Multilayer bandpass filter

Abstract

To achieve the desired characteristics by suppressing the electromagnetic field coupling between two inductors.SOLUTION: A bandpass filter 1 includes inductors L2 and L3 that are electromagnetically coupled to each other, a terminal 105 electrically connected to the inductor L2, a terminal 106 electrically connected to the inductor L3, and a laminate 10 for integrating the inductors L2 and L3 and the terminals 105 and 106, and the terminals 105 and 106 are each connected to the ground and are not electrically connected to each other in the laminate 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a layered bandpass filter including two inductors. [Background technology]

[0002] One type of bandpass filter used in a communication device is a bandpass filter that includes a plurality of inductors. Each of the plurality of inductors is configured, for example, by a distributed constant line. The distributed constant line is configured to have a predetermined line length.

[0003] Patent Document 1 describes a multilayer bandpass filter having two coils. Each of the two coils is formed by a plurality of coil electrodes formed on a dielectric layer that constitutes a laminate. The two coils are electrically connected to two external terminal electrodes, i.e., two ground terminals, respectively. The two external terminal electrodes are electrically connected to each other by the ground electrodes that are formed on the dielectric layers that constitute the laminate.

[0004] Patent Document 2 describes a bandpass filter including four LC parallel resonators. Each of the four LC parallel resonators includes an inductor. The inductor is formed by a line conductor pattern formed on a dielectric layer that constitutes a laminate. In each of the four LC parallel resonators, the line conductor pattern forming the inductor is electrically connected to a ground terminal formed on the bottom surface of the bandpass filter via other line conductor patterns, via conductor patterns, and ground conductor patterns. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-261362 [Patent Document 2] International Publication No. 2019 / 097774 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, the market has been demanding smaller and more space-saving compact mobile communication devices, which has also led to demands for smaller bandpass filters used in such devices. When a bandpass filter contains two inductors, the electromagnetic field coupling between the two inductors can become too strong as the bandpass filter becomes smaller. This can sometimes make it impossible to achieve the desired characteristics.

[0007] The present invention has been made in consideration of these problems, and its object is to provide a multilayer bandpass filter that can suppress electromagnetic field coupling between two inductors and achieve desired characteristics. [Means for solving the problem]

[0008] The multilayer bandpass filter of the present invention includes a first inductor and a second inductor that are electromagnetically coupled to each other, a first ground terminal electrically connected to the first inductor, a second ground terminal electrically connected to the second inductor, and a laminate that integrates the first inductor, the second inductor, the first ground terminal, and the second ground terminal. The first ground terminal and the second ground terminal are each connected to ground and are not electrically connected to each other in the laminate.

[0009] In the multilayer bandpass filter of the present invention, the first inductor may have a first end electrically connected to the first ground terminal and a second end opposite the first end. The second inductor may have a third end electrically connected to the second ground terminal and a fourth end opposite the third end. The multilayer bandpass filter may further include a first capacitor electrically connected to the second end of the first inductor and integrated with the laminate, and a second capacitor electrically connected to the fourth end of the second inductor and integrated with the laminate.

[0010] In the multilayer bandpass filter of the present invention, the first capacitor may be arranged between the first inductor and ground in terms of the circuit configuration. The second capacitor may be arranged between the second inductor and ground in terms of the circuit configuration. The first capacitor may include a first capacitor conductor layer electrically connected to ground. The second capacitor may include a second capacitor conductor layer electrically connected to ground. The first capacitor conductor layer and the second capacitor conductor layer may be connected to each other.

[0011] The layered bandpass filter of the present invention may further include a first input / output terminal, a second input / output terminal, a third inductor, and a fourth inductor. The first input / output terminal, the second input / output terminal, the third inductor, and the fourth inductor may be integrated into the layered body. The first inductor and the second inductor may be arranged between the first input / output terminal and the second input / output terminal in terms of the circuit configuration. The third inductor may be arranged between the first inductor and the first input / output terminal in terms of the circuit configuration. The fourth inductor may be arranged between the second inductor and the second input / output terminal in terms of the circuit configuration. [Effects of the Invention]

