filter

Abstract

The filter of the present application includes first and second resonators, and first and second stub resonators. The first and second resonators each include a first conductor portion, and a second conductor portion electrically connected to the first conductor portion and having a smaller impedance than the first conductor portion. The first stub resonator is electrically connected to the first conductor portion of the first resonator. The second stub resonator is electrically connected to the first conductor portion of the second resonator. The shape of the first stub resonator and the shape of the second stub resonator are different from each other.

Description

Technical Field

[0001] This invention relates to a filter having a resonator composed of a distributed constant circuit. Background Technology

[0002] As an electronic component used in communication devices, there exists a bandpass filter that comprises multiple resonators. Each of these resonators is, for example, composed of a distributed constant circuit. The distributed constant circuit is configured to have a specified circuit length.

[0003] As a type of resonator composed of a distributed constant circuit, there exists a stub-type resonator. For example, Chinese Patent Application Publication No. 1434539A describes a technique using a stub element as a means of adjusting directivity and coupling. Furthermore, Japanese Patent Application Publication No. 2011-119841 describes a technique using an open-ended stub as a means of suppressing spurious components at higher resonant frequencies.

[0004] In bandpass filters, it is sometimes required to increase the absolute value of the attenuation (hereinafter also referred to as the pass attenuation) on the high-frequency side of the passband. Therefore, it is necessary to control the spurious emissions generated on the high-frequency side of the passband.

[0005] Currently, a communication service using the fifth-generation mobile communication system (hereinafter referred to as 5G) is being provided. In 5G, it is envisioned to utilize frequency bands above 10 GHz, particularly the 10–30 GHz quasi-millimeter wave band or the 30–300 GHz millimeter wave band. Thus, when utilizing a higher and wider frequency band than currently available, even in bandpass filters, it is required to meet characteristics within a higher and wider frequency band than currently possible. However, in existing technologies, it is difficult to obtain sufficient characteristics. Summary of the Invention

[0006] The purpose of this invention is to provide a filter that can increase the pass attenuation in a wide bandwidth on the high-frequency side of the passband.

[0007] The filter of the present invention comprises: a first resonator and a second resonator, each comprising: a first conductor portion and a second conductor portion having an impedance smaller than that of the first conductor portion; a first stub-type resonator, which is constructed of a distributed constant circuit and electrically connected to the first conductor portion of the first resonator; and a second stub-type resonator, which is constructed of a distributed constant circuit and electrically connected to the first conductor portion of the second resonator. The shapes of the first stub-type resonator and the second stub-type resonator are different from each other.

[0008] In the filter of the present invention, the lengths of the first stub resonator and the second stub resonator may be different from each other.

[0009] Alternatively, in the filter of the present invention, each of the first conductor portion and the second conductor portion may be a distributed constant line.

[0010] Alternatively, the filter of the present invention can also be a bandpass filter that selectively allows frequency signals within a specified passband to pass through. In this case, the first conductor portion of the first resonator may also include: a first connecting portion connected to a first stub-type resonator, and a first non-connected portion other than the first connecting portion. Furthermore, the first conductor portion of the second resonator may also include: a second connecting portion connected to a second stub-type resonator, and a second non-connected portion other than the second connecting portion. The current density at the center frequency of the passband of the first connecting portion may also be greater than the current density at the center frequency of the passband of the first non-connected portion. The current density at the center frequency of the passband of the second connecting portion may also be greater than the current density at the center frequency of the passband of the second non-connected portion.

[0011] Alternatively, in the filter of the present invention, the impedance ratio of the impedance of the second conductor portion of the first resonator and the second resonator to the impedance of the first conductor portion may be 0.3 or less.

[0012] Alternatively, in the filter of the present invention, the first conductor portion of the first resonator and the first conductor portion of the second resonator may each comprise a plurality of portions extending in multiple directions that are not mutually exclusive.

[0013] Furthermore, the filter of the present invention may also include a stack comprising multiple stacked dielectric layers. The first resonator, the second resonator, the first stub resonator, and the second stub resonator may also be integrated into a stack. In this case, in each of the first and second resonators, the first conductor portion and the second conductor portion may be arranged at different positions in the stacking direction of the multiple dielectric layers and electrically connected to each other. Additionally, the filter of the present invention may also include multiple vias connecting the first conductor portion and the second conductor portion of each of the first and second resonators. Furthermore, the first conductor portion of the first resonator and the first conductor portion of the second resonator may be arranged at the same position in the stacking direction. Furthermore, the second conductor portion of the first resonator and the second conductor portion of the second resonator may also be arranged at the same position in the stacking direction.

[0014] Additionally, the filter of the present invention may also include a third resonator, which is configured in the circuit structure between the first and second resonators. In this case, the third resonator may also include a third conductor portion and a fourth conductor portion with an impedance smaller than that of the third conductor portion. The third conductor portion may also have an asymmetrical shape.

[0015] The filter of the present invention comprises: a first stub resonator electrically connected to a first conductor portion of a first resonator, and a second stub resonator electrically connected to a first conductor portion of a second resonator. The shapes of the first stub resonator and the second stub resonator are different from each other. Therefore, according to the present invention, a filter capable of increasing pass-through attenuation in a wide bandwidth on the high-frequency side of the passband can be realized.

[0016] Other objects, features and benefits of the present invention will become quite clear from the following description. Attached Figure Description

[0017] Figure 1 This is a circuit diagram illustrating the circuit structure of the filter according to the first embodiment of the present invention.

[0018] Figure 2 This is a perspective view showing the appearance of the filter according to the first embodiment of the present invention.

[0019] Figures 3A to 3C This is an explanatory diagram showing the pattern formation surfaces of the first to third dielectric layers of the filter stack according to the first embodiment of the present invention.

[0020] Figures 4A to 4C This is an explanatory diagram showing the pattern formation surface of the fourth to sixth dielectric layers of the filter stack according to the first embodiment of the present invention.

[0021] Figures 5A to 5C This is an explanatory diagram showing the pattern formation surface of the seventh to ninth dielectric layers of the filter stack according to the first embodiment of the present invention.

[0022] Figure 6 This is a perspective view showing the interior of the filter stack according to the first embodiment of the present invention.

[0023] Figure 7 This is a perspective view showing a portion of the interior of a filter stack according to a first embodiment of the present invention.

[0024] Figure 8 This is a perspective view showing a portion of the interior of a filter stack according to a first embodiment of the present invention.

[0025] Figure 9 This is a circuit diagram showing the circuit structure of the filter in the first comparative example.

[0026] Figure 10 This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer of the filter stack of the first comparative example.

[0027] Figure 11This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer of the filter stack of the second comparative example.

[0028] Figure 12 This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer of the filter stack of the third comparative example.

[0029] Figure 13 This is a characteristic graph showing the attenuation characteristics of the model of the first comparative example.

[0030] Figure 14 This is a characteristic graph showing the attenuation characteristics of the model of the second comparative example.

