacitor electrodes PC1 and PC4 arranged on the dielectric layer LY8 partially overlaps with the band-shaped capacitor electrode PC14 arranged on the dielectric layer LY9 when viewed in plan from the stacking direction. Capacitor electrodes PC1, PC4, and PC14 constitute capacitor C14 in FIG.

In the dielectric layer LY3, the first terminal and the second terminal of the flat plate electrode PL23A are connected by a band-shaped flat plate electrode PL50A extending in the X-axis direction. Further, in the dielectric layer LY2, the first terminal and the second terminal of the flat plate electrode PL23B are connected by a band-shaped flat plate electrode PL50B extending in the X-axis direction. Inductor L23A in FIG. 2 is configured by plate electrodes PL50A and PL50B.

In the dielectric layer LY3, a ring-shaped structure is formed by the flat electrode PL23A and the flat electrode PL50A. Similarly, in the dielectric layer LY2, a ring-shaped structure is formed by the flat electrode PL23B and the flat electrode PL50B. As explained below, by arranging the inductor L23A formed by the flat plate electrodes PL50A and PL50B, the degree of coupling between the resonators RC2 and RC3 can be strengthened.

In the following description, the plate electrodes PL50A and PL50B may be collectively referred to as the "plate electrode PL50", and the plate electrodes PL23A and PL23B may be collectively referred to as the "plate electrode PL23".

(Explanation of the degree of coupling between resonators)
The degree of coupling between resonators RC2 and resonators RC3 in filter device 100 of the first embodiment will be described using FIGS. 5 and 6. FIG. 5 shows the case of the filter device 100X of Comparative Example 1, and FIG. 6 shows the case of the filter device 100 of the first embodiment.

Note that in FIGS. 5 and 6, in order to simplify the explanation, equivalent circuits of only the configurations corresponding to the resonator RC2 and the resonator RC3 are shown. Further, portions corresponding to the connection nodes N2A and N3A in FIG. 2 are shown as an input terminal T10 and an output terminal T20 in FIGS. 5 and 6, respectively.

First, in FIG. 5, an inductor L10 and an inductor L20 are connected in series between an input terminal T10 and an output terminal T20. An inductor L30 is connected between a connection node N10 between the inductors L10 and L20 and the ground terminal GND. Further, a capacitor C10 is connected between the input terminal T10 and the ground terminal GND, and a capacitor C20 is connected between the output terminal T20 and the ground terminal GND.

In relation to FIG. 2, inductor L10 corresponds to inductors L2A and L2B, and inductor L20 corresponds to inductors L3A and L3B. Further, inductor L30 corresponds to inductors L23B and L5. Capacitors C10 and C20 correspond to capacitors C2 and C3, respectively. That is, in the filter device 100X, the "inductor L23A" is removed from the resonators RC2 and RC3 in FIG. 2.

In addition, in FIG. 6, inductors L10A and L10B on the left correspond to inductors L2A and L2B in FIG. 2, respectively, and inductors L20A and L20B correspond to inductors L3A and L3B in FIG. 2, respectively. And inductor L12 corresponds to inductor L23A in FIG. 2.

In the configuration shown in FIG. 5, the degree of coupling between the resonators RC2 and RC3 is generally determined by the inductance value (L30/L10) of the inductor L30 relative to the inductance value of the inductor L10, or the inductance value relative to the inductance value of the inductor L20. It can be expressed by the inductance value (L30/L20) of inductor L30. Therefore, in FIG. 5, when increasing the degree of coupling between the resonators RC2 and RC3, it is possible to increase the inductance value of the inductor L30 or to decrease the inductance values of the inductors L10 and L20.

In order to increase the inductance value of the inductor L30, in the configuration shown in FIG. 4, it is necessary to increase the inductance value of the via VG1. In other words, it is necessary to increase the length of the via VG1, but in that case, the dimension of the filter device main body in the Z-axis direction will be increased. This may impede miniaturization of the device or may make implementation difficult due to size constraints of the device.

On the other hand, when reducing the inductance values of inductors L10 and L20, the total inductance value in the resonator becomes smaller, so in order to make the resonant frequency of the resonator a desired frequency, it is necessary to reduce the capacitance of capacitors C10 and C20 in the resonator. It is necessary to increase the value. In this case, it is necessary to increase the area of the capacitance electrodes forming the capacitors C10 and C20. However, if the area of the capacitance electrode is increased, the area of the dielectric layer needs to be increased, which may cause an increase in the size of the device or may make it difficult to realize the required device dimensions. Furthermore, if the inductance value of the resonator is decreased and the capacitance value is increased, the impedance of the resonator itself decreases, and as a result, there is a possibility that the required filter characteristics may not be obtained.

On the other hand, the configuration of this embodiment 1 as shown in the left diagram of Figure 6 is configured such that a Δ connection (dashed line area AR10) consisting of inductors L10B, L20B, and L12 is placed between inductors L10A, L20A, and L30. When this area AR10 is subjected to a Δ-Y transformation, it becomes equivalent to a configuration in which inductor L10C connected to inductor L10A, inductor L20C connected to inductor L20A, and inductor L30C connected to inductor L30 are connected at connection node N20, as shown in the right diagram of Figure 6.

