Filter

Abstract

To provide a filter capable of increasing a pass attenuation amount in a wide frequency band on a high-pass side of a passband.SOLUTION: A filter 1 comprises first and second resonators 10 and 20 and first and second stub type resonators 91 and 92. Each of the first and second resonators 10 and 20 includes a first conductor portion and a second conductor portion which is electrically connected to the first conductor portion and of which the impedance is smaller than that of the first conductor portion. The first stub type resonator 91 is electrically connected to a first conductor portion 11 of the first resonator 10. The second stub type resonator 92 is electrically connected to a first conductor portion 21 of the second resonator 20. A shape of the first stub type resonator 91 and a shape of the second stub type resonator 92 are different from each other.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a filter including a resonator formed of a distributed constant line.

Background Art

[0002] One of the electronic components used in communication devices is a band-pass filter including a plurality of resonators. Each of the plurality of resonators is configured by, for example, a distributed constant line. The distributed constant line is configured to have a predetermined line length.

[0003] One of the resonators formed of a distributed constant line is a stub type resonator. For example, Patent Document 1 describes a technique using a stub element as means for adjusting directivity and coupling degree. Further, Patent Document 2 describes a technique using a tip open stub as means for suppressing spurious components at a higher-order resonance frequency.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a band-pass filter, it may be required to increase the absolute value of the attenuation amount (hereinafter, also referred to as the pass attenuation amount) on the high-frequency side of the pass band. For this purpose, it is necessary to control spurious generated on the high-frequency side of the pass band.

[0006] Currently, communication services using the fifth-generation mobile communication system (hereinafter referred to as 5G) have begun to be provided. In 5G, the use of frequency bands of 10 GHz or higher, particularly the quasi-millimeter wave band of 10 to 30 GHz and the millimeter wave band of 30 to 300 GHz, is assumed. Thus, when a higher and wider frequency band than before is used, even in a bandpass filter, it is required to satisfy characteristics in a higher and wider frequency band than before. However, it has been difficult to obtain sufficient characteristics with conventional technologies.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide a filter capable of increasing the pass attenuation amount in a wide frequency band on the high-frequency side of the passband.

Means for Solving the Problems

[0008] The filter of the present invention includes a first resonator and a second resonator each including 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 formed of a distributed constant line and electrically connected to the first conductor portion of the first resonator, and a second stub-type resonator formed of a distributed constant line and electrically connected to the first conductor portion of the second resonator. The shape of the first stub-type resonator and the shape of the second stub-type resonator are different from each other.

[0009] In the filter of the present invention, the length of the first stub-type resonator and the length of the second stub-type resonator may be different from each other.

[0010] Also, in the filter of the present invention, each of the first conductor portion and the second conductor portion may be a distributed constant line.

[0011] Further, the filter of the present invention may be a band-pass filter that selectively passes signals having frequencies within a predetermined passband. In this case, the first conductor portion of the first resonator may include a first connection portion to which the first stub-type resonator is connected and a first non-connection portion other than the first connection portion. Also, the first conductor portion of the second resonator may include a second connection portion to which the second stub-type resonator is connected and a second non-connection portion other than the second connection portion. The current density at the center frequency of the passband in the first connection portion may be greater than the current density at the center frequency of the passband in the first non-connection portion. The current density at the center frequency of the passband in the second connection portion may be greater than the current density at the center frequency of the passband in the second non-connection portion.

[0012] Further, in the filter of the present invention, for each of the first resonator and the second resonator, First with respect to the impedance of the conductor portion Second the impedance ratio, which is the ratio of the impedance of the conductor portion, may be 0.3 or less.

[0013] Also, 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 include a plurality of portions extending in a plurality of different directions from each other.

