Filter device, and high-frequency front-end circuit provided with the same

Abstract

A filter device (100) includes: a dielectric substrate (110); ground electrodes (PG1, PG2) connected to a ground terminal (GND); and a plurality of resonators disposed between the ground electrodes and electromagnetically coupled to each other. The two ground electrodes are disposed at different positions in a normal direction of the dielectric substrate. Each of the plurality of resonators includes: a first capacitance electrode partially overlapping the ground electrode (PG1) when the dielectric substrate is viewed in plan; a second capacitance electrode partially overlapping the ground electrode (PG2) when the dielectric substrate is viewed in plan; and a via connecting between the capacitance electrodes. The plurality of resonators includes: a resonator (RC1) connected to an input terminal (T1); a resonator (RC2) connected to an output terminal (T2); and a resonator (RC3) disposed between the resonators (RC1, RC2). The filter device further includes shunt electrodes (PB1, PB2) connecting the via to the ground terminal in each of the resonator (RC1) and the resonator (RC2).

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 technology for improving characteristics of a stacked LC filter. BACKGROUND

[0002] A filter device configured with a plurality of LC resonators is known. A band-pass filter configured with a plurality of LC resonators that are direct-current insulated from a ground node by capacitors is disclosed, for example, in International Publication No. 2018 / 100923 (Patent Literature 1). By direct-current insulating the LC resonators that constitute the band-pass filter from the ground node, it is possible to suppress a case where the ground electrode and the corresponding conductor function as inductors in a case where a current flows in the ground electrode and other conductors connected to the ground electrode. Thereby, it is possible to prevent the characteristics of the band-pass filter from deviating from the desired characteristics.

[0003] Prior art documents

[0004] Patent Literature 1: International Publication No. 2018 / 100923 Specification SUMMARY

[0005] PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] In the band-pass filter disclosed in International Publication No. 2018 / 100923 (Patent Literature 1), it is possible to mainly adjust the attenuation characteristics on the high-frequency side compared to the passband. However, depending on the characteristics of the device that uses the band-pass filter, there are cases where it is necessary to adjust the attenuation characteristics on the low-frequency side compared to the passband as well.

[0007] The present disclosure is achieved in order to solve the above-described problems, and aims to improve the attenuation characteristics of the cutoff bands on the high-frequency side and the low-frequency side compared to the passband in a filter device including a plurality of LC resonators.

[0008] MEANS OF SOLVING THE PROBLEMS

[0009] The filter device according to the present disclosure includes a dielectric substrate, first and second ground electrodes connected to a ground terminal, and a plurality of resonators disposed between the first and second ground electrodes and electromagnetically coupled to each other. The first and second ground electrodes are disposed at different positions in a normal direction of the dielectric substrate. The plurality of resonators are disposed between the first and second ground electrodes. Each of the plurality of resonators includes a first capacitance electrode partially overlapping the first ground electrode when the dielectric substrate is viewed from the normal direction, a second capacitance electrode partially overlapping the second ground electrode when the dielectric substrate is viewed from the normal direction, and at least one first via connecting the first and second capacitance electrodes. The plurality of resonators include a first resonator connected to an input terminal, a second resonator connected to an output terminal, and a third resonator disposed between the first and second resonators. The filter device further includes at least one of a first shunt electrode connected to the first via included in the first resonator and the ground terminal, and a second shunt electrode connected to the first via included in the second resonator and the ground terminal.

[0010] Effects of the invention

[0011] In the filter device according to the present disclosure, each resonator is configured to include capacitance electrodes (first and second capacitance electrodes) partially overlapping the two ground electrodes, respectively, and a via (first via) connecting between the capacitance electrodes. Also, in at least one of the resonators (first and second resonators) connected to the input and output terminals, the via forming an inductor is connected to the ground terminal through a shunt electrode. With this configuration, it is possible to adjust the attenuation characteristic on the low frequency side compared to the passband. Further, for the resonator circuit (third resonator) disposed between the first and second resonators, the ground terminal is direct current insulated. With this configuration, it is possible to adjust the attenuation characteristic on the high frequency side compared to the passband. Thus, it is possible to adjust the attenuation characteristics on the high and low frequency sides compared to the passband in the filter device. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a block diagram of a communication device having a high frequency front-end circuit to which the filter device of Embodiment 1 is applied.

[0013] Figure 2 is an equivalent circuit diagram of the filter device of Embodiment 1.

[0014] Figure 3 is Figure 2 is an appearance perspective view of the filter device of

[0015] Figure 4 is a view showing Figure 2is an exploded perspective view of one example of a stacked configuration of the filter device of

[0016] Figure 5 is a graph for illustrating Figure 2

[0017] Figure 6 is an equivalent circuit diagram of the filter device of Embodiment 2.

[0018] Figure 7 is an exploded perspective view of one example of a stacked configuration of the filter device of Figure 6

[0019] Figure 8 is a graph for illustrating Figure 6

[0020] Figure 9 is an equivalent circuit diagram of the filter device of Embodiment 3.

[0021] Figure 10 is an exploded perspective view of one example of a stacked configuration of the filter device of Figure 9

[0022] Figure 11 is a graph for illustrating Figure 9

[0023] Figure 12 is an exploded perspective view of one example of a stacked configuration of the filter device of Embodiment 4. DETAILED DESCRIPTION

[0024] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings. Furthermore, the same reference numerals are applied to the same or equivalent parts throughout the drawings, and repeated description will not be given.

[0025] [Embodiment 1]

[0026] (Basic configuration of communication device)

[0027] Figure 1 is a block diagram of a communication device 10 having a high-frequency front-end circuit 20 to which the filter device of Embodiment 1 is applied. The communication device 10 is, for example, a mobile telephone base station.

[0028] Referring to Figure 1 , the communication device 10 has 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. In addition, the high-frequency front-end circuit 20 includes band-pass filters 22, 28, an amplifier 24, and an attenuator 26. Furthermore, in Figure 1 ​​​​​In the present embodiment, the case where the high-frequency front-end circuit 20 includes a transmission circuit that transmits a high-frequency signal from the antenna 12 is described, but the high-frequency front-end circuit 20 can also include a reception circuit that receives a high-frequency signal via the antenna 12.

[0029] The communication device 10 emits a high-frequency signal from the antenna 12 after up-converting a transmission signal transmitted from the RF circuit 50. The transmission signal output from the RF circuit 50, that is, a digital signal after modulation, is converted into an analog signal by the D / A converter 40. The mixer 30 mixes the transmission signal converted into an analog signal from a digital 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 band-pass filter 28 removes unnecessary waves generated by up-conversion, and extracts only a transmission signal of a desired frequency band. The attenuator 26 adjusts the strength of the transmission signal. The amplifier 24 power-amplifies the transmission signal after the attenuator 26 to a prescribed level. The band-pass filter 22 removes unnecessary waves generated in the amplification process, and passes only a signal component of a frequency band prescribed by a communication standard. The transmission signal after the band-pass filter 22 is emitted from the antenna 12.