Here, when Δ-Y conversion is performed, the inductance value of inductor L10C becomes smaller than the inductance value of inductor L10B (L10B>L10C), and the inductance value of inductor L20C becomes smaller than the inductance value of inductor L20B (L20B >L20C).

Comparing the configuration in the right diagram of FIG. 6 with the configuration of the filter device 100X in FIG. , inductors L30 and L30C correspond to inductor L30 of filter device 100X. As described above, since L10B>L10C, L20B>L20C, and L30C>0, in the filter device 100, by adding the inductor L12, the inductance values of the inductors L10 and L20 of the filter device 100X can be changed. This is equivalent to a configuration in which the inductance value of the inductor L30 is increased and the inductance value of the inductor L30 is increased. Therefore, the degree of coupling between resonator RC2 and resonator RC3 in filter device 100 can be made larger than in the case of filter device 100X.

In this case, as shown in FIG. 4, this can be realized by arranging the flat electrodes PL50A and PL50B, so that it is possible to suppress the increase in size of the device. Furthermore, by appropriately setting the inductance values of the inductors L10B, L20B, and L12, it is possible to suppress a decrease in impedance.

FIG. 7 is a diagram for explaining the relationship between the resonant frequency and the degree of coupling between resonators in the filter devices of Embodiment 1 and Comparative Example 1. The upper part of FIG. 7 shows an internal perspective view of the resonators RC2 and RC3 in the filter device 100 of the first embodiment and the filter device 100X of the first comparative example. The lower part of FIG. 7 shows a graph showing the relationship between the resonant frequency and the degree of coupling between resonators in the case of filter devices 100 and 100X having similar device sizes.

As explained in FIG. 4, the filter device 100 has a ring-shaped structure in the dielectric layers LY2 and LY3 by the flat plate electrode PL23 connecting the vias V20, V30, and VG1, and the flat plate electrode PL50 connecting the vias V20 and V30. is formed. On the other hand, in the filter device 100X, the vias V20, V30, and VG1 are connected by a flat plate electrode PL23X having a substantially T-shape.

In the lower part of FIG. 7, the horizontal axis shows the resonant frequency, and the vertical axis shows the degree of inter-resonator coupling between the resonators RC2 and RC3. In the graph, a solid line LN10 indicates the case of the filter device 100 of the first embodiment, and a broken line LN11 indicates the case of the filter device 100X of the first comparative example.

As shown in the graph of FIG. 7, when the filter devices 100 and 100X have the same device size, when the resonance frequency is 6.0 GHz or higher, the filter device 100 has a higher degree of inter-resonator coupling at the same resonance frequency. is obtained. For example, for a resonant frequency of 6.5 GHz, the degree of coupling in filter device 100 is 0.50 and the degree of coupling in filter device 100X is 0.30.

On the other hand, in order to obtain a coupling degree of 0.50 in the filter device 100X, it is necessary to set the resonance frequency to a higher frequency of 8.0 GHz. Generally, as the resonant frequency increases, the required circuit element values become smaller, resulting in a smaller device size, and as the resonant frequency becomes lower, the required circuit element values increase, resulting in a larger device size. Therefore, for example, if the desired resonant frequency is 6.5 GHz and an attempt is made to obtain a coupling degree of 0.50 using the configuration of the filter device 100X, the device size will end up being larger than the filter device 100. . Conversely, if the configuration of the filter device 100 is used when the desired resonant frequency is 8.0 GHz, sufficient coupling is already obtained, so the circuit element values are reduced to increase the resonant frequency. The device size can be further reduced. That is, by using a configuration of the filter device 100 that can achieve the same degree of coupling at a lower resonant frequency, it is possible to downsize the entire device.

(filter characteristics)
FIG. 8 is a diagram for explaining filter characteristics in the filter device 100 of the first embodiment. In FIG. 8, the frequency is shown on the horizontal axis, and the insertion loss of the filter device 100 is shown on the vertical axis.

FIG. 8 shows the change in filter characteristics when the length of the flat electrode PL50 in the X-axis direction, in other words, the distance between the vias V20 and V30 constituting the resonator RC2 and the resonator RC3, respectively, is changed. There is. More specifically, the dashed line LN22 in FIG. 8 is the characteristic when the vias V20 and V30 are at the farthest positions as shown in FIG. This is a characteristic in the case of a position approaching along the X-axis direction. Moreover, the solid line LN20 is the characteristic when the vias V20 and V30 are located closer to each other than the position in the case of the broken line LN21.

As shown in FIG. 8, the shorter the distance between the vias V20 and V30, in other words, the stronger the coupling between the resonators RC2 and RC3, the wider the frequency bandwidth (pass band) of the filter device becomes. I know what you're doing.

In the solid line LN20, the loss on the high frequency side of the passband (near f1) is slightly large, but this can be fixed by adjusting the inductance value by changing the line width of the flat plate electrode and/or by adjusting the inductance value by changing the line width of the flat plate electrode. This can be improved by adjusting the capacitance value by changing the area of .

