Dielectric filter

Abstract

A filter device is provided. A filter device (100) is provided with a laminated body (110) and a plurality of resonators (140). The laminated body (110) includes a plurality of dielectric layers and has a cubic shape. Each of the plurality of resonators (140) extends in a first direction orthogonal to the stacking direction inside the stacked body (110). On side surfaces (115, 116) orthogonal to the first direction of the laminated body (110), a region (RG1) in which the plurality of resonators (140) are disposed protrudes in the first direction than a region (RG2) in which the plurality of resonators (140) are not disposed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a dielectric filter, and more particularly to a technique for suppressing a structural defect in a manufacturing process of a dielectric filter. BACKGROUND

[0002] A band-pass filter using a laminated dielectric resonator obtained by laminating a plurality of internal electrode layers in a dielectric is disclosed in Japanese Patent Application Publication No. 2007-235465 (Patent Literature 1). In the band-pass filter disclosed in Japanese Patent Application Publication No. 2007-235465 (Patent Literature 1), an inductor portion of the internal electrode layer is composed of an elongated pattern, and has a shape in which the width of the elongated pattern is gradually narrowed locally. By adopting such a structure, it is possible to lower the resonant frequency without lowering the Q value, and thus it is possible to achieve miniaturization of the resonator.

[0003] Patent Literature 1: Japanese Patent Application Publication No. 2007-235465

[0004] The dielectric filter disclosed in Japanese Patent Application Publication No. 2007-235465 (Patent Literature 1) is used, for example, for filtering a high-frequency signal in a small mobile terminal typified by a mobile phone or a smartphone.

[0005] In a dielectric filter, there is a dielectric filter manufactured by laminating a plurality of dielectric layers in which a flat conductor is arranged and performing press bonding or sintering. In a manufacturing process of such a laminated dielectric filter, if there is a portion in which the conductor density in the lamination direction is large locally, a structural defect such as a crack between the conductor and the dielectric, and a deformation of the internal structure such as bending or dimensional change of the conductor due to the difference in the coefficient of thermal expansion between the portion in which the conductor density is large and the portion in which the conductor density is small occurs, and it can lead to damage of the device or a decrease in the filter characteristics. SUMMARY

[0006] The present disclosure is achieved to solve such a problem, and aims to suppress a structural defect in a manufacturing process of a dielectric filter.

[0007] The dielectric filter of the present disclosure includes a laminated body, and a plurality of resonators. The laminated body includes a plurality of dielectric layers, and has a substantially cuboid shape. The plurality of resonators respectively extend in a first direction orthogonal to a lamination direction inside the laminated body. In a first side surface and a second side surface of the laminated body orthogonal to the first direction, a first region in which the plurality of resonators are arranged protrudes toward the first direction more than a second region in which the plurality of resonators are not arranged.

[0008] In the dielectric filter of the present disclosure, a structure in which a first region in which a plurality of conductors constituting a resonator is arranged is protruded than a second region in which no conductor is arranged at a side surface of a laminate that forms an outline of the filter is adopted. By adopting such a structure, stress between the first region and the second region due to shrinkage of the dielectric layer of the second region in a manufacturing process of the filter can be reduced, and thus a construction defect in the dielectric filter can be suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 is a block diagram of a communication device having a filter device of Embodiment 1.

[0010] Figure 2 is an appearance perspective view of the filter device of Embodiment 1.

[0011] Figure 3 is a perspective view showing an internal configuration of the filter device of Embodiment 1.

[0012] Figure 4 is a side view perspective view of the filter device of Embodiment 1 when viewed from the positive direction of the X axis.

[0013] Figure 5 is a side view of the filter device of Embodiment 2 when viewed from the positive direction of the Y axis.

[0014] Figure 6 is a cross-sectional view at line VI-VI of the filter device of Figure 5 .

[0015] Figure 7 is a side view of the filter device of Embodiment 3 when viewed from the positive direction of the Y axis.

[0016] Figure 8 is a cross-sectional view at line VIII-VIII of the filter device of Figure 7 .

[0017] Figure 9 is a cross-sectional view at line IX-IX of the filter device of Figure 7 .

[0018] Figure 10 is a side view of the filter device of Embodiment 4 when viewed from the positive direction of the Y axis.

[0019] Figure 11 is a cross-sectional view at line XI-XI of the filter device of Figure 10 .

[0020] Figure 12 is a cross-sectional view at line XII-XII of the filter device of Figure 10 .

[0021] Figure 13 is a side view of the filter device of Embodiment 5 when viewed from the positive direction of the Y axis.

[0022] Figure 14 is Figure 13 is a cross-sectional view at the line XIV-XIV of the filter device of DETAILED DESCRIPTION

[0023] Hereinafter, an embodiment of the present disclosure will be explained in detail with reference to the accompanying drawings. Further, the same reference numerals are applied to the same or corresponding parts and a repeated explanation is not given. Figure 1

[0024] [Embodiment 1]

[0025] (Basic structure of communication device)

[0026] Figure 1 is a block diagram of a communication device 10 having a high-frequency front-end circuit 20 to which the filter device 100 of Embodiment 1 is applied. The communication device 10 is, for example, a mobile terminal typified by a smartphone or a mobile phone base station.

