Filter device and high frequency front-end circuit including same

Abstract

To provide a filter device with a resonator that improves filter characteristics by suppressing an influence of an external shield electrode, and a filter device.SOLUTION: A filter device 100 has a laminate, an input terminal T1, an output terminal T2, a ground terminal GND, a common electrode PC, a ground electrode PG1, a first resonator, a second resonator, a shield electrode PG2, and ground vias VG1 and VG2. The first resonator includes first vias VL1A and VL1B and a flat plate electrode P1. The first via is connected to the common electrode at one end and to the input terminal at the other end. The flat plate electrode is connected to the first via and overlaps at least partially with the ground electrode when viewed in plan view from a stacking direction. The second resonator includes second vias VL2A and VL2B and a flat plate electrode P2. The second via is connected to the common electrode at one end and to the output terminal at the other end. The flat plate electrode P2 is connected to the second via and overlaps at least partially with the ground electrode when viewed in plan view from the stacking direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a filter device and a high-frequency front-end circuit including the same, and more particularly to a technique for improving the characteristics of a filter device. [Background technology]

[0002] International Publication No. 2022 / 019112 (Patent Document 1) discloses a filter device in which multiple resonators are connected to a common electrode arranged on the upper surface of a main body, and an internal shield electrode connected to a ground electrode is arranged further above the common electrode. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 019112 Summary of the Invention [Problem to be solved by the invention]

[0004] In the filter device disclosed in International Publication No. 2022 / 019112 (Patent Document 1), the internal shield electrode suppresses coupling between the shield electrode (external shield electrode) of an external device located outside the filter device and the common electrode of the filter device, thereby suppressing fluctuations in filter characteristics caused by the external shield electrode.

[0005] On the other hand, in the filter device disclosed in International Publication No. 2022 / 019112 (Patent Document 1), the via connecting the internal shield electrode and the ground electrode is shared with the ground via of each resonator, so the resonators may be coupled to each other via the internal shield electrode. Therefore, even when an internal shield electrode as in International Publication No. 2022 / 019112 (Patent Document 1) is used, the external shield electrode may have a significant effect on the coupling between the resonators. To further improve the filter characteristics, it is necessary to eliminate the effect of such an external shield electrode as much as possible.

[0006] The present disclosure has been made to solve such problems, and its purpose is to suppress the influence of an external shield electrode in a filter device having a resonator and improve the filter characteristics. [Means for solving the problem]

[0007] A filter device according to an aspect of the present disclosure includes a laminate including a plurality of dielectric layers stacked together, an input terminal, an output terminal, a ground terminal, a common electrode disposed on a first surface of the laminate, a ground electrode connected to the ground terminal, a first resonator, a second resonator, a shield electrode, and a first and second ground via. The input terminal, the output terminal, and the ground terminal are disposed on the second surface of the laminate. The first resonator and the second resonator are disposed in a layer between the common electrode and the ground electrode. The shield electrode is disposed closer to the first surface than the common electrode and overlaps the entire common electrode when viewed from above in the stacking direction of the laminate. The first ground via connects the shield electrode and the ground electrode via the common electrode. The second ground via connects the shield electrode and the ground electrode directly without using the common electrode. The first resonator includes a first via and a first plate electrode. One end of the first via is connected to the common electrode and the other end is connected to the input terminal. The first plate electrode is connected to the first via and at least partially overlaps with the ground electrode when viewed from above in the stacking direction. The second resonator includes a second via and a second plate electrode. One end of the second via is connected to the common electrode and the other end is connected to the output terminal. The second plate electrode is connected to the second via and at least partially overlaps with the ground electrode when viewed from above in the stacking direction.

[0008] A filter device according to another aspect of the present disclosure includes a laminate including a plurality of dielectric layers stacked together, an input / output terminal, a ground terminal, a first electrode disposed on a first surface of the laminate, a ground electrode connected to the ground terminal, a resonator disposed in a layer between the first electrode and the ground electrode, a shield electrode, and fifth and sixth ground vias. The input / output terminal and the ground terminal are disposed on a second surface of the laminate. The shield electrode is disposed closer to the first surface than the first electrode and overlaps with the first electrode when viewed in a plan view from the stacking direction of the laminate. The fifth ground via connects the shield electrode and the ground electrode via the first electrode. The sixth ground via connects the shield electrode and the ground electrode directly, without using the first electrode. The resonator includes a fifth via having one end connected to the first electrode and the other end connected to the input / output terminal, and a second electrode connected to the fifth via and at least partially overlapping with the ground electrode when viewed in a plan view from the stacking direction.