[0012] In the multilayer bandpass filter of the present invention, the first ground terminal and the second ground terminal are each connected to ground and are not electrically connected to each other in the laminate, thereby suppressing electromagnetic field coupling between the first inductor and the second inductor, thereby achieving the advantageous effect of realizing a multilayer bandpass filter that can achieve desired characteristics. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a circuit diagram showing a circuit configuration of a layered bandpass filter according to an embodiment of the present invention. [Figure 2]1 is a perspective view showing the appearance of a multilayer bandpass filter according to an embodiment of the present invention. [Figure 3] 1 is an explanatory diagram illustrating a terminal formation surface of a first dielectric layer in a laminate of a multilayer bandpass filter according to an embodiment of the present invention. [Figure 4] 1 is an explanatory diagram showing a pattern-formed surface of a first dielectric layer in a laminate of a multilayer bandpass filter according to an embodiment of the present invention. [Figure 5] 3 is an explanatory diagram showing a pattern-formed surface of a second dielectric layer in a laminate of a multilayer bandpass filter according to an embodiment of the present invention. FIG. [Figure 6] 3 is an explanatory diagram showing a pattern-formed surface of a third dielectric layer in a laminate of a multilayer bandpass filter according to an embodiment of the present invention. FIG. [Figure 7] 3 is an explanatory diagram showing a pattern-formed surface of a fourth dielectric layer in a laminate of a multilayer bandpass filter according to an embodiment of the present invention. FIG. [Figure 8] 1 is a perspective view showing the inside of a laminate of a multilayer bandpass filter according to an embodiment of the present invention. [Figure 9] 9 is a cross-sectional view showing a part of the inside of the stacked body shown in FIG. 8. [Figure 10] FIG. 10 is a circuit diagram showing a circuit configuration of a layered bandpass filter of a comparative example. [Figure 11] FIG. 10 is a characteristic diagram showing frequency characteristics of the voltage standing wave ratio of the first input / output port of each of the model of the first embodiment and the model of the comparative example. [Figure 12] FIG. 10 is a characteristic diagram showing frequency characteristics of the voltage standing wave ratio of the second input / output port of each of the model of the first embodiment and the model of the comparative example. [Figure 13] FIG. 4 is a characteristic diagram showing the passing attenuation characteristics of the model of the first embodiment and the model of the comparative example. [Figure 14] 10 is an explanatory diagram showing a pattern-formed surface of a fourth dielectric layer in a laminate of the multilayer bandpass filter of the first modified example. FIG. [Figure 15]10 is an explanatory diagram showing a pattern-formed surface of a fourth dielectric layer in a laminate of a multilayer bandpass filter according to a second modified example. FIG. [Figure 16] FIG. 10 is a characteristic diagram showing frequency characteristics of the voltage standing wave ratio of the first input / output port of each of the models according to the first to third embodiments. [Figure 17] FIG. 10 is a characteristic diagram showing frequency characteristics of the voltage standing wave ratio of the second input / output port of each of the models according to the first to third embodiments. [Figure 18] FIG. 10 is a characteristic diagram showing frequency characteristics of insertion loss of each band-pass filter of the models of the first to third embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the configuration of a layered bandpass filter (hereinafter simply referred to as a bandpass filter) 1 according to an embodiment of the present invention will be described. The bandpass filter 1 according to this embodiment includes at least a first inductor and a second inductor that are electromagnetically coupled to each other.

[0015] An example of the circuit configuration of the bandpass filter 1 will be described below with reference to Fig. 1. The bandpass filter 1 includes a first input / output port 2, a second input / output port 3, inductors L1, L2, L3, and L4, and capacitors C1, C2, C3, C4, C5, C6, C7, and C8.

[0016] In terms of the circuit configuration, inductors L1, L2, L3, and L4 are provided between the first input / output port 2 and the second input / output port 3. In terms of the circuit configuration, inductors L1, L2, L3, and L4 are arranged in this order from the first input / output port 2 side. In terms of the circuit configuration, inductor L1 is arranged between inductor L2 and the first input / output port 2. In terms of the circuit configuration, inductor L4 is arranged between inductor L3 and the second input / output port 3. In this application, the expression "in terms of the circuit configuration" is used to refer to the arrangement on a circuit diagram, rather than the arrangement in a physical configuration.

[0017] Inductor L1 corresponds to the "third inductor" of the present invention. Inductor L2 corresponds to the "first inductor" of the present invention. Inductor L3 corresponds to the "second inductor" of the present invention. Inductor L4 corresponds to the "fourth inductor" of the present invention.

[0018] Inductors L1 to L4 are configured such that inductors L1 and L2 are adjacent to each other in the circuit configuration and are electromagnetically coupled to each other, inductors L2 and L3 are adjacent to each other in the circuit configuration and are electromagnetically coupled to each other, and inductors L3 and L4 are adjacent to each other in the circuit configuration and are electromagnetically coupled to each other.

[0019] One end of inductor L1 is connected to the first input / output port 2. One end of inductor L4 is connected to the second input / output port 3. Capacitor C1 is provided between one end of inductor L1 and ground. Capacitor C2 is provided between one end of inductor L2 and ground. Capacitor C3 is provided between one end of inductor L3 and ground. Capacitor C4 is provided between one end of inductor L4 and ground.