[0027] Referring to Figure 1 , the communication device 10 is provided with 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 a band-pass filter 22, 28, an amplifier 24, and an attenuator 26. Further, in Figures 2-4 , a case where the high-frequency front-end circuit 20 includes a transmission circuit that transmits a high-frequency signal from the antenna 12 is explained, but the high-frequency front-end circuit 20 can include a reception circuit that receives a high-frequency signal via the antenna 12.

[0028] The communication device 10 up-converts a signal transferred from the RF circuit 50 into a high-frequency signal and radiates it from the antenna 12. A modulated digital signal output from the RF circuit 50 is converted into an analog signal by the D / A converter 40. The mixer 30 mixes and up-converts a signal converted into an analog signal by the D / A converter 40 with an oscillation signal from the local oscillator 32 into a high-frequency signal. The band-pass filter 28 removes an unnecessary wave generated by the up-conversion and extracts only a signal of a desired frequency band. The attenuator 26 adjusts the intensity of the signal. The amplifier 24 amplifies the power of the signal that has passed through the attenuator 26 to a prescribed level. The band-pass filter 22 removes an unnecessary wave generated in the amplification process and passes only a signal component of a frequency band determined by a communication standard. The signal that has passed through the band-pass filter 22 is radiated as a transmission signal from the antenna 12.

[0029] ​As the band-pass filter 22, 28 in the communication device 10 described above, a filter device corresponding to the present disclosure can be employed.

[0030] (Configuration of filter device)

[0031] Next, the detailed structure of the filter device 100 of Embodiment 1 will be described. The filter device 100 is a dielectric filter composed of distributed parameter elements, i.e., a plurality of resonators. Figure 2

[0032] is an external perspective view of the filter device 100. In Figure 2 , only the structure observable from the external surface of the filter device 100 is shown, and the internal structure is omitted. Figure 3 is a perspective view showing the internal configuration of the filter device 100. Figure 4 is a side perspective view of the filter device 100. Figure 2

[0033] Referring to Figure 2 , the filter device 100 has a substantially cuboid-shaped laminate 110 obtained by laminating a plurality of dielectric layers in the lamination direction. In the following description, the lamination direction of the laminate 110 is set as the "Z-axis direction", the direction perpendicular to the Z-axis direction and along the long side of the laminate 110 is set as the "X-axis direction", and the direction along the short side of the laminate 110 is set as the "Y-axis direction" (first direction). Hereinafter, the positive direction of the Z-axis in each drawing will be referred to as the upper side, and the negative direction of the Z-axis will be referred to as the lower side.

[0034] The laminate 110 has an upper surface 111, a lower surface 112, a side surface 113, a side surface 114, a side surface 115, and a side surface 116. The side surface 113 is the side surface of the laminate 110 in the positive direction of the X-axis, and the side surface 114 is the side surface in the negative direction of the X-axis. The side surfaces 115 and 116 are the side surfaces of the laminate 110 perpendicular to the Y-axis direction.

[0035] Each dielectric layer of the laminate 110 is formed of, for example, a ceramic such as low temperature co-fired ceramic (LTCC) or a resin. In the interior of the laminate 110, a distributed parameter element that forms a resonator and a capacitor and an inductor for coupling between the distributed parameter elements are constituted by a plurality of plate conductors formed in each dielectric layer and a plurality of vias formed between the dielectric layers. In the present specification, the "via" means a conductor that connects the conductors provided in different dielectric layers to each other and extends in the lamination direction. The via is formed of, for example, a conductive paste, a plating, and / or a metal pin.

[0036] As Figure 3 ​As shown, the filter device 100 is provided with shield conductors 121, 122 that cover the side surfaces 115, 116 of the laminate 110, respectively. In addition, the shield conductors 121, 122 also cover parts of the upper surface 111 and the lower surface 112 of the laminate 110. As shown in Figure 4 and Figure 3 As detailed in and

[0037] , parts of the side surfaces 115, 116 of the laminate 110 protrude in the Y-axis direction, and in conjunction therewith, the shield conductors 121, 122 also partially protrude in the Y-axis direction.

[0038] In the shield conductors 121, 122, the part disposed at the lower surface 112 of the laminate 110 is connected to a ground electrode on the mounting substrate, not shown, by a connection conductor such as a solder bump. That is, the shield conductors 121, 122 also function as ground terminals.