[0009] A filter device according to yet another aspect of the present disclosure includes a laminate formed by stacking a plurality of dielectric layers, an input terminal, an output terminal, a ground terminal, a common electrode arranged on a first surface side of the laminate, a ground electrode connected to the ground terminal, a first resonator, a second resonator, a first shield electrode, a second shield electrode, and first to fourth ground vias. The input terminal, the output terminal, and the ground terminal are arranged on the second surface of the laminate. The first resonator and the second resonator are arranged on a layer between the common electrode and the ground electrode. The first shield electrode and the second shield electrode are arranged closer to the first surface than the common electrode. The first ground via is connected to the common electrode. The pole The first shield electrode and the ground electrode are connected via a ground via. The second ground via directly connects the first shield electrode and the ground electrode without going through the common electrode. The third ground via connects the second shield electrode and the ground electrode via the common electrode. The fourth ground via connects the second shield electrode and the ground electrode directly without going through the common electrode. When viewed in a plane in the stacking direction of the laminate, the common electrode is almost entirely covered by the first shield electrode and the second shield electrode. The first resonator includes a first via having one end connected to the common electrode and the other end connected to the input terminal, and a first flat plate electrode connected to the first via and at least partially overlapping with the ground electrode when viewed in a plane in the stacking direction. The second resonator includes a second via having one end connected to the common electrode and the other end connected to the output terminal, and a second flat plate electrode connected to the second via and at least partially overlapping with the ground electrode when viewed in a plane in the stacking direction. [Effects of the Invention]

[0010] In the filter device according to the present disclosure, the shield electrode is connected to ground vias (first ground via, third ground via, fifth ground via) that are connected to the ground electrode via the common electrode, and ground vias (second ground via, fourth ground via, sixth ground via) that are connected directly to the ground electrode without going through the common electrode. With this configuration, most of the signal (current) flowing through the resonator is transmitted to the ground electrode via the ground vias via the common electrode, and almost no signal is transmitted through the path that passes through the ground vias and shield electrode without going through the common electrode. Therefore, even if an external shield electrode of an external device of the filter device is located close to the filter device, the influence of the external shield electrode can be suppressed, thereby improving the filter characteristics. [Brief explanation of the drawings]

[0011] [Figure 1] 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. [Figure 2] 1 is an equivalent circuit diagram of a filter device according to a first embodiment. [Figure 3] 1 is an external perspective view of a filter device according to a first embodiment. [Figure 4] 1 is an exploded perspective view showing a layered structure of a filter device according to a first embodiment. [Figure 5] FIG. 10 is an exploded perspective view showing a laminated structure of a filter device of a comparative example. [Figure 6] 3 is a diagram illustrating signal paths in the filter devices of the first embodiment and the comparative example. FIG. [Figure 7] 5A and 5B are diagrams for explaining the pass characteristics of the filter devices of the first embodiment and the comparative example. [Figure 8] FIG. 10 is an exploded perspective view showing a layered structure of a filter device according to a second embodiment. [Figure 9] FIG. 11 is an exploded perspective view showing a layered structure of a filter device according to a third embodiment. [Figure 10] FIG. 10 is an exploded perspective view showing the layered structure of a filter device according to a fourth embodiment. [Figure 11] FIG. 10 is an equivalent circuit diagram of a filter device according to a fifth embodiment. [Figure 12] FIG. 10 is an exploded perspective view showing an example of a laminated structure of a filter device according to a fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0013] [Embodiment 1] (Basic configuration of communication equipment) 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 embodiment 1 is applied. The communication device 10 is, for example, a mobile terminal or a mobile phone base station.

[0014] 1, a 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. Although the description of FIG. 1 illustrates a case in which the high-frequency front-end circuit 20 includes a transmission circuit that transmits a high-frequency signal from the antenna 12, the high-frequency front-end circuit 20 may also include a reception circuit that receives a high-frequency signal via the antenna 12.

[0015] The communication device 10 upconverts a transmission signal transmitted from the RF circuit 50 to a high-frequency signal and radiates it from the antenna 12. The modulated digital signal output from the RF circuit 50, which is the transmission signal, is converted to an analog signal by the D / A converter 40. The mixer 30 upconverts the transmission signal, converted from digital to analog by the D / A converter 40, to a high-frequency signal by mixing it with an oscillation signal from the local oscillator 32. The bandpass filter 28 removes unwanted waves generated by the upconversion and extracts only the transmission signal in the desired frequency band. The attenuator 26 adjusts the intensity of the transmission signal. The amplifier 24 power-amplifies the transmission signal that has passed through the attenuator 26 to a predetermined level. The bandpass filter 22 removes unwanted waves generated during the amplification process and passes only signal components in the frequency band specified by the communication standard. The transmission signal that has passed through the bandpass filter 22 is radiated from the antenna 12.

[0016] A filter device according to the present disclosure can be employed as the bandpass filters 22, 28 in the communication device 10 described above.

[0017] (Configuration of filter device) Next, the detailed configuration of the filter device 100 according to the first embodiment will be described with reference to FIGS.

[0018] Fig. 2 is an equivalent circuit diagram of the filter device 100. Referring to Fig. 2, the filter device 100 includes an input terminal T1, an output terminal T2, a ground terminal GND, 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.

[0019] The resonator RC1 includes inductors L1A and L1B connected in series between the input terminal T1 and the ground terminal GND, an inductor L2B connected in parallel with the inductor L1B, and a capacitor C1 connected in parallel with the inductors L1A and L1B. A connection node N1A between the inductor L1A and the capacitor C1 is connected to the input terminal T1. A connection node N3B between the inductor L1B and the capacitor C1 is connected to the ground terminal GND. The inductance value of the inductor L2B is greater than the inductance value of the inductor L1B.