[0031] Figure 15 This is a characteristic graph showing the attenuation characteristics of the model of the third comparative example.

[0032] Figure 16 This is a characteristic diagram of the attenuation characteristics of the model illustrating the embodiment.

[0033] Figure 17 This is an explanatory diagram showing the pattern formation surface of the eighth dielectric layer of the filter stack of the fourth comparative example.

[0034] Figure 18 This is a characteristic graph showing the attenuation characteristics of the model of the fourth comparative example.

[0035] Figure 19 This is a circuit diagram illustrating the circuit structure of the filter according to the second embodiment of the present invention. Detailed Implementation

[0036] [First Implementation Method]

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, referring to... Figure 1 The structure of the filter 1 according to the first embodiment of the present invention will be described. Figure 1 This is a circuit diagram showing the circuit structure of filter 1. Filter 1 is configured to function as a bandpass filter that selectively allows signals of frequencies within a specified passband to pass through.

[0038] The filter 1 of this embodiment includes a first resonator 10, a second resonator 20, and a third resonator 30 disposed between the first resonator 10 and the second resonator 20 in a circuit structure. Furthermore, in this application, the expression "in a circuit structure" refers to the configuration in a circuit diagram, rather than the configuration in a physical structure.

[0039] The first to third resonators 10, 20, and 30 are configured such that the first resonator 10 and the third resonator 30 are adjacent in circuit structure and electromagnetically coupled, and the second resonator 20 and the third resonator 30 are adjacent in circuit structure and electromagnetically coupled. Figure 1 In the diagram, the curve marked K13 represents the electric field coupling between the first resonator 10 and the third resonator 30, and the curve marked K23 represents the electric field coupling between the second resonator 20 and the third resonator 30.

[0040] Furthermore, the first resonator 10 is magnetically coupled to the second resonator 20, which is not adjacent in circuit structure. This electromagnetic coupling between two non-adjacent resonators in circuit structure is called jump coupling. Figure 1 In the diagram, the curve marked K12 represents the magnetic field coupling between the first resonator 10 and the second resonator 20.

[0041] The first resonator 10 includes a first conductor portion 11 and a second conductor portion 12 with an impedance smaller than that of the first conductor portion 11. The first conductor portion 11 and the second conductor portion 12 are electrically connected to each other. The first conductor portion 11 is grounded. Furthermore, both the first conductor portion 11 and the second conductor portion 12 are distributed constant lines. In this embodiment, specifically, the first conductor portion 11 is a distributed constant line with a narrow width, and the second conductor portion 12 is a distributed constant line with a width larger than that of the first conductor portion 11.

[0042] The first resonator 10 further includes a third conductor portion 13 electrically connecting the first conductor portion 11 and the second conductor portion 12. The third conductor portion 13 may also include a distribution constant line with a width smaller than the distribution constant line constituting the second conductor portion 12. The width of the distribution constant line of the third conductor portion 13 may be the same as or different from the width of the distribution constant line constituting the first conductor portion 11.

[0043] The structure of the second resonator 20 is basically the same as that of the first resonator 10. That is, the second resonator 20 includes a first conductor portion 21 and a second conductor portion 22 with a smaller impedance than the first conductor portion 21. The first conductor portion 21 and the second conductor portion 22 are electrically connected to each other. The first conductor portion 21 is grounded. In addition, the first conductor portion 21 and the second conductor portion 22 are each a distributed constant line. In this embodiment, in particular, the first conductor portion 21 is a distributed constant line with a small width, and the second conductor portion 22 is a distributed constant line with a larger width than the first conductor portion 21.

[0044] The second resonator 20 further includes a third conductor portion 23 electrically connecting the first conductor portion 21 and the second conductor portion 22. The third conductor portion 23 may also include a distribution constant line with a width smaller than the distribution constant line constituting the second conductor portion 22. The width of the distribution constant line of the third conductor portion 23 may be the same as or different from the width of the distribution constant line constituting the first conductor portion 21.

[0045] The third resonator 30 includes a first conductor portion 31 and a second conductor portion 32 with an impedance smaller than that of the first conductor portion 31. The first conductor portion 31 corresponds to the "third conductor portion" in this invention, and the second conductor portion 32 corresponds to the "fourth conductor portion" in this invention. The first conductor portion 31 and the second conductor portion 32 are electrically connected to each other. The first conductor portion 31 is grounded. Furthermore, both the first conductor portion 31 and the second conductor portion 32 are distributed constant lines. In this embodiment, specifically, the first conductor portion 31 is a distributed constant line with a small width, and the second conductor portion 32 is a distributed constant line with a larger width than that of the first conductor portion 31.

[0046] The first to third resonators, 10, 20, and 30, are all step impedance resonators composed of narrow and wide distributed constant lines. Furthermore, the first to third resonators, 10, 20, and 30, are all quarter-wavelength resonators with one end short-circuited and the other end open.

[0047] The impedances of the first conductor sections 11, 21, and 31 are, for example, in the range of 15 to 35 Ω. The impedances of the second conductor sections 12, 22, and 32 are, for example, in the range of 1 to 5 Ω. Here, in each of the first to third resonators 10, 20, and 30, the ratio of the impedance of the second conductor section to the impedance of the first conductor section is called the impedance ratio. In each of the first to third resonators 10, 20, and 30, the impedance ratio is less than 1.

[0048] From the viewpoint of reducing the resonator's size, a low impedance ratio is preferable. For example, the impedance ratio can be adjusted by changing the widths of the distributed constant lines constituting the first conductor portion and the distributed constant lines constituting the second conductor portion. As the impedance ratio decreases, the width of the distributed constant lines constituting the first conductor portion decreases relatively, while the width of the distributed constant lines constituting the second conductor portion increases relatively.

[0049] In this embodiment, specifically, the impedance ratio of each of the first to third resonators 10, 20, and 30 is 0.3 or less. In one example, the impedance of the second conductor portion of each of the first and second resonators 10 and 20 is 2.87Ω, and the impedance of the first conductor portion of each of the first and second resonators 10 and 20 is 27Ω. In this case, the impedance ratio of each of the first and second resonators 10 and 20 is 0.106. Furthermore, in another example, the impedance of the second conductor portion 32 of the third resonator 30 is 2.55Ω, and the impedance of the first conductor portion 31 of the third resonator 30 is 27Ω. In this case, the impedance ratio of the third resonator 30 is 0.094.

[0050] However, if the impedance ratio is reduced too much, the desired characteristics may not be obtained. For example, in a step impedance resonator (1 / 4 wavelength resonator) with one end short-circuited and the other end open, if the impedance ratio is reduced too much, the resonator essentially becomes a 1 / 2 wavelength resonator consisting only of a second conductor portion open at both ends. As a result, the desired characteristics are not obtained. To prevent this, in this embodiment, the impedance ratios of the first to third resonators 10, 20, and 30 are each set to 0.06 or higher.

