Multilayer filter device

Abstract

The present invention relates to a stacked filter device. The filter device comprises: a filter including at least one inductor and at least one capacitor; a stacked body including a plurality of stacked dielectric layers and a plurality of conductor layers. The plurality of dielectric layers include at least one first dielectric layer composed of a first dielectric material and at least one second dielectric layer composed of a second dielectric material. The plurality of conductor layers include at least one first conductor layer connected to at least one first dielectric layer and at least one second conductor layer connected to at least one second dielectric layer. The temperature coefficient of the resonance frequency of the first dielectric material is a positive value. The temperature coefficient of the resonance frequency of the second dielectric material is a negative value.

Description

Technical Field

[0001] The present invention relates to a multilayer filter device including a filter and a multilayer body. Background Art

[0002] In recent years, the market requires miniaturization and space saving of small mobile communication equipment, and also requires miniaturization of bandpass filters used in such communication equipment. As a bandpass filter suitable for miniaturization, a bandpass filter using a laminated body including a plurality of laminated dielectric layers and a plurality of conductor layers is known. Hereinafter, a bandpass filter using a laminated body is referred to as a laminated bandpass filter.

[0003] The characteristics of the stacked bandpass filter can change according to the temperature. Japanese Patent Application Laid-Open No. 11-228222 discloses a dielectric magnetic composition having a small temperature change rate of a dielectric constant and a ceramic electronic component using the dielectric magnetic composition.

[0004] In a stacked bandpass filter, in addition to the dielectric constant of the dielectric layers constituting the stacked body, the pass attenuation characteristics may also change according to the temperature. The pass attenuation characteristics are represented by a curve that plots the attenuation of the signal passing through the stacked bandpass filter at each frequency. When the temperature changes, the curve representing the pass attenuation characteristics will deviate to the high frequency side or the low frequency side.

[0005] However, one of the specifications required of a stacked bandpass filter is a passband. The absolute value of the attenuation in the passband is required to be less than a specified value. However, when the pass-attenuation characteristics of the passband and its vicinity deviate due to temperature, the required value may not be met. In particular, in a stacked bandpass filter that requires a narrow passband, the required value may not be met even when the pass-attenuation characteristics deviate slightly. Summary of the invention

[0006] An object of the present invention is to provide a multilayer filter device capable of suppressing a change in pass attenuation characteristics due to temperature.

[0007] The laminated filter device of the present invention is a laminated filter device having a filter and a laminated body, wherein the filter includes at least one inductor and at least one capacitor, and the laminated body includes a plurality of laminated dielectric layers and a plurality of conductor layers, and is used to integrate the at least one inductor and the at least one capacitor. The at least one inductor and the at least one capacitor are formed using a plurality of conductor layers.

[0008] The plurality of dielectric layers include at least one first dielectric layer and at least one second dielectric layer. The plurality of conductor layers include at least one first conductor layer connected to at least one first dielectric layer and at least one second conductor layer connected to at least one second dielectric layer. The first dielectric layer is composed of a first dielectric material having a positive temperature coefficient of resonance frequency. The second dielectric layer is composed of a second dielectric material having a negative temperature coefficient of resonance frequency.

[0009] In the laminated filter device of the present invention, the laminate may also have a bottom surface and an upper surface located at both ends of the stacking direction of the plurality of dielectric layers, and four side surfaces connecting the bottom surface and the upper surface. In this case, at least one first dielectric layer may also be arranged closer to the bottom surface than the upper surface.

[0010] In the multilayer filter device of the present invention, the at least one second dielectric layer may be a plurality of second dielectric layers. In this case, the at least one first dielectric layer may be disposed between one of the plurality of second dielectric layers and another of the plurality of second dielectric layers.

[0011] In addition, in the laminated filter device of the present invention, at least one capacitor may also be a plurality of capacitors. In this case, at least one first conductor layer may also be a plurality of first conductor layers. At least one of the plurality of capacitors may also be composed of at least one first dielectric layer and two of the plurality of first conductor layers configured in a manner of clamping at least one first dielectric layer.

[0012] Furthermore, in the multilayer filter device of the present invention, at least one inductor may be formed using at least one second conductor layer.

[0013] In the multilayer filter device of the present invention, the filter may be a bandpass filter that selectively passes signals with frequencies within a predetermined passband. In this case, the width of the passband may be within a range of 10 to 600 MHz.

[0014] In the stacked filter device of the present invention, the plurality of dielectric layers include at least one first dielectric layer and at least one second dielectric layer. The first dielectric layer is composed of a first dielectric material having a positive temperature coefficient of resonance frequency, and the second dielectric layer is composed of a second dielectric material having a negative temperature coefficient of resonance frequency. Thus, according to the present invention, a stacked filter device capable of suppressing changes in attenuation characteristics due to temperature can be realized.

[0015] Other objects, features and advantages of the present invention will become more apparent from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1This is a circuit diagram showing a circuit configuration of a filter according to one embodiment of the present invention.

[0017] Figure 2 It is a perspective view showing the appearance of a multilayer filter device according to one embodiment of the present invention.

[0018] Figure 3A to Figure 3C It is an explanatory diagram showing the pattern formation surface of the first to third dielectric layers in the laminated body of the laminated filter device according to one embodiment of the present invention.

[0019] Figure 4A to Figure 4C It is an explanatory diagram showing the pattern formation surface of the fourth to sixth dielectric layers in the laminated body of the laminated filter device according to one embodiment of the present invention.

[0020] Figure 5A It is an explanatory diagram showing the pattern formation surface of the seventh and eighth dielectric layers in the laminated body of the laminated filter device according to one embodiment of the present invention.

[0021] Figure 5B It is an explanatory diagram showing a pattern-formed surface of a ninth dielectric layer in a laminated body of a laminated filter device according to an embodiment of the present invention.