[0020] The resonator RC2 includes inductors L2A and L2B connected in series between the output terminal T2 and the ground terminal GND, an inductor L1B connected in parallel to the inductor L2B, and a capacitor C2 connected in parallel to the inductors L2A and L2B. A connection node N2A between the inductor L2A and the capacitor C2 is connected to the output terminal T2. A connection node N4B between the inductor L2B and the capacitor C2 is connected to the ground terminal GND. In other words, the parallel-connected inductors L1B and L2B are shared with the resonator RC1.

[0021] The resonator RC3 includes inductors L3A and L1B connected in series, an inductor L2B connected in parallel to the inductor L1B, and a capacitor C3 connected in parallel to the inductors L3A and L1B. A connection node N3A between the inductor L3A and the capacitor C3 is connected to the connection node N1A (i.e., the input terminal T1) of the resonator RC1 via a capacitor C13. In the resonator RC3, the parallel-connected inductors L1B and L2B are also shared with the resonator RC1.

[0022] The resonator RC4 includes inductors L4A and L2B connected in series, an inductor L1B connected in parallel to the inductor L2B, and a capacitor C4 connected in parallel to the inductors L4A and L2B. A connection node N4A between the inductor L4A and the capacitor C4 is connected to the connection node N2A (i.e., the output terminal T2) of the resonator RC2 via a capacitor C24. In the resonator RC4, the parallel-connected inductors L1B and L2B are also shared with the resonator RC1.

[0023] A connection node N1A (input terminal T1) of the resonator RC1 and a connection node N2A (output terminal T2) of the resonator RC2 are connected via a capacitor C12. Furthermore, the portions indicated by connection nodes N1B and N2B, where the inductors L1A, L2A, L3A, and L4A of the resonators are connected to one another, correspond to a common electrode PC, which will be described later with reference to FIG.

[0024] The resonators are magnetically coupled to each other. Thus, the filter device 100 has a configuration in which four stages of resonators that are 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.

[0025] 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 layered structure of the filter device 100. As shown in FIG.

[0026] 3 and 4, the filter device 100 includes a rectangular or approximately rectangular parallelepiped laminate 110 in which a plurality of dielectric layers LY1 to LY8 are stacked in a stacking direction. The dielectric layers LY1 to LY8 are formed of ceramics such as low-temperature co-fired ceramics (LTCC) or resin. Inside the laminate 110, a plurality of electrodes provided on each dielectric layer and a plurality of vias provided between the dielectric layers form inductors and capacitors of an LC parallel resonator. In this specification, the term "via" refers to a conductor provided in a dielectric layer to connect electrodes provided on different dielectric layers. The vias are formed, for example, by conductive paste, plating, and / or metal pins.

[0027] In the following description, the stacking direction of the dielectric layers LY1 to LY8 in the laminate 110 is referred to as the "Z-axis direction," the direction perpendicular to the Z-axis direction and along the long side of the laminate 110 is referred to as the "X-axis direction," and the direction along the short side of the laminate 110 is referred to as the "Y-axis direction." In the following, the positive direction of the Z-axis in each drawing may be referred to as the upper side, and the negative direction may be referred to as the lower side.

[0028] A directionality mark DM for identifying the orientation of the filter device 100 is arranged on the upper surface 111 (dielectric layer LY1) of the laminate 110. External terminals (an input terminal T1, an output terminal T2, and a ground terminal GND) for connecting the filter device 100 to an external device are arranged on the lower surface 112 (dielectric layer LY8) of the laminate 110. The input terminal T1, the output terminal T2, and the ground terminal GND are each a flat plate electrode, and are LGA (Land Grid Array) terminals regularly arranged on the lower surface 112 of the laminate 110. The "upper surface 111" and the "lower surface 112" of the first embodiment correspond to the "first surface" and the "second surface" in this disclosure, respectively.

[0029] 2, the filter device 100 has four-stage LC parallel resonators. More specifically, the filter device 100 includes a resonator RC1 including vias VL1A and VL1B and a capacitor electrode P1, a resonator RC2 including vias VL2A and VL2B and a capacitor electrode P2, a resonator RC3 including a via VL3 and a capacitor electrode P3, and a resonator RC4 including a via VL4 and a capacitor electrode P4. Each of the vias VL1B, VL2B, VL3, and VL4 is connected to a common electrode PC disposed on a dielectric layer LY3.

[0030] The common electrode PC is connected to a ground electrode PG1 disposed on the dielectric layer LY6 and a shield electrode PG2 disposed on the dielectric layer LY2 by vias VG1 and VG3. The ground electrode PG1 is directly connected to the shield electrode PG2 by vias VG2 and VG4. The ground electrode PG1 is also connected to the ground terminal GND on the dielectric layer LY8 by vias VG5 and VG6. Capacitor electrodes P1, P2, P3, and P4 are disposed on the dielectric layer LY6.