[0039] In addition, the filter device 100 is provided with an input terminal Tl and an output terminal T2 at the lower surface 112 of the laminate 110. On the one hand, the input terminal Tl is disposed at the lower surface 112 at a position close to the side surface 113 in the positive direction of the X-axis. On the other hand, the output terminal T2 is disposed at the lower surface 112 at a position close to the side surface 114 in the negative direction of the X-axis. The input terminal Tl and the output terminal T2 are connected to corresponding electrodes on the mounting substrate by a connection conductor such as a solder bump. Figure 4 Figure 2 Next, the internal configuration of the filter device 100 will be described with reference to Figure 4 and In addition to the configuration shown in

[0040] , the filter device 100 is provided with flat electrodes 130, 135, a plurality of resonators 141-145, capacitor electrodes 161-165, connection conductors 151-155, 171-175. Furthermore, in the following description, the resonators 141-145, the capacitor electrodes 161-165, and the connection conductors 151-155, 171-175 will sometimes be collectively referred to as "resonators 140", "capacitor electrodes 160", "connection conductors 150", and "connection conductors 170", respectively.

[0041] The flat plate electrode 135 is provided in the dielectric layer close to the lower surface 112 of the laminate 110. The flat plate electrode 135 has a substantially H-shaped form in which a notch portion is formed at a portion opposite to the input terminal Tl and the output terminal T2 when viewed from the stacking direction. The flat plate electrode 135 is connected to the shield conductors 121, 122 at end portions thereof along the X axis.

[0042] In the laminate 110, resonators 141 to 145 are arranged between the flat plate electrode 130 and the flat plate electrode 135. In the filter device 100, the resonators 141 to 145 are arranged in the X axis direction inside the laminate 110. More specifically, in the order of the resonators 141, 142, 143, 144, 145, from the positive direction of the X axis toward the negative direction.

[0043] The resonators 141 to 145 each extend in the Y axis direction (first direction). On one hand, the end portion (first end portion) of each of the resonators 141 to 145 in the positive direction of the Y axis is connected to the shield conductor 121. On the other hand, the end portion (second end portion) of each of the resonators 141 to 145 in the negative direction of the Y axis is separated from the shield conductor 122.

[0044] Each of the resonators 141 to 145 is constituted by a plurality of conductors arranged in the stacking direction. The number of the conductors constituting each resonator is, for example, 13 or more. In the resonator 140, the plurality of conductors constituting each resonator are electrically connected by a connection conductor 170 at a position close to the second end portion on the side of the shield conductor 122. In addition, the resonators 141 to 145 are connected to the flat plate electrodes 130, 135 via connection conductors 151 to 155, respectively, at positions close to the first end portions connected to the shield conductor 121. Each of the connection conductors 151 to 155 extends from the flat plate electrode 130 through the plurality of conductors of the corresponding resonator to the flat plate electrode 135. Each of the connection conductors 151 to 155 is electrically connected to the plurality of conductors forming the corresponding resonator.

[0045] In such a structure, a large portion of the current flowing through each resonator flows to the ground terminal (i.e., the flat plate electrodes 130, 135 and the shield conductor 121) via the connection conductors 151 to 155. Therefore, the effective length of each resonator is the length from the second end portion to the connection conductor. The length from the second end portion to the connection conductor (151 to 155) in each resonator is designed to be λ / 4 Figure 3 ). The resonator 140 functions as a distributed constant type TEM mode resonator in which the plurality of conductors serve as central conductors and the flat plate electrodes 130, 135 serve as outer conductors.

[0046] The resonator 141 is connected to the input terminal Tl via the via holes V10, Vl l and the flat plate electrode PLl. In addition, in the resonator 141, the plurality of conductors are connected to the flat plate electrode 130 via the connection conductor 151. Figure 3Although obscured by the resonators, resonator 145 is connected to the output terminal T2 via a via and the plate electrode PL2. Resonators 141 to 145 are magnetically coupled to each other. The high-frequency signal input to the input terminal T1 is transmitted in sequence through resonators 141 to 145 and output from the output terminal T2. At this time, the degree of coupling between the resonators allows the filter device 100 to function as a bandpass filter.

[0047] Capacitor electrodes C10 to C50 protruding between the resonator 140 and adjacent resonators are provided at the second end side. The capacitor electrodes are configured such that a portion of the multiple conductors constituting the resonator extends outward. The degree of capacitive coupling between the resonators can be adjusted by the length of the capacitor electrodes in the Y-axis direction, the distance between them and adjacent resonators, and / or the number of conductors constituting the capacitor electrodes.

[0048] In the filter device 100, such as Figure 3 As shown, capacitor electrode C10 protrudes from resonator 141 toward resonator 142, and capacitor electrode C20 protrudes from resonator 142 toward resonator 141. Additionally, capacitor electrode C30 protrudes from resonator 143 toward resonator 142, and capacitor electrode C40 protrudes from resonator 144 toward resonator 143. Furthermore, capacitor electrode C50 protrudes from resonator 145 toward resonator 144.

[0049] Furthermore, capacitor electrodes C10 to C50 are not essential; as long as the desired coupling level between the resonators can be achieved, some or all of the electrodes may not be required. Additionally, in Figure 4 Based on the structure, the filter device may also include capacitor electrodes protruding from resonator 142 toward resonator 143, capacitor electrodes protruding from resonator 143 toward resonator 144, and capacitor electrodes protruding from resonator 144 toward resonator 145.