[0022] Figure 5C It is an explanatory diagram showing the pattern formation surface of the tenth to sixteenth dielectric layers in the laminated body of the laminated filter device according to one embodiment of the present invention.

[0023] Fig. 6A and Figure 6B It is an explanatory diagram showing the pattern formation surface of the seventeenth and eighteenth dielectric layers in the laminated body of the laminated filter device according to one embodiment of the present invention.

[0024] Figure 7 It is a perspective view showing the interior of a laminated body of a laminated filter device according to one embodiment of the present invention.

[0025] Figure 8 It is a characteristic diagram showing the pass attenuation characteristics of a multilayer filter device according to a comparative example.

[0026] Fig. 9 It is a characteristic diagram showing the pass attenuation characteristics of a multilayer filter device according to a comparative example.

[0027] Fig.10 It is a characteristic diagram showing the relationship between temperature and frequency variation in a multilayer filter device of a comparative example.

[0028] Fig.11 It is a characteristic diagram showing the pass attenuation characteristics of the multilayer filter device of the embodiment.

[0029] Fig.12 It is a characteristic diagram showing the pass attenuation characteristics of the multilayer filter device of the embodiment.

[0030] Fig.13 It is a characteristic diagram showing the relationship between temperature and frequency variation in the multilayer filter device of the embodiment.

[0031] Fig.14 It is a characteristic diagram showing the reflection loss at the first port of the multilayer filter device of the embodiment.

[0032] Fig.15 It is a characteristic diagram showing the reflection loss at the second port of the multilayer filter device of the embodiment.

[0033] Fig.16 This is a characteristic diagram showing an example of the pass attenuation characteristics of the multilayer filter device according to one embodiment of the present invention.

[0034] Fig.17 This is a characteristic diagram showing an example of the pass attenuation characteristics of the multilayer filter device according to one embodiment of the present invention. DETAILED DESCRIPTION

[0035] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, the structure of a stacked filter device (hereinafter referred to as a filter device) 1 according to an embodiment of the present invention will be described in detail. The filter device 1 of this embodiment includes a filter 5 including at least one inductor and at least one capacitor. The filter 5 of this embodiment is a bandpass filter that selectively passes a signal of a frequency within a specified passband.

[0036] Next, refer to Figure 1 An example of the configuration of the filter 5 will be described. Figure 1 : is a circuit diagram showing a circuit configuration of a filter 5. The filter 5 includes a first port 2, a second port 3, inductors L1, L2, L3, L4, and capacitors C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, and C12. The first and second ports 2 and 3 function as input and output ports of a bandpass filter, respectively.

[0037] In circuit structure, inductors L1 to L4 and capacitors C1 to C12 are provided between first port 2 and second port 3. In the present application, expressions such as "in circuit structure" are not physical configurations but are used to indicate configurations on a circuit diagram.

[0038] One end of the inductor L1 is connected to the first port 2. The capacitor C1 is connected in parallel with the inductor L1. One end of the capacitor C2 is connected to the other end of the inductor L1. The other end of the capacitor C2 is connected to the ground line.

[0039] One end of the capacitor C3 is connected to the other end of the inductor L1. One end of the capacitor C4 is connected to the other end of the capacitor C3. One end of the capacitor C5 is connected to the other end of the capacitor C4. One end of the capacitor C6 is connected to the other end of the capacitor C5.

[0040] One end of the inductor L2 and one end of the capacitor C7 are connected to the connection point of the capacitor C3 and the capacitor C4, respectively. The other end of the inductor L2 and the other end of the capacitor C7 are connected to the ground line, respectively.

[0041] One end of the inductor L3 and one end of the capacitor C8 are connected to the connection point of the capacitor C5 and the capacitor C6, respectively. The other end of the inductor L3 and the other end of the capacitor C8 are connected to the ground line, respectively.

[0042] One end of the capacitor C9 is connected to one end of the capacitor C3. One end of the capacitor C10 is connected to the other end of the capacitor C9. The other end of the capacitor C10 is connected to the other end of the capacitor C6.

[0043] One end of the inductor L4 is connected to the other end of the capacitor C6. The other end of the inductor L4 is connected to the second port 3. The capacitor C11 is connected in parallel with the inductor L4. One end of the capacitor C12 is connected to one end of the inductor L4. The other end of the capacitor C12 is connected to the ground line.

[0044] Next, refer to Figure 2 The other structures of the filter device 1 will be described. Figure 2 It is a perspective view showing the appearance of the filter device 1 .

[0045] The filter device 1 further includes a laminate 50 including a plurality of laminated dielectric layers and a plurality of conductor layers. The laminate 50 is a laminate for integrating the first port 2, the second port 3, and the inductors L1 to L4 and the capacitors C1 to C12 of the filter 5. The inductors L1 to L4 and the capacitors C1 to C12 are formed using a plurality of conductor layers.

[0046] The stacked body 50 has a bottom surface 50A and an upper surface 50B located at both ends of the stacking direction T of the plurality of dielectric layers, and four side surfaces 50C to 50F connecting the bottom surface 50A and the upper surface 50B. The side surfaces 50C and 50D face opposite sides, and the side surfaces 50E and 50F also face opposite sides. The side surfaces 50C to 50F are perpendicular to the upper surface 50B and the bottom surface 50A.

[0047] Here, if Figure 2 As shown, the X direction, Y direction, and Z direction are defined. The X direction, Y direction, and Z direction are orthogonal to each other. In this embodiment, a direction parallel to the stacking direction T is set as the Z direction. In addition, the direction opposite to the X direction is set as the -X direction, the direction opposite to the Y direction is set as the -Y direction, and the direction opposite to the Z direction is set as the -Z direction.