[0031] The input terminal T1 is connected to a capacitor electrode P1 arranged on the dielectric layer LY6 by a via VL1A. The capacitor electrode P1 is connected to a common electrode PC arranged on the dielectric layer LY2 by a via VL1B. The capacitor electrode P1 is a substantially L-shaped flat plate electrode. When the laminate 110 is viewed from above in the lamination direction (Z-axis direction), a portion of the capacitor electrode P1 overlaps with a ground electrode PG1 on the dielectric layer LY7. The capacitor electrode P1 and the ground electrode PG1 form the capacitor C1 in FIG. 2.

[0032] The via VL1B and the common electrode PC form the inductor L1A in Fig. 2. The portions of the vias VG1 and VG3 between the common electrode PC and the ground electrode PG1 form the inductor L1B in Fig. 2. The portions of the vias VG1 and VG3 between the common electrode PC and the shield electrode PG2, the shield electrode PG2, and the vias VG2 and VG4 form the inductor L2B in Fig. 2. That is, the capacitor electrode P1, the ground electrode PG1, the shield electrode PG2, the vias VL1B, VG1 to VG4, and the common electrode PC form the resonator RC1.

[0033] The output terminal T2 is connected to a capacitor electrode P2 arranged on the dielectric layer LY6 by a via VL2A. The capacitor electrode P2 is connected to a common electrode PC arranged on the dielectric layer LY2 by a via VL2B. The capacitor electrode P2 is a generally L-shaped flat plate electrode. When the laminate 110 is viewed from above in the lamination direction, a portion of the capacitor electrode P2 overlaps with the ground electrode PG1 on the dielectric layer LY7. The capacitor electrode P2 and the ground electrode PG1 form the capacitor C2 in FIG. 2. The via VL2B and the common electrode PC form the inductor L2A in FIG. 2. That is, the capacitor electrode P2, the ground electrode PG1, the shield electrode PG2, the vias VL2B, VG1 to VG4, and the common electrode PC form a resonator RC2.

[0034] The capacitor electrode P1 of the resonator RC1 is connected to a capacitor electrode P5 arranged on the dielectric layer LY5 by a via VL5. The capacitor electrode P5 is a rectangular plate electrode. When the laminate 110 is viewed from above in the stacking direction, a portion of the capacitor electrode P5 overlaps with the capacitor electrode P3 of the resonator RC3 arranged on the dielectric layer LY6. The capacitor electrodes P3 and P5 form the capacitor C13 in FIG. 2. The via VL3 connects the capacitor electrode P3 and the common electrode PC. The capacitor electrode P3, the ground electrode PG1, the shield electrode PG2, the vias VL3, VG1 to VG4, and the common electrode PC form the resonator RC3.

[0035] The capacitor electrode P2 of the resonator RC2 is connected to a capacitor electrode P6 arranged on the dielectric layer LY5 by a via VL6. The capacitor electrode P6 is a rectangular plate electrode. When the laminate 110 is viewed from above in the stacking direction, a portion of the capacitor electrode P6 overlaps with the capacitor electrode P4 of the resonator RC4 arranged on the dielectric layer LY6. The capacitor electrodes P4 and P6 form the capacitor C24 in FIG. 2. The via VL4 connects the capacitor electrode P4 and the common electrode PC. The capacitor electrode P4, the ground electrode PG1, the shield electrode PG2, the vias VL4, VG1 to VG4, and the common electrode PC form the resonator RC4.

[0036] A rectangular capacitor electrode P7 is disposed on the dielectric layer LY4. When the laminate 110 is viewed from above in the lamination direction, the capacitor electrode P7 partially overlaps with the capacitor electrodes P5 and P6 disposed on the dielectric layer LY5. The capacitor electrodes P5 to P7 form the capacitor C12 in FIG. 2.

[0037] "Vias VL1A, VL1B" in the first embodiment correspond to "first vias" in the present disclosure. "Vias VL2A, VL2B" in the first embodiment correspond to "second vias" in the present disclosure. "Via VL3" and "Via VL4" in the first embodiment correspond to "third vias" and "fourth vias", respectively, in the present disclosure. "Vias VG1, VG3" in the first embodiment correspond to "first ground vias" in the present disclosure. "Vias VG2, VG4" in the first embodiment correspond to "second ground vias" in the present disclosure. "Capacitor electrodes P1 to P7" in the first embodiment correspond to "first plate electrode" to "seventh plate electrode", respectively, in the present disclosure.

[0038] (filter characteristics) Next, the filter characteristics of the filter device 100 of the first embodiment will be described in comparison with a comparative example using Figures 5 to 7. Figure 5 is an exploded perspective view of a filter device 100X of the comparative example. In the filter device 100X, vias VG2 and VG4 in the filter device 100 described in Figure 4 are omitted. The other configurations of the filter device 100X are the same as those of the filter device 100. The description of elements in Figure 5 that overlap with those in Figure 4 will not be repeated.

[0039] Fig. 6 is a diagram illustrating signal paths in the filter devices of the first embodiment and the comparative example. In Fig. 6, the left diagram shows a part of an exploded perspective view of the filter device 100 of the first embodiment, and the right diagram shows a part of an exploded perspective view of the filter device 100X of the comparative example. In explaining Fig. 6, the signal flowing through the second-stage resonator RC3 will be described with reference to Figs. 2 and 4 as appropriate.