As described above, in a stacked filter device including multiple stages of resonators, by configuring an annular structure by providing an inductor connecting two resonators, an increase in device size can be suppressed and The degree of coupling can be increased. This makes it possible to achieve desired characteristics of the filter device.

In addition, in the above description, the configuration for increasing the degree of coupling between the second and third stage resonators of a filter device including four stages of resonators was explained as an example; The above configuration can be applied between the two resonators.

“Resonator RC2” and “resonator RC3” in Embodiment 1 correspond to the “first resonator” and “second resonator” in the present disclosure, respectively. Further, "resonator RC1" and "resonator RC4" in the first embodiment correspond to the "third resonator" and "fourth resonator" in the present disclosure, respectively. “Via VG1” in Embodiment 1 corresponds to “common via” in the present disclosure. "Capacitor electrode PC2A" and "capacitor electrode PC3A" in Embodiment 1 correspond to "first capacitor electrode" and "second capacitor electrode" in the present disclosure, respectively. “Via V20” and “Via V30” in the first embodiment correspond to the “first via” and “second via” in the present disclosure, respectively. “Plant electrodes PL23A, PL23B” in Embodiment 1 correspond to “first plate electrode” and “second plate electrode” in the present disclosure. “Plant electrodes PL50A, PL50B” in Embodiment 1 correspond to “third plate electrode” in the present disclosure.

Furthermore, in the equivalent circuit diagram shown in FIG. 2, "capacitor C2" and "capacitor C3" in Embodiment 1 correspond to "first capacitor" and "second capacitor" in the present disclosure, respectively. “Inductor L2A,” “inductor L2B,” “inductor L3A,” “inductor L3B,” and “inductor L23A” in Embodiment 1 correspond to “first inductor” to “fifth inductor” in the present disclosure, respectively. "Inductor L23B" and "inductor L5" in Embodiment 1 correspond to the "common inductor" in the present disclosure.

[Modified example]
Next, the configuration of a modified filter device according to the first embodiment will be described using FIGS. 9 to 12. 9 to 12 are schematic diagrams schematically showing only the resonators RC2 and RC3 in FIG. 2.

FIG. 9 is a diagram corresponding to the filter device 100 of FIG. 4, and shows a portion of the annular structure formed in the dielectric layers LY2 and LY3 of FIG. 4. In addition, capacitor electrodes PC2B and PC3B opposite to capacitor electrodes PC2A and PC3A are omitted, and are shown facing the ground electrode PG. In the filter device 100, the flat plate electrode PL50 and the flat plate electrode PL23 forming an annular structure are composed of wiring patterns arranged on the same dielectric layer.

(Modification 1)
In Modification 1, an example will be described in which the portion forming the annular structure is configured by wiring patterns arranged in different dielectric layers and vias connecting them.

Figure 10 is a diagram showing a filter device 100A of modified example 1. In the filter device 100A, the portion corresponding to the plate electrode PL23 in the filter device 100 of Figure 9 is composed of plate electrodes PL20, PL30, and P23 and vias VL20 and VL30.

The plate electrode PL20 is a substantially rectangular strip-shaped electrode, and extends in the negative direction of the Y-axis from the end of the plate electrode PL50 to which the via V20 is connected. Similarly, the plate electrode PL30 is a substantially rectangular strip-shaped electrode, and extends in the negative direction of the Y-axis from the end of the plate electrode PL50 to which the via V30 is connected.

The flat electrode P23 is arranged in a dielectric layer between the dielectric layer on which the flat electrodes PL20 and PL30 are arranged and the dielectric layer on which the ground electrode PG is arranged. The plate electrode P23 is a substantially rectangular strip-shaped electrode extending in the X-axis direction, and one end is connected to the end of the plate electrode PL20 in the negative direction of the Y-axis by a via VL20. The other end of the flat electrode P23 is connected to the end of the flat electrode PL30 in the negative direction of the Y axis by a via VL30. The flat electrode P23 is connected to the ground electrode PG via the via VG1.

In the filter device 100A, the inductor constituting the resonator RC2 is constituted by the vias V20, VL20 and flat plate electrodes PL20, P23, and the inductor constituting the resonator RC3 is constituted by the vias V30, VL30 and the flat plate electrodes PL30, P23. be done. The resonator RC2 and the resonator RC3 are connected to each other by a flat electrode PL50 corresponding to the inductor L23A in FIG. 2. That is, a ring-shaped structure is formed across a plurality of layers by connecting flat plate electrodes P23 arranged in a dielectric layer different from flat plate electrodes PL20, PL30, and PL50 using vias VL20 and VL30.

In this way, also in the filter device 100A, the inductor connecting the resonator RC2 and the resonator RC3 is arranged to form an annular structure, so that the degree of coupling between the resonator RC2 and the resonator RC3 can be strengthened. .