[0051] The filter 1 also includes: a first port 2, a second port 3, and conductor portions 4 and 5. The first to third resonators 10, 20, and 30 are arranged in the circuit structure between the first port 2 and the second port 3.

[0052] Conductor section 4 electrically connects the first port 2 and the first resonator 10. One end of conductor section 4 is connected to the first port 2. The other end of conductor section 4 is connected to the first resonator 10 between the first conductor section 11 and the third conductor section 13.

[0053] Conductor 5 electrically connects the second port 3 and the second resonator 20. One end of conductor 5 is connected to the second port 3. The other end of conductor 5 is connected to the second resonator 20 between the first conductor portion 21 and the third conductor portion 23.

[0054] The filter 1 also includes: a first stub resonator 91 electrically connected to the first conductor portion 11 of the first resonator 10, and a second stub resonator 92 electrically connected to the first conductor portion 21 of the second resonator 20. The first and second stub resonators 91 and 92 are each configured with a free distribution constant circuit.

[0055] The first stubular resonator 91 is connected midway through the first conductor section 11. Figure 1In the circuit diagram, symbol 11A represents the portion of the first conductor portion 11 that is located in the circuit structure between the connection point with the first stub resonator 91 and the second conductor portion 12, and symbol 11B represents the portion in the circuit structure located between the connection point with the first stub resonator 91 and the ground wire.

[0056] The second stubular resonator 92 is connected midway through the first conductor section 21. Figure 1 In the circuit diagram, symbol 21A represents the portion of the first conductor portion 21 that is located in the circuit structure between the connection point with the second stub resonator 92 and the second conductor portion 22, and symbol 21B represents the portion located in the circuit structure between the connection point with the second stub resonator 92 and the ground wire.

[0057] As described below, the shapes of the first stub resonator 91 and the second stub resonator 92 are different. In particular, in this embodiment, the lengths of the first stub resonator 91 and the second stub resonator 92 are different.

[0058] The first and second stub-type resonators 91 and 92 can be either open stubs with one end disconnected or short stubs with one end grounded. Figure 1 The image shows examples of the first and second stub-type resonators 91 and 92, which are open-circuit stubs.

[0059] Next, refer to Figure 2 The other structures of filter 1 will be described. Figure 2 This is a perspective view showing the appearance of filter 1.

[0060] The filter 1 also includes a stack 50. The stack 50 includes: multiple stacked dielectric layers, multiple conductor layers formed on the multiple dielectric layers, and multiple through holes. The first to third resonators 10, 20, and 30 and the first and second stub resonators 91 and 92 are integrated into the stack 50. The first to third resonators 10, 20, and 30 and the first and second stub resonators 91 and 92 are constructed using multiple conductor layers.

[0061] The laminate 50 has: a first surface 50A and a second surface 50B located at both ends of the lamination direction T of the plurality of dielectric layers, and four side surfaces 50C to 50F connecting the first surface 50A and the second surface 50B. Side surfaces 50C and 50D face opposite sides to each other, and side surfaces 50E and 50F also face opposite sides to each other. Side surfaces 50C to 50F are perpendicular to the first surface 50A and the second surface 50B.

[0062] Here, as Figure 2As shown, the X, Y, and Z directions are defined. The X, Y, and Z directions are perpendicular to each other. In this embodiment, the direction parallel to the stacking direction T is designated as the Z direction. Furthermore, the direction opposite to the X direction is designated as the -X direction, the direction opposite to the Y direction as the -Y direction, and the direction opposite to the Z direction as the -Z direction.

[0063] like Figure 2 As shown, the first surface 50A is located at the -Z direction end of the laminate 50. The first surface 50A is also the bottom surface of the laminate 50. The second surface 50B is located at the Z direction end of the laminate 50. The second surface 50B is also the top surface of the laminate 50. The side surface 50C is located at the -X direction end of the laminate 50. The side surface 50D is located at the X direction end of the laminate 50. The side surface 50E is located at the -Y direction end of the laminate 50. The side surface 50F is located at the Y direction end of the laminate 50.

[0064] The planar shape of the laminate 50 when viewed from the Z direction, i.e., the shape of the first surface 50A or the second surface 50B, is an elongated shape in one direction. In this embodiment, in particular, the planar shape of the laminate 50 when viewed from the Z direction is a rectangular shape that elongates in a direction parallel to the X direction.

[0065] The filter 1 further includes a plurality of terminals 111, 112, 113, 114, 115, and 116 disposed on the first surface 50A of the laminate 50. Terminal 111 extends along the Y direction near side surface 50C. Terminal 112 extends along the Y direction near side surface 50D. Terminals 113 to 116 are disposed between terminals 111 and 112. Terminals 113 and 114 are arranged sequentially along the X direction near side surface 50E. Terminals 115 and 116 are arranged sequentially along the X direction near side surface 50F.

[0066] Terminal 111 corresponds to the first port 2, and terminal 112 corresponds to the second port 3. Therefore, the first and second ports 2 and 3 are disposed on the first surface 50A of the laminate 50. Terminals 113 to 116 are grounded. Hereinafter, terminal 111 will also be referred to as the first terminal 111, terminal 112 will also be referred to as the second terminal 112, and terminals 113 to 116 will also be referred to as grounded terminals 113 to 116.

[0067] Next, refer to Figures 3A to 5C An example of the plurality of dielectric layers and the plurality of conductor layers constituting the laminate 50 will be described. In this example, the laminate 50 has nine dielectric layers stacked together. Hereinafter, these nine dielectric layers will be referred to as the first to ninth dielectric layers in order from bottom to top. In addition, the first to ninth dielectric layers will be represented by the symbols 51 to 59.

[0068] Figure 3AThe patterned surface of the first dielectric layer 51 is shown. Terminals 111, 112, 113, 114, 115, and 116 are formed on the patterned surface of the dielectric layer 51. Additionally, through-holes 51T1, 51T2, 51T3, 51T4, 51T5, and 51T6 are formed on the dielectric layer 51, respectively, and are connected to the terminals 111, 112, 113, 114, 115, and 116.

[0069] Figure 3B The patterned surface of the second dielectric layer 52 is shown. A conductor layer 521 is formed on the patterned surface of the dielectric layer 52. Additionally, vias 52T1, 52T2, 52T3, 52T4, 52T5, and 52T6 are formed in the dielectric layer 52. Vias 51T1 and 51T2 formed in the dielectric layer 51 are connected to vias 52T1 and 52T2, respectively. Vias 51T3 to 51T6 and vias 52T3 to 52T6 formed in the dielectric layer 51 are connected to the conductor layer 521.

[0070] Figure 3C The patterned surface of the third dielectric layer 53 is shown. Conductor layers 531, 532, 533, and 534 are formed on the patterned surface of the dielectric layer 53. Conductor layer 532 is connected to conductor layer 531. Conductor layer 534 is connected to conductor layer 533. Figure 3C In the diagram, the boundaries of conductor layers 531 and 532, and the boundaries of conductor layers 533 and 534 are represented by dotted lines, respectively.