[0050] Furthermore, in the filter device 100, a capacitor electrode 160 is disposed opposite to the second end of the resonator 140. The cross-section of the capacitor electrode 160, parallel to the ZX plane, has the same cross-section as the resonator 140. The capacitor electrode 160 is connected to the shielding conductor 122. Thus, the resonator 140 and the corresponding capacitor electrode 160 constitute a capacitor. It is possible to adjust... Figure 2 The gap (distance in the Y-axis direction) GP between the resonator 140 and the capacitor electrode 160 is shown, and the capacitance value of the capacitor formed by the resonator 140 and the corresponding capacitor electrode 160 is adjusted.

[0051] like Figure 4As described in the description, in the filter device 100 of Embodiment 1, the side surfaces 115, 116 of the laminate 110 partially protrude outwards. More specifically, as Figure 5 As shown, in the laminate 110, the portion RG1 on the side surfaces 115 and 116 where the conductors constituting the resonator 140 and capacitor electrode 160 are arranged protrudes in the Y-axis direction compared to the portion RG2 on the side surfaces 115 and 116 where the conductors of the resonator 140 and capacitor electrode 160 are not arranged. In one example, the dimension h of the region RG1 in the lamination direction is designed to be less than 1 / 2 of the dimension H of the laminate 110 in the lamination direction (h ≤ H / 2). Furthermore, the aforementioned region RG2 may include not only the regions on the upper surface 131 side and the lower surface 132 side of the region RG1, but also the regions between the resonators, between the capacitor electrodes, and from the resonators and capacitor electrodes at both ends to the side surfaces 113 and 114.

[0052] Furthermore, in the filter device 100 of Embodiment 1, the shielding conductors 121 and 122 are each a double-layer structure composed of different conductors. Specifically, the shielding conductor 121 includes two electrode layers 1211 and 1212, and the shielding conductor 122 includes two electrode layers 1221 and 1222.

[0053] Electrode layers 1211 and 1221 are formed by coating or printing a conductive paste containing copper (Cu), nickel (Ni), silver (Ag), etc., onto the surface of the laminate 110, followed by firing and curing. Furthermore, in the following description, this electrode layer formed by printing or other methods is also referred to as a "substrate electrode." Electrode layers 1212 and 1222 are formed by sputtering or plating nickel, tin (Sn), or a Ni-Sn alloy onto the electrode layers 1211 and 1221, which serve as substrate electrodes. The thickness of electrode layers 1211 and 1221 is greater than the thickness of electrode layers 1212 and 1222.

[0054] The shielding conductors 121 and 122 cover portions of the upper surface 111 and the lower surface 112, as well as the side surfaces 115 and 116. Therefore, the shielding conductors 121 and 122 in region RG1 of the side surfaces 115 and 116 protrude outwards than the shielding conductors 121 and 122 in region RG2.

[0055] The above-described laminated dielectric filter is generally manufactured by laminating a plurality of dielectric layers configured with a flat conductor and performing press bonding or sintering. Since the shrinkage rate of the dielectric such as ceramic is larger than the shrinkage rate of the conductor, in the manufacturing process of the dielectric filter, if there are a dielectric layer having a large conductor density in the lamination direction like the region RG1 and a dielectric layer having a small conductor density like the region RG2, stress in the compression direction is generated on the conductor at the interface between the conductor and the dielectric due to the difference in the coefficient of thermal expansion between the two regions. In this way, it is possible that cracks between the conductor and the dielectric, peeling between the dielectric layers, deformation caused by buckling of the conductor, and / or deterioration of the flatness of the surface of the laminate, and the like, are generated. If such a structural defect is generated, these can become important factors in reducing the strength of the filter device or shortening the device life. Also, it can not be possible to achieve the desired capacitance value and inductance value in the design, and the filter characteristics can be reduced.

[0056] In the filter device 100 of Embodiment 1, a structure is adopted in which the dielectric layer at the region RG1 in the laminate 110 where the conductor is disposed protrudes with respect to the dielectric layer at the region RG2 where the conductor is not disposed. The above-described such structure can be achieved by adjusting the temperature rising curve in the sintering process so that the shrinkage timing of the dielectric (ceramic) within the region RG2 is different from the shrinkage timing of the conductor in the region RG1. By such adjustment of the shrinkage timing, the stress generated at the interface between the dielectric and the conductor is reduced, and thus it is possible to suppress the generation of structural defects such as cracks in the manufacturing process of the filter device 100. Therefore, it is possible to prevent breakage and the like of the filter device 100, and it is possible to suppress the reduction of the filter characteristics.

[0057] Further, if the region RG2 is made sufficiently large compared to the region RG1, it is easy to relax the stress generated in the conductor at the time of shrinkage of the region RG1. Therefore, it is preferable to set the dimension h of the region RG1 in the lamination direction to be 1 / 2 or less of the dimension H of the laminate 110 in the lamination direction.

[0058] In addition, by forming a step formed by the protruding portion on the shielding conductor 121, 122, it is possible to prevent the inflow of solder to the upper surface 111 side by the step when the filter device 100 is mounted to the mounting substrate by solder connection.