Note that "via VG1" in Modification 1 corresponds to "common via" in the present disclosure. The "flat plate electrode P23" in Modification 1 corresponds to the "common electrode" in the present disclosure. “Via V20”, “Via VL20”, “Via V30” and “Via VL30” in Modification 1 are the “third via”, “fourth via”, “fifth via” and “sixth via” in the present disclosure. ” respectively. “Capacitor electrode PC2A” and “capacitor electrode PC3A” in Modification 1 correspond to the “third capacitor electrode” and “fourth capacitor electrode” in the present disclosure, respectively. “Plane electrode PL20,” “plate electrode PL30,” and “plate electrode PL50” in Modification 1 correspond to the “fourth plate electrode,” “fifth plate electrode,” and “sixth plate electrode” in the present disclosure, respectively. .

(Modification 2)
In the filter device 100 of FIG. 9, both the ground electrode constituting the capacitor in each resonator and the ground electrode to which the inductor of each resonator is connected are ground electrodes PG disposed on the lower surface 112 side of the main body 110. An example consisting of .

In modification 2, ground electrodes are arranged on the upper surface 111 side and the lower surface 112 side of the main body 110, one of the ground electrodes is used to configure the capacitor of the resonator, and the inductor of each resonator is connected to the other ground electrode. The following describes the configuration.

FIG. 11 is a diagram showing a filter device 100B according to a second modification. In the filter device 100B, a ground electrode PG1 is arranged on the lower surface 112 side of the main body 110, and a ground electrode PG2 is arranged on the upper surface 111 side. The ground electrode PG1 and the ground electrode PG2 are connected to each other by a via (not shown), and are further connected to the ground terminal GND.

Capacitor electrode PC2A forming capacitor C2 of resonator RC2 and capacitor electrode PC3A forming capacitor C3 of resonator RC3 are arranged to face ground electrode PG1. Capacitor electrode PC2A is connected to ground electrode PG2 via via V20A. Further, capacitor electrode PC3A is connected to ground electrode PG2 via via V30A.

The vias V20A and V30A are connected to each other by a substantially rectangular plate electrode PL23C. The vias V20A and V30A are also connected to each other by a plate electrode PL50B that is arranged on a dielectric layer between the dielectric layer on which the plate electrode PL23C is arranged and the dielectric layer on which the capacitor electrodes PC2A and PC3A are arranged.

In filter device 100B, a portion of via V20A between capacitor electrode PC2A and flat plate electrode PL50B corresponds to via V20 in filter device 100 of FIG. Further, a portion of via V30A between capacitor electrode PC3A and flat plate electrode PL50B corresponds to via V30 in filter device 100 of FIG. 9. The portion between the flat electrode PL50B and the flat electrode PL23C in the vias V20A and V30A and the portion formed by the flat electrode PL23C corresponds to the flat electrode PL23 in the filter device 100 of FIG. The portion between the flat electrode PL23C and the ground electrode PG2 in the vias V20A and V30A corresponds to the via VG1 in the filter device 100 of FIG. 9. Flat electrode PL50B corresponds to flat electrode PL50 in filter device 100 in FIG. 9. That is, the filter device 100B has a configuration substantially equivalent to the filter device 100 shown in FIG. 9, and has an annular structure formed by the vias V20A and V20B and the flat electrodes PL23C and PL50B.

In this way, by arranging two resonators RC2 and RC3 between two ground electrodes and connecting these resonators RC2 and RC3 with an inductor (flat plate electrode PL50B), resonators RC2 and RC3 are The degree of bonding can be strengthened.

Note that in the filter device 100B, the via portion connecting the flat electrode PL23C and the ground electrode PG2 may be shared.

(Modification 3)
In Modified Example 3, a configuration will be described in which capacitor electrodes forming the resonator capacitor are not provided individually, and the resonator capacitor is formed by a capacitance component between a wiring pattern forming an annular structure and a ground electrode. .

FIG. 12 is a diagram showing a filter device 100C according to modification 3. In the filter device 100C, resonators RC2 and RC3 are configured by plate electrodes PL20C, PL30C, PL23D, PL50C and vias VG1A and VG1B arranged on the same dielectric layer.

Each of the flat plate electrodes PL20C and PL30C is a substantially rectangular strip-shaped electrode extending in the Y-axis direction. The end of the flat plate electrode PL20C in the negative direction of the Y-axis is connected to the ground electrode PG by a via VG1A, and the end in the positive direction of the Y-axis is an open end. Similarly, the end of the plate electrode PL30C in the negative direction of the Y-axis is connected to the ground electrode PG by a via VG2A, and the end in the positive direction of the Y-axis is an open end.

The flat plate electrodes PL23D and PL50C are substantially rectangular strip-shaped electrodes extending in the X-axis direction. The plate electrodes PL20C and PL30C are connected to each other by a plate electrode PL23D at a position near the end in the negative direction of the Y-axis. Further, the flat electrodes PL20C and PL30C are connected to each other by a flat electrode PL50C at a position in the positive direction of the Y axis than the flat electrode PL23D. That is, an annular structure is formed by the plate electrodes PL20C, PL30C, PL23D, and PL50C.

In the filter device 100C, a capacitor of a resonator is configured by the capacitance component between the flat plate electrodes PL20C, PL30C and the ground electrode PG, and a resonator RC2, RC3 is configured by the inductor configured by the capacitance component and the flat plate electrode. be done.