[0071] Additionally, vias 53T1, 53T2, 53T3, 53T4, 53T5, and 53T6 are formed in the dielectric layer 53. Vias 52T1 and 53T1 formed in the dielectric layer 52 are connected to the conductor layer 532. Vias 52T2 and 53T2 formed in the dielectric layer 52 are connected to the conductor layer 534. Vias 52T3 to 52T6 formed in the dielectric layer 52 are connected to vias 53T3 to 53T6, respectively.

[0072] Figure 4A The patterned surface of the fourth dielectric layer 54 is shown. A conductor layer 541 is formed on the patterned surface of the dielectric layer 54. Additionally, vias 54T1, 54T2, 54T3, 54T4, 54T5, 54T6, and 54T7 are formed in the dielectric layer 54. Vias 53T1 to 53T6 formed in the dielectric layer 53 are connected to vias 54T1 to 54T6, respectively. Via 54T7 is connected to the conductor layer 541.

[0073] Figure 4BThe patterned surface of the fifth dielectric layer 55 is shown. A conductor layer 551 is formed on the patterned surface of the dielectric layer 55. Additionally, vias 55T1, 55T2, 55T7, and 55T8 are formed in the dielectric layer 55. The vias 54T1, 54T2, and 54T7 formed in the dielectric layer 54 are connected to the vias 55T1, 55T2, and 55T7, respectively. The vias 54T3 to 54T6 and via 55T8 formed in the dielectric layer 54 are connected to the conductor layer 551.

[0074] Figure 4C The patterned surface of the sixth dielectric layer 56 is shown. Through-holes 56T1, 56T2, 56T7, and 56T8 are formed in the dielectric layer 56. Through-holes 55T1, 55T2, 55T7, and 55T8 formed in the dielectric layer 55 are connected to through-holes 56T1, 56T2, 56T7, and 56T8, respectively.

[0075] Figure 5A The patterned surface of the seventh dielectric layer 57 is shown. Conductor layers 571, 572, 573, and 574 are formed on the patterned surface of the dielectric layer 57. Conductor layers 571 and 572 each have a first end and a second end located on opposite sides. The first ends of conductor layers 571 and 572 are connected to each other. Figure 5A In the diagram, the boundaries between conductor layers 571 and 572 are represented by dotted lines. A via 56T1 formed in dielectric layer 56 is connected to a portion near the second end of conductor layer 571. A via 56T2 formed in dielectric layer 56 is connected to a portion near the second end of conductor layer 572.

[0076] Conductor layer 573 is connected midway through conductor layer 571. Conductor layer 574 is connected midway through conductor layer 572. Figure 5A In the diagram, the boundaries of conductor layers 571 and 573, as well as the boundaries of conductor layers 572 and 574, are represented by dotted lines.

[0077] Additionally, vias 57T7 and 57T8 are formed in dielectric layer 57. Via 56T7 formed in dielectric layer 56 is connected to via 57T7. Via 56T8 and via 57T8 formed in dielectric layer 56 are connected to the vicinity of the first end of conductor layer 571 and the vicinity of the first end of conductor layer 572.

[0078] Figure 5B The patterned surface of the eighth dielectric layer 58 is shown. A conductor layer 581 is formed on the patterned surface of the dielectric layer 58. The conductor layer 581 has a first end and a second end located on opposite sides. A via 57T7 formed in the dielectric layer 57 is connected to a portion near the first end of the conductor layer 581.

[0079] Additionally, a via 58T8 is formed in the dielectric layer 58. The vias 57T8 and 58T8 formed in the dielectric layer 57 are connected to the portion near the second end of the conductor layer 581.

[0080] Figure 5C The patterned surface of the ninth dielectric layer 59 is shown. A conductor layer 591 is formed on the patterned surface of the dielectric layer 59. A via 58T8 formed in the dielectric layer 58 is connected to the conductor layer 591.

[0081] Figure 2 The stack 50 shown is constructed by stacking the first to ninth dielectric layers 51 to 59 in such a way that the pattern-forming surface of the first dielectric layer 51 becomes the first surface 50A of the stack 50, and the surface opposite to the pattern-forming surface of the ninth dielectric layer 59 becomes the second surface 50B of the stack 50.

[0082] Figure 6 The interior of the laminate 50, consisting of the first to ninth dielectric layers 51-59, is shown. Figure 6 As shown, inside the laminate 50, there are laminated... Figures 3A to 5C The diagram shows multiple conductor layers and multiple vias.

[0083] The following is about Figure 1 The components of the circuit of filter 1 shown are... Figures 3A to 5C The correspondence of the constituent elements inside the stacked body 50 shown will be explained. First, the first resonator 10 will be explained. The first conductor portion 11 is composed of conductor layer 571. The second conductor portion 12 is composed of conductor layer 531. The third conductor portion 13 is composed of conductor layer 532.

[0084] Conductor layer 532 (third conductor portion 13) and through holes 53T1, 54T1, 55T1, and 56T1 connect conductor layer 571 constituting first conductor portion 11 and conductor layer 531 constituting second conductor portion 12. Furthermore, conductor layer 571 constituting first conductor portion 11 is connected to ground terminals 113-116 via through holes 51T3-51T6, conductor layer 521, through holes 52T3-52T6, 53T3-53T6, through holes 54T3-54T6, conductor layer 551, and through holes 55T8 and 56T8.

[0085] Next, the second resonator 20 will be described. The first conductor portion 21 is composed of conductor layer 572. The second conductor portion 22 is composed of conductor layer 533. The third conductor portion 23 is composed of conductor layer 534.

[0086] Conductor layer 534 (third conductor portion 23) and through holes 53T2, 54T2, 55T2, and 56T2 connect conductor layer 572 constituting first conductor portion 21 and conductor layer 533 constituting second conductor portion 22. Furthermore, conductor layer 572 constituting first conductor portion 21 is connected to ground terminals 113-116 via through holes 51T3-51T6, conductor layer 521, through holes 52T3-52T6, 53T3-53T6, through holes 54T3-54T6, conductor layer 551, and through holes 55T8 and 56T8.

[0087] Next, the third resonator 30 will be described. The first conductor portion 31 is composed of a conductor layer 581. The second conductor portion 32 is composed of a conductor layer 541.

[0088] The conductor layer 581 constituting the first conductor portion 31 is connected to the ground terminals 113-116 via through holes 51T3-51T6, conductor layer 521, through holes 52T3-52T6, 53T3-53T6, through holes 54T3-54T6, conductor layer 551, and through holes 55T8, 56T8, and 57T8.

[0089] Next, the first and second stub-type resonators 91 and 92 will be described. The first stub-type resonator 91 is composed of a conductor layer 573. The second stub-type resonator 92 is composed of a conductor layer 574.