[0059] The "side surface 115" and "side surface 116" in Embodiment 1 correspond to the "first side surface" and "second side surface" in the present disclosure, respectively. The "region RG1" and "region RG2" in Embodiment 1 correspond to the "first region" and "second region" in the present disclosure, respectively. The "flat plate electrode 130" and "flat plate electrode 135" in Embodiment 1 correspond to the "first flat plate electrode" and "second flat plate electrode" in the present disclosure, respectively. The "shielding conductor 121" and "shielding conductor 122" in Embodiment 1 correspond to the "first shielding conductor" and "second shielding conductor" in the present disclosure, respectively. The "connection conductor 151 to 155" in Embodiment 1 each correspond to the "first connection conductor" in the present disclosure. The "connection conductor 171 to 175" in Embodiment 1 each correspond to the "second connection conductor" in the present disclosure.

[0060] [Embodiment 2]

[0061] In Embodiment 2, other structures of the shielding conductors formed at the side surfaces 115, 116 of the laminate 110 are described.

[0062] Figure 6 is a side view of the filter device 100A of Embodiment 2 as viewed from the positive direction of the Y axis. In addition, Figure 5 is Figure 5 is a cross-sectional view of the filter device 100A at the line VI-VI of

[0063] The shielding conductors 121, 122 in the filter device 100 of Embodiment 1 are each arranged to cover the entire surface of the side surface 115, 116. On the other hand, as shown in Figure 6 in the filter device 100A of Embodiment 2, the shielding conductor 121A arranged at the side surface 115 is formed with a notch portion 125 at the region RG2 of the portion on the upper side and the lower side of the resonator 140 than the resonator 140. That is, in this portion, the side surface 115 of the laminate 110 is exposed.

[0064] As shown in Figure 7 on the other hand, in the portion between the adjacent resonators and between the resonator at the end portion and the side surface 113, 114, the shielding conductors 121A, 122A are arranged from the upper surface 111 to the lower surface 112 via the side surface 115. By not arranging the shielding conductors in this portion of the resonator, connection with the flat plate electrodes 130, 135 inside the laminate 110 is ensured.

[0065] If the firing process is performed in a state where the entire side surfaces 115, 116 are covered with the base electrodes, i.e., the electrode layers 1211, 1221 of the shield conductors 121, 122, as in the filter device 100, the dielectric is constrained by the electrode layers 1211, 1221, and thus, the cross section of the laminate can be deformed into a drum shape. Thus, a tensile stress in the stacking direction is generated for the dielectric layer, and peeling can occur between the dielectric layers and / or between the dielectric and the conductor. As in the filter device 100A of Embodiment 2, in the portion of the side surface 115 where the resonator 140 is disposed, notches 125 are formed at the upper side and the lower side of the resonator 140, and thus, the constraint by the shield conductors in the portion of the relaxation region RG2 is relaxed. Thus, the generation of the stress in the stacking direction can be reduced, and the structural defects caused by the peeling of the dielectric and the conductor can be prevented.

[0066] In addition, since the difference in the shrinkage of the shield conductors between the region RG1 and the region RG2 is also eliminated, the nonlinear warping of the end portion of the conductor caused by the difference in the shrinkage of the shield conductors can be reduced.

[0067] [Embodiment 3]

[0068] In Embodiment 3, a structure in which the shield conductors of the region RG1 in which the conductors are disposed are formed by sputtering or plating treatment without using the base electrodes is described.

[0069] Figure 8 is a side view of the filter device 100B of Embodiment 3 as viewed from the positive direction of the Y axis. Figure 7 is a cross-sectional view of the filter device 100B of Embodiment 3 taken along the line VIII-VIII of Figure 9 Figure 7 is a cross-sectional view of the filter device 100B of Embodiment 3 taken along the line IX-IX of Figures 7-9

[0070] Referring to Figure 8 In the filter device 100B of Embodiment 3 as well, notches 125 are formed in the shield conductors 121B, 122B at the upper side and the lower side of the resonator 140 and the capacitor electrode 160, as in the filter device 100A of Embodiment 2. However, as in Figure 9 and Figure 9 ​​As shown, at the end portions of the conductors of the resonator 140 and the capacitor electrode 160 at the region RG1, the electrode layers 121B1, 122B1 configuring the base electrodes are not provided, and only the electrode layers 121B2, 122B2 formed by the sputtering or plating process are provided. In other words, the electrode layers 121B1, 122B1 are provided at portions between the adjacent resonators 140 and between the adjacent capacitor electrodes 160, and at portions from the side surfaces 115, 116 to the side surfaces 113, 114.

[0071] As described above, when the base electrodes, i.e., the electrode layers 121B1, 122B1 are coated and fired, stress is generated due to the constraint of the electrode layers 121B1, 122B1 to the dielectric layer. Therefore, by not providing the base electrodes at the portions of the conductors where the resonators 140 and the capacitor electrodes 160 are provided, the stress at the portions at the time of the firing process can be reduced. Therefore, the stress acting on the dielectric and the conductor can be suppressed, and the generation of a structural defect in the manufacturing process can be suppressed.