[0048] like Figure 2 As shown, the bottom surface 50A is located at the end of the stack 50 in the -Z direction. The upper surface 50B is located at the end of the stack 50 in the Z direction. The side surface 50C is located at the end of the stack 50 in the -X direction. The side surface 50D is located at the end of the stack 50 in the X direction. The side surface 50E is located at the end of the stack 50 in the -Y direction. The side surface 50F is located at the end of the stack 50 in the Y direction.

[0049] The filter device 1 further includes a plurality of terminals 111, 112, and 113 provided on the bottom surface 50A of the laminate 50. The terminal 111 extends in the Y direction near the side surface 50C. The terminal 112 extends in the Y direction near the side surface 50D. The terminal 113 is arranged between the terminal 111 and the terminal 112.

[0050] The terminal 111 corresponds to the first port 2, and the terminal 112 corresponds to the second port 3. Therefore, the first and second ports 2 and 3 are provided on the bottom surface 50A of the stacked body 50. The terminal 113 is connected to the ground.

[0051] The plurality of dielectric layers include at least one first dielectric layer and at least one second dielectric layer. The plurality of conductor layers include at least one first conductor layer connected to the at least one first dielectric layer and at least one second conductor layer connected to the at least one second dielectric layer.

[0052] Here, the temperature coefficient of the resonant frequency of the dielectric material is described. First, the resonant frequency of the dielectric material at the reference temperature Tref is set to fref, and the resonant frequency of the dielectric material at the specified temperature Tr is set to fr. In addition, the temperature coefficient of the resonant frequency of the dielectric material in the temperature range from the reference temperature Tref to the temperature Tr is represented by the symbol tf. The temperature coefficient tf of the resonant frequency (unit: ppm / °C) is represented by the following formula (1).

[0053] tf=[(fr-fref) / {fref(Tr-Tref)}]×10 6 …(1)

[0054] The temperature coefficient tf of the resonance frequency at -40 to 85°C is the temperature coefficient of the resonance frequency obtained by equation (1) when the reference temperature Tref is set to -40°C and the predetermined temperature Tr is set to 85°C. In the following description, the temperature coefficient tf of the resonance frequency is referred to as the temperature coefficient tf of the resonance frequency at -40 to 85°C.

[0055] The first dielectric layer is composed of a first dielectric material having a positive temperature coefficient tf of the resonance frequency. The temperature coefficient tf of the resonance frequency of the first dielectric material is, for example, in the range of 1 to 1000 ppm / °C. In addition, the relative dielectric constant of the first dielectric material is, for example, in the range of 10 to 80. As the first dielectric material, for example, a dielectric material having a composition formula of {α(xBaO·yNd 2 O 3 ·zTiO 2 )+β(2MgO·SiO 2 )} as a main component of a ceramic (hereinafter referred to as a first ceramic). Wherein α>0, β>0, x>0, y>0, z>0.

[0056] The second dielectric layer is composed of a second dielectric material having a negative temperature coefficient tf of the resonant frequency. The temperature coefficient tf of the resonant frequency of the second dielectric material is, for example, in the range of -1000 to -1 ppm / °C. In addition, the relative dielectric constant of the second dielectric material is, for example, in the range of 5 to 9. As the second dielectric material, for example, a dielectric material having a composition formula of {γ(2MgO·SiO 2 )+δ((Ca, Sr)TiO 3 )} as a main component of a ceramic (hereinafter referred to as a second ceramic). Wherein γ>0, δ≧0.

[0057] The ratio of the absolute value of the temperature coefficient tf of the resonance frequency of the first dielectric material to the absolute value of the temperature coefficient tf of the resonance frequency of the second dielectric material is preferably within a range of 0.1 to 10, for example.

[0058] Next, refer to Figure 3A to Figure 6B An example of a plurality of dielectric layers and a plurality of conductor layers constituting the laminate 50 is described. In this example, the laminate 50 has 18 laminated dielectric layers. Hereinafter, the 18 dielectric layers are referred to as the first to the 18th dielectric layers in order from the bottom. In addition, the first to the 18th dielectric layers are represented by reference numerals 51 to 68.

[0059] Figure 3AThe pattern forming surface of the first dielectric layer 51 is shown. Terminals 111, 112, and 113 are formed on the pattern forming surface of the dielectric layer 51. In addition, through holes 51T1, 51T3, 51T4, 51T5, 51T6, and 51T8 are formed in the dielectric layer 51. The through hole 51T1 is connected to the terminal 111. The through holes 51T3 to 51T6 are connected to the terminal 113. The through hole 51T8 is connected to the terminal 112.

[0060] Figure 3B The pattern forming surface of the second dielectric layer 52 is shown. Conductor layers 521, 522 and a grounding conductor layer 523 are formed on the pattern forming surface of the dielectric layer 52. In addition, through holes 52T1, 52T4, 52T6, and 52T8 are formed in the dielectric layer 52. The through hole 51T1 and the through hole 52T1 formed in the dielectric layer 51 are connected to the conductor layer 521. The through holes 51T3 to 51T6 and the through holes 52T4 and 52T6 formed in the dielectric layer 51 are connected to the grounding conductor layer 523. The through hole 51T8 and the through hole 52T8 formed in the dielectric layer 51 are connected to the conductor layer 522.

[0061] Figure 3C : shows the pattern forming surface of the third dielectric layer 53. A conductor layer 531 is formed on the pattern forming surface of the dielectric layer 53. In addition, through holes 53T1, 53T4, 53T6, and 53T8 are formed in the dielectric layer 53. The through holes 52T1 and 52T8 formed in the dielectric layer 52 are connected to the through holes 53T1 and 53T8, respectively. The through holes 52T4 and 52T6 formed in the dielectric layer 52 and the through holes 53T4 and 53T6 are connected to the conductor layer 531.