[0030] As the band-pass filters 22, 28 in the above-described communication device 10, a filter device according to the present disclosure can be employed.

[0031] (Configuration of Filter Device)

[0032] Hereinafter, the filter device 100 of Embodiment 1 will be described in detail using Figures 2 to 4 The filter device 100 of Embodiment 1 has the configuration described below.

[0033] Figure 2 is an equivalent circuit diagram of the filter device 100. Referring to Figure 2 , the filter device 100 includes an input terminal T1, an output terminal T2, a ground terminal GND, and resonators RC11 to RC14. The resonators RC11 to RC14 are LC resonators each including an inductor and a capacitor. The resonator RC11 is connected to the input terminal T1, and the resonator RC12 is connected to the output terminal T2. The resonators RC13, RC14 are disposed between the resonator RC11 and the resonator RC12.

[0034] The resonator RC11 includes inductors L111, L112, L113, and capacitors C111, C112. The inductors L111, L112 and the capacitor C112 are connected in series between the input terminal T1 and the ground terminal GND in that order. The inductor L113 is connected between the connection node of the inductor L111 and the inductor L112 and the ground terminal GND. The capacitor C111 is connected between the input terminal T1 and the ground terminal GND.

[0035] The resonator RC12 includes inductors L121, L122, and L123, and capacitors C121 and C122. Inductors L121, L122, and capacitor C122 are connected in series in this order between the output terminal T2 and the ground terminal GND. Inductor L123 is connected between the junction of inductors L121 and L122 and the ground terminal GND. Capacitor C121 is connected between the output terminal T2 and the ground terminal GND.

[0036] The resonator RC13 includes an inductor L131 and capacitors C131 and C132. One end of inductor L131 is connected to the ground terminal GND via capacitor C131. The other end of inductor L131 is connected to the ground terminal GND via capacitor C132. Inductor L131 is DC insulated from the ground terminal GND through capacitors C131 and C132.

[0037] The resonator RC14 includes an inductor L141 and capacitors C141 and C142. One end of inductor L141 is connected to the ground terminal GND via capacitor C141. The other end of inductor L141 is connected to the ground terminal GND via capacitor C142. Inductor L141 is DC insulated from the ground terminal GND through capacitors C141 and C142.

[0038] Each resonator is coupled to the others via electromagnetic coupling. Thus, the filter device 100 has a configuration of four resonators electromagnetically coupled to each other between the input terminal T1 and the output terminal T2. A high-frequency signal input to the input terminal T1 is transmitted through the electromagnetic coupling of resonators RC11 to RC14 and output from the output terminal T2. At this time, only the signal within the frequency band determined by the resonant frequency of each resonator is transmitted to the output terminal T2. That is, the filter device 100 functions as a bandpass filter that allows signals of the desired frequency band to pass through by adjusting the resonant frequencies of each resonator.

[0039] Figure 3 This is a perspective view of the filter device 100. Figure 4 This is an exploded perspective view showing an example of the stacked structure of the filter device 100.

[0040] Reference Figure 3 and Figure 4The filter device 100 includes a cubic or approximately cubic dielectric substrate 110 formed by stacking multiple dielectric layers LY1 to LY11 in a predetermined direction. In the dielectric substrate 110, the direction in which the multiple dielectric layers LY1 to LY11 are stacked is referred to as the stacking direction. Each dielectric layer of the dielectric substrate 110 is formed, for example, from a ceramic such as low-temperature co-fired ceramic (LTCC) or from a resin. Inside the dielectric substrate 110, inductors and capacitors for constructing an LC resonant circuit are formed by multiple electrodes disposed in each dielectric layer and multiple pathways disposed between the dielectric layers. Furthermore, in this specification, "path" refers to a conductor disposed in a dielectric layer for connecting electrodes disposed in different dielectric layers. Paths are formed by, for example, conductive paste, plating, and / or metal pins.

[0041] Furthermore, in the following description, the stacking direction of the dielectric substrate 110 is referred to as the "Z-axis direction", the direction perpendicular to the Z-axis direction and along the long side of the dielectric substrate 110 is referred to as the "X-axis direction", and the direction along the short side of the dielectric substrate 110 is referred to as the "Y-axis direction". In addition, the positive direction of the Z-axis in each figure is sometimes referred to as the upper side and the negative direction as the lower side.

[0042] The upper surface 111 (dielectric layer LY1) of the dielectric substrate 110 is provided with a directional mark DM for determining the direction of the filter device 100. The lower surface 112 (dielectric layer LY11) of the dielectric substrate 110 is provided with an input terminal T1, an output terminal T2 and a ground terminal GND.

[0043] Input terminal T1, output terminal T2, and two ground terminals GND are each plate-shaped electrodes. Input terminal T1 is configured to connect to one side of dielectric layer LY11 along the Y-axis. Input terminal T1 is connected to side electrode 121 provided on side surface 114 of dielectric substrate 110. Output terminal T2 is configured to connect to the other side of dielectric layer LY11 along the Y-axis. Output terminal T2 is connected to side electrode 120 provided on side surface 113 of dielectric substrate 110.

[0044] Two grounding terminals GND are configured to be connected to the two sides of the dielectric layer LY11 along the X-axis, respectively. One grounding terminal GND is connected to the side electrode 122 disposed on the side 115 of the dielectric substrate 110. The other grounding terminal GND is connected to the side electrode 123 disposed on the side 116 of the dielectric substrate 110.

[0045] The dielectric layer LY2 of the dielectric substrate 110 is provided with a flat ground electrode PG1. Additionally, the dielectric layer LY10 of the dielectric substrate 110 is provided with a flat ground electrode PG2. The ground electrodes PG1 and PG2 are connected to the ground terminal GND disposed on the dielectric layer LY11 via side electrodes 122 and 123.

[0046] The filter device 100 is connected to an external device using the input terminal T1, output terminal T2 and ground terminal GND disposed on the lower surface 112 of the dielectric substrate 110, or using the side electrodes 120 to 123.

[0047] like Figure 2 As described, the filter device 100 includes a four-stage LC resonator. More specifically, the filter device 100 includes resonators RC11, RC12, RC13, and RC14. Resonator RC11 includes paths V10 and V11 and capacitor electrodes PC11 and PC12. Resonator RC12 includes paths V20 and V21 and capacitor electrodes PC21 and PC22. Resonator RC13 includes path V30 and capacitor electrodes PC31 and PC32. Resonator RC14 includes path V40 and capacitor electrodes PC41 and PC42.

[0048] The capacitor electrode PC11 is a rectangular flat plate electrode disposed on the dielectric layer LY3. When viewed from above in the normal direction (Z-axis direction) of the dielectric substrate 110, a portion of the capacitor electrode PC11 overlaps with the ground electrode PG1 disposed on the dielectric layer LY2. The structure consists of the capacitor electrode PC11 and the ground electrode PG1. Figure 2 The capacitor C111 has a rectangular plate electrode PC12 disposed on the dielectric layer LY9. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC12 overlaps with the ground electrode PG2 disposed on the dielectric layer LY10. The capacitor consists of the capacitor electrode PC12 and the ground electrode PG2. Figure 2 The capacitor C112.