[0072] Further, in the filter device 100B, in the dielectric of the portions of the conductors where the resonators 140 and the capacitor electrodes 160 are provided (region RG1), glass containing a metal component (e.g., copper) that easily diffuses in the firing process is added. Thereby, the concentration of copper contained in the dielectric layer can be made higher than at the region RG2, and the adhesion of the metal member attached by the sputtering and plating processes can be improved.

[0073] In addition, in the filter device 100B, as shown in Figure 10 The conductor width of the conductors configuring the resonators 140 at the end portions of the side surface 115 and the conductor width of the conductors configuring the capacitor electrodes 160 at the end portions of the side surface 116 are wider than the conductor widths of the other portions. Furthermore, the enlarged conductor portions are connected to the base electrodes, i.e., the electrode layers 121B1, 122B1. Thereby, the electrical connection between the conductors configuring the resonators 140 and the capacitor electrodes 160 and the flat electrodes 130, 135 is ensured.

[0074] Also, the capacitor electrodes 160 are each provided with a connection conductor 180 connecting the conductors configuring the capacitor electrodes 160 to the flat electrodes 130, 135. Thereby, reliable electrical connection between the capacitor electrodes 160 and the flat electrodes 130, 135 can be achieved.

[0075] The "connection conductor 180" in Embodiment 3 corresponds to the "third connection conductor" in the present disclosure.

[0076] [Embodiment 4]

[0077] In Embodiment 3, the shield conductor of only the portion of the conductor where the resonator 140 and the capacitor electrode 160 are provided is formed using a sputtering or plating process, and the shield conductor of the other portion is formed in a two-layer structure using a base electrode.

[0078] In Embodiment 4, the entire shield conductor provided at the side surfaces 115, 116 is formed using a sputtering or plating process.

[0079] Figure 11 is a side view of the filter device 100C of Embodiment 4 as viewed from the positive direction of the Y axis. Figure 10 is a plan view of the filter device 100C of Embodiment 4. Figure 12 is a cross-sectional view of the filter device 100C of Embodiment 4 at the line XI-XI. Figure 10 is a cross-sectional view of the filter device 100C of Embodiment 4 at the line XII-XII. Figures 10-12 is a cross-sectional view of the filter device 100C of Embodiment 4 at the line XII-XII.

[0080] Referring to Figure 11 , the shield conductors 121C, 122C in the filter device 100C of Embodiment 4 have substantially the same shape as the filter device 100A of Embodiment 2, and a notch portion 125 is formed at the upper side and the lower side of the resonator 140. However, as shown in Figure 12 and Figure 12 , the shield conductors 121C, 122C are conductors formed in a single-layer structure using a sputtering or plating process. In this way, the shield conductors are formed by the sputtering or plating process without using a base electrode, and thus it is possible to eliminate the constraint on the formation of the dielectric layer by the base electrode in the firing process. Therefore, it is possible to suppress the stress between the dielectric and the conductor and to suppress the occurrence of a structural defect in the manufacturing process.

[0081] On the other hand, in the case of performing a plating process, it is preferable to increase the conductivity of the region where the shield conductor should be formed. Therefore, in the filter device 100C, as shown in Figure 13 , the adjacent resonators are connected to each other and the adjacent capacitor electrodes are connected to each other at the side surfaces. Also, in the filter device 100C, a plurality of plate electrodes 190 are stacked and provided near the side surfaces 115, 116 at the region RG2 where there is no notch portion 125. The end portions of the plate electrodes 190 are exposed at the side surfaces 115, 116. Thus, it is possible to homogenize the conductivity of the side surfaces 115, 116 of the region to the same degree as the resonator portion, and thus it is possible to improve the adhesion of the metal member in the plating process.

[0082] Further, in the filter device 100C, as in Embodiment 3, a glass containing a metal component that easily diffuses in the firing process can be added to the dielectric layer of the region RG1 and the dielectric layer of the portion where the flat electrode 190 is provided in the region RG2.

[0083] As described above, the shielding conductor of the side surface of the laminate is formed by sputtering or plating without using a base electrode, whereby the stress generated in the firing process can be reduced and the occurrence of structural defects can be suppressed.

[0084] [Embodiment 5]

[0085] In Embodiment 5, a structure in which the shielding conductor formed by sputtering or plating is provided only in the portion of the side surface from the upper surface to the lower surface of the resonator and the capacitor electrode is described.

[0086] Figure 14 is a side view of the filter device 100D of Embodiment 5 as viewed from the positive direction of the Y axis. Figure 12 is a cross-sectional view of the filter device 100D of Embodiment 5 at the line XIV-XIV. Figure 13

[0087] In the filter device 100D, as shown in ​ , the shielding conductor 121D is provided only in the portion where the resonator 140 is provided, from the upper surface 111 via the side surface 115 to the lower surface 112. In other words, the region between the resonators adjacent in the side surface 115 and the region near the side surfaces 113 and 114 are not provided with the shielding conductor.