[0090] Next, conductor portions 4 and 5 will be described. Conductor portion 4 is composed of through holes 51T1 and 52T1. Through hole 51T1 is connected to the first terminal 111. Through hole 52T1 is connected to the conductor layer 532 constituting the third conductor portion 13, and is connected to the conductor layer 571 constituting the first conductor portion 11 via through holes 53T1, 54T1, 55T1, and 56T1.

[0091] The conductor portion 5 is formed by through holes 51T2 and 52T2. Through hole 51T2 is connected to the second terminal 112. Through hole 52T2 is connected to the conductor layer 534 constituting the third conductor portion 23, and is connected to the conductor layer 572 constituting the first conductor portion 21 via through holes 53T2, 54T2, 55T2, and 56T2.

[0092] Next, refer to Figures 2 to 8 The structural features of the filter 1 in this embodiment will be described. Figure 7 and Figure 8 This is a perspective view showing a portion of the interior of the laminate 50. Figure 7 The image primarily shows multiple conductor layers and multiple through-holes constituting the first and second resonators 10, 20 and the first and second stub-type resonators 91, 92. Figure 8The image mainly shows multiple conductor layers and multiple through holes that constitute the third resonator 30.

[0093] The first resonator 10 is disposed in the region on the -X direction side within the laminate 50. That is, the first resonator 10 is disposed closer to the side surface 50C than the side surface 50D. Figure 7 As shown, the first conductor portion 11 (conductor layer 571) and the second conductor portion 12 (conductor layer 531) of the first resonator 10 are arranged at different positions in the stacking direction T. The second conductor portion 12 is disposed between the first surface 50A, on which a plurality of terminals 111 to 116 are disposed, and the first conductor portion 11.

[0094] The first conductor portion 11 (conductor layer 571) includes a plurality of portions extending in a plurality of directions perpendicular to the stacking direction T. In particular, the first conductor portion 11 (conductor layer 571) includes four portions extending in a direction parallel to the X direction and three portions extending in a direction parallel to the Y direction.

[0095] The second conductor portion 12 (conductor layer 531) is elongated in a direction intersecting the long side direction of the laminate 50. In this embodiment, in particular, the second conductor portion 12 (conductor layer 531) is a rectangular shape that elongates in a direction parallel to the Y direction.

[0096] The second resonator 20 is disposed in the region on the X-direction side within the laminate 50. That is, the second resonator 20 is disposed closer to the side surface 50D than the side surface 50C. Figure 7 As shown, the first conductor portion 21 (conductor layer 572) and the second conductor portion 22 (conductor layer 533) of the second resonator 20 are arranged at different positions in the stacking direction T. The second conductor portion 22 is disposed between the first surface 50A, on which a plurality of terminals 111 to 116 are disposed, and the first conductor portion 21.

[0097] The first conductor portion 21 (conductor layer 572) includes a plurality of portions extending in a plurality of directions perpendicular to the stacking direction T. In particular, the first conductor portion 21 (conductor layer 572) includes four portions extending in a direction parallel to the X direction and three portions extending in a direction parallel to the Y direction.

[0098] The second conductor portion 22 (conductor layer 533) is elongated in a direction intersecting the length direction of the laminate 50. In this embodiment, in particular, the second conductor portion 22 (conductor layer 533) is a rectangular shape that elongates in a direction parallel to the Y direction.

[0099] When viewed from the Z direction, at least a portion of the third resonator 30 is disposed between the first resonator 10 and the second resonator 20. In this embodiment, in particular, a portion of the third resonator 30 is disposed between the first resonator 10 and the second resonator 20.

[0100] like Figure 8 As shown, the first conductor portion 31 (conductor layer 581) and the second conductor portion 32 (conductor layer 541) of the third resonator 30 are arranged at different positions in the stacking direction T. The second conductor portion 32 is disposed between the first surface 50A, on which a plurality of terminals 111 to 116 are disposed, and the first conductor portion 31.

[0101] The first conductor portion 31 (conductor layer 581) includes a plurality of portions extending in a plurality of directions perpendicular to the stacking direction T. In particular, the first conductor portion 31 (conductor layer 581) includes three portions extending in a direction parallel to the X direction and four portions extending in a direction parallel to the Y direction.

[0102] The first conductor portion 31 (conductor layer 581) has an asymmetrical shape with respect to any XZ plane intersecting the first conductor portion 31, and also has an asymmetrical shape with respect to any YZ plane intersecting the first conductor portion 31. Hereinafter, any XZ plane intersecting the first conductor portion 31 will be referred to as a first imaginary plane, and any YZ plane intersecting the first conductor portion 31 will be referred to as a second imaginary plane. The first imaginary plane may also intersect the center of the laminate 50 in a direction parallel to the Y direction. The second imaginary plane may also intersect the center of the laminate 50 in a direction parallel to the X direction.

[0103] The second conductor portion 32 (conductor layer 541) is elongated in the longitudinal direction of the laminate 50. In this embodiment, in particular, the second conductor portion 32 (conductor layer 541) is elongated in a rectangular shape in a direction parallel to the X direction.

[0104] like Figure 5A and Figure 6 As shown, the first conductor portion 11 (conductor layer 571) of the first resonator 10 and the first conductor portion 21 (conductor layer 572) of the second resonator 20 are arranged at the same position in the stacking direction T. Figure 5A , Figure 5B and Figure 6As shown, the first conductor portion 31 (conductor layer 581) of the third resonator 30 is positioned differently from the first conductor portions 11 and 21 in the stacking direction T. Furthermore, when viewed from the Z direction, a portion of the first conductor portion 11 and a portion of the first conductor portion 21 overlap with the first conductor portion 31. Additionally, the shape of the first conductor portion 31 differs from the shapes of the first conductor portion 11 and the first conductor portion 21.

[0105] In addition, such as Figure 3C and Figure 6 As shown, the second conductor portion 12 (conductor layer 531) of the first resonator 10 and the second conductor portion 22 (conductor layer 533) of the second resonator 20 are positioned at the same location in the stacking direction T. Figure 3C , Figure 4A and Figure 6 As shown, the second conductor portion 32 (conductor layer 541) of the third resonator 30 is positioned differently from the second conductor portions 12 and 22 in the stacking direction T. Furthermore, when viewed from the Z direction, a portion of the second conductor portion 12 and a portion of the second conductor portion 22 overlap with the second conductor portion 32. Additionally, the shape of the second conductor portion 32 differs from the shapes of the second conductor portion 12 and the second conductor portion 22.