[0049] Capacitor electrode PC11 is connected to capacitor electrode PC12 via passages V10 and V11. Passage V10 is connected to connection electrode PA1 disposed on dielectric layer LY4. Connection electrode PA1 is connected to input terminal T1 via side electrode 121.

[0050] Passages V10 and V11 are also connected to a shunt electrode PB1 disposed on the dielectric layer LY8. The shunt electrode PB1 is a strip-shaped flat electrode with a first end and a second end; the first end is connected to the side electrode 122, and the second end is connected to the side electrode 123. That is, the shunt electrode PB1 is the electrode connecting the middle portion of passages V10 and V11 to the ground terminal GND. The shunt electrode PB1 constitutes... Figure 2 The inductor L113 in the middle. The inductance of inductor L113 can be adjusted by changing the size of the shunt electrode PB1 in the X-axis direction.

[0051] Furthermore, the portion consisting of the pathways V10 and V11 between the capacitor electrode PC11 and the shunt electrode PB1 constitutes... Figure 2 The inductor L111. Additionally, the portion consisting of the passages V10 and V11 between the capacitor electrode PC12 and the shunt electrode PB1 constitutes... Figure 2 Inductor L112. The inductance of inductors L111 and L112 can be adjusted by changing the dielectric layer of the shunt electrode PB1.

[0052] The capacitor electrode PC21 is a rectangular flat plate electrode disposed on the dielectric layer LY3. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC21 overlaps with the ground electrode PG1 disposed on the dielectric layer LY2. The structure consists of the capacitor electrode PC21 and the ground electrode PG1. Figure 2 The capacitor C121 has a rectangular plate electrode PC22 disposed on the dielectric layer LY9. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC22 overlaps with the ground electrode PG2 disposed on the dielectric layer LY10. The capacitor consists of the capacitor electrode PC22 and the ground electrode PG2. Figure 2 Capacitor C122.

[0053] Capacitor electrode PC21 is connected to capacitor electrode PC22 via passages V20 and V21. Passage V20 is connected to connection electrode PA2 disposed on dielectric layer LY4. Connection electrode PA2 is connected to output terminal T2 via side electrode 120.

[0054] Passages V20 and V21 are also connected to a shunt electrode PB2 disposed on the dielectric layer LY8. The shunt electrode PB2 is a strip-shaped flat electrode with a first end and a second end; the first end is connected to the side electrode 122, and the second end is connected to the side electrode 123. That is, the shunt electrode PB2 is the electrode connecting the middle portion of passages V20 and V21 to the ground terminal GND. The shunt electrode PB2 constitutes... Figure 2 The inductor L123 in the middle. The inductance of inductor L123 can be adjusted by changing the size of the shunt electrode PB2 in the X-axis direction.

[0055] Furthermore, the passages V20 and V21 between the capacitor electrode PC21 and the shunt electrode PB2 constitute a portion of the circuit. Figure 2 The inductor L121. Additionally, the portion consisting of the passages V20 and V21 between the capacitor electrode PC22 and the shunt electrode PB2 constitutes... Figure 2 Inductor L122. The inductance of inductors L121 and L122 can be adjusted by changing the dielectric layer of the shunt electrode PB2.

[0056] The capacitor electrode PC31 is a rectangular flat plate electrode disposed on the dielectric layer LY3. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC31 overlaps with the ground electrode PG1 disposed on the dielectric layer LY2. The structure consists of the capacitor electrode PC31 and the ground electrode PG1. Figure 2 The capacitor C131 has a rectangular plate electrode PC32 disposed on the dielectric layer LY9. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC32 overlaps with the ground electrode PG2 disposed on the dielectric layer LY10. The capacitor consists of the capacitor electrode PC32 and the ground electrode PG2. Figure 2 The capacitor C132. Capacitor electrode PC31 is connected to capacitor electrode PC32 via passage V30. Passage V30 constitutes... Figure 2 Inductor L131.

[0057] The capacitor electrode PC41 is a rectangular flat plate electrode disposed on the dielectric layer LY3. When viewed from the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC41 overlaps with the ground electrode PG1 disposed on the dielectric layer LY2. The structure consists of the capacitor electrode PC41 and the ground electrode PG1. Figure 2 The capacitor C141 has a rectangular plate electrode PC42 disposed on the dielectric layer LY9. When viewed from above in the normal direction of the dielectric substrate 110, a portion of the capacitor electrode PC42 overlaps with the ground electrode PG2 disposed on the dielectric layer LY10. The capacitor consists of the capacitor electrode PC42 and the ground electrode PG2. Figure 4 The capacitor C142. Capacitor electrode PC41 is connected to capacitor electrode PC42 via passage V40. Passage V40 constitutes... Figure 5 Inductor L141.

[0058] In dielectric layer LY3, the capacitor electrode PC11 of resonator RC11 is positioned near side 114, and the capacitor electrode PC21 of resonator RC12 is positioned near side 113. Furthermore, the capacitor electrode PC31 of resonator RC13 and the capacitor electrode PC41 of resonator RC14 are positioned parallel to the X-axis between capacitor electrodes PC11 and PC21 in dielectric layer LY3. Additionally, capacitor electrodes PC12, PC22, PC32, and PC42 in dielectric layer LY9 also have the same configuration. Furthermore… Figure 5 The resonator configuration shown is only an example. It can also be configured such that resonator RC13 is configured between resonator RC11 and resonator RC12, and resonator RC14 is configured between resonator RC12 and resonator RC13.

[0059] Resonators RC11 and RC12 are ring resonators where two capacitor electrodes are connected by two paths. By including multiple paths, the resistive component of the path between the capacitor electrodes can be reduced, and the current flowing through each path can be reduced. Therefore, the Q value can be improved compared to the case where the two capacitor electrodes are connected by a single path. In addition, the Q value can also be improved by increasing the hollow diameter of the coil by forming a ring. Furthermore, multiple paths can also be used to connect the capacitor electrodes for resonators RC13 and RC14.

[0060] As described above, by using multiple resonators, including a resonator that is DC insulated from the ground terminal, to form a filter device, the coupling between the resonators can be easily changed from magnetic coupling to capacitive coupling for transmission characteristics, and the impedance of the ground side can be made capacitive on the high-frequency side, thereby improving the attenuation characteristics on the high-frequency side and generating attenuation poles on the high-frequency side compared to the passband.

[0061] Furthermore, in the filter device 100, the resonator RC11 connected to the input terminal T1 and the resonator RC12 connected to the output terminal T2 respectively include shunt electrodes PB1 and PB2. Due to the impedance reduction on the low-frequency side of the resonators RC11 and RC12 caused by the shunt electrodes, and the inductance connected in series with capacitors C112 and C122, attenuation poles are generated on the low-frequency side of the passband.