Even in such a configuration, the degree of coupling between the resonators RC2 and RC3 can be strengthened by connecting the two resonators RC2 and RC3 with an inductor to form an annular structure.

Note that in the filter device 100C, a via connecting the flat electrode PL23D and the ground electrode PG may be arranged instead of the vias VG1A and VG1B. Furthermore, in order to ensure the capacitance value between the plate electrodes PL20C, PL30C and the ground electrode PG, a capacitor electrode wider than the plate electrodes PL20C, PL30C may be provided at the open ends of the plate electrodes PL20C, PL30C.

[Embodiment 2]
In Embodiment 2, a filter device in which some of the resonators have different configurations will be described.

FIG. 13 is an equivalent circuit diagram of filter device 200 according to the second embodiment. The filter device 200 is generally a two-stage filter device in which two resonators RC11A and RC12 are arranged between an input terminal T10 and an output terminal T20. The filter device 200 may be used alone in a two-stage configuration as shown in FIG. 13, or as a second to third stage resonator in a four-stage filter device as in the first embodiment. It's okay. Note that in order to make the correspondence with Embodiment 1 easier to understand, the same reference numerals as the circuit in FIG. 6 are used in FIG. 13 and FIGS. 14 and 17 described later.

Referring to FIG. 13, in filter device 200, resonator RC11A includes a capacitor C10A and inductors L10A, L10B, and L30. One end of the capacitor C10A is connected to the input terminal T10. Inductors L10A, L10B, and L30 are connected in series in this order between the other end of capacitor C10A and ground terminal GND.

Resonator RC12 has the same configuration as resonator RC3 in FIG. 6, and includes a capacitor C20 and inductors L20A, L20B, and L30. Capacitor C20 is connected between output terminal T20 and ground terminal GND. Further, the inductors L20A, L20B, and L30 are connected in series in this order between the output terminal T20 and the ground terminal GND. That is, the inductors L20A, L20B, and L30 connected in series are connected in parallel with the capacitor C20 between the output terminal T20 and the ground terminal GND. Note that the inductor L30 is shared with the resonator RC11A.

A capacitor C30 is connected between a connection node N31 between the capacitor C10A and the inductor L10A and the output terminal T20. Further, an inductor L12 is connected between a connection node N33 between the inductor L10A and the inductor L10B and a connection node N34 between the inductor L20A and the inductor L20B. Inductors L12, L10B, and L20B form an annular structure (region AR10) similarly to filter device 100 of Embodiment 1. Note that in the filter device 200, the capacitor C30 is not necessarily essential, and a configuration without the capacitor C30 may be used.

FIG. 14 is an equivalent circuit diagram of the filter device 200X of Comparative Example 2. Filter device 200X basically has the same configuration as the second and third stage resonators of filter device 100 of the first embodiment. Resonators RC11 and RC12 in filter device 200X correspond to RC2 and RC3 in filter device 100, respectively. Further, capacitor C30 in filter device 200X corresponds to capacitor C23 in filter device 100 (FIG. 1).

That is, when compared with the filter device 200X of Comparative Example 2, the filter device 200 of the second embodiment has a configuration in which the capacitor C10 is removed and the capacitor C10A is added between the filter device 200 and the input terminal T10.

FIG. 15 is a circuit diagram obtained by equivalently converting the circuit of FIG. 14. Inductor L10D in FIG. 15 corresponds to inductors L10A, L10B, and L30 in FIG. 14. Inductor L12A in FIG. 15 corresponds to inductors L10A, L12, and L20A in FIG. 14. Inductor L20D in FIG. 15 corresponds to inductors L20A, L20B, and L30 in FIG. 14.

That is, the filter device 200 includes a high-pass filter (HPF) composed of capacitors C10A, C30 and inductors L10D, L12A included in region AR20 in FIG. 15, and an LC parallel resonator of capacitor C20 and inductor L20D included in region AR21. This corresponds to a configuration in which a bandpass filter (BPF) configured of is connected in series between the input terminal T10 and the output terminal T20.

On the other hand, the filter device 200X of Comparative Example 2 corresponds to a configuration in which two LC parallel resonators (ie, bandpass filters) are connected in series between the input terminal T10 and the output terminal T20.

FIG. 16 is a diagram for explaining filter characteristics in filter device 200 of the second embodiment. In FIG. 16, the insertion loss in the filter device 200 (solid line LN30) and the insertion loss in the filter device 200X of Comparative Example 2 (broken line LN35) are shown.

The filter device 200 has a configuration in which the bandpass filter on the input terminal side of the filter device 200X of Comparative Example 2 is replaced with a high-pass filter, so compared to the filter device 200X, there is less attenuation on the lower frequency side than the passband. The amount will be slightly smaller. However, since the shunt capacitor is removed, the loss is reduced compared to the filter device 200X on the high frequency side, and the pass characteristics are improved. Also in the filter device 200, since an annular structure is formed by providing the inductor L12 that connects the two resonators, it is possible to increase the degree of coupling between the resonators while suppressing an increase in device size.