[0088] The shielding conductor 121D of this side surface portion is formed by sputtering or plating without using a base electrode. Therefore, near the side surface 115 of the region RG2 of the laminate 110 on the upper surface side and the lower surface side of the resonator 140, a plurality of flat electrodes 195 are stacked and provided. By the flat electrodes 195, the adhesion of the metal member at the time of sputtering or plating can be improved.

[0089] On the side surface 116 side, the shielding conductor 122D is also provided only in the portion where the capacitor electrode 160 is provided, from the upper surface 111 via the side surface 116 to the lower surface 112. Further, near the side surface 116 of the region RG2 of the laminate 110 on the upper surface side and the lower surface side of the capacitor electrode 160, a plurality of flat electrodes 196 are stacked and provided. By the flat electrodes 196, the adhesion of the metal member at the time of sputtering or plating can be improved at the side surface 116.

[0090] ​Further, as for the portions of the shield conductors 121D, 122D at the upper surface 111 and the lower surface 112, a double-layer structure of an electrode (base electrode) formed by a process such as printing and an electrode formed using a sputtering or plating process is adopted. Specifically, the shield conductor 121D is composed of a base electrode, i.e., an electrode layer 1211D, and an electrode layer 1212D formed using a plating process or the like. Further, the shield conductor 122D is composed of a base electrode, i.e., an electrode layer 1221D, and an electrode layer 1222D formed using a plating process or the like.

[0091] At the upper surface 111 and the lower surface 112, it is necessary to make the electrical connection between the connection conductor 150 on the resonator 140 side and the shield conductor 121D and the electrical connection between the connection conductor 180 on the capacitor electrode 160 side and the shield conductor 122D more reliable. Therefore, in the filter device 100D, a double-layer structure using a base electrode is adopted for the portions of the shield conductors 121D, 122D at the upper surface 111 and the lower surface 112. Further, the base electrode is provided only at the portions of the upper surface 111 and the lower surface 112, and thus in the firing process, stress caused by the electrode between the dielectric and the conductor hardly occurs.

[0092] Further, in the filter device 100D, as in Embodiment 3, glass containing a metal component that easily diffuses in the firing process can be added to the dielectric layer of the region RG1 and the dielectric layer of the region RG2 in which the flat plate electrodes 195, 196 are provided.

[0093] As described above, by forming the shield conductors of the side surfaces of the laminated body using a sputtering or plating process without using a base electrode, it is possible to reduce stress occurring in the firing process and suppress the occurrence of structural defects.

[0094] [TECHNICAL SCHEME]

[0095] The person skilled in the art will understand that the above-described embodiments are specific examples of the following technical scheme.

[0096] (First item), a technical scheme of a dielectric filter has a laminated body, and a plurality of resonators. The laminated body includes a plurality of dielectric layers and has a substantially cuboid shape. The plurality of resonators each extend in a first direction orthogonal to the laminated direction inside the laminated body. At a first side surface and a second side surface of the laminated body orthogonal to the first direction, a first region in which the plurality of resonators are provided protrudes in the first direction more than a second region in which the plurality of resonators are not provided.

[0097] (Second), the medium filter of the first item, further comprising: a first plate electrode and a second plate electrode, and a first shield conductor and a second shield conductor. The first plate electrode and the second plate electrode are arranged separately in the stacking direction inside the stack. The first shield conductor and the second shield conductor are arranged on the first side surface and the second side surface of the stack, respectively, and are connected to the first plate electrode and the second plate electrode. A plurality of resonators are arranged between the first plate electrode and the second plate electrode. The first end of each of the plurality of resonators is connected to the first shield conductor, and the second end is separated from the second shield conductor.

[0098] (Third), the medium filter of the second item, wherein in the first shield conductor, a notch is formed in at least a portion of the second region from the first region to the side of the first plate electrode and the side of the second plate electrode.

[0099] (Fourth), the medium filter of the second item, wherein each of the plurality of resonators is composed of a plurality of conductors extending in the first direction and stacked in the stacking direction.

[0100] (Fifth), the medium filter of the fourth item, further comprising a first connection conductor arranged on the side of the first end of each of the plurality of resonators, connecting the resonator to the first plate electrode and the second plate electrode, and electrically connecting the plurality of conductors to each other.

[0101] (Sixth), the medium filter of the fourth or fifth item, further comprising a second connection conductor arranged on the side of the second end of each of the plurality of resonators, electrically connecting the plurality of conductors to each other.

[0102] (Seventh), the medium filter of the second item, further comprising a capacitor electrode opposite to the second end of each of the plurality of resonators and connected to the second shield conductor.

[0103] (Eighth), the medium filter of the seventh item, wherein in the second shield conductor, a notch is formed in at least a portion of the second region from the first region to the side of the first plate electrode and the side of the second plate electrode.

[0104] (Ninth), the medium filter of the seventh item, wherein the capacitor electrode is composed of a plurality of conductors extending in the first direction and stacked in the stacking direction. The medium filter further comprises a third connection conductor connecting the capacitor electrode to the first plate electrode and the second plate electrode, and electrically connecting the plurality of conductors to each other.