[0040] The signal transmitted from resonator RC1 to resonator RC3 via capacitor C13 is transmitted to common electrode PC through via VL3. In common electrode PC, the signal is transmitted to via VG1, which is closest to via VL3, and most of the signal flows to ground electrode PG1 via the path indicated by solid arrow AR1. In addition, a portion of the signal transmitted to via VG1 is also transmitted to shield electrode PG2.

[0041] In the comparative example filter device 100X shown in the right diagram, which does not have vias VG2 and VG4, a signal transmitted to the shield electrode PG2 flows to the ground electrode PG1 through the via VG3 used for the resonators RC2 and RC4, as indicated by the dashed arrow AR3. That is, a signal coupling the resonators RC3 and RC4 is transmitted via the shield electrode PG2. Therefore, when a shield electrode (external shield electrode) of an external device is placed close to the filter device 100X, the coupling between the resonators RC3 and RC4 is affected by the external shield electrode.

[0042] On the other hand, in the filter device 100 according to the first embodiment, the signal transmitted to the shield electrode PG2 is transmitted to the via VG2 that is closest to the via VG1, and then flows to the ground electrode PG1 via the via VG2 as indicated by the dashed arrow AR2, with almost no signal flowing to the via VG3. That is, since the signal that couples the resonators RC3 and RC4 does not flow through the shield electrode PG2, even if an external shield electrode is present, the signal does not affect the coupling between the resonators RC3 and RC4.

[0043] Note that the path length from the common electrode PC via the shield electrode PG2 to the ground electrode PG1 is longer than the path length from the common electrode PC via only the via VG1 to the ground electrode PG1, resulting in a larger inductance value, and therefore most of the signal flows through the path via only the via VG1. Therefore, even in the case of the filter device 100X of the comparative example, the influence of the external shield electrode can be reduced compared to a configuration without the shield electrode PG2. However, by providing vias VG2 and VG4 that directly connect the shield electrode PG2 and the ground electrode PG1 as in the first embodiment, the influence of the external shield electrode on the coupling between the resonators can be further reduced compared to the comparative example.

[0044] FIG. 7 shows the outer shield in the filter devices according to the first embodiment and the comparative example. electrode 7 is a diagram illustrating a change in pass characteristics depending on whether or not an external shield electrode is present. In FIG. 7, the left diagram shows a graph of the pass characteristics of the filter device 100 according to the first embodiment, and the right diagram shows a graph of the pass characteristics of the filter device 100X according to the comparative example. In each graph, the horizontal axis represents frequency, and the vertical axis represents insertion loss. In each graph, the solid lines LN10 and LN20 represent the pass characteristics when there is no external shield electrode, and the dashed lines LN11 and LN21 represent the pass characteristics when there is an external shield electrode.

[0045] 7, in the comparative example on the right, when there is an external shield electrode, the pass band expands toward the lower frequency side compared to when there is no external shield electrode, in other words, the attenuation characteristics between the pass band and non-pass band are reduced. Note that, although such a change in characteristics may not necessarily have a negative effect on the desired filter characteristics, if the filter characteristics vary depending on whether or not there is an external shield electrode, the performance of the equipment to which the filter device is applied may become unstable.

[0046] On the other hand, in the case of the first embodiment shown on the left, there is almost no change in the pass characteristics depending on whether or not there is an external shield electrode. Therefore, by adopting the configuration of the first embodiment, it is possible to suppress the influence of the external shield electrode, improve (stabilize) the filter characteristics, and stabilize the performance of the equipment to which the filter device is applied.

[0047] In the above description, the filter device is configured with four resonators, but the number of resonators may be five or more.

[0048] [Embodiment 2] In the second embodiment, a configuration in which the shield electrode is formed by a plurality of flat plate electrodes will be described.

[0049] Fig. 8 is an exploded perspective view showing a layered structure of filter device 100A according to Embodiment 2. In filter device 100A, shield electrode PG2 of filter device 100 according to Embodiment 1 is replaced with shield electrodes PG21 and PG22. In Fig. 8, the description of elements that overlap with those of filter device 100 shown in Fig. 4 will not be repeated.

[0050] Referring to FIG. 8, a shield electrode PG21 provided for the first-stage resonator RC1 and the second-stage resonator RC3, and a shield electrode PG22 provided for the third-stage resonator RC4 and the fourth-stage resonator RC2 are arranged on the dielectric layer LY2 of the filter device 100A.

[0051] Each of the shield electrodes PG21, PG22 is a rectangular flat electrode, and has a size approximately the same as that of the shield electrode PG2 of the filter device 100 in Fig. 4. In other words, when viewed from above in the stacking direction of the laminate 110, the common electrode PC is almost entirely covered by the shield electrodes PG21, PG22. Vias VG1 and VG2 are connected to the shield electrode PG21, and vias VG3 and VG4 are connected to the shield electrode PG22.

[0052] Even in this configuration where the shield electrode is divided into two, vias are provided in each shield electrode that are connected to the ground electrode PG1 without going through a resonator, so even if an external shield electrode of an external device is placed nearby, the effect on coupling between the resonators can be reduced. Furthermore, because the shield electrode is divided, coupling between resonators RC3 and RC4 via the shield electrode can also be suppressed.