[0020] Capacitor C5 is provided between one end of inductor L1 and one end of inductor L2. Capacitor C6 is provided between one end of inductor L3 and one end of inductor L4. Capacitors C7 and C8 are provided between the first input / output port 2 and the second input / output port 3. In this embodiment, no capacitor is provided between one end of inductor L2 and one end of inductor L3.

[0021] The other end of inductor L1 and the other end of inductor L2 are connected to each other. The other end of inductor L3 and the other end of inductor L4 are connected to each other. In this embodiment, the other end of inductor L2 and the other end of inductor L3 are not connected to each other.

[0022] figure 1In this figure, symbols L5 to L8 indicate inductance components occurring between the inductors L1 to L4 and the ground, respectively. Specifically, the inductance components L5 to L8 may be inductance components occurring in a conductor connecting the inductors L1 to L4 and a ground electrode of a substrate on which the bandpass filter 1 is mounted. The inductance component L5 occurs between the other end of the inductor L1 and the ground. The inductance component L6 occurs between the other end of the inductor L2 and the ground. The inductance component L7 occurs between the other end of the inductor L3 and the ground. The inductance component L8 occurs between the other end of the inductor L4 and the ground. Particularly in this embodiment, the inductance components L6 and L7 are separate inductance components.

[0023] Next, other configurations of the bandpass filter 1 will be described with reference to Fig. 2. Fig. 2 is a perspective view showing the appearance of the bandpass filter 1.

[0024] The bandpass filter 1 further includes a laminate 10 including a plurality of laminated dielectric layers and a plurality of conductors. The laminate 10 integrates the first input / output port 2, the second input / output port 3, the inductors L1 to L4, and the capacitors C1 to C8.

[0025] The laminate 10 has a bottom surface 10A and a top surface 10B located at both ends in the stacking direction of the multiple dielectric layers, and four side surfaces 10C to 10F connecting the bottom surface 10A and the top surface 10B. The side surfaces 10C and 10D face in opposite directions from each other, and the side surfaces 10E and 10F also face in opposite directions from each other. The side surfaces 10C to 10F are perpendicular to the top surface 10B and the bottom surface 10A.

[0026] Here, the X direction, Y direction, and Z direction are defined as shown in FIG. 2. The X direction, Y direction, and Z direction are perpendicular to each other. In this embodiment, a direction parallel to the stacking direction is defined as the Z direction. The direction opposite to the X direction is defined as the -X direction, the direction opposite to the Y direction is defined as the -Y direction, and the direction opposite to the Z direction is defined as the -Z direction.

[0027] As shown in FIG. 2, the bottom surface 10A is located at the end of the laminate 10 in the -Z direction. The top surface 10B is located at the end of the laminate 10 in the Z direction. The side surface 10C is located at the end of the laminate 10 in the -X direction. The side surface 10D is located at the end of the laminate 10 in the X direction. The side surface 10E is located at the end of the laminate 10 in the -Y direction. The side surface 10F is located at the end of the laminate 10 in the Y direction.

[0028] The bandpass filter 1 further includes terminals 101, 102, 103, 104, 105, 106, and 107 integrated with the laminate 10. In this embodiment, the terminals 101 to 107 are particularly provided on the bottom surface 10A of the laminate 10. The terminals 101, 102, and 103 are arranged in this order in the X direction at positions closer to the side surface 10F than to the side surface 10E. The terminals 104, 105, 106, and 107 are arranged in this order in the X direction at positions closer to the side surface 10E than to the side surface 10F.

[0029] Terminal 101 corresponds to the first input / output port 2, and terminal 103 corresponds to the second input / output port 3. Terminal 101 corresponds to the "first input / output terminal" in the present invention. Terminal 103 corresponds to the "second input / output terminal" in the present invention.

[0030] Each of terminals 102, 104, 105, 106, and 107 is connected to ground. Terminal 105 corresponds to a "first ground terminal" in the present invention. Terminal 106 corresponds to a "second ground terminal" in the present invention.

[0031] 3 to 7, an example of the plurality of dielectric layers and the plurality of conductors that make up the laminate 10 will be described. In this example, the plurality of dielectric layers includes a first dielectric layer 11, a second dielectric layer 12, a third dielectric layer 13, a fourth dielectric layer 14, and one or more dielectric layers not shown.

[0032] FIG. 3 shows the terminal-forming surface of the dielectric layer 11. FIG. 4 shows the pattern-forming surface of the dielectric layer 11. The terminal-forming surface of the dielectric layer 11 and the pattern-forming surface of the dielectric layer 11 face in opposite directions. FIG. 5 shows the pattern-forming surface of the dielectric layer 12. FIG. 6 shows the pattern-forming surface of the dielectric layer 13. FIG. 7 shows the pattern-forming surface of the dielectric layer 14. The pattern-forming surfaces of the dielectric layers 12 to 14 face in the same direction as the pattern-forming surface of the dielectric layer 11.