[0106] like Figures 5A to 5C As shown, the shapes of the first stub resonator 91 (conductor layer 573) and the second stub resonator 92 (conductor layer 574) are different. Specifically, the lengths of the first stub resonator 91 and the second stub resonator 92 are different. Figures 5A to 5C In the example shown, the first stubular resonator 91 is longer than the second stubular resonator 92. The first stubular resonator 91 comprises two portions extending in a direction parallel to the X direction and one portion extending in a direction parallel to the Y direction. The second stubular resonator 92 extends in a direction parallel to the X direction. Furthermore, the widths of the first stubular resonator 91 and the second stubular resonator 92 are the same or approximately the same.

[0107] The first conductor portion 11 of the first resonator 10 includes: a first connecting portion connected to the first stub-type resonator 91, and a first non-connecting portion other than the first connecting portion. Specifically, the first connecting portion is... Figure 5A The portion 571a of the conductor layer 571 shown, near the boundary with the conductor layer 573 indicated by the dotted line. Figure 5A In the diagram, arrows indicate the approximate location of part 571a. The first non-connected part is the portion of conductor layer 571 other than part 571a.

[0108] The current density at the center frequency of the passband of the first connected portion (part 571a) of the filter 1 (bandpass filter) is less than the current density at the center frequency of the passband of the first unconnected portion of the filter 1 (bandpass filter). That is, the first stub resonator 91 is connected to or near the portion with the highest current density in the first conductor portion 11.

[0109] The first conductor portion 21 of the second resonator 20 includes: a second connecting portion connected to the second stub-type resonator 92, and a second non-connecting portion other than the second connecting portion. Specifically, the first connecting portion is... Figure 5A The portion 572a of the conductor layer 572 shown, near the boundary with the conductor layer 574 indicated by the dotted line. Figure 5A In the diagram, arrows indicate the approximate location of part 572a. The second non-connected part is the portion of conductor layer 572 other than part 572a.

[0110] The current density at the center frequency of the passband of filter 1 (bandpass filter) in the second connected portion (part 572a) is less than the current density at the center frequency of the passband of filter 1 (bandpass filter) in the second unconnected portion. That is, the second stub resonator 92 is connected to or near the portion with the highest current density in the first conductor portion 21.

[0111] As described above, in this embodiment, the first conductor portion 11 and the second conductor portion 12 of the first resonator 10 are arranged at different positions in the stacking direction T. Therefore, according to this embodiment, the first conductor portion 11 and the second conductor portion 12 can be arranged in an overlapping configuration. Thus, according to this embodiment, compared to the case where the first conductor portion 11 and the second conductor portion 12 are formed on the same dielectric layer and arranged at the same position in the stacking direction T, the area used to assemble the first resonator 10 can be substantially reduced.

[0112] The above description of the first resonator 10 also applies to the second and third resonators 20 and 30. Thus, according to this embodiment, the filter 1 can be miniaturized.

[0113] Furthermore, in this embodiment, when viewed from the Z direction, a portion of the first conductor portion 11 of the first resonator 10 and a portion of the first conductor portion 21 of the second resonator 20 overlap with the first conductor portion 31 of the third resonator 30. Similarly, when viewed from the Z direction, a portion of the second conductor portion 12 of the first resonator 10 and a portion of the second conductor portion 22 of the second resonator 20 overlap with the second conductor portion 32 of the third resonator 30. Therefore, according to this embodiment, the filter 1 can also be miniaturized.

[0114] Furthermore, in this embodiment, each of the first conductor portions 11, 21, and 31 includes multiple portions extending in multiple different directions. Therefore, according to this embodiment, compared to the case where each of the first conductor portions 11, 21, and 31 extends in one direction, the area used to assemble each of the first conductor portions 11, 21, and 31 can be substantially reduced.

[0115] In this embodiment, conductor layer 591 is connected to ground terminals 113-116 via vias 51T3-51T6, conductor layer 521, vias 52T3-52T6, 53T3-53T6, vias 54T3-54T6, conductor layer 551, and vias 55T8, 56T8, 57T8, and 58T8. The first to third resonators 10, 20, and 30 are disposed between conductor layer 521 and conductor layer 591. When viewed from the Z direction, each of conductor layers 521 and 591 overlaps with the first to third resonators 10, 20, and 30. Conductor layers 521 and 591 function as shielding layers.

[0116] Furthermore, in this embodiment, the impedance of the first conductor portion 11 of the first resonator 10 is greater than that of the second conductor portion 12 of the first resonator 10. The first stub resonator 91 is electrically connected to the first conductor portion 11 with the high impedance. In particular, in this embodiment, the first stub resonator 91 is connected to the portion of the first conductor portion 11 with the highest current density. Thus, according to this embodiment, the influence of the first stub resonator 91 on the fundamental resonance of the first resonator 10 can be suppressed, and spurious emissions can be controlled.

[0117] The above description of the first resonator 10 and the first stub resonator 91 also applies to the second resonator 20 and the second stub resonator 92. According to this embodiment, the influence of the second stub resonator 92 on the fundamental resonance of the second resonator 20 can be suppressed, and spurious emissions can be controlled.

[0118] Next, the first simulation results will be explained, showing that by using the first and second stubular resonators 91 and 92, the absolute value of the attenuation (hereinafter referred to as the pass attenuation) can be increased in a wide bandwidth on the high-frequency side of the passband. First, the models of the first to third comparative examples and the model of the embodiment used in the first simulation will be explained. The model of the first comparative example is the model of the filter of the first comparative example. Figure 9 This is a circuit diagram showing the circuit structure of the filter in the first comparative example. Figure 10This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer of the laminate of the filter of the first comparative example. The structure of the filter of the first comparative example is substantially the same as that of the filter 1 of this embodiment, except that the first and second stubular resonators 91 and 92 are not provided, and the conductor layers 573 and 574 formed on the dielectric layer 57 of the laminate 50 are not provided.

[0119] The model of the second comparison example is the model of the filter of the second comparison example. Figure 11 This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer 57 of the laminate 50 of the filter of the second comparative example. In the filter of the second comparative example, a conductor layer 575 is formed in the dielectric layer 57 instead of the conductor layer 573 of this embodiment. Figure 11 In the diagram, the boundary between conductor layer 571 and conductor layer 575 is represented by a dotted line. In the filter of the second comparative example, the first stubular resonator 91 is composed of conductor layer 575. The other structures of the filter of the second comparative example are the same as those of the filter 1 of this embodiment.

[0120] In the model of the second comparative example, specifically, the shape of the first stubular resonator 91 (conductor layer 575) is the same as the shape of the second stubular resonator 92 (conductor layer 574). That is, the first stubular resonator 91 extends in a direction parallel to the X direction.

[0121] The model of the third comparison example is the model of the filter of the third comparison example. Figure 12 This is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer 57 of the laminate 50 of the filter of the third comparative example. In the filter of the third comparative example, a conductor layer 576 is formed in the dielectric layer 57 instead of the conductor layer 574 of this embodiment. Figure 12 In the diagram, the boundary between conductor layer 572 and conductor layer 576 is represented by a dotted line. In the filter of the third comparative example, the second stubular resonator 92 is composed of conductor layer 576. The other structures of the filter of the third comparative example are the same as those of the filter 1 of this embodiment.