[0062] In addition, the shunt electrode may be included in only one of the resonators RC11 on the input side and RC12 on the output side, but when seeking symmetry in the input and output impedance characteristics of the filter, it is preferable to include the shunt electrode in both resonators RC11 and RC12.

[0063] Figure 5 This is a diagram used to illustrate the pass-through characteristics of the filter device 100. Figure 5The upper part of the diagram shows the pass-through characteristics of the filter device 100, and the lower part shows the pass-through characteristics of a comparative filter device. Furthermore, the comparative filter device is a bandpass filter configured by removing the shunt electrodes PB1 and PB2 from the filter device 100. Additionally, in Figure 6 In the diagram, solid lines LN10 and LN15 represent insertion loss, while dashed lines LN11 and LN16 represent reflection loss.

[0064] Reference Figure 2 In the comparative example without shunt electrodes (see the lower diagram), as shown by the solid line LN15, although attenuation poles are generated on the high-frequency side compared to the passband, no attenuation poles are generated on the low-frequency side compared to the passband. On the other hand, in the case of the filter device 100 of Embodiment 1, attenuation poles are generated on both the high-frequency and low-frequency sides compared to the passband. Therefore, it can be seen that in the filter device 100, the attenuation amount and attenuation steepness characteristics near the low-frequency side compared to the passband are improved.

[0065] As described above, in a filter device comprising multiple resonators, by using DC-isolated resonators and including shunt electrodes in the resonators connected to the input and output terminals, attenuation poles are generated on both the high-frequency and low-frequency sides of the bandpass filter compared to the passband. This improves the attenuation characteristics in the cutoff band of the filter device.

[0066] Furthermore, compared to the capacitance of capacitors C111, C121, C131, and C141, which are composed of capacitor electrodes PC12, PC22, PC32, and PC42, which are composed of capacitor electrodes PC12, PC22, PC32, and PC42, which are composed of capacitor electrodes PC12, PC22, PC32, and PC42, the capacitance of capacitors C112, C122, C132, and C142, which are composed of capacitor electrodes PC12, PC22, PC32, and PC42, is larger, and the ground electrode PG2 is positioned closer to the ground terminal GND than the ground electrode PG1. By forming such a configuration, the influence of the parasitic inductance of the ground terminal GND on the reduction of attenuation characteristics on the high-frequency side can be minimized.

[0067] Specifically, the dielectric constant of the dielectric layer LY9 between the capacitor electrodes PC12, PC22, PC32, and PC42 (serving as the second capacitor electrodes) and the ground electrode PG2 is higher than the dielectric constant of the dielectric layer LY2 between the capacitor electrodes PC11, PC21, PC31, and PC41 (serving as the first capacitor electrodes) and the ground electrode PG1. Alternatively, the spacing between the capacitor electrodes PC12, PC22, PC32, and PC42 (serving as the second capacitor electrodes) and the ground electrode PG2 is shorter than the spacing between the capacitor electrodes PC11, PC21, PC31, and PC41 (serving as the first capacitor electrodes) and the ground electrode PG1.

[0068] Furthermore, in the above example, the filter device was described with a configuration of four resonators, but the filter device may also be configured with three resonators in addition to resonator RC14.

[0069] Furthermore, in Embodiment 1, "resonator RC11," "resonator RC12," "resonator RC13," and "resonator RC14" correspond to the "first resonator," "second resonator," "third resonator," and "fourth resonator" in this disclosure, respectively. In Embodiment 1, "ground electrode PG1" and "ground electrode PG2" correspond to the "first ground electrode" and "second ground electrode" in this disclosure, respectively. In each resonator of Embodiment 1, "paths V10, V11, V20, V21, V30, and V40" correspond to the "first path" in this disclosure. In each resonator of Embodiment 1, "capacitor electrodes PC11, PC21, PC31, and PC41" correspond to the "first capacitor electrode" in this disclosure. In each resonator of Embodiment 1, "capacitor electrodes PC12, PC22, PC32, and PC42" correspond to the "second capacitor electrode" in this disclosure. In Embodiment 1, "shunt electrode PB1" and "shunt electrode PB2" correspond to the "first shunt electrode" and "second shunt electrode" in this disclosure, respectively. In Embodiment 1, "side electrodes 122 and 123" correspond to "first side electrodes" in this disclosure. In Embodiment 1, "side electrode 121" and "side electrode 120" correspond to "second side electrode" and "third side electrode" in this disclosure, respectively.

[0070] [Implementation Method 2]

[0071] In Embodiment 2, the configuration of a filter device capable of adjusting input and output impedance will be described.

[0072] Figure 6 This is an equivalent circuit diagram of the filter device 100A according to Embodiment 2. In the filter device 100A, it becomes... Figure 7 In the filter device 100 of Embodiment 1 described herein, impedance adjustment capacitors are added to the input-side resonator RC11 and the output-side resonator RC12. Furthermore, in Figure 2 and the following Figure 4 In this process, the steps described in Implementation Method 1 are not repeated. Figure 6 and Figure 7 Explanation of recurring elements.

[0073] Reference Figure 6 The filter device 100A is the same as the filter device 100 in Embodiment 1, and includes an input terminal T1, an output terminal T2, a ground terminal GND, and resonators RC11A, RC12A, RC13, and RC14.

[0074] The resonator RC11A connected to the input terminal T1 has the following configuration: compared to the configuration of the resonator RC11 in the filter device 100, a capacitor C113 is added, connected between the input terminal T1 and the ground terminal GND. Furthermore, the resonator RC12A connected to the output terminal T2 has the following configuration: compared to the configuration of the resonator RC12 in the filter device 100, a capacitor C123 is added, connected between the output terminal T2 and the ground terminal GND. Moreover, resonators RC13 and RC14 have the same configuration as the resonators RC13 and RC14 in the filter device 100.

[0075] By adjusting the capacitor C113 in resonator RC11A and the capacitor C123 in resonator RC12A respectively, corresponding to the devices connected to the input terminal T1 and output terminal T2 of the filter device 100A, the impedance between the filter device and the device can be adjusted. This reduces reflection loss.

[0076] Figure 7 It is shown Figure 4 An exploded perspective view of an example of the stacked structure of a filter device 100A. Figure 6 In the middle, becoming in Figure 6 The exploded perspective view of the filter device 100 shown includes the addition of capacitor electrodes PD1 and PD2 disposed on the dielectric layer LY7.

[0077] The capacitor electrode PD1 is a strip-shaped plate electrode extending along the X-axis. When viewed from the normal direction of the dielectric substrate 110, it partially overlaps with the shunt electrode PB1 disposed on the dielectric layer LY8. One end of the capacitor electrode PD1 is connected to the input terminal T1 and the connection electrode PA1 via the side electrode 121 disposed on the side surface 114 of the dielectric substrate 110.