[0014] Further, the filter of the present invention may further include a laminate including a plurality of stacked dielectric layers. The first resonator, the second resonator, the first stub-type resonator, and the second stub-type resonator may be integrated into the laminate. In this case, in each of the first resonator and the second resonator, the first conductor portion and the second conductor portion may be arranged at different positions from each other in the stacking direction of the plurality of dielectric layers and may be electrically connected to each other. Further, the filter of the present invention may further include a plurality of through holes connecting the first conductor portion and the second conductor portion of each of the first resonator and the second resonator. Also, 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. Also, the second conductor portion of the first resonator and the second conductor portion of the second resonator may be arranged at the same position in the stacking direction.

[0015] Further, the filter of the present invention may further include a third resonator arranged between the first resonator and the second resonator in terms of circuit configuration. In this case, the third resonator may include a third conductor portion and a fourth conductor portion having an impedance smaller than that of the third conductor portion. The third conductor portion may have an asymmetric shape.

Advantages of the Invention

[0016] The filter of the present invention includes a first stub-type resonator electrically connected to the first conductor portion of the first resonator and a second stub-type resonator electrically connected to the first conductor portion of the second resonator. The shape of the first stub-type resonator and the shape of the second stub-type resonator are different from each other. Thus, according to the present invention, there is an effect that it becomes possible to realize a filter capable of increasing the passing attenuation amount in a wide frequency band on the high-frequency side of the passing band.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Mode for Carrying Out the Invention

[0018] [First Embodiment] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, with reference to FIG. 1, the configuration of the filter 1 according to the first embodiment of the present invention will be described. FIG. 1 is a circuit diagram showing the circuit configuration of the filter 1. The filter 1 is configured to function as a band-pass filter that selectively passes signals having frequencies within a predetermined pass band.

[0019] The filter 1 according to the present 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 terms of circuit configuration. In the present application, the expression "in terms of circuit configuration" is used to refer to the arrangement on the circuit diagram, not the arrangement in the physical configuration.

[0020] The first to third resonators 10, 20, 30 are configured such that the first resonator 10 and the third resonator 30 are adjacent to each other in terms of circuit configuration and are electromagnetically coupled, and the second resonator 20 and the third resonator 30 are adjacent to each other in terms of circuit configuration and are electromagnetically coupled. In FIG. 1, the curve marked with the symbol K13 represents the electric field coupling between the first resonator 10 and the third resonator 30, and the curve marked with the symbol K23 represents the electric field coupling between the second resonator 20 and the third resonator 30.

[0021] Further, the first resonator 10 is magnetically coupled to a second resonator 20 that is not adjacent in terms of circuit configuration. In this way, the electromagnetic coupling between two resonators that are not adjacent in terms of circuit configuration is called skip coupling. In FIG. 1, the curve marked with the symbol K12 shows the magnetic coupling between the first resonator 10 and the second resonator 20.

[0022] The first resonator 10 includes a first conductor portion 11 and a second conductor portion 12 having 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 connected to the ground. Further, each of the first conductor portion 11 and the second conductor portion 12 is a distributed constant line. In particular, in the present embodiment, the first conductor portion 11 is a distributed constant line with a small width, and the second conductor portion 12 is a distributed constant line with a width larger than that of the first conductor portion 11.

[0023] The first resonator 10 further includes a third conductor portion 13 that electrically connects the first conductor portion 11 and the second conductor portion 12. The third conductor portion 13 may include a distributed constant line with a width smaller than that of the distributed constant line constituting the second conductor portion 12. The width of the distributed constant line of the third conductor portion 13 may be the same as or different from the width of the distributed constant line constituting the first conductor portion 11.

[0024] The configuration 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 having an impedance smaller than that of 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 connected to the ground. Further, each of the first conductor portion 21 and the second conductor portion 22 is a distributed constant line. In particular, in the present embodiment, 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 width larger than that of the first conductor portion 21.

[0025] The second resonator 20 further includes a third conductor portion 23 that electrically connects the first conductor portion 21 and the second conductor portion 22. The third conductor portion 23 may include a distributed constant line having a width smaller than that of the distributed constant line constituting the second conductor portion 22. The width of the distributed constant line of the third conductor portion 23 may be the same as or different from the width of the distributed constant line constituting the first conductor portion 21.