[0033] As shown in Fig. 3, terminals 101 to 107 are formed on the terminal formation surface of the first dielectric layer 11. Note that Fig. 3 shows the terminals 101 to 107 as viewed from the pattern formation surface side of the dielectric layer 11. As shown in Fig. 4, conductor layers 111, 112, 113, 114, 115, 116, 117, 118, and 119 are formed on the pattern formation surface of the first dielectric layer 11.

[0034] Furthermore, through holes 11T1, 11T2, 11T3, 11T4, 11T5, 11T6, and 11T7 are formed in the dielectric layer 11. The through hole 11T1 connects the terminal 101 and the conductor layer 111. The through hole 11T2 connects the terminal 102 and the conductor layer 112. The through hole 11T3 connects the terminal 103 and the conductor layer 113. The through hole 11T4 connects the terminal 104 and the conductor layer 114. The through hole 11T5 connects the terminal 105 and the conductor layer 115. The through hole 11T6 connects the terminal 106 and the conductor layer 116. The through hole 11T7 connects the terminal 107 and the conductor layer 117.

[0035] For convenience, the through holes formed in the dielectric layer 12 are shown in FIG. 4 by dashed lines.

[0036] As shown in Figure 5, inductor conductor layers 121, 122, 123, and 124 and conductor layers 125, 126, 127, 128, 129, 1210, and 1211 are formed on the pattern formation surface of the second dielectric layer 12. Each of the inductor conductor layers 121, 122, 123, and 124 has a first end and a second end located opposite each other. Each of the inductor conductor layers 121 and 124 includes a plurality of portions extending in a plurality of mutually different directions. Each of the inductor conductor layers 122 and 123 includes a portion extending in one direction.

[0037] Furthermore, through holes 12T1, 12T2, 12T3, 12T4, 12T5, 12T6, 12T7, 12T8, 12T9, 12T10, 12T11, 12T12, and 12T13 are formed in the dielectric layer 12. The through hole 12T1 connects the conductor layer 111 formed on the dielectric layer 11 to the conductor layer 125. The through hole 12T2 connects the conductor layer 112 formed on the dielectric layer 11 to the conductor layer 126. The through hole 12T3 connects the conductor layer 113 formed on the dielectric layer 11 to the conductor layer 127.

[0038] Through hole 12T4 connects conductor layer 114 formed on dielectric layer 11 to a portion of conductor layer 121 near the first end. Through hole 12T5 connects conductor layer 115 formed on dielectric layer 11 to a portion of conductor layer 122 near the first end. Through hole 12T6 connects conductor layer 116 formed on dielectric layer 11 to a portion of conductor layer 123 near the first end. Through hole 12T7 connects conductor layer 117 formed on dielectric layer 11 to a portion of conductor layer 124 near the first end.

[0039] The through hole 12T8 is formed by connecting the conductor layer 111 formed on the dielectric layer 11 and the conductor layer 121The through hole 12T9 connects the conductor layer 118 formed on the dielectric layer 11 to a portion of the conductor layer 122 near the second end. The through hole 12T10 connects the conductor layer 119 formed on the dielectric layer 11 to a portion of the conductor layer 123 near the second end. The through hole 12T11 connects the conductor layer 113 formed on the dielectric layer 11 to a portion of the conductor layer 124 near the second end.

[0040] The through hole 12T12 connects the conductor layer 118 formed on the dielectric layer 11 with the conductor layer 128. The through hole 12T13 connects the conductor layer 119 formed on the dielectric layer 11 with the conductor layer 1211.

[0041] In addition, Fig. 5 For convenience, a plurality of through holes formed in the dielectric layer 13 are shown by dashed lines in FIG.

[0042] 6, capacitor conductor layers 131, 132, 133, 134, 135, 136, 137, 138, 139, and 1310 are formed on the pattern formation surface of the third dielectric layer 13. Furthermore, through holes 13T1, 13T3, 13T4, 13T5, 13T6, 13T7, 13T8, 13T9, 13T10, 13T11, 13T12, 13T13, 13T14, 13T15, 13T16, 13T17, 13T21, and 13T22 are formed in the dielectric layer 13.

[0043] The through hole 13T8 connects a portion of the conductor layer 121 formed on the dielectric layer 12 near the second end to the conductor layer 131. The through hole 13T9 connects a portion of the conductor layer 122 formed on the dielectric layer 12 near the second end to the conductor layer 132. The through hole 13T10 connects a portion of the conductor layer 123 formed on the dielectric layer 12 near the second end to the conductor layer 133. The through hole 13T11 connects a portion of the conductor layer 124 formed on the dielectric layer 12 near the second end to the conductor layer 134.