[0078] As shown above, the shunt electrode PB1 is connected to the ground terminal GND via the side electrodes 122 and 123, so it is composed of the capacitor electrode PD1 and the shunt electrode PB1. Figure 8 The capacitor C113 is used in the filter. By changing the width of the capacitor electrode PD1, the area overlapping with the shunt electrode PB1 is adjusted, thereby changing the capacitance of capacitor C113. This allows adjustment of the input impedance of the filter device 100A.

[0079] The capacitor electrode PD2 is a strip-shaped plate electrode extending along the X-axis. When viewed from above in the normal direction of the dielectric substrate 110, it partially overlaps with the shunt electrode PB2 disposed on the dielectric layer LY8. In addition, one end of the capacitor electrode PD2 is connected to the output terminal T2 and the connection electrode PA2 via the side electrode 120 disposed on the side surface 113 of the dielectric substrate 110.

[0080] As shown above, the shunt electrode PB2 is connected to the ground terminal GND via the side electrodes 122 and 123, therefore it is composed of the capacitor electrode PD2 and the shunt electrode PB2. Figure 6 The capacitor C123 is used in the filter. By changing the width of the capacitor electrode PD2, the area overlapping with the shunt electrode PB2 is adjusted, thereby changing the capacitance of capacitor C123. This allows adjustment of the output impedance of the filter device 100A.

[0081] Figure 8 It is shown Figure 8 A graph showing the pass-through characteristics of the filter device 100A. Furthermore, in... Figure 5 In the diagram, the solid line LN20 represents the insertion loss, and the dashed line LN21 represents the reflection loss.

[0082] Reference Figure 9 Since the filter device 100A is also the same as the filter device 100 in Embodiment 1, shunt electrodes PB1 and PB2 are respectively arranged in the resonator RC11A connected to the input terminal T1 and the resonator RC12A connected to the output terminal T2, attenuation poles are generated on both the high-frequency side and the low-frequency side compared with the passband.

[0083] Furthermore, in the filter device 100A, optimal input and output impedance matching can be achieved through the capacitor electrodes PD1 and PD2 respectively disposed on the resonators RC11A and RC12A. Thus, with... Figure 9 Compared to the filter device 100 shown, it can reduce the overall reflection loss in the passband.

[0084] As described above, by configuring shunt electrodes and impedance adjustment capacitor electrodes for the resonator connected to the input and output terminals, it is possible to improve the attenuation characteristics in the cutoff band of the filter device and reduce the reflection loss in the passband.

[0085] Furthermore, in Embodiment 2, "resonator RC11A" and "resonator RC12A" correspond to the "first resonator" and "second resonator" in this disclosure, respectively. Additionally, in Embodiment 2, "capacitor electrode PD1" and "capacitor electrode PD2" correspond to the "third capacitor electrode" and "fourth capacitor electrode" in this disclosure, respectively.

[0086] [Implementation Method 3]

[0087] In Embodiments 1 and 2, the configuration of a filter device having four resonators was described. In Embodiment 3, an example of a filter device comprising five resonators will be described.

[0088] Figure 10 This is an equivalent circuit diagram of the filter device 100B according to Embodiment 3. (Refer to...) Figure 9 The filter device 100B includes an input terminal T1, an output terminal T2, a ground terminal GND, and resonators RC21 to RC25. Each of the resonators RC21 to RC25 is an LC resonator including an inductor and a capacitor. Resonator RC21 is connected to the input terminal T1, and resonator RC22 is connected to the output terminal T2. Resonators RC23 to RC25 are arranged in this order between resonators RC21 and RC22.

[0089] The resonator RC21 includes inductors L211, L212, and L213, and capacitors C211 and C212. Inductors L211, L212, and capacitor C212 are connected in series in this order between the input terminal T1 and the ground terminal GND. Inductor L213 is connected between the junction of inductors L211 and L212 and the ground terminal GND. Capacitor C211 is connected between the input terminal T1 and the ground terminal GND.

[0090] The resonator RC22 includes inductors L221, L222, and L223, and capacitors C221 and C222. Inductors L221, L222, and capacitor C222 are connected in series in this order between the output terminal T2 and the ground terminal GND. Inductor L223 is connected between the junction of inductors L221 and L222 and the ground terminal GND. Capacitor C221 is connected between the output terminal T2 and the ground terminal GND.

[0091] The resonator RC23 includes inductors L231 and L232, and capacitors C231 and C232. One end of inductor L231 is connected to the ground terminal GND via capacitor C231. The other end of inductor L231 is connected to the ground terminal GND via capacitor C232. Inductor L232 is connected in parallel with inductor L231. Inductors L231 and L232 are DC insulated from the ground terminal GND through capacitors C231 and C232.

[0092] The resonator RC24 includes inductors L241 and L242, and capacitors C241 and C242. One end of inductor L241 is connected to the ground terminal GND via capacitor C241. The other end of inductor L241 is connected to the ground terminal GND via capacitor C242. Inductor L242 is connected in parallel with inductor L241. Inductors L241 and L242 are DC insulated from the ground terminal GND through capacitors C241 and C242.

[0093] The resonator RC25 includes an inductor L251 and capacitors C251 and C252. One end of inductor L251 is connected to the ground terminal GND via capacitor C251. The other end of inductor L251 is connected to the ground terminal GND via capacitor C252. Inductor L251 is DC insulated from the ground terminal GND through capacitors C251 and C252.

[0094] Each resonator is coupled to the others via electromagnetic coupling. Thus, the filter device 100B has a configuration of five resonators electromagnetically coupled to each other between the input terminal T1 and the output terminal T2. A high-frequency signal input to the input terminal T1 is transmitted through the electromagnetic coupling of resonators RC21 to RC25 and output from the output terminal T2. At this time, only the signal within the frequency band determined by the resonant frequency of each resonator is transmitted to the output terminal T2. That is, the filter device 100B functions as a bandpass filter that allows signals of the desired frequency band to pass through by adjusting the resonant frequencies of each resonator.

[0095] Figure 10 It is shown Figure 9 An exploded perspective view of an example of the stacked structure of the filter device 100B. (Refer to...) Figure 9 The filter device 100B includes a cubic or approximately cubic dielectric substrate 110B formed by stacking multiple dielectric layers LY21 to LY31 along a predetermined direction. Each dielectric layer of the dielectric substrate 110B is formed of ceramic such as LTCC or resin, just like the dielectric substrate 110 of the filter device 100.

[0096] The upper surface 111 (dielectric layer LY21) of the dielectric substrate 110B is provided with a directional mark DM for determining the orientation of the filter device 100B. An input terminal T1, an output terminal T2, and a ground terminal GND are provided on the lower surface 112 (dielectric layer LY31) of the dielectric substrate 110B. The input terminal T1, output terminal T2, and ground terminal GND are connected to side electrodes provided on the side of the dielectric substrate 110B, similar to those on the filter device 100.