[0122] In the model of the third comparative example, in particular, the shape of the second stubular resonator 92 (conductor layer 576) is the same as that of the first stubular resonator 91 (conductor layer 573). That is, the second stubular resonator 92 comprises two portions extending in a direction parallel to the X direction and one portion extending in a direction parallel to the Y direction.

[0123] The model in this embodiment is the model of filter 1 of this embodiment. In the simulation, in each of the models of the first to third comparative examples and the model of this embodiment, the impedance ratio of the first and second resonators 10 and 20 is set to 0.106, and the impedance ratio of the third resonator 30 is set to 0.094.

[0124] In the first simulation, the models of the first to third comparative examples and the model of the embodiment were designed to function as bandpass filters. Furthermore, the pass-through attenuation characteristics of the comparative example models and the model of the embodiment were determined.

[0125] Figure 13 This is a characteristic graph showing the attenuation characteristics of the model of the first comparative example. Figure 14 This is a characteristic graph showing the attenuation characteristics of the model of the second comparative example. Figure 15 This is a characteristic graph showing the attenuation characteristics of the model of the third comparative example. Figure 16 This is a characteristic graph illustrating the attenuation characteristics of the model in the embodiment. Figures 13 to 16 In the various graphs, the horizontal axis represents frequency, and the vertical axis represents attenuation.

[0126] like Figures 13 to 16 As shown, in any of the models in the first to third comparative examples and the embodiment, multiple spurious signals are generated on the high-frequency side of the passband. The frequencies of each of the multiple spurious signals are different in the models in the first to third comparative examples and the embodiment. As described above, in the model of the first comparative example, the first and second stubular resonators 91 and 92 are not provided. In the models in the second to third comparative examples and the embodiment, the shapes of the first and second stubular resonators 91 and 92 are different. Figures 13 to 16 The first simulation results shown indicate that multiple stray particles can be controlled by the first and second stubular resonators 91 and 92.

[0127] In addition, when the model of the first comparative example ( Figure 13 ) and the model of the second comparative example ( Figure 14 When comparing the models in the first and second comparative examples, the peaks with relatively small attenuation all exist in the frequency band of 17–18 GHz. In the model of the second comparative example, the minimum attenuation of the aforementioned peaks is slightly larger than that in the model of the first comparative example.

[0128] In addition, in the model of the third comparative example ( Figure 15 In the model of the first to third comparative examples, the peak with relatively small attenuation exists in the frequency band of 14 to 18 GHz. When focusing on the frequency band of the aforementioned peak and its vicinity, the attenuation in the model of the third comparative example is greater than that in the models of the first and second comparative examples. On the other hand, when focusing on the frequency band of 24 to 31 GHz, the attenuation in the model of the third comparative example is smaller than that in the models of the first and second comparative examples.

[0129] Additionally, in the model of the embodiment ( Figure 16 In the model of the first and second comparative examples, the peak with relatively small attenuation exists in the frequency band of 14-16 GHz. When focusing on the frequency band of the aforementioned peak and its vicinity in each of the models of the embodiments, the attenuation in the model of the embodiment is greater than that in the models of the first and second comparative examples. Furthermore, when focusing on the frequency band of 27-31 GHz in each of the models of the third comparative example, the attenuation in the model of the embodiment is smaller than that in the model of the third comparative example.

[0130] Depend on Figures 13 to 16 The first simulation results shown demonstrate that, according to this embodiment, spurious emissions generated on the high-frequency side of the passband can be controlled using the first and second stubular resonators 91 and 92. Furthermore, from... Figures 14 to 16 The first simulation results show that, according to this embodiment, by making the shapes of the first stub resonator 91 and the second stub resonator 92 different from each other, the pass attenuation can be increased in a wide bandwidth on the high-frequency side of the passband.

[0131] Next, the second simulation results will be explained, showing that the shape of the first conductor portion 31 of the third resonator 30 can increase the passband attenuation (absolute value of the attenuation) on the high-frequency side. First, the model of the fourth comparative example used in the second simulation will be explained. The model of the fourth comparative example is the model of the filter of the fourth comparative example.

[0132] Figure 17 This is an explanatory diagram showing the pattern formation surface of the eighth dielectric layer of the laminated structure of the filter of the fourth comparative example. In the filter of the fourth comparative example, a conductor layer 1581 is formed in the eighth dielectric layer 58 instead of the conductor layer 581 of this embodiment. In the filter of the fourth comparative example, the first conductor portion 31 of the third resonator 30 is formed by... Figure 17 The conductor layer 1581 shown is formed. In the filter of the fourth comparative example, the first conductor portion 31 (conductor layer 1581) has a shape symmetrical with respect to the YZ plane intersecting the center of the stack 50 in a direction parallel to the X direction. The other structures of the filter of the fourth comparative example are substantially the same as those of the filter 1 of this embodiment.

[0133] Figure 18 This is a characteristic plot showing the attenuation characteristics of the model in the fourth comparative example. Figure 18 In the diagram, the horizontal axis represents frequency, and the vertical axis represents attenuation. In the model of the fourth comparative example, peaks with relatively small attenuation exist in the frequency band of 15–18 GHz. The models of the fourth comparative example and the embodiment (see...) Figure 16 In the model of the fourth comparative example, when focusing on the frequency bands of the aforementioned peaks and their vicinity, the attenuation is smaller than that of the example.

[0134] As described above, in this embodiment, the first conductor portion 31 (conductor layer 581) has an asymmetrical shape. The second simulation results show that, according to this embodiment, by making the first conductor portion 31 asymmetrical, the passband attenuation can be increased on the high-frequency side of the passband.

[0135] [Second Implementation]

[0136] Next, refer to Figure 19 The second embodiment of the present invention will now be described. Figure 19 This is a circuit diagram showing the circuit structure of the filter according to this embodiment.

[0137] The filter 1 in this embodiment differs from the first embodiment in the following ways. The filter 1 in this embodiment includes a fourth resonator 40. The fourth resonator 40 is arranged in the circuit structure between the second resonator 20 and the third resonator 30. In this embodiment, the first to fourth resonators 10, 20, 30, and 40 are configured such that the first resonator 10 and the third resonator 30 are adjacent in the circuit structure and electromagnetically coupled, the third resonator 30 and the fourth resonator 40 are adjacent in the circuit structure and electromagnetically coupled, and the second resonator 20 and the fourth resonator 40 are adjacent in the circuit structure and electromagnetically coupled. Figure 19 In the diagram, the curve marked K13 represents the electric field coupling between the first resonator 10 and the third resonator 30, the curve marked K34 represents the magnetic field coupling between the third resonator 30 and the fourth resonator 40, and the curve marked K24 represents the electric field coupling between the second resonator 20 and the fourth resonator 40.