[0062] Figure 4A : shows the pattern forming surface of the fourth dielectric layer 54. Conductor layers 541, 542, 543, 544, and 545 are formed on the pattern forming surface of the dielectric layer 54. In addition, through holes 54T1, 54T2, 54T3, 54T4, 54T5, 54T6, 54T7, and 54T8 are formed in the dielectric layer 54. Through holes 53T1 and 53T8 formed in the dielectric layer 53 are connected to through holes 54T1 and 54T8, respectively. Through holes 54T2, 54T3, 54T5, and 54T7 are connected to conductor layers 541, 542, 543, and 545, respectively. Through holes 53T4 and 53T6 formed in the dielectric layer 53 and through holes 54T4 and 54T6 are connected to the conductor layer 544.

[0063] Figure 4BThe pattern forming surface of the fifth dielectric layer 55 is shown. Conductor layers 551, 552, and 553 are formed on the pattern forming surface of the dielectric layer 55. In addition, through holes 55T1, 55T2, 55T3, 55T4, 55T5, 55T6, 55T7, and 55T8 are formed in the dielectric layer 55. Through holes 54T1, 54T3 to 54T6, and 54T8 formed in the dielectric layer 54 are connected to the through holes 55T1, 55T3 to 55T6, and 55T8, respectively. Through holes 54T2 and through holes 55T2 formed in the dielectric layer 54 are connected to the conductor layer 551. Through holes 54T7 and through holes 55T7 formed in the dielectric layer 54 are connected to the conductor layer 553.

[0064] Figure 4C The pattern forming surface of the sixth dielectric layer 56 is shown. Conductor layers 561 and 562 are formed on the pattern forming surface of the dielectric layer 56. In addition, through holes 56T1, 56T2, 56T3, 56T4, 56T5, 56T6, 56T7, and 56T8 are formed in the dielectric layer 56. Through holes 55T1, 55T2, 55T4, and 55T6 to 55T8 formed in the dielectric layer 55 are connected to the through holes 56T1, 56T2, 56T4, and 56T6 to 56T8, respectively. Through hole 55T3 and through hole 56T3 formed in the dielectric layer 55 are connected to the conductor layer 561. Through hole 55T5 and through hole 56T5 formed in the dielectric layer 55 are connected to the conductor layer 562.

[0065] Figure 5A : represents the pattern forming surface of each of the seventh dielectric layer 57 and the eighth dielectric layer 58. Through holes 57T1, 57T2, 57T3, 57T4, 57T5, 57T6, 57T7, and 57T8 are formed in each of the dielectric layers 57 and 58. The through holes 56T1 to 56T8 formed in the dielectric layer 56 are connected to the through holes 57T1 to 57T8 formed in the dielectric layer 57, respectively. In addition, in the dielectric layers 57 and 58, the through holes with the same reference numerals adjacent to each other are connected to each other.

[0066] Figure 5B The pattern forming surface of the ninth dielectric layer 59 is shown. A conductor layer 591 is formed on the pattern forming surface of the dielectric layer 59. In addition, through holes 59T1, 59T2, 59T3, 59T4, 59T5, 59T6, 59T7, and 59T8 are formed in the dielectric layer 59. The through holes 57T1 to 57T8 formed in the dielectric layer 58 are connected to the through holes 59T1 to 59T8, respectively.

[0067] Figure 5CThe pattern forming surfaces of the 10th to 16th dielectric layers 60 to 66 are shown. Through holes 60T1, 60T2, 60T3, 60T4, 60T5, 60T6, 60T7, and 60T8 are formed in each of the dielectric layers 60 to 66. The through holes 59T1 to 59T8 formed in the dielectric layer 59 are connected to the through holes 60T1 to 60T8 formed in the dielectric layer 60, respectively. In addition, in the dielectric layers 60 to 66, the through holes with the same reference numerals adjacent to each other are connected to each other.

[0068] Fig. 6A The pattern forming surface of the 17th dielectric layer 67 is shown. Conductor layers 671, 672, 673, and 674 are formed on the pattern forming surface of the dielectric layer 67. Each of the conductor layers 671 to 674 has a first end and a second end located on opposite sides. In addition, through holes 67T1, 67T2, 67T3, 67T4, 67T5, 67T6, 67T7, and 67T8 are formed in the dielectric layer 67. The through hole 60T1 and the through hole 67T1 formed in the dielectric layer 66 are connected to the vicinity of the first end of the conductor layer 671. The through hole 60T2 and the through hole 67T2 formed in the dielectric layer 66 are connected to the vicinity of the second end of the conductor layer 671. The through hole 60T3 and the through hole 67T3 formed in the dielectric layer 66 are connected to the vicinity of the first end of the conductor layer 672. The through hole 60T4 and the through hole 67T4 formed in the dielectric layer 66 are connected to the portion near the second end of the conductor layer 672. The through hole 60T5 and the through hole 67T5 formed in the dielectric layer 66 are connected to the portion near the first end of the conductor layer 673. The through hole 60T6 and the through hole 67T6 formed in the dielectric layer 66 are connected to the portion near the second end of the conductor layer 673. The through hole 60T7 and the through hole 67T7 formed in the dielectric layer 66 are connected to the portion near the first end of the conductor layer 674. The through hole 60T8 and the through hole 67T8 formed in the dielectric layer 66 are connected to the portion near the second end of the conductor layer 674.