[0097] A flat ground electrode PG1 is disposed on the dielectric layer LY22 of the dielectric substrate 110B. Additionally, a flat ground electrode PG2 is disposed on the dielectric layer LY30 of the dielectric substrate 110B. The ground electrodes PG1 and PG2 are connected to the ground terminal GND disposed on the dielectric layer LY31 via side electrodes.

[0098] like Figure 9 As described, the filter device 100B includes a 5-stage LC resonator. More specifically, the filter device 100B includes resonators RC21, RC22, RC23, RC24, and RC25. Resonator RC21 includes paths V10B and V15B and capacitor electrodes PC11B and PC12B. Resonator RC22 includes paths V20 and V25B and capacitor electrodes PC21B and PC22B. Resonator RC23 includes paths V30B and V31B and capacitor electrodes PC31B and PC32B. Resonator RC24 includes paths V40B and V41B and capacitor electrodes PC41B and PC42B. Resonator RC25 includes path V50B and capacitor electrodes PC51B and PC52B.

[0099] The capacitor electrode PC11B is a rectangular flat plate electrode disposed on the dielectric layer LY23. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC11B overlaps with the ground electrode PG1 disposed on the dielectric layer LY22. The structure consists of the capacitor electrode PC11B and the ground electrode PG1. Figure 9 The capacitor C211 has a rectangular plate electrode PC12B disposed on the dielectric layer LY29. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC12B overlaps with the ground electrode PG2 disposed on the dielectric layer LY30. The capacitor consists of the capacitor electrode PC12B and the ground electrode PG2. Figure 9 The capacitor is C212.

[0100] Capacitor electrode PC11B is connected to capacitor electrode PC12B via passage V10B. Passage V10B is connected to connection electrode PA1B disposed on dielectric layer LY24. Connection electrode PA1B is connected to input terminal T1 via side electrode 121.

[0101] The passage V10B is also connected to a shunt electrode PB1B disposed on the dielectric layer LY28. The shunt electrode PB1B is a strip-shaped flat electrode with a first end and a second end, the first end and the second end being connected to the ground terminal GND via side electrodes 122 and 123, respectively. That is, the shunt electrode PB1B is the electrode connecting the middle portion of the passage V10B to the ground terminal GND. The passage is constructed using the shunt electrode PB1B. Figure 9The inductor L213 in the middle. The inductance of inductor L213 can be adjusted by changing the size of the shunt electrode PB1B in the X-axis direction.

[0102] The shunt electrode PB1B and the capacitor electrode PC12B are connected not only through passage V10B but also through passage V15B. The portion of passage V10B between the capacitor electrode PC11B and the shunt electrode PB1B constitutes this connection. Figure 9 The inductor L211. Additionally, it is formed by a portion of the path V10B between the capacitor electrode PC12B and the shunt electrode PB1B, and the path V15B. Figure 9 The inductor L212. The inductance of inductors L211 and L212 can be adjusted by changing the dielectric layer of the shunt electrode PB1B. Furthermore, the inductance of inductor L212 can be adjusted by changing the number of paths V15B. Additionally, if the desired inductance is obtained through path V10B, path V15B can be omitted.

[0103] The capacitor electrode PC21B is a rectangular flat plate electrode disposed on the dielectric layer LY23. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC21B overlaps with the ground electrode PG1 disposed on the dielectric layer LY22. The structure consists of the capacitor electrode PC21B and the ground electrode PG1. Figure 9 The capacitor C221 has a rectangular plate electrode PC22B disposed on the dielectric layer LY29. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC22B overlaps with the ground electrode PG2 disposed on the dielectric layer LY30. The capacitor consists of the capacitor electrode PC22B and the ground electrode PG2. Figure 9 The capacitor is C222.

[0104] Capacitor electrode PC21B is connected to capacitor electrode PC22B via passage V20B. Passage V20B is connected to connection electrode PA2B disposed on dielectric layer LY24. Connection electrode PA2B is connected to output terminal T2 via side electrode 120.

[0105] The path V20B is also connected to a shunt electrode PB2B disposed on the dielectric layer LY28. The shunt electrode PB2B is a strip-shaped plate electrode with a first end and a second end, the first end and the second end being connected to the ground terminal GND via side electrodes, respectively. That is, the shunt electrode PB2B is the electrode connecting the middle portion of the path V20B to the ground terminal GND. The path V20B is composed of the shunt electrode PB2B. Figure 9 The inductor L223 in the example. The inductance of inductor L223 can be adjusted by changing the size of the shunt electrode PB2B in the X-axis direction.

[0106] The shunt electrode PB2B and the capacitor electrode PC22B are connected not only through passage V20B but also through passage V25B. The portion of passage V20B between the capacitor electrode PC21B and the shunt electrode PB2B constitutes this connection. Figure 9 The inductor L221. Additionally, it is formed by a portion of the path V20B between the capacitor electrode PC22B and the shunt electrode PB2B, and the path V25B. Figure 9 The inductor L222. The inductance of inductors L221 and L222 can be adjusted by changing the dielectric layer of the shunt electrode PB2B. Furthermore, the inductance of inductor L222 can be adjusted by changing the number of paths V25B. Additionally, if the desired inductance is obtained through path V20B, path V25B can be omitted.

[0107] The capacitor electrode PC31B is a rectangular flat plate electrode disposed on the dielectric layer LY23. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC31B overlaps with the ground electrode PG1 disposed on the dielectric layer LY22. The structure consists of the capacitor electrode PC31B and the ground electrode PG1. Figure 9 The capacitor C231 has a rectangular plate electrode PC32B disposed on the dielectric layer LY29. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC32B overlaps with the ground electrode PG2 disposed on the dielectric layer LY30. The capacitor consists of the capacitor electrode PC32B and the ground electrode PG2. Figure 9 The capacitor C232. Capacitor electrode PC31B is connected to capacitor electrode PC32B via passages V30B and V31B. Passages V30B and V31B constitute... Figure 9 Inductors L231 and L232.

[0108] The capacitor electrode PC41B is a rectangular flat plate electrode disposed on the dielectric layer LY23. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC41B overlaps with the ground electrode PG1 disposed on the dielectric layer LY22. The structure consists of the capacitor electrode PC41B and the ground electrode PG1. Figure 9 The capacitor C241 has a rectangular plate electrode PC42B disposed on the dielectric layer LY29. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC42B overlaps with the ground electrode PG2 disposed on the dielectric layer LY30. The capacitor consists of the capacitor electrode PC42B and the ground electrode PG2. Figure 9 Capacitor C242. Capacitor electrode PC41B is connected to capacitor electrode PC42B via passages V40B and V41B. Passages V40B and V41B constitute... Figure 10Inductors L241 and L242.