[0053] The "shield electrode PG21" and the "shield electrode PG22" in the second embodiment correspond to the "first shield electrode" and the "second shield electrode" in the present disclosure. The "vias VG1" to "vias VG4" in the second embodiment correspond to the "first ground via" to "fourth ground via" in the present disclosure, respectively.

[0054] [Embodiment 3] In the third embodiment, an example in which a filter device is configured with two resonators will be described.

[0055] 9 is an exploded perspective view showing a layered structure of a filter device 100B according to the third embodiment. The filter device 100B has a configuration in which the resonators RC3 and RC4 in the filter device 100 according to the first embodiment are omitted. More specifically, the filter device 100B has a configuration in which the capacitor electrodes P3 and P4 and the vias VL3 and VL4 in FIG. 4 are omitted. In FIG. 9, the description of elements that overlap with those in the filter device 100 shown in FIG. 4 will not be repeated.

[0056] Even in a two-stage resonator configuration such as the filter device 100B, the vias VG2 and VG4, which are connected to the ground electrode PG1 without going through the resonators, are arranged in the shield electrode PG2, so that even if the external shield electrode of an external device is located nearby, the effect on the coupling between the resonators can be reduced.

[0057] [Embodiment 4] In the fourth embodiment, an example in which a filter device is configured with three resonators will be described.

[0058] 10 is an exploded perspective view showing a layered structure of a filter device 100C according to the fourth embodiment. The filter device 100C has a configuration in which the resonator RC4 in the filter device 100 according to the first embodiment is omitted. In FIG. 10, the description of the elements that overlap with those of the filter device 100 shown in FIG. 4 will not be repeated.

[0059] 4 is deleted from the filter device 100C. In the filter device 100C, the capacitor electrode P3 and the via VL3 that configure the resonator RC3 are disposed near the center of the laminate 110 in the X-axis direction. When viewed from above in the lamination direction of the laminate 110, the capacitor electrode P3 partially overlaps with the capacitor electrodes P5 and P6 that are disposed on the dielectric layer LY5.

[0060] Even in a three-stage resonator configuration such as the filter device 100C, the vias VG2 and VG4, which are connected to the ground electrode PG1 without going through a resonator, are connected to the shield electrode PG2, so that even if the external shield electrode of an external device is located nearby, the effect on the coupling between the resonators can be reduced.

[0061] [Embodiment 5] In the fifth embodiment, an example in which a filter device is configured with one resonator will be described.

[0062] Fig. 11 is an equivalent circuit diagram of a filter device 100D according to the fifth embodiment, and Fig. 12 is an exploded perspective view showing the layered structure of the filter device 100D.

[0063] 11, the filter device 100D has a configuration in which a resonator RC11 is connected between a path connecting an input terminal T1 and an output terminal T2 and a ground terminal GND. The resonator RC11 includes inductors L11, L12, and L13 and a capacitor C11. One end of the inductor L11 is connected to the input terminal T1 and the output terminal T2. The inductors L12 and L13 are connected in parallel between the other end of the inductor L11 and the ground terminal GND. The inductance value of the inductor L13 is larger than the inductance value of the inductor L12. The capacitor C11 is connected between the input terminal T1, the output terminal T2, and the ground terminal GND.

[0064] 12, a laminate 110D in a filter device 100D has a configuration in which a plurality of dielectric layers LY11 to LY16 are stacked. As with the filter device 100 of the first embodiment, a directional mark DM is arranged on the upper surface 111 (dielectric layer LY11). Furthermore, an input terminal T1, an output terminal T2, and a ground terminal GND are arranged on the lower surface 112 (dielectric layer LY16). Note that in the fifth embodiment, the input terminal T1 and the output terminal T2 are formed by a single common flat plate electrode. Therefore, in the following description, the input terminal T1 and the output terminal T2 will also be collectively referred to as the "input / output terminal T12."

[0065] The input / output terminal T12 is connected to a capacitor electrode P12 arranged on the dielectric layer LY14 by a via VL11. The capacitor electrode P12 is a flat electrode having a substantially L-shape, and when viewed from above in the normal direction of the laminate 110D, it partially overlaps with a ground electrode PG11 arranged on the dielectric layer LY15. The ground electrode PG11 is connected to a ground terminal GND on the dielectric layer LY16 by vias VG13 and VG14. That is, the capacitor electrode P12 and Ground electrode PG11This constitutes the capacitor C11 in FIG.

[0066] The capacitor electrode P12 is further connected to a plate electrode P11 disposed on the dielectric layer LY13 by a via VL12. The via VL12 and the plate electrode P11 form the inductor L11 in Fig. 11. The plate electrode P11 is connected to a shield electrode PG12 disposed on the dielectric layer LY12 and a ground electrode PG11 disposed on the dielectric layer LY15 by a via VG11.

[0067] The shield electrode PG12 is a plate electrode having a substantially rectangular shape, and overlaps with the plate electrode P11 of the dielectric layer LY13 when viewed from above in the normal direction of the laminate 110D. The shield electrode PG12 is directly connected to the ground electrode PG11 by a via VG12 without going through the plate electrode P11.