[0069] Figure 6BThe pattern forming surface of the 18th dielectric layer 68 is shown. Conductor layers 681, 682, 683, and 684 are formed on the pattern forming surface of the dielectric layer 68. Each of the conductor layers 681 to 684 has a first end and a second end located on opposite sides to each other. The through hole 67T1 formed in the dielectric layer 67 is connected to the vicinity of the first end of the conductor layer 681. The through hole 67T2 formed in the dielectric layer 67 is connected to the vicinity of the second end of the conductor layer 681. The through hole 67T3 formed in the dielectric layer 67 is connected to the vicinity of the first end of the conductor layer 682. The through hole 67T4 formed in the dielectric layer 67 is connected to the vicinity of the second end of the conductor layer 682. The through hole 67T5 formed in the dielectric layer 67 is connected to the vicinity of the first end of the conductor layer 683. The through hole 67T6 formed in the dielectric layer 67 is connected to the vicinity of the second end of the conductor layer 683. The through hole 67T7 formed in the dielectric layer 67 is connected to the vicinity of the first end of the conductor layer 684. The through hole 67T8 formed in the dielectric layer 67 is connected to the vicinity of the second end of the conductor layer 684.

[0070] Figure 2 The illustrated stacked body 50 is constructed by stacking 1st to 18th dielectric layers 51 to 68 such that the patterned surface of the 1st dielectric layer 51 is the bottom surface 50A of the stacked body 50 and the surface opposite to the patterned surface of the 18th dielectric layer 68 is the top surface 50B of the stacked body 50 .

[0071] Figure 7 2 shows the interior of a stacked body 50 formed by stacking the first to eighteenth dielectric layers 51 to 68. Figure 7 As shown, inside the stacked body 50, Figure 3A to Figure 6B Multiple conductor layers and multiple vias are shown stacked.

[0072] The following, Figure 1 The components of the filter 5 shown in the circuit are Figure 3A to Figure 6B The corresponding relationship of the components inside the laminated body 50 shown in FIG. Figure 4C to Figure 6B The conductor layers 671, 681 and the through holes 56T1, 56T2, 57T1, 57T2, 59T1, 59T2, 60T1, 60T2, 67T1, 67T2 are shown.

[0073] Inductor L2 is composed of Figure 4C to Figure 6B The conductor layers 672, 682 and the through holes 56T3, 56T4, 57T3, 57T4, 59T3, 59T4, 60T3, 60T4, 67T3, 67T4 are shown.

[0074] Inductor L3 is composed of Figure 4C to Figure 6BThe conductor layers 673, 683 and the through holes 56T5, 56T6, 57T5, 57T6, 59T5, 59T6, 60T5, 60T6, 67T5, 67T6 are shown.

[0075] Inductor L4 is composed of Figure 4C to Figure 6B The conductor layers 674, 684 and the through holes 56T7, 56T8, 57T7, 57T8, 59T7, 59T8, 60T7, 60T8, 67T7, 67T8 are shown.

[0076] Capacitor C1 is composed of Figure 3B and Figure 4A The illustrated conductor layers 521, 541 are formed with dielectric layers 52, 53 between these conductor layers.

[0077] Capacitor C2 consists of Figure 3B The ground conductor layer 523 shown, Figure 4B The illustrated conductor layer 551 and dielectric layers 52 to 54 between these conductor layers are formed.

[0078] Capacitor C3 consists of Figure 4A and Figure 4C The illustrated conductor layers 541 and 561 are formed with dielectric layers 54 and 55 between these conductor layers.

[0079] Capacitor C4 is composed of Figure 4B and Figure 4C The conductor layers 552, 561 shown in FIG. 1 and the dielectric layer 55 between these conductor layers are formed. The capacitor C5 is composed of Figure 4B and Figure 4C The conductor layers 552, 562 shown in the figure and the dielectric layer 55 between these conductor layers are formed. The capacitor C6 is composed of Figure 4A and Figure 4C The illustrated conductor layers 545, 562 are formed with dielectric layers 54, 55 between these conductor layers.

[0080] Capacitor C7 consists of Figure 3B The ground conductor layer 523 shown, Figure 4A The capacitor C8 is composed of the conductor layer 542 shown in FIG. 1 and the dielectric layers 52 and 53 between these conductor layers. Figure 4A The illustrated conductor layer 543 and the dielectric layers 52 and 53 between these conductor layers.

[0081] Capacitor C9 consists of Figure 4B and Figure 5B The conductor layers 551 and 591 shown in the figure and the dielectric layers 55 to 58 between these conductor layers are formed. The capacitor C10 is composed of Figure 4B and Figure 5BThe shown conductor layers 553 and 591 are composed of dielectric layers 55 to 58 between these conductor layers.

[0082] Capacitor C11 is composed of Figure 3B and Figure 4A The illustrated conductor layers 522, 545 are formed with dielectric layers 52, 53 between these conductor layers.

[0083] Capacitor C12 is composed of Figure 3B The ground conductor layer 523 shown, Figure 4B The shown conductor layer 553 and dielectric layers 52 to 54 between these conductor layers are formed.

[0084] Next, refer to Figure 1 to Figure 7 The structural features of the filter device 1 of the present embodiment are described. As described above, the plurality of dielectric layers constituting the laminate 50 include a first dielectric layer and a second dielectric layer. In the present embodiment, the dielectric layers 52 to 55 correspond to the first dielectric layer, and the dielectric layers 51, 56 to 68 correspond to the second dielectric layer. Hereinafter, the dielectric layers 52 to 55 are all described as the first dielectric layers 52 to 55, and the dielectric layers 51, 56 to 68 are all described as the second dielectric layers 51, 56 to 68.

[0085] The second dielectric layer 51 is interposed between the first dielectric layers 52 to 55 and the bottom surface 50A of the stacked body 50. The second dielectric layers 56 to 68 are interposed between the first dielectric layers 52 to 55 and the top surface 50B of the stacked body 50. The first dielectric layers 52 to 55 are arranged closer to the bottom surface 50A than the top surface 50B. In addition, the first dielectric layers 52 to 55 are arranged between the second dielectric layers 51 and the second dielectric layer 56.