[0105] (Tenth), the dielectric filter described in the second item, the first shield conductor and the second shield conductor are formed by applying a metal paste to the first side surface and the second side surface, respectively, and performing a firing process.

[0106] (Eleventh), the dielectric filter described in the second item, the first shield conductor and the second shield conductor are formed by performing a sputtering or plating process on the first side surface and the second side surface.

[0107] (Twelfth), the dielectric filter described in the eleventh item, the concentration of copper contained in the dielectric layer of the first region is higher than the concentration of copper contained in the dielectric layer of the second region.

[0108] (Thirteenth), the dielectric filter described in the second item, the first shield conductor and the second shield conductor are formed by applying a metal paste to the first side surface and the second side surface, respectively, performing a firing process, and then performing a sputtering or plating process.

[0109] (Fourteenth), the dielectric filter described in the first item, the size of the first region in the stacking direction is less than or equal to 1 / 2 of the size of the laminate in the stacking direction.

[0110] The embodiments disclosed herein are illustrative in all aspects and should not be considered as limiting. The scope of the present application is not represented by the description of the above-described embodiments, but is represented by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0111] Explanation of Reference Signs

[0112] 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-D…filter device; 110…laminated body; 111…upper surface; 112…lower surface; 113-116…side surface; 121, 121A-D, 122, 122A-D…shielding conductor; 125…notch portion; 130, 135, 190, 195, 196, PL1, PL2…flat plate electrode; 140-145…resonator; 150-155, 170-175, 180…connection conductor; 160, 161-165, C10-C50…capacitor electrode; 121B1, 121B2, 122B1, 122B2, 1211, 1212, 1221, 1222, 1211D, 1212D, 1221D, 1222D…electrode layer; RG1, RG2…region; T1…input terminal; T2…output terminal; V10, V11…via hole.

Claims

1. A dielectric filter, wherein, have: A laminate comprising multiple dielectric layers and having a generally rectangular parallelepiped shape; and Multiple resonators extend within the aforementioned stack in a first direction orthogonal to the stacking direction. On the first and second side surfaces of the aforementioned laminate, which are orthogonal to the first direction, the first region where the plurality of resonators are disposed protrudes in the first direction more than the second region where the plurality of resonators are not disposed.

2. The dielectric filter according to claim 1, wherein, It also has: The first and second plate electrodes are separately disposed in the stacking direction within the aforementioned laminate; and A first shielding conductor and a second shielding conductor are respectively disposed on the first side surface and the second side surface of the laminate, and connected to the first plate electrode and the second plate electrode. The plurality of resonators are disposed between the first plate electrode and the second plate electrode. The first end of each of the plurality of resonators is connected to the first shielding conductor, and the second end of each of the plurality of resonators is separated from the second shielding conductor.

3. The dielectric filter according to claim 2, wherein, In the first shielding conductor, at least a portion of the second region extending from the first region to the side adjacent to the first plate electrode and the side adjacent to the second plate electrode is formed with a gap.

4. The dielectric filter according to claim 2, wherein, The aforementioned resonators are composed of multiple conductors that extend freely in the aforementioned first direction and are stacked in the aforementioned stacking direction.

5. The dielectric filter according to claim 4, wherein, It also includes a first connecting conductor, which is disposed on the first end side of each of the plurality of resonators, so that the resonator is connected to the first plate electrode and the second plate electrode, and the plurality of conductors are electrically connected to each other.

6. The dielectric filter according to claim 4 or 5, wherein, It also includes a second connecting conductor, which is disposed on the second end side of each of the plurality of resonators, and electrically connects the plurality of conductors to each other.

7. The dielectric filter according to claim 2, wherein, It also includes a capacitor electrode, which is opposite to the second end of each of the plurality of resonators and connected to the second shielding conductor.

8. The dielectric filter according to claim 7, wherein, In the second shielding conductor, at least a portion of the second region extending from the first region to the side adjacent to the first plate electrode and the side adjacent to the second plate electrode is formed with a gap.

9. The dielectric filter according to claim 7, wherein, The capacitor electrodes described above are composed of a plurality of conductors extending in the first direction and stacked in the stacking direction. The aforementioned dielectric filter also includes a third connecting conductor that connects the capacitor electrode to the first plate electrode and the second plate electrode, and electrically connects the plurality of conductors to each other.

10. The dielectric filter according to claim 2, wherein, The first shielding conductor and the second shielding conductor are formed by coating the first side surface and the second side surface with metal paste and then firing them.

11. The dielectric filter according to claim 2, wherein, The first shielding conductor and the second shielding conductor are formed by sputtering or plating the first side surface and the second side surface.

12. The dielectric filter according to claim 11, wherein, The copper concentration in the dielectric layer of the first region is higher than that in the dielectric layer of the second region.

13. The dielectric filter according to claim 2, wherein, The first shielding conductor and the second shielding conductor are formed by coating the first side surface and the second side surface with metal paste and firing them, followed by sputtering or plating.

14. The dielectric filter according to claim 1, wherein, The dimension of the first region in the stacking direction is less than 1 / 2 of the dimension of the stacked body in the stacking direction.

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