[0044] The through hole 13T12 connects the conductor layer 128 formed on the dielectric layer 12 to the conductor layer 135. The through hole 13T13 connects the conductor layer 129 formed on the dielectric layer 12 to the conductor layer 136. The through hole 13T14 connects the conductor layer 129 formed on the dielectric layer 12 to the conductor layer 137. The through hole 13T15 connects the conductor layer 1210 formed on the dielectric layer 12 to the conductor layer 138. The through hole 13T16 connects the conductor layer 1210 formed on the dielectric layer 12 to the conductor layer 139. The through hole 13T17 connects the conductor layer 1211 formed on the dielectric layer 12 to the conductor layer 1310.

[0045] As shown in Fig. 7, capacitor conductor layers 141, 142, 143, 144, 145, 146, and 147 are formed on the pattern formation surface of the fourth dielectric layer 14. The conductor layers 142 and 143 are connected to each other. Furthermore, through holes 14T1, 14T3, 14T4, 14T5, 14T6, 14T7, 14T21, and 14T22 are formed in the dielectric layer 14. The through holes 13T1, 13T3 to 13T7, 13T21, and 13T22 shown in Fig. 6 are connected to the through holes 14T1, 14T3 to 14T7, 14T21, and 14T22, respectively.

[0046] The through holes 13T1 and 14T1 connect the conductor layer 125 formed on the dielectric layer 12 to the conductor layer 145. The through holes 13T3 and 14T3 connect the conductor layer 127 formed on the dielectric layer 12 to the conductor layer 147. The through holes 13T4 and 14T4 connect the conductor layer 141 to a portion near the first end of the conductor layer 121 formed on the dielectric layer 12. The through holes 13T5 and 14T5 connect the conductor layer 141 to a portion near the first end of the conductor layer 122 formed on the dielectric layer 12. The through holes 13T6 and 14T6 connect the conductor layer 144 to a portion near the first end of the conductor layer 123 formed on the dielectric layer 12. The through holes 13T7 and 14T7 connect the conductor layer 144 to a portion near the first end of the conductor layer 124 formed on the dielectric layer 12.

[0047] 5 and the conductor layer 142. The through holes 13T22 and 14T22 connect the conductor layer 126 and the conductor layer 143 shown in FIG.

[0048] The laminate 10 shown in Fig. 2 is configured by laminating first to fourth dielectric layers 11-14 and one or more dielectric layers (not shown) so that the terminal-forming surface of the first dielectric layer 11 becomes the bottom surface 10A of the laminate 10. Fig. 8 shows the inside of the laminate 10. Fig. 9 shows a portion of the inside of the laminate 10. As shown in Figs. 8 and 9, the multiple conductor layers and multiple through-holes (conductors) shown in Figs. 3 to 7 are laminated inside the laminate 10.

[0049] The following describes the correspondence between the circuit components of the bandpass filter 1 shown in Fig. 1 and the internal components of the laminate 10 shown in Figs. 3 to 7. The inductor L1 is formed by the inductor conductive layer 121 shown in Fig. 5. The inductor L2 is formed by the inductor conductive layer 122 shown in Fig. 5. The inductor L3 is formed by the inductor conductive layer 123 shown in Fig. 5. The inductor L4 is formed by the inductor conductive layer 124 shown in Fig. 5.

[0050] Capacitor C1 is composed of capacitor conductor layer 131 shown in Figure 6, capacitor conductor layer 141 shown in Figure 7, and dielectric layer 14 between these conductor layers. Capacitor C2 is composed of capacitor conductor layer 132 shown in Figure 6, capacitor conductor layer 142 shown in Figure 7, and dielectric layer 14 between these conductor layers. Capacitor C3 is composed of capacitor conductor layer 133 shown in Figure 6, capacitor conductor layer 143 shown in Figure 7, and dielectric layer 14 between these conductor layers. Capacitor C4 is composed of capacitor conductor layer 134 shown in Figure 6, capacitor conductor layer 144 shown in Figure 7, and dielectric layer 14 between these conductor layers.

[0051] Capacitor C5 is composed of capacitor conductor layer 135 shown in Fig. 6, capacitor conductor layer 145 shown in Fig. 7, and dielectric layer 14 between these conductor layers. Capacitor C6 is composed of capacitor conductor layer 1310 shown in Fig. 6, capacitor conductor layer 147 shown in Fig. 7, and dielectric layer 14 between these conductor layers.