[0086] In addition, in this embodiment, the conductor layers 521 to 523, 531, 541 to 545, and 551 to 553 correspond to the first conductor layer. The conductor layers 521 to 523 are in contact with the pattern-formed surface of the first dielectric layer 52. The conductor layer 531 is in contact with the pattern-formed surface of the first dielectric layer 53. The conductor layers 541 to 545 are in contact with the pattern-formed surface of the first dielectric layer 54. The conductor layers 551 to 553 are in contact with the pattern-formed surface of the first dielectric layer 55.

[0087] Conductive layers 591, 671 to 673, and 681 to 683 correspond to the second conductive layer. Conductive layer 591 is in contact with the pattern-formed surface of second dielectric layer 59. Conductive layers 671 to 673 are in contact with the pattern-formed surface of second dielectric layer 67. Conductive layers 681 to 683 are in contact with the pattern-formed surface of second dielectric layer 68.

[0088] The conductor layers 561 and 562 correspond to both the first conductor layer and the second conductor layer. The conductor layers 561 and 562 are in contact with the surface of the first dielectric layer 55 opposite to the pattern-formed surface and the pattern-formed surface of the second dielectric layer 56 .

[0089] Capacitors other than capacitors C9 and C10 are composed of at least one first dielectric layer and two first conductor layers arranged so as to sandwich the at least one first dielectric layer. For example, capacitor C1 is composed of first dielectric layers 52 and 53 and conductor layers 521 and 541 arranged so as to sandwich the first dielectric layers 52 and 53.

[0090] The inductors L1 to L4 are formed using the second conductor layers 671 to 674 and 681 to 684. In addition, the through holes 56T1 to 56T8, 57T1 to 57T8, 59T1 to 59T8, 60T1 to 60T8, and 67T1 to 67T8 forming the inductors L1 to L4 are formed in the second dielectric layers 56 to 67. From these, it can be said that the inductors L1 to L4 are buried in the second dielectric layers 56 to 68.

[0091] Next, the function and effect of the filter device 1 of the present embodiment are described. In the present embodiment, the laminate 50 includes first dielectric layers 52 to 55 and second dielectric layers 51, 56 to 68. The first dielectric layers 52 to 55 are formed of a first dielectric material. The second dielectric layers 51, 56 to 68 are formed of a second dielectric material. The temperature coefficient tf of the resonance frequency of the first dielectric material is a positive value, and the temperature coefficient tf of the resonance frequency of the second dielectric material is a negative value. According to the present embodiment, by combining two dielectric materials whose temperature coefficients tf of the resonance frequency have opposite signs to each other as described above, it is possible to suppress the change in the pass attenuation characteristics of the filter 5 due to temperature.

[0092] The following describes the experimental results of investigating the effects of the present embodiment. First, the filter device produced in the experiment is described. In the experiment, a filter device of the embodiment and a filter device of the comparative example are produced. The structure of the filter device of the embodiment and the reference Figure 1 to Figure 7 The filter device 1 of the present embodiment described has the same structure. The filter device of the comparative example has the same structure as the filter device of the embodiment except for the structure of the dielectric layer. In the filter device of the comparative example, all of the plurality of dielectric layers are first dielectric layers.

[0093] In the experiment, the first ceramic described above was used as the first dielectric material constituting the first dielectric layer. The temperature coefficient tf of the resonance frequency of the first dielectric material was 40 ppm / ° C. The relative dielectric constant of the first dielectric material at 1.9 GHz was 33.

[0094] In the experiment, the second ceramic described above was used as the second dielectric material constituting the second dielectric layer. The temperature coefficient tf of the resonance frequency of the second dielectric material was -70 ppm / ° C. The relative dielectric constant of the second dielectric material at 1.9 GHz was 7.1.

[0095] In the experiment, the filter device of the embodiment was designed so that the passband of the filter 5 was 4.4 to 5.0 GHz. The filter device of the comparative example was designed so that the passband of the filter 5 was 3.0 to 4.2 GHz.

[0096] Next, the method for measuring the characteristics of the filter device of the embodiment and the filter device of the comparative example is described. In the experiment, the temperature of the filter device of the embodiment is changed to -40°C, 25°C, and 85°C, and the pass attenuation characteristics of the filter device of the embodiment are obtained. In addition, in the experiment, the temperature of the filter device of the comparative example is changed to -40°C, 25°C, and 105°C, and the pass attenuation characteristics of the filter device of the comparative example are obtained.

[0097] Next, the results of the experiment will be described. First, a filter device of a comparative example will be described. Figure 8 and Fig. 9 The pass attenuation characteristics of the filter device of the comparative example are shown. Figure 8 It shows the attenuation characteristics at a temperature of 25°C. Fig. 9 The attenuation characteristics at temperatures of -40°C, 25°C, and 105°C are shown. Fig. 9 In the figure, the pass attenuation characteristics near the passband are magnified. Figure 8 and Fig. 9 In each of the above, the horizontal axis represents the frequency and the vertical axis represents the attenuation. Fig. 9 In the figure, reference numeral 81 indicates the through-attenuation characteristics at −40° C., reference numeral 82 indicates the through-attenuation characteristics at 25° C., and reference numeral 83 indicates the through-attenuation characteristics at 105° C. Fig. 9 It can be seen that in the filter device of the comparative example, the curve representing the pass attenuation characteristic changes in a manner shifting toward the low frequency side or the high frequency side due to temperature. In the filter device of the comparative example, in particular, the curve representing the pass attenuation characteristic shifts toward the low frequency side as the temperature increases.