[0138] The structure of the fourth resonator 40 is basically the same as that of the third resonator 30. That is, the fourth resonator 40 includes a first conductor portion 41 and a second conductor portion 42 with an impedance smaller than that of the first conductor portion 41. The first conductor portion 41 and the second conductor portion 42 are electrically connected to each other. The first conductor portion 41 is grounded. In addition, the first conductor portion 41 and the second conductor portion 42 are each a distributed constant line. In this embodiment, in particular, the first conductor portion 41 is a distributed constant line with a small width, and the second conductor portion 42 is a distributed constant line with a larger width than that of the first conductor portion 41.

[0139] The fourth resonator 40, like the first to third resonators 10, 20 and 30, is a step impedance resonator composed of a narrow-width distribution constant line and a wide-width distribution constant line.

[0140] Although not illustrated, the first conductor portion 41 and the second conductor portion 42 of the fourth resonator 40, like the first conductor portion 31 and the second conductor portion 32 of the third resonator 30, are arranged at different positions in the stacking direction T. The first conductor portion 31 and the first conductor portion 41 can also be arranged at the same position in the stacking direction T, or they can be arranged at different positions in the stacking direction T. Similarly, the second conductor portion 32 and the second conductor portion 42 can also be arranged at the same position in the stacking direction T, or they can be arranged at different positions in the stacking direction T.

[0141] In this embodiment, from the Z direction (refer to...) Figure 2 During observation, at least a portion of the third resonator 30 and at least a portion of the fourth resonator 40 are disposed between the first resonator 10 and the second resonator 20.

[0142] Furthermore, in this embodiment, when viewed from the Z direction, a portion of the first conductor portion 11 of the first resonator 10 may overlap with the first conductor portion 31 of the third resonator 30. In this case, when viewed from the Z direction, a portion of the first conductor portion 21 of the second resonator 20 may also overlap with the first conductor portion 41 of the fourth resonator 40.

[0143] Furthermore, in this embodiment, when viewed from the Z direction, a portion of the second conductor portion 12 of the first resonator 10 may overlap with the second conductor portion 32 of the third resonator 30. In this case, when viewed from the Z direction, a portion of the second conductor portion 22 of the second resonator 20 may also overlap with the second conductor portion 42 of the fourth resonator 40.

[0144] The filter 1 of this embodiment further includes: a third stub resonator 93 electrically connected to the first conductor portion 31 of the third resonator 30, and a fourth stub resonator 94 electrically connected to the first conductor portion 41 of the fourth resonator 40. The third and fourth stub resonators 93 and 94 are each distributed constant circuits.

[0145] The third stubular resonator 93 is connected midway through the first conductor section 31. Figure 19 In the circuit diagram, symbol 31A represents the portion of the first conductor portion 31 that is located in the circuit structure between the connection point with the third stub resonator 93 and the second conductor portion 32, and symbol 31B represents the portion in the circuit structure located between the connection point with the third stub resonator 93 and the ground wire.

[0146] The fourth stub-type resonator 94 is connected midway through the first conductor section 41. Figure 19In the circuit diagram, symbol 41A represents the portion of the first conductor portion 41 that is located in the circuit structure between the connection point with the fourth stub resonator 94 and the second conductor portion 42, and symbol 41B represents the portion in the circuit structure located between the connection point with the fourth stub resonator 94 and the ground wire.

[0147] The third and fourth stub resonators 93 and 94 are used, for example, to control spurious emissions generated in the frequency domain above the passband. The third and fourth stub resonators 93 and 94 can also be open-circuit stubs with one end open or short-circuit stubs with one end grounded.

[0148] The other structures, functions, and effects of this embodiment are the same as those of the first embodiment.

[0149] Furthermore, the present invention is not limited to the embodiments described above, and various modifications are possible. For example, the number or structure of the resonators is not limited to those shown in the embodiments, as long as they satisfy the scope of the claims. The number of resonators can also be one, two, or more than five.

[0150] As can be seen from the above description, various modes or variations of the present invention can be implemented. Therefore, within the equivalent scope of the claims, the present invention can also be implemented in ways other than the preferred mode described above.

Claims

1. A filter, characterized in that, A bandpass filter is a filter that selectively allows frequency signals within a specified passband to pass through. The filter has the following features: The first resonator and the second resonator each include: a first conductor portion and a second conductor portion with an impedance smaller than that of the first conductor portion; The first stub resonator is composed of a distributed constant line and is electrically and directly connected to the first conductor portion of the first resonator. as well as The second stub-type resonator, which is composed of a distributed constant circuit, is electrically and directly connected to the first conductor portion of the second resonator. The shapes of the first stubular resonator and the second stubular resonator are different. The first conductor portion of the first resonator includes: a first connecting portion connected to the first stub resonator, and a first non-connecting portion other than the first connecting portion. The first conductor portion of the second resonator includes: a second connecting portion connected to the second stub resonator, and a second non-connecting portion other than the second connecting portion. The current density at the center frequency of the passband in the first connected portion is greater than the current density at the center frequency of the passband in the first unconnected portion. The current density at the center frequency of the passband in the second connected portion is greater than the current density at the center frequency of the passband in the second unconnected portion.

2. The filter according to claim 1, characterized in that, The lengths of the first stub resonator and the second stub resonator are different.

3. The filter according to claim 1, characterized in that, Each of the first conductor section and the second conductor section is a distributed constant line.

4. The filter according to claim 1, characterized in that, The impedance ratio of the second conductor portion of the first resonator and the second resonator to the impedance of the first conductor portion is 0.3 or less.

5. The filter according to claim 1, characterized in that, The first conductor portion of the first resonator and the first conductor portion of the second resonator each comprise multiple portions extending in multiple different directions.

6. The filter according to claim 1, characterized in that, It also includes: a laminate containing multiple stacked dielectric layers, The first resonator, the second resonator, the first stub resonator, and the second stub resonator are integrated into the stack.

7. The filter according to claim 6, characterized in that, In each of the first and second resonators, the first conductor portion and the second conductor portion are arranged at different positions in the stacking direction of the plurality of dielectric layers and are electrically connected to each other.

8. The filter according to claim 7, characterized in that, It also includes: multiple through holes that connect the first conductor portion and the second conductor portion of each of the first resonator and the second resonator.

9. The filter according to claim 7, characterized in that, The first conductor portion of the first resonator and the first conductor portion of the second resonator are arranged at the same position in the stacking direction.

10. The filter according to claim 7, characterized in that, The second conductor portion of the first resonator and the second conductor portion of the second resonator are arranged at the same position in the stacking direction.

11. The filter according to claim 1, characterized in that, It also includes a third resonator, which is configured in the circuit structure between the first resonator and the second resonator.

12. The filter according to claim 11, characterized in that, The third resonator comprises: a third conductor portion and a fourth conductor portion with an impedance smaller than that of the third conductor portion. The third conductor portion has an asymmetrical shape.

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