"Resonator RC11A" and "resonator RC12" in the second embodiment correspond to the "fifth resonator" and "sixth resonator" in the present disclosure, respectively. "Capacitor C10A", "Capacitor C20", and "Capacitor C30" in Embodiment 2 correspond to "third capacitor" to "fifth capacitor" in the present disclosure, respectively. “Inductor L10A,” “inductor L10B,” “inductor L20A,” “inductor L20B,” and “inductor L12” in the second embodiment correspond to the “sixth inductor” to “tenth inductor” in the present disclosure, respectively. "Inductor L30" in the second embodiment corresponds to the "common inductor" in the present disclosure. “Connection node N31” in the second embodiment corresponds to the “third node” in the present disclosure.

[Embodiment 3]
In Embodiment 3, a configuration will be described in which resonator RC12 in filter device 200 of Embodiment 2 is further made into a high-pass filter.

FIG. 17 is an equivalent circuit diagram of filter device 200A according to the third embodiment. The filter device 200A has a configuration in which the resonator RC12 in the filter device 200 of the second embodiment is replaced with a resonator RC12A.

More specifically, capacitor C20 in filter device 200 is removed, and capacitor C20A is added between inductor L20A and output terminal T20. Capacitor C30 is connected between a connection node N31 between capacitor C10A and inductor L10A and a connection node N32 between capacitor C20A and inductor L20A. That is, although not shown, when the circuit of FIG. 17 is equivalently transformed as shown in FIG. 15, it corresponds to a configuration in which two high-pass filters are arranged between the input terminal T10 and the output terminal T20. Therefore, the filter device 200A has a slightly smaller amount of attenuation than the filter device 200, but the efficiency is further improved.

Also in the filter device 200A, as shown in the area AR10, an annular structure is formed by the inductor L12 to which the two resonators are connected. degree can be increased.

The "resonator RC12A" in the third embodiment corresponds to the "seventh resonator" in the present disclosure. “Capacitor C20A” in the third embodiment corresponds to the “sixth capacitor” in the present disclosure. “Connection node N32” in the third embodiment corresponds to the “fourth node” in the present disclosure.

[Mode]
(Section 1) The filter device includes a main body, an input terminal, an output terminal, a ground terminal, a first resonator, and a second resonator. The first resonator and the second resonator are arranged in the main body and transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. Each of the first resonator and the second resonator has a first path connected from a first node to a ground terminal via a capacitor, and a second path connected from the first node to a ground terminal without a capacitor. including the route. A part of the second path of the first resonator and the second path of the second resonator are shared. The filter device further includes a third path connected to the first node of the first resonator and the first node of the second resonator.

(Section 2) In the filter device according to Item 1, an annular structure is formed by the second path of the first resonator, the second path of the second resonator, and the third path.

(Section 3) In the filter device according to Item 2, the main body has a structure in which a plurality of dielectric layers are laminated. The annular structure is formed in the same layer of the body.

(Section 4) The filter device according to Item 3 further includes a ground electrode connected to a ground terminal and a common via connected to the ground electrode. The first resonator includes a first capacitor electrode disposed facing the ground electrode, a first via connected to the first capacitor electrode, and a first plate electrode connected to the first via and the common via. include. The second resonator includes a second capacitor electrode arranged opposite to the ground electrode, a second via connected to the second capacitor electrode, and a second plate electrode connected to the second via and the common via. include. The filter device further includes a third flat electrode connected to the first via and the second via.

(Section 5) In the filter device according to Item 4, the first path of the first resonator is configured by the first capacitor electrode and the first via. The first plate electrode and the common via constitute a second path of the first resonator. The second capacitor electrode and the second via constitute a first path of the second resonator. The second plate electrode and the common via constitute a second path of the second resonator. A third path is configured by the third flat electrode.

(Section 6) In the filter device according to Item 2, the main body has a structure in which a plurality of dielectric layers are laminated. The annular structure is formed across multiple layers of the body.

(Section 7) The filter device according to Item 6 includes a ground electrode connected to a ground terminal, a common electrode arranged on a dielectric layer different from the ground electrode, and a ground electrode connected to the common electrode. It further includes a common via. The first resonator includes a third capacitor electrode arranged opposite to the ground electrode, a third via connected to the third capacitor electrode, a fourth via connected to the common electrode, a third via and a third via connected to the common electrode. and a fourth flat plate electrode connected to four vias. The second resonator includes a fourth capacitor electrode arranged opposite to the ground electrode, a fifth via connected to the fourth capacitor electrode, a sixth via connected to the common electrode, a fifth via and a fifth via connected to the common electrode. 6 vias and a fifth flat plate electrode connected to the fifth via. The filter device further includes a sixth flat electrode connecting the third via and the fifth via.

(Item 8) In the filter device described in Item 7, the third capacitor electrode and the third via form the first path of the first resonator. The fourth plate electrode, the third via, the fourth via, the common electrode, and the common via form the second path of the first resonator. The fourth capacitor electrode and the fifth via form the first path of the second resonator. The fifth plate electrode, the fifth via, the sixth via, the common electrode, and the common via form the second path of the second resonator. The sixth plate electrode forms the third path.