[0098] In the filter device of the comparative example, the frequency at which the attenuation becomes -10 dB on the low-frequency side of the passband is 2.871 GHz at a temperature of -40°C, 2.862 GHz at a temperature of 25°C, and 2.849 GHz at a temperature of 105°C. In addition, in the filter device of the comparative example, the frequency at which the attenuation becomes -10 dB on the high-frequency side of the passband is 4.589 GHz at a temperature of -40°C, 4.574 GHz at a temperature of 25°C, and 4.552 GHz at a temperature of 105°C.

[0099] Here, the frequency variation is defined as follows. The frequency at which the attenuation becomes -10 dB at a temperature of 25°C is set as the reference frequency. Then, the variation from the reference frequency at which the attenuation becomes -10 dB at a certain temperature is set as the frequency variation at that temperature. The frequency variation is obtained on the low frequency side of the passband and the high frequency side of the passband. In addition, according to the above definition, the frequency variation at 25°C is 0.

[0100] On the low-frequency side of the passband, the frequency fluctuation at -40°C is 0.31%, and the frequency fluctuation at 105°C is -0.45%. On the high-frequency side of the passband, the frequency fluctuation at -40°C is 0.33%, and the frequency fluctuation at 105°C is -0.48%.

[0101] Fig.10 : is a characteristic diagram showing the relationship between temperature and frequency variation in a filter device of a comparative example. Fig.10 In the figure, the horizontal axis represents temperature and the vertical axis represents frequency variation. Fig.10 In FIG. 1 , the straight line indicated by the dotted line is an approximate straight line indicating the relationship between the temperature and the frequency variation. The slope of the approximate straight line indicates the variation of the pass attenuation characteristic near the passband when the temperature changes. Fig.10 The slope of the approximate straight line shown is -54.6 ppm / °C.

[0102] Next, the filter device according to the embodiment will be described. Fig.11 and Fig.12 The pass attenuation characteristics of the filter device of the embodiment are shown. Fig.11 It shows the attenuation characteristics at a temperature of 25°C. Fig.12 The attenuation characteristics at temperatures of -40°C, 25°C, and 85°C are shown. Fig.12 In the figure, the pass attenuation characteristics near the passband are magnified. Fig.11 and Fig.12 In each of the above, the horizontal axis represents the frequency and the vertical axis represents the attenuation. Fig.11In the figure, reference numeral 91 indicates the through-attenuation characteristics at −40° C., reference numeral 92 indicates the through-attenuation characteristics at 25° C., and reference numeral 93 indicates the through-attenuation characteristics at 85° C. Fig.12 It can be seen that in the filter device of the embodiment, the curve representing the pass attenuation characteristic hardly deviates toward the low frequency side or the high frequency side due to temperature.

[0103] In the filter device of the embodiment, the frequency at which the attenuation becomes -10 dB on the low-frequency side of the passband is 4.092 GHz at a temperature of -40°C, 4.093 GHz at a temperature of 25°C, and 4.093 GHz at a temperature of 85°C. In addition, the frequency at which the attenuation becomes -10 dB on the high-frequency side of the passband is 5.329 GHz at a temperature of -40°C, 5.331 GHz at a temperature of 25°C, and 5.332 GHz at a temperature of 85°C.

[0104] In addition, in the filter device of the embodiment, the frequency fluctuation amount at -40°C on the low frequency side of the passband is -0.02%, and the frequency fluctuation amount at 85°C on the low frequency side of the passband is 0%. In addition, in the filter device of the embodiment, the frequency fluctuation amount at -40°C on the high frequency side of the passband is -0.04%, and the frequency fluctuation amount at 85°C on the high frequency side of the passband is 0.02%.

[0105] Fig.13 : is a characteristic diagram showing the relationship between temperature and frequency variation in the filter device of the embodiment. Fig.13 In the figure, the horizontal axis represents temperature and the vertical axis represents frequency variation. Fig.13 In FIG. 1 , the straight line indicated by the dotted line is an approximate straight line indicating the relationship between the temperature and the frequency variation. Fig.13 The slope of the approximate straight line shown is 3.2 ppm / °C.

[0106] according to Fig. 9 , Fig.10 , Fig.12 and Fig.13 As can be seen from the results shown, in the filter device of the embodiment, the change in the pass attenuation characteristic accompanying the temperature change is small. As can be understood from the results, according to this embodiment, compared with the case where all of the multiple dielectric layers are formed by the same dielectric material, the change in the pass attenuation characteristic of the filter 5 due to temperature can be suppressed.

[0107] So far, the change of the pass attenuation characteristic of the filter 5 due to temperature has been described. However, according to the present embodiment, it is also possible to suppress the change of the characteristics of the filter 5 other than the pass attenuation characteristic due to temperature. Fig.14It is a characteristic diagram showing the reflection loss at the first port 2 of the filter device of the embodiment. Fig.15 : is a characteristic diagram showing the reflection loss of the second port 3 of the filter device of the embodiment. Fig.14 and Fig.15 In the figure, the horizontal axis represents frequency and the vertical axis represents reflection loss. Fig.14 In the figure, reference numeral 94 indicates the reflection loss at -40°C, reference numeral 95 indicates the reflection loss at 25°C, and reference numeral 96 indicates the reflection loss at 90°C. Fig.15 In the figure, reference numeral 97 indicates the reflection loss at -40°C, reference numeral 98 indicates the reflection loss at 25°C, and reference numeral 99 indicates the reflection loss at 90°C. Fig.14 and Fig.15 It can be seen that in the filter device of the example, the change in reflection loss due to the change in temperature is small. As can be understood from this result, according to the present embodiment, the change in reflection loss due to temperature can be suppressed.

[0108] Next, other effects of the present embodiment will be described. In the present embodiment, the first dielectric layers 52 to 55 are used to constitute a plurality of capacitors other than the capacitors C9 and C10.