[0068] That is, the path from the plate electrode P11 to the ground electrode PG11 via only the via VG11 forms the inductor L12 in Fig. 11. Also, the path from the plate electrode P11 to the ground electrode PG11 via the via VG11, the shield electrode PG12, and the via VG12 forms the inductor L13 in Fig. 11. The plate electrode P11 corresponds to the connection node of the inductors L11, L12, and L13 in Fig. 11.

[0069] Even in this configuration, the current flowing through the resonator RC11 mainly flows through a path with a short path length (small inductance value) from the plate electrode P11 to the ground electrode PG11 via only the via VG11, and hardly flows through the path via the shield electrode PG12. Therefore, even if a shield electrode of an external device is present on the upper surface 111 of the filter device 100D, the influence on the filter device 100D can be reduced.

[0070] Note that the "plate electrode P11" in the fifth embodiment corresponds to the "first electrode" in the present disclosure. The "via VG11" and the "via VG12" in the fifth embodiment correspond to the "fifth ground via" and the "sixth ground via" in the present disclosure, respectively. The "via VL12" in the fifth embodiment corresponds to the "fifth via" in the present disclosure. The "capacitor electrode P12" in the fifth embodiment corresponds to the "second electrode" in the present disclosure. [Aspect] (Item 1) A filter device according to one aspect includes a laminate including a plurality of dielectric layers stacked together, an input terminal, an output terminal, a ground terminal, a common electrode disposed on a first surface of the laminate, a ground electrode connected to the ground terminal, a first resonator, a second resonator, a shield electrode, and a first and second ground via. The input terminal, the output terminal, and the ground terminal are disposed on the second surface of the laminate. The first resonator and the second resonator are disposed in a layer between the common electrode and the ground electrode. The shield electrode is disposed closer to the first surface than the common electrode and overlaps the entire common electrode when viewed from above in the stacking direction of the laminate. The first ground via connects the shield electrode and the ground electrode via the common electrode. The second ground via connects the shield electrode and the ground electrode directly without using the common electrode. The first resonator includes a first via and a first flat plate electrode. One end of the first via is connected to the common electrode and the other end is connected to the input terminal. The first plate electrode is connected to the first via and at least partially overlaps with the ground electrode when viewed from above in the stacking direction. The second resonator includes a second via and a second plate electrode. One end of the second via is connected to the common electrode and the other end is connected to the output terminal. The second plate electrode is connected to the second via and at least partially overlaps with the ground electrode when viewed from above in the stacking direction.

[0071] (Item 2) In the filter device described in item 1, the path length from the common electrode to the ground electrode via the shield electrode and the second ground via is longer than the path length from the common electrode to the ground electrode via the first ground via.

[0072] (Item 3) In the filter device described in item 1, the inductance value of the path from the common electrode to the ground electrode via the shield electrode and the second ground via is greater than the inductance value of the path from the common electrode to the ground electrode via the first ground via.

[0073] (4) The filter device according to any one of paragraphs 1 to 3 further includes a third resonator disposed between the first and second resonators. The third resonator includes a third plate electrode that at least partially overlaps with the ground electrode when viewed from above in the stacking direction, and a third via disposed between the common electrode and the third plate electrode.

[0074] (Item 5) The filter device according to item 4 further includes a fourth resonator disposed between the second resonator and the third resonator. The fourth resonator includes a fourth plate electrode that at least partially overlaps with the ground electrode when viewed from above in the stacking direction, and a fourth via disposed between the common electrode and the fourth plate electrode.

[0075] (Item 6) The filter device described in item 5 further includes fifth to seventh plate electrodes. The fifth plate electrode is connected to the first plate electrode and at least partially overlaps with the third plate electrode when viewed in plan from the stacking direction. The sixth plate electrode is connected to the second plate electrode and at least partially overlaps with the fourth plate electrode when viewed in plan from the stacking direction. The seventh plate electrode at least partially overlaps with the fifth and sixth plate electrodes when viewed in plan from the stacking direction.

[0076] (Item 7) A filter device according to another aspect includes a laminate including a plurality of dielectric layers stacked together, an input / output terminal, a ground terminal, a first electrode disposed on a first surface of the laminate, a ground electrode connected to the ground terminal, a resonator disposed in a layer between the first electrode and the ground electrode, a shield electrode, and fifth and sixth ground vias. The input / output terminal and the ground terminal are disposed on a second surface of the laminate. The shield electrode is disposed closer to the first surface than the first electrode and overlaps with the first electrode when viewed in a plan view from the stacking direction of the laminate. The fifth ground via connects the shield electrode and the ground electrode via the first electrode. The sixth ground via connects the shield electrode and the ground electrode directly, without using the first electrode. The resonator includes a fifth via having one end connected to the first electrode and the other end connected to the input / output terminal, and a second electrode connected to the fifth via and at least partially overlapping with the ground electrode when viewed in a plan view from the stacking direction.