[0052] Capacitor C7 is composed of capacitor conductor layers 136 and 137 shown in Fig. 6, capacitor conductor layers 145 and 146 shown in Fig. 7, and dielectric layer 14 between these conductor layers. Capacitor C8 is composed of capacitor conductor layers 138 and 139 shown in Fig. 6, capacitor conductor layers 146 and 147 shown in Fig. 7, and dielectric layer 14 between these conductor layers.

[0053] Next, structural features of the bandpass filter 1 according to this embodiment will be described. Terminals 105 and 106 are each connected to ground (ground electrodes of the substrate). Terminal 105 is connected to a portion of inductor conductor layer 122 constituting inductor L2 near a first end thereof via through-hole 11T5, conductor layer 115, and through-hole 12T5. Terminal 106 is connected to a portion of inductor conductor layer 123 constituting inductor L3 near a first end thereof via through-hole 11T6, conductor layer 116, and through-hole 12T6.

[0054] Furthermore, the terminals 105 and 106 are not electrically connected to each other within the laminate 10. The inductor conductor layer 122 and the inductor conductor layer 123 are also not electrically connected to each other within the laminate 10. In other words, the inductor conductor layer 122 and the inductor conductor layer 123 are not connected to each other via one or more other conductor layers and one or more through holes.

[0055] inductorOne end of inductor L2 corresponds to the "first end" in the present invention. The other end of inductor L2 (the end opposite to one end of inductor L2) corresponds to the "second end" in the present invention. One end of inductor L3 corresponds to the "third end" in the present invention. The other end of inductor L3 (the end opposite to one end of inductor L3) corresponds to the "fourth end" in the present invention.

[0056] One end (first end) of the inductor L2 is electrically connected to a terminal 105 that is connected to the ground. Third The terminal 105 and the terminal 106 are not electrically connected to each other within the laminate 10.

[0057] The capacitor C2 is electrically connected to the other end (second end) of the inductor L2, and the capacitor C3 is electrically connected to the other end (fourth end) of the inductor L3.

[0058] Next, the operation and effect of the bandpass filter 1 according to this embodiment will be described. The electromagnetic field coupling between the inductors L2 and L3 becomes stronger as the distance between the inductors L2 and L3 becomes smaller. Therefore, when the laminate 10 is made smaller, the electromagnetic field coupling between the inductors L2 and L3 may become too strong. This may result in the passband of the bandpass filter 1 being wider than the required specifications.

[0059] In contrast to this, in this embodiment, the terminals 105 and 106 are not electrically connected to each other within the laminate 10. As a result, according to this embodiment, compared to when the inductors L2 and L3 are electrically connected to each other within the laminate 10, Inductor L2 electrically connected to terminal 105and the inductor L3 electrically connected to the terminal 106 can be suppressed. As a result, according to this embodiment, desired characteristics can be achieved. Note that when the inductors L2 and L3 are electrically connected to each other in the laminate 10, this is not limited to the case where the inductors L2 and L3 are connected to each other via one or more conductor layers and one or more through holes, but also includes the case where the inductors L2 and L3 are electrically connected to one terminal.

[0060] Furthermore, when the laminate 10 is miniaturized, the length of each of the inductors L2 and L3 becomes shorter, and the inductance of each of the inductors L2 and L3 may become smaller than desired. In contrast, in this embodiment, an inductance component L6 occurs between the inductor L2 and ground, and an inductance component L7 occurs between the inductor L3 and ground. The inductance components L6 and L7 are separate inductance components. As a result, according to this embodiment, the inductance of each of the inductors L2 and L3 can be substantially increased.

[0061] The effects of this embodiment will be described below with reference to the results of a first simulation. In the first simulation, a model of a first example corresponding to bandpass filter 1 according to this embodiment and a model of bandpass filter 201 of a comparative example were used.

[0062] FIG. 10 is a circuit diagram showing the circuit configuration of a bandpass filter 201 of the comparative example. Similar to the bandpass filter 1 according to the present embodiment, the bandpass filter 201 of the comparative example includes inductors L1 to L4, capacitors C1 to C8, a laminate 10 (see FIG. 2), and terminals 101 to 104 and 107 (see FIG. 2). Furthermore, the bandpass filter 201 of the comparative example includes one terminal connected to ground instead of the terminals 105 and 106 (see FIG. 2) of the present embodiment. The inductors L2 and L3 are electrically connected to this one terminal. In the bandpass filter 201 of the comparative example, the inductors L2 and L3 are electrically connected to each other within the laminate 10. The other configuration of the bandpass filter 201 of the comparative example is the same as the configuration of the bandpass filter 1 according to the present embodiment.

[0063] In the bandpass filter 201 of the comparative example, an inductance component L9 occurs instead of the inductance components L6 and L7 (see FIG. 1) in the present embodiment. The inductance component L9 occurs between the inductors L2 and L3 and the ground.