[0109] The capacitor electrode PC51B is a rectangular flat plate electrode disposed on the dielectric layer LY23. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC51B overlaps with the ground electrode PG1 disposed on the dielectric layer LY22. The structure consists of the capacitor electrode PC51B and the ground electrode PG1. Figure 11 The capacitor C251 has a rectangular plate electrode PC52B disposed on the dielectric layer LY29. When viewed from the normal direction of the dielectric substrate 110B, a portion of the capacitor electrode PC52B overlaps with the ground electrode PG2 disposed on the dielectric layer LY30. The capacitor consists of the capacitor electrode PC52B and the ground electrode PG2. Figure 9 The capacitor C252. Capacitor electrode PC51B is connected to capacitor electrode PC52B via passage V50B. Passage V50B constitutes... Figure 11 The inductor L251.

[0110] Furthermore, the capacitor electrodes on the dielectric layer LY23 of the dielectric substrate 110B are arranged from side 114 to side 113 in the order of capacitor electrode PC11B, capacitor electrode PC31B, capacitor electrode PC51B, capacitor electrode PC41B, and capacitor electrode PC21B. Similarly, the capacitor electrodes on the dielectric layer LY29 are arranged from side 114 to side 113 of the dielectric substrate 110B in the order of capacitor electrode PC12B, capacitor electrode PC32B, capacitor electrode PC52B, capacitor electrode PC42B, and capacitor electrode PC22B.

[0111] In addition, Figure 11 In the filter device 100B, resonators RC23 and RC24 are ring resonators where two capacitor electrodes are connected by two paths. By including multiple paths in resonators RC23 and RC24, the resistive component of the path between the capacitor electrodes can be reduced, and the current flowing through each path can be reduced. Therefore, compared with the case where the two capacitor electrodes are connected by a single path, the Q value can be improved. In addition, since the hollow diameter of the coil can be increased by forming a ring, the Q value can also be improved. Furthermore, resonator RC25 can also be a ring resonator.

[0112] Figure 11 It is shown Figure 5 A graph showing the pass-through characteristics of the filter device 100B. Figure 12 In the diagram, the solid line LN30 represents the insertion loss, and the dashed line LN31 represents the reflection loss.

[0113] Reference Figure 12As shown by the solid line LN30, it can be seen that in the filter device 100B, attenuation poles are generated on both the high-frequency and low-frequency sides of the passband. This improves the attenuation characteristics in the cutoff bands on both the high-frequency and low-frequency sides of the passband.

[0114] It is known that as the number of stages in a resonator increases, the attenuation in the cutoff band generally increases. Figure 2 In the middle, the attenuation of the attenuation pole near the low-frequency side of the passband is approximately 43dB, which is consistent with... Figure 12 Compared to the attenuation of the 4-stage filter device 100 in Embodiment 1 shown (approximately 34 dB), a greater attenuation is achieved.

[0115] Furthermore, while the example above described a filter device with 5 resonators, the number of resonators can also be 6 or higher. However, as the number of resonators increases, the passband characteristics tend to become broadband. Therefore, the number of resonators is determined by considering the balance between the desired attenuation and the passband bandwidth.

[0116] As described above, in filter devices with five or more resonators, it is also possible to generate attenuation poles on both the high-frequency and low-frequency sides compared to the passband of a bandpass filter by using DC-isolated resonators and including shunt electrodes in the resonators connected to the input and output terminals. This improves the attenuation characteristics in the cutoff band of the filter device.

[0117] Furthermore, in Embodiment 3, "resonator RC21," "resonator RC22," "resonator RC23," "resonator RC24," and "resonator RC25" correspond to the "first resonator," "second resonator," "third resonator," "fourth resonator," and "fifth resonator" of this disclosure, respectively. In each resonator of Embodiment 3, "paths V10B, V20B, V30B, V31B, V40B, V41B, and V50B" correspond to the "first path" of this disclosure. "Path V15B" and "path 25B" in Embodiment 3 correspond to the "second path" and "third path" of this disclosure, respectively. In each resonator of Embodiment 3, "capacitor electrodes PC11B, PC21B, PC31B, PC41B, and PC51B" correspond to the "first capacitor electrode" of this disclosure. In each resonator of Embodiment 3, "capacitor electrodes PC12B, PC22B, PC32B, PC42B, and PC52B" correspond to the "second capacitor electrode" of this disclosure. In Embodiment 3, “shunt electrode PB1B” and “shunt electrode PB2B” correspond to “first shunt electrode” and “second shunt electrode” in this disclosure, respectively.

[0118] [Implementation Method 4]

[0119] In the above embodiments, the configuration of using side electrodes formed on the side of the dielectric substrate 110 is described for the connection between the ground electrodes PG1 and PG2 and the ground terminal GND, the connection between the connection electrode PA1 and the input terminal T1, and the connection between the connection electrode PA2 and the output terminal T2.

[0120] In Embodiment 4, a configuration is described in which the connection with the external terminal is not made through a side electrode, but through a passage provided in the dielectric substrate.

[0121] Figure 7 This is an exploded perspective view showing an example of the stacked structure of the filter device 100C according to Embodiment 4. Figure 12 The filter device 100A described in Embodiment 2 includes additional pathways VT1, VT2, VG1, and VG2. Furthermore, although not shown in the figures, in the case of filter device 100C, these pathways are not included. Explanation of reference numerals The side electrodes are 120-123. Furthermore, in... ​ In China, for the sake of ​ Explanations of repeated elements will not be repeated.

[0122] Reference ​ In the filter device 100C, passages VT1, VT2, VG1, and VG2 are provided along each side of the dielectric substrate 110 from dielectric layer LY2 to dielectric layer LY11. More specifically, passage VT1 is provided along the side 114 of the dielectric substrate 110 from dielectric layer LY2 to dielectric layer LY11. Furthermore, this passage VT1 is connected to a connection electrode PA1, a capacitor electrode PD1, and an input terminal T1.

[0123] Similarly, the passage VT2 is provided along the side 113 of the dielectric substrate 110 from the dielectric layer LY2 to the dielectric layer LY11. Furthermore, the passage VT2 is connected to the connection electrode PA2, the capacitor electrode PD2, and the output terminal T2.

[0124] Furthermore, multiple pathways VG1 are provided along the side surface 115 of the dielectric substrate 110 from the dielectric layer LY2 to the dielectric layer LY11, and multiple pathways VG2 are provided along the side surface 116 of the dielectric substrate 110 from the dielectric layer LY2 to the dielectric layer LY11. The pathways VG1 and VG2 are connected to a ground electrode PG1, a ground electrode PG2, and a ground terminal GND.

[0125] In this configuration, the filter device 100C is connected to an external device via the input terminal T1, the output terminal T2, and the ground terminal GND, which are located on the lower surface 112. That is, the filter device 100C has an LGA (Land Grid Array) terminal configuration. This configuration eliminates the need for connections using side electrodes, thus reducing the mounting area.

[0126] Furthermore, the “paths VG1, VG2” in Embodiment 4 correspond to the “fourth path” in this disclosure. The “paths VT1” and “paths VT2” in Embodiment 4 correspond to the “fifth path” and “sixth path” in this disclosure, respectively.