(Clause 9) The filter device described in any one of clauses 1 to 8 further includes a third resonator connected to the input terminal and electromagnetically coupled to the first resonator, and a fourth resonator connected to the output terminal and electromagnetically coupled to the second resonator.

(Section 10) A filter device according to another aspect includes an input terminal, an output terminal, a ground terminal, a first resonator, and a second resonator. The first resonator and the second resonator transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. The first resonator includes a first capacitor connected between a first node and a ground terminal, a first inductor having one end connected to the first node, and a first inductor connected to the other end of the first inductor. 2 inductors, and a common inductor connected between the other end of the second inductor and a ground terminal. The second resonator includes a second capacitor connected between the second node and the ground terminal, a third inductor having one end connected to the second node, and a common inductor connected to the other end of the third inductor. and a fourth inductor connected therebetween. The filter device further includes a fifth inductor connected between the other end of the first inductor and the other end of the third inductor.

(Section 11) The filter device according to any one of Items 1 to 10 is a bandpass filter that passes signals in a specific frequency band.

(Section 12) A filter device according to another aspect includes a main body, an input terminal, an output terminal, a ground terminal, a fifth resonator, and a sixth resonator. The fifth resonator and the sixth resonator are arranged in the main body and transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. The fifth resonator includes a third capacitor connected between the third node and the input terminal, a sixth inductor having one end connected to the third node, and a sixth inductor connected to the other end of the sixth inductor. 7 inductor, and a common inductor connected between the other end of the seventh inductor and a ground terminal. The sixth resonator includes a fourth capacitor connected between the output terminal and the ground terminal, an eighth inductor whose one end is connected to the output terminal, and a common inductor between the other end of the eighth inductor and the common inductor. and a ninth inductor connected thereto. The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor.

(Section 13) The filter device according to Item 12 further includes a fifth capacitor connected to the fifth resonator and the sixth resonator.

(Section 14) A filter device according to another aspect includes a main body, an input terminal, an output terminal, a ground terminal, a fifth resonator, and a seventh resonator. The fifth resonator and the seventh resonator are arranged in the main body and transmit signals from the input terminal to the output terminal by electromagnetically coupling each other. The fifth resonator includes a third capacitor connected between the third node and the input terminal, a sixth inductor having one end connected to the third node, and a sixth inductor connected to the other end of the sixth inductor. 7 inductor, and a common inductor connected between the other end of the seventh inductor and a ground terminal. The seventh resonator includes a sixth capacitor connected between the fourth node and the output terminal, an eighth inductor having one end connected to the fourth node, and the other end of the eighth inductor and a common inductor. and a ninth inductor connected therebetween. The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor.

(Section 15) The filter device according to Item 14 further includes a fifth capacitor connected to the fifth resonator and the seventh resonator.

(Section 16) A high frequency front end circuit comprising the filter device according to any one of Items 1 to 15.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments described above, and it is intended that all changes within the meaning and range equivalent to the claims are included.

10 communication device, 12 antenna, 20 high frequency front end circuit, 22, 28 band pass filter, 24 amplifier, 26 attenuator, 30 mixer, 32 local oscillator, 40 D/A converter, 50 RF circuit, 100, 100A to 100C, 100X, 200, 200 A, 200 , L1, L2A, L2B, L3A, L3B, L4, L5, L10, L10A to L10D, L12, L12A, L20, L20A to L20D, L23A, L23B, L30, L30C Inductor, LY1 to LY10 Dielectric layer, N1A to N4A , N2B, N3B, N10, N20, N31 to N34 Connection node, P23, PL10A, PL10B, PL11B, PL11A, PL20, PL20C, PL23, PL23A to PL23D, PL23X, PL30, PL30C, PL40A, PL40B, PL41A, PL41 B, PL50 , PL50A~PL50C Flat plate electrode, PC1, PC2A, PC2B, PC3A, PC3B, PC4, PC14, PC23 Capacitor electrode, PG, PG1, PG2 Ground electrode, RC1~RC4, RC11, RC11A, RC12, RC12A Resonator, T1, T10 Input terminals, T2, T20 Output terminals, V10 to V12, V20, V20A, V20B, V30, V30A, V40 to V42, VG1 to VG6, VG1A, VG1B, VG2A, VL20, VL30 Via.