[0064] In the first simulation, for each of the model of the first embodiment and the model of the comparative example, the frequency characteristics of the voltage standing wave ratio of the first input / output port 2 (terminal 101), the frequency characteristics of the voltage standing wave ratio of the second input / output port 3 (terminal 103), and the pass attenuation characteristics between the first input / output port 2 (terminal 101) and the second input / output port 3 (terminal 103) were determined.

[0065] figure 11 FIG. 1 is a characteristic diagram showing the frequency characteristics of the voltage standing wave ratio of the first input / output port 2. 12 FIG. 10 is a characteristic diagram showing the frequency characteristics of the voltage standing wave ratio of the second input / output port 3. 13 1 is a characteristic diagram showing attenuation characteristics of a passing frequency. 11 Or figure 13 In this figure, the horizontal axis represents frequency. 11 and Figure 12 In the figure, the vertical axis represents the voltage standing wave ratio (VSWR). 13In the figure, the vertical axis represents the amount of attenuation. 11 Or figure 13 In the figure, the solid line indicates the characteristics of the model of the first embodiment, and the dashed line indicates the characteristics of the model of the comparative example. 11 Or figure 13 From this, it can be seen that the model of the first embodiment has a narrower passband than the model of the comparative example.

[0066] As can be seen from the results of the first simulation, according to this embodiment, when a relatively narrow passband is required, the electromagnetic field coupling between inductor L2 and inductor L3 can be suppressed to meet the required specifications.

[0067] [Variations] Next, first and second modified examples of the bandpass filter 1 according to the present embodiment will be described. First, the first modified example will be described. In the first modified example, the laminate 10 includes a dielectric layer 214 instead of the dielectric layer 14 shown in FIG. 7. FIG. 14 is an explanatory diagram showing the pattern-formed surface of the dielectric layer 214. Capacitor conductor layers 141, 142, 143, 144, 145, 146, and 147 are formed on the pattern-formed surface of the dielectric layer 214, similar to the dielectric layer 14. For convenience, FIG. 14 also shows capacitor conductor layers 132 and 133 formed on the pattern-formed surface of the dielectric layer 13 (see FIG. 6).

[0068] In the first modified example, the position of the portion of conductor layer 142 facing conductor layer 132 and the position of the portion of conductor layer 143 facing conductor layer 133 are the same as those shown in Fig. 7. However, in the first modified example, the gap between conductor layer 142 and conductor layer 143 is smaller than the gap between conductor layer 142 and conductor layer 143 shown in Fig. 7.

[0069] Next, a second modified example will be described. In the second modified example, the laminate 10 includes a dielectric layer 314 instead of the dielectric layer 14 shown in FIG. 7. FIG. 15 is an explanatory diagram showing the pattern-formed surface of the dielectric layer 314. On the pattern-formed surface of the dielectric layer 314, similar to the dielectric layer 14, capacitor conductor layers 141, 142, 143, 144, 145, 146, and 147 are formed. For convenience, FIG. 15 also shows capacitor conductor layers 132 and 133 formed on the pattern-formed surface of the dielectric layer 13 (see FIG. 6).

[0070] In the second modification, the distance between the conductor layer 132 and the conductor layer 133 is 6 The distance between the conductor layer 132 and the conductor layer 133 shown in Large In the second modified example, the distance between the portion of the conductor layer 142 facing the conductor layer 132 and the portion of the conductor layer 143 facing the conductor layer 133 is also larger than the distance between the two portions shown in FIG. Large It has become.

[0071] Next, the functions and effects of the first and second modified examples will be described with reference to the results of a second simulation. The second simulation used the model of the first embodiment used in the first simulation, a model of the second embodiment corresponding to the first modified example of the band-pass filter 1, and a model of the third embodiment corresponding to the second modified example of the band-pass filter 1. In the second simulation, for each of the models of the first to third embodiments, the frequency characteristics of the voltage standing wave ratio of the first input / output port 2 (terminal 101), the frequency characteristics of the voltage standing wave ratio of the second input / output port 3 (terminal 103), and the frequency characteristics of the insertion loss of the band-pass filter 1 were obtained.