[0127] It should be considered that all aspects of the embodiments disclosed herein are merely illustrative and not limiting. The scope of the invention is not shown by the description of the above embodiments, but by the scope of the claims, which is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

[0128] ​

[0129] 10 Communication device; 12 Antenna; 20 High-frequency front-end circuit; 22, 28 Bandpass filters; 24 Amplifier; 26 Attenuator; 30 Mixer; 32 Local oscillator; 40 D / A converter; 50 RF circuit; 100, 100A~100C filter devices; 110, 110B Dielectric substrate; 111 Upper surface; 112 Lower surface; 113~116 Side surfaces; 120~123 Side electrodes; C111~C113, C121~C123 Capacitors C131, C132, C141, C142, C211, C212, C221, C222, C231, C232, C241, C242, C251, C252; DM directional marking; GND ground terminal; Inductors L111~L113, L121~L123, L131, L141, L211~L213, L221~L223, L231, L232, L241, L242, L251 LY1~LY11, LY21~LY31 dielectric layers; PA1, PA1B, PA2, PA2B connecting electrodes; PB1, PB1B, PB2, PB2B shunt electrodes; PC11~PC14, PC11B, PC12B, PC21, PC21B, PC22, PC22B, PC31, PC31B, PC32, PC32B, PC41, PC41B, PC42, PC42B, PC51B, PC 52B, PD1, PD2 capacitor electrodes; PG1, PG2 ground electrodes; RC11~RC14, RC11A, RC12A, RC21~RC25 resonators; T1 input terminal; T2 output terminal; V10, V10B, V11, V15B, V20, V20B, V21, V25B, V30B, V30, V31B, V40, V40B, V41B, V50B, VG1, VG2, VT1, VT2 paths.

Claims

1. A filter device comprising: a dielectric substrate; an input terminal; an output terminal; a ground terminal; a first ground electrode and a second ground electrode disposed at different positions in a normal direction of the dielectric substrate, connected to the ground terminal; and a plurality of resonators disposed between the first ground electrode and the second ground electrode in the normal direction, electromagnetically coupled to each other, each of the plurality of resonators including: a first capacitance electrode partially overlapping the first ground electrode when the dielectric substrate is viewed from the normal direction; a second capacitance electrode partially overlapping the second ground electrode when the dielectric substrate is viewed from the normal direction; and at least one first via connecting the first capacitance electrode and the second capacitance electrode, the plurality of resonators including: a first resonator connected to the input terminal; a second resonator connected to the output terminal; and a third resonator disposed between the first resonator and the second resonator, the filter device further comprising at least one of a first shunt electrode connected to at least one first via included in the first resonator and the ground terminal, and a second shunt electrode connected to at least one first via included in the second resonator and the ground terminal, each of the first shunt electrode and the second shunt electrode being a strip having a first end portion and a second end portion to which the ground terminal is connected.

2. The filter device according to claim 1, wherein in at least one of the plurality of resonators, the first capacitance electrode and the second capacitance electrode are connected by a plurality of first vias.

3. The filter device according to claim 1, wherein the filter device comprises the first shunt electrode, the first resonator further includes a second via connecting a second capacitance electrode in the first resonator and the first shunt electrode.

4. The filter device according to claim 1, wherein the filter device further comprises a third capacitance electrode connected to the input terminal, partially overlapping the first shunt electrode when the dielectric substrate is viewed from the normal direction.

5. The filter device according to claim 1, wherein the filter device comprises the second shunt electrode, the second resonator further includes a third via connecting a second capacitance electrode in the second resonator and the second shunt electrode.

6. The filter device according to claim 1, wherein the filter device further comprises a fourth capacitance electrode connected to the output terminal, partially overlapping the second shunt electrode when the dielectric substrate is viewed from the normal direction.

7. The filter device according to any one of claims 1 to 6, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Further provided is a first side electrode disposed on a side of the dielectric substrate, connecting the first ground electrode and the second ground electrode to the ground terminal.

8. The filter device according to any one of claims 1 to 6, wherein Further provided is a fourth via provided inside the dielectric substrate, connecting the first ground electrode and the second ground electrode to the ground terminal.

9. The filter device of any one of claims 1 to 6, wherein, Further provided is: a second side electrode disposed on a side of the dielectric substrate, connecting the first resonator to the input terminal; and a third side electrode disposed on a side of the dielectric substrate, connecting the second resonator to the output terminal.

10. The filter device of any one of claims 1 to 6, wherein, Further provided is: a fifth via provided inside the dielectric substrate, connecting the first resonator to the input terminal; and a sixth via provided inside the dielectric substrate, connecting the second resonator to the output terminal.

11. The filter device according to any one of claims 1 to 6, wherein the plurality of resonators further includes a fourth resonator disposed between the second resonator and the third resonator.

12. The filter device according to claim 11, wherein the plurality of resonators further includes a fifth resonator disposed between the third resonator and the fourth resonator.

13. The filter device according to any one of claims 1 to 6, wherein the second ground electrode is disposed at a position closer to the ground terminal than the first ground electrode, a dielectric layer between the second capacitance electrode and the second ground electrode has a higher dielectric constant than a dielectric layer between the first capacitance electrode and the first ground electrode.

14. The filter device according to any one of claims 1 to 6, wherein the second ground electrode is disposed at a position closer to the ground terminal than the first ground electrode, a distance between the second capacitance electrode and the second ground electrode is shorter than a distance between the first capacitance electrode and the first ground electrode.

15. The filter device according to any one of claims 1 to 6, wherein the filter device is a bandpass filter.

16. A high-frequency front-end circuit, including the filter device according to any one of claims 1 to 6.

17. A filter device including: a dielectric substrate; an input terminal; an output terminal; a ground terminal; a first ground electrode and a second ground electrode disposed at different positions in a normal direction of the dielectric substrate, connected to the ground terminal; and a plurality of resonators disposed between the first ground electrode and the second ground electrode in the normal direction, electromagnetically coupled to each other, the plurality of resonators each includes: a first capacitance electrode partially overlapping the first ground electrode when the dielectric substrate is viewed from the normal direction; a second capacitance electrode partially overlapping the second ground electrode when the dielectric substrate is viewed from the normal direction; and a resonator body electromagnetically coupled to the first capacitance electrode and the second capacitance electrode. at least one first via connecting the first capacitance electrode and the second capacitance electrode, the plurality of resonators includes: a first resonator connected to the input terminal; a second resonator connected to the output terminal; and a third resonator disposed between the first resonator and the second resonator, the filter device further includes at least one of a first shunt electrode and a second shunt electrode, the first shunt electrode being connected to at least one first via included in the first resonator and the ground terminal, the second shunt electrode being connected to at least one first via included in the second resonator and the ground terminal, in the first resonator, the first shunt electrode partially overlaps the first capacitance electrode and the second capacitance electrode, respectively, when the dielectric substrate is viewed from the normal direction, in the second resonator, the second shunt electrode partially overlaps the first capacitance electrode and the second capacitance electrode, respectively, when the dielectric substrate is viewed from the normal direction.

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