[0077] (Item 8) A filter device according to another aspect includes a laminate in which a plurality of dielectric layers are stacked, an input terminal, an output terminal, a ground terminal, a common electrode arranged on a first surface side of the laminate, a ground electrode connected to the ground terminal, a first resonator, a second resonator, a first shield electrode, a second shield electrode, and first to fourth ground vias. The input terminal, the output terminal, and the ground terminal are arranged on the second surface of the laminate. The first resonator and the second resonator are arranged on a layer between the common electrode and the ground electrode. The first shield electrode and the second shield electrode are arranged on the first surface side of the common electrode. The first ground via is connected to the common electrode. The poleThe first shield electrode and the ground electrode are connected via a ground via. The second ground via directly connects the first shield electrode and the ground electrode without going through the common electrode. The third ground via connects the second shield electrode and the ground electrode via the common electrode. The fourth ground via connects the second shield electrode and the ground electrode directly without going through the common electrode. When viewed in a plane in the stacking direction of the laminate, the common electrode is almost entirely covered by the first shield electrode and the second shield electrode. The first resonator includes a first via having one end connected to the common electrode and the other end connected to the input terminal, and a first flat plate electrode connected to the first via and at least partially overlapping with the ground electrode when viewed in a plane in the stacking direction. The second resonator includes a second via having one end connected to the common electrode and the other end connected to the output terminal, and a second flat plate electrode connected to the second via and at least partially overlapping with the ground electrode when viewed in a plane in the stacking direction.

[0078] (Item 9) The filter device according to any one of items 1 to 8 is a band-pass filter.

[0079] (10th Item) A high-frequency front-end circuit according to another aspect includes the filter device according to any one of the first to tenth items.

[0080] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0081] 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 100D, 100X filter device, 110, 110D laminate, 111 upper surface, 112 lower surface, N1A to N4A, N1B to N4B connection node, C1 to C4, C11 to C13, C24 capacitor, DM direction mark, GND ground terminal, L1A to L4A, L1B, L2B, L11 to L13 inductor, LY1 to LY8, LY11 to LY16 Dielectric layer, VG1 to VG6, VG11 to VG14, VL1A, VL1B, VL2A, VL2B, VL3 to VL6, VL11, VL12 vias, P1 to P7, P12, P14 capacitor electrodes, P11 plate electrode, PC common electrode, PG1, PG11 ground electrodes, PG2, PG12, PG21, PG22 shield electrodes, RC1 to RC4, RC11 resonators, T1 input terminal, T2 output terminal, T12 input / output terminal.

Claims

1. a laminate having a first surface and a second surface and including a plurality of dielectric layers stacked on top of one another; an input terminal, an output terminal, and a ground terminal disposed on the second surface of the laminate; a common electrode disposed on the first surface side of the laminate; a ground electrode connected to the ground terminal; a first resonator and a second resonator disposed on a layer between the common electrode and the ground electrode; a shield electrode that is disposed closer to the first surface than the common electrode and that overlaps the entire common electrode when viewed from above in the stacking direction of the stacked body; a first ground via including a first ground conductor and a second ground conductor connecting the shield electrode and the ground electrode via the common electrode; a second ground via including a third ground conductor and a fourth ground conductor that directly connect the shield electrode and the ground electrode without passing through the common electrode; The first resonator is a first via having one end connected to the common electrode and the other end connected to the input terminal; a first plate electrode connected to the first via and at least partially overlapping with the ground electrode when viewed in a plan view from the stacking direction; the first ground conductor; The second resonator is a second via having one end connected to the common electrode and the other end connected to the output terminal; a second plate electrode connected to the second via and at least partially overlapping with the ground electrode when viewed in a plan view from the stacking direction; the second ground conductor; A filter device, wherein a distance between the first ground conductor and the third ground conductor is shorter than a distance between the first ground conductor and the second ground conductor.

2. 2. The filter device according to claim 1, wherein a path length from the common electrode to the ground electrode via the shield electrode and the second ground via is longer than a path length from the common electrode to the ground electrode via the first ground via.

3. 2. The filter device of claim 1, wherein the inductance value of a path from the common electrode to the ground electrode via the shield electrode and the second ground via is greater than the inductance value of a path from the common electrode to the ground electrode via the first ground via.

4. further comprising a third resonator disposed between the first resonator and the second resonator; The third resonator is a third plate electrode that at least partially overlaps with the ground electrode when viewed in a plan view from the stacking direction; 4. The filter device according to claim 1, further comprising a third via arranged between the common electrode and the third plate electrode.

5. further comprising a fourth resonator disposed between the second resonator and the third resonator; The fourth resonator is a fourth plate electrode that at least partially overlaps with the ground electrode when viewed in a plan view from the stacking direction; The filter device of claim 4 , further comprising a fourth via disposed between the common electrode and the fourth plate electrode.

6. a fifth plate electrode connected to the first plate electrode and at least partially overlapping with the third plate electrode when viewed from above in the stacking direction; a sixth plate electrode connected to the second plate electrode and at least partially overlapping with the fourth plate electrode when viewed from above in the stacking direction; The filter device according to claim 5 , further comprising a seventh plate electrode that at least partially overlaps with the fifth plate electrode and the sixth plate electrode when viewed from above in the stacking direction.

7. 10. The filter device of claim 1, wherein the filter device is a bandpass filter.

8. A high-frequency front-end circuit comprising the filter device according to claim 1.

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