[0072] FIG. 16 is a characteristic diagram showing the frequency characteristics of the voltage standing wave ratio of the first input / output port 2. FIG. 17 is a characteristic diagram showing the frequency characteristics of the voltage standing wave ratio of the second input / output port 3. FIG. 18 is a characteristic diagram showing the frequency characteristics of the insertion loss of the bandpass filter 1. In FIGS. 16 to 18, the horizontal axis represents frequency. In FIGS. 16 and 17, the vertical axis represents the voltage standing wave ratio (VSWR). In FIG. 18, the vertical axis represents the insertion loss. In addition, in FIGS. 16 to 18, reference numeral 91 represents the characteristics of the model of the first embodiment, reference numeral 92 represents the characteristics of the model of the second embodiment, and reference numeral 93 represents the characteristics of the model of the third embodiment. It can be seen from FIGS. 16 to 18 that the model of the second embodiment has a wider pass band than the model of the first embodiment, and that the model of the third embodiment has a narrower pass band than the model of the first embodiment. Therefore, in the first modified example, the electromagnetic field coupling between inductor L2 and inductor L3 is stronger than in the bandpass filter 1 shown in Figures 1 to 9. In addition, in the second modified example, the electromagnetic field coupling between inductor L2 and inductor L3 is weaker than in the bandpass filter 1 shown in Figures 1 to 9.

[0073] As can be seen from the results of the second simulation, the characteristics (pass band) of the bandpass filter 1 can be adjusted by changing the shapes and arrangement of the capacitor conductor layers 132, 133 and the capacitor conductor layers 142, 143.

[0074] The present invention is not limited to the above-described embodiment and may be modified in various ways. For example, the bandpass filter of the present invention may include two, three, five or more inductors instead of inductors L1 to L4. [Explanation of symbols]

[0075] 1...bandpass filter, 2...first input / output port, 3...second input / output port, 10...laminated body, 11-14...dielectric layers, C1-C8...capacitors, L1-L4...inductors.

Claims

1. a first inductor and a second inductor that are electromagnetically coupled to each other; a first ground terminal electrically connected to the first inductor; a second ground terminal electrically connected to the second inductor; a laminate for integrating the first inductor, the second inductor, the first ground terminal, and the second ground terminal; a first capacitor integrated into the stack; a second capacitor integrated into the stack; a third ground terminal integrated into the laminate; the first ground terminal and the second ground terminal are each connected to ground and are not electrically connected to each other in the laminate; the first inductor has a first end electrically connected to the first ground terminal and a second end opposite the first end; the second inductor has a third end electrically connected to the second ground terminal and a fourth end opposite the third end; the first capacitor is electrically connected to the second end of the first inductor and the third ground terminal; the second capacitor is electrically connected to the fourth end of the second inductor and the third ground terminal.

2. A first inductor and a second inductor that are electromagnetically coupled to each other; a first ground terminal electrically connected to the first inductor; a second ground terminal electrically connected to the second inductor; a first input / output terminal; a second input / output terminal; a third inductor; and a fourth inductor; and a laminate for integrating the first inductor, the second inductor, the third inductor, the fourth inductor, the first input / output terminal, the second input / output terminal, the first ground terminal, and the second ground terminal, the first inductor and the second inductor are arranged between the first input / output terminal and the second input / output terminal in a circuit configuration and are not connected to each other; the third inductor is arranged between the first inductor and the first input / output terminal in a circuit configuration and is connected to the first inductor; the fourth inductor is arranged between the second inductor and the second input / output terminal in a circuit configuration and is connected to the second inductor; the first ground terminal and the second ground terminal are each connected to ground, and are not electrically connected to each other in the laminate.

3. the first inductor has a first end electrically connected to the first ground terminal and a second end opposite the first end; the second inductor has a third end electrically connected to the second ground terminal and a fourth end opposite the third end; The layered bandpass filter further includes: a first capacitor electrically connected to the second end of the first inductor and integrated into the layered body; 3. The multilayer bandpass filter according to claim 2, further comprising: a second capacitor electrically connected to the fourth end of the second inductor and integrated into the laminate.

4. the first capacitor is arranged between the first inductor and the ground in a circuit configuration; 4. The multilayer bandpass filter according to claim 1, wherein the second capacitor is arranged between the second inductor and the ground in terms of circuit configuration.

5. the first capacitor includes a first capacitor conductor layer electrically connected to the ground; the second capacitor includes a second capacitor conductor layer electrically connected to the ground; 5. The multilayer bandpass filter according to claim 4, wherein the first capacitor conductor layer and the second capacitor conductor layer are connected to each other.

6. Furthermore, a first input / output terminal; a second input / output terminal; a third inductor; and a fourth inductor; the first input / output terminal, the second input / output terminal, the third inductor, and the fourth inductor are integrated into the laminate; the first inductor and the second inductor are arranged between the first input / output terminal and the second input / output terminal in terms of a circuit configuration; the third inductor is arranged between the first inductor and the first input / output terminal in terms of the circuit configuration; 2. The multilayer bandpass filter according to claim 1, wherein the fourth inductor is arranged between the second inductor and the second input / output terminal in terms of circuit configuration.

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