Claims (16)

A filter device,
The main body and
input terminal and
output terminal and
a ground terminal;
a first resonator and a second resonator arranged in the main body and transmitting a signal from the input terminal to the output terminal by electromagnetically coupling each other;
Each of the first resonator and the second resonator is
a first path connected from a first node to the ground terminal via a capacitor;
a second path connected from the first node to the ground terminal without a capacitor;
A part of the second path of the first resonator and the second path of the second resonator are shared,
The filter device further includes a third path connected to a first node of the first resonator and a first node of the second resonator. The filter device according to claim 1, wherein the second path of the first resonator, the second path of the second resonator, and the third path form an annular structure. The main body has a structure in which a plurality of dielectric layers are laminated,
3. The filter device of claim 2, wherein the annular structure is formed in the same layer of the body. The filter device includes:
a ground electrode connected to the ground terminal;
further comprising a common via connected to the ground electrode,
The first resonator is
a first capacitor electrode arranged opposite to the ground electrode;
a first via connected to the first capacitor electrode;
a first plate electrode connected to the first via and the common via;
The second resonator is
a second capacitor electrode arranged opposite to the ground electrode;
a second via connected to the second capacitor electrode;
a second flat electrode connected to the second via and the common via;
The filter device according to claim 3, further comprising a third flat electrode connected to the first via and the second via. A first path of the first resonator is configured by the first capacitor electrode and the first via,
A second path of the first resonator is configured by the first plate electrode and the common via,
A first path of the second resonator is configured by the second capacitor electrode and the second via,
A second path of the second resonator is configured by the second flat electrode and the common via,
The filter device according to claim 4, wherein the third path is configured by the third flat plate electrode. The main body has a structure in which a plurality of dielectric layers are laminated,
3. The filter device of claim 2, wherein the annular structure is formed across multiple layers of the body. The filter device includes:
a ground electrode connected to the ground terminal;
a common electrode disposed on a dielectric layer different from the ground electrode;
further comprising a common via connected to the ground electrode and the common electrode,
The first resonator is
a third capacitor electrode arranged opposite to the ground electrode;
a third via connected to the third capacitor electrode;
a fourth via connected to the common electrode;
a fourth flat electrode connected to the third via and the fourth via,
The second resonator is
a fourth capacitor electrode arranged opposite to the ground electrode;
a fifth via connected to the fourth capacitor electrode;
a sixth via connected to the common electrode;
a fifth flat electrode connected to the fifth via and the sixth via,
The filter device according to claim 6, further comprising a sixth flat electrode connecting the third via and the fifth via. A first path of the first resonator is configured by the third capacitor electrode and the third via,
A second path of the first resonator is configured by the fourth plate electrode, the third via, the fourth via, the common electrode, and the common via,
A first path of the second resonator is configured by the fourth capacitor electrode and the fifth via,
A second path of the second resonator is configured by the fifth flat plate electrode, the fifth via, the sixth via, the common electrode, and the common via,
The filter device according to claim 7, wherein the third path is configured by the sixth flat electrode. a third resonator connected to the input terminal and electromagnetically coupled to the first resonator;
The filter device according to claim 1, further comprising a fourth resonator connected to the output terminal and electromagnetically coupled to the second resonator. A filter device,
input terminal and
output terminal and
a ground terminal;
comprising a first resonator and a second resonator that transmit a signal from the input terminal to the output terminal by electromagnetically coupling each other;
The first resonator is
a first capacitor connected between a first node and the ground terminal;
a first inductor having one end connected to the first node;
a second inductor connected to the other end of the first inductor;
a common inductor connected between the other end of the second inductor and the ground terminal;
The second resonator is
a second capacitor connected between a second node and the ground terminal;
a third inductor having one end connected to the second node;
a fourth inductor connected between the other end of the third inductor and the common inductor,
The filter device further includes a fifth inductor connected between the other end of the first inductor and the other end of the third inductor. The filter device according to claim 1 or 10, wherein the filter device is a bandpass filter that passes signals in a specific frequency band. A filter device,
The main body and
input terminal and
output terminal and
a ground terminal;
a fifth resonator and a sixth resonator arranged in the main body and transmitting a signal from the input terminal to the output terminal by electromagnetically coupling each other;
The fifth resonator is
a third capacitor connected between a third node and the input terminal;
a sixth inductor having one end connected to the third node;
a seventh inductor connected to the other end of the sixth inductor;
a common inductor connected between the other end of the seventh inductor and the ground terminal;
The sixth resonator is
a fourth capacitor connected between the output terminal and the ground terminal;
an eighth inductor having one end connected to the output terminal;
a ninth inductor connected between the other end of the eighth inductor and the common inductor,
The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor. The filter device according to claim 12, further comprising a fifth capacitor connected to the fifth resonator and the sixth resonator. A filter device,
The main body and
input terminal and
output terminal and
a ground terminal;
a fifth resonator and a seventh resonator arranged in the main body and transmitting a signal from the input terminal to the output terminal by electromagnetically coupling each other;
The fifth resonator is
a third capacitor connected between a third node and the input terminal;
a sixth inductor having one end connected to the third node;
a seventh inductor connected to the other end of the sixth inductor;
a common inductor connected between the other end of the seventh inductor and the ground terminal,
The seventh resonator is
a sixth capacitor connected between a fourth node and the output terminal;
an eighth inductor having one end connected to the fourth node;
a ninth inductor connected between the other end of the eighth inductor and the common inductor,
The filter device further includes a tenth inductor connected between the other end of the sixth inductor and the other end of the eighth inductor. The filter device according to claim 14, further comprising a fifth capacitor connected to the fifth resonator and the seventh resonator. A high frequency front end circuit comprising the filter device according to any one of claims 1, 10, 12 and 14.

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