[0109] The relative dielectric constant of the first dielectric layers 52 to 55 is larger than that of the second dielectric layers 51 and 56 to 68. Therefore, according to this embodiment, the area of ​​the conductor layer constituting the capacitor can be reduced. As a result, according to this embodiment, the filter device 1 can be miniaturized.

[0110] In the present embodiment, the inductors L1 to L4 are buried in the second dielectric layers 56 to 68 having a smaller relative permittivity than the first dielectric layers 52 to 55. Thus, according to the present embodiment, the formation of capacitance between the inductors and the deterioration of characteristics such as the generation of parasitics can be suppressed.

[0111] In addition, in the present embodiment, the first dielectric layers 52 to 55 are arranged between the second dielectric layer 51 and the second dielectric layer 56. That is, the second dielectric layer 51 having a relatively small dielectric constant is interposed between the first dielectric layers 52 to 55 and the bottom surface 50A of the laminate 50. Therefore, according to the present embodiment, compared with the case where the first dielectric layer is interposed between the first dielectric layers 52 to 55 and the bottom surface 50A of the laminate 50, the influence of the ground on the substrate on which the filter device 1 is mounted can be suppressed.

[0112] In addition, in this embodiment, the attenuation characteristics of the filter 5 can be suppressed from changing due to temperature, so the filter device 1 of this embodiment is a bandpass filter with a low-frequency cutoff frequency as the lower limit of the passband and a high-frequency cutoff frequency as the upper limit of the passband set, and is particularly suitable for a bandpass filter requiring a narrow passband. The width of the passband can also be in the range of 10 to 600 MHz, or in a narrower range of 10 to 200 MHz.

[0113] Fig.16 and Fig.17 FIG. 5 shows an example of the passband attenuation characteristics of the filter device 1 when the filter 5 is designed so that the passband becomes 950 to 1050 MHz. Fig.17 In the figure, the pass attenuation characteristics near the passband are magnified. Fig.16 and Fig.17 In each of , the horizontal axis represents the frequency and the vertical axis represents the attenuation.

[0114] In addition, the present invention is not limited to the above-mentioned embodiment, and various changes can be made. For example, the stacked filter device of the present invention is not limited to a bandpass filter, and can be applied to all stacked filter devices including a plurality of filters, such as a duplexer for separating two signals with different frequency bands and a triplexer for separating three signals with different frequency bands.

[0115] The structures of the filter 5 and the laminate 50 of the present invention are not limited to the examples shown in the embodiment, but are arbitrary as long as the requirements of the claims are met. For example, the laminate 50 may include a first dielectric layer disposed on the second dielectric layer 68 .

[0116] It is obvious from the above description that various modes and modifications of the present invention can be implemented. Therefore, within the scope of equivalents of the claims, the present invention can be implemented even in modes other than the best mode described above.

Claims

1. A stacked filter device, characterized in that: have: a filter comprising at least one inductor and at least one capacitor; a laminated body including a plurality of laminated dielectric layers and a plurality of conductor layers, and for integrating the at least one inductor and the at least one capacitor, The at least one inductor and the at least one capacitor are formed using the plurality of conductor layers, The plurality of dielectric layers include at least one first dielectric layer and at least one second dielectric layer, The plurality of conductor layers include at least one first conductor layer connected to the at least one first dielectric layer and at least one second conductor layer connected to the at least one second dielectric layer, The at least one first dielectric layer is composed of a first dielectric material having a positive temperature coefficient of resonance frequency, The at least one second dielectric layer is composed of a second dielectric material having a negative temperature coefficient of resonance frequency, The relative dielectric constant of the at least one first dielectric layer is greater than that of the at least one second dielectric layer, The at least one second dielectric layer is a plurality of second dielectric layers, The at least one first dielectric layer is disposed between one of the plurality of second dielectric layers and the other ones of the plurality of second dielectric layers, The at least one first dielectric layer and each of the plurality of second dielectric layers have a pattern forming surface, When viewed from the stacking direction of the plurality of dielectric layers, the outer edge of the pattern forming surface of the at least one first dielectric layer coincides with the outer edge of the pattern forming surface of one of the plurality of second dielectric layers and the outer edges of the pattern forming surfaces of the other plurality of the second dielectric layers. The number of the plurality of second dielectric layers is greater than the number of the at least one first dielectric layer, and an absolute value of a temperature coefficient of a resonance frequency of the first dielectric material and an absolute value of a temperature coefficient of a resonance frequency of the second dielectric material are different from each other, The stacked body has a bottom surface and an upper surface located at both ends of the stacking direction and four side surfaces connecting the bottom surface and the upper surface. The laminated filter device further includes a plurality of terminals provided on the bottom surface of the laminated body. The plurality of terminals include two terminals that function as input and output ports of the filter, respectively, and one terminal that is connected to a ground line. The one of the plurality of second dielectric layers is interposed between the at least one first dielectric layer and the bottom surface of the stack, The other ones of the plurality of second dielectric layers are interposed between the at least one first dielectric layer and the upper surface of the stack, The at least one inductor is a plurality of inductors, The at least one second conductor layer is a plurality of second conductor layers, The plurality of inductors are formed using the plurality of second conductor layers, and are buried in the other ones of the plurality of second dielectric layers, but are not buried in the one of the plurality of second dielectric layers.

2. The multilayer filter device according to claim 1, wherein: The at least one capacitor is a plurality of capacitors, The at least one first conductor layer is a plurality of first conductor layers, At least one of the plurality of capacitors is constituted by the at least one first dielectric layer and two of the plurality of first conductor layers arranged so as to sandwich the at least one first dielectric layer.

3. The multilayer filter device according to claim 1, wherein: The filter is a bandpass filter that selectively passes signals having frequencies within a predetermined passband.

4. The multilayer filter device according to claim 3, wherein: The width of the passband is in the range of 10 to 600 MHz.

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