[0026] The third resonator 30 includes a first conductor portion 31 and a second conductor portion 32 having an impedance smaller than that of the first conductor portion 31. The first conductor portion 31 corresponds to the "third conductor portion" in the present invention, and the second conductor portion 32 corresponds to the "fourth conductor portion" in the present invention. The first conductor portion 31 and the second conductor portion 32 are electrically connected to each other. The first conductor portion 31 is connected to the ground. Further, each of the first conductor portion 31 and the second conductor portion 32 is a distributed constant line. In particular, in the present embodiment, the first conductor portion 31 is a distributed constant line having a small width, and the second conductor portion 32 is a distributed constant line having a width larger than that of the first conductor portion 31.

[0027] Each of the first to third resonators 10, 20, 30 is a stepped impedance resonator composed of a distributed constant line having a small width and a distributed constant line having a large width. Further, each of the first to third resonators 10, 20, 30 is a 1 / 4 wavelength resonator having one end short-circuited and the other end open.

[0028] The impedance of each of the first conductor portions 11, 21, 31 is, for example, in the range of 15 to 35 Ω. The impedance of each of the second conductor portions 12, 22, 32 is, for example, in the range of 1 to 5 Ω. Here, in each of the first to third resonators 10, 20, 30, First with respect to the impedance of the conductor portion Second the ratio of the impedance of the conductor portion is referred to as the impedance ratio. In each of the first to third resonators 10, 20, 30, the impedance ratio is smaller than 1.

[0029] From the perspective of reducing the resonator size, it is preferable that the impedance ratio be small. For example, by adjusting the width of each of the distributed constant lines constituting the first conductor portion and the distributed constant lines constituting the second conductor portion, it is possible to adjust the impedance ratio. As the impedance ratio decreases, the width of the distributed constant line constituting the first conductor portion becomes relatively small, and the width of the distributed constant line constituting the second conductor portion becomes relatively large.

[0030] In particular, in this embodiment, the impedance ratio in each of the first to third resonators 10, 20, and 30 is 0.3 or less. In one example, the impedance of the conductor portion of each of the first and second resonators 10 and 20 is 2.87 Ω, and the impedance of the conductor portion of each of the first and second resonators 10 and 20 Second is 27 Ω. In this case, the impedance ratio in each of the first and second resonators 10 and 20 is 0.106. Also, in one example, the impedance of the First third resonator 30 is 2.55 Ω, and the impedance of the Second conductor portion 32 third resonator 30 is 27 Ω. In this case, the impedance ratio in the third resonator 30 is 0.094. First conductor portion 31

[0031] Incidentally, if the impedance ratio is made too small, the desired characteristics may not be obtained. For example, in a stepped impedance resonator (quarter-wavelength resonator) with one end short-circuited and the other end open, if the impedance ratio is made too small, this resonator becomes a half-wavelength resonator consisting substantially only of a second conductor portion with both ends open. As a result, the desired characteristics cannot be obtained. To prevent this, in this embodiment, the impedance ratio in each of the first to third resonators 10, 20, and 30 is set to 0.06 or more.

[0032] ​Filter 1 further 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 between the first port 2 and the second port 3 in terms of circuit configuration.

[0033] Conductor portion 4 electrically connects the first port 2 and the first resonator 10. One end of conductor portion 4 is connected to the first port 2. The other end of conductor portion 4 is connected to the first resonator 10 between the first conductor portion 11 and the third conductor portion 13.

[0034] Conductor portion 5 electrically connects the second port 3 and the second resonator 20. One end of conductor portion 5 is connected to the second port 3. The other end of conductor portion 5 is connected to the second resonator 20 between the first conductor portion 21 and the third conductor portion 23.

[0035] Filter 1 further includes a first stub-type resonator 91 electrically connected to the first conductor portion 11 of the first resonator 10 and a second stub-type resonator 92 electrically connected to the first conductor portion 21 of the second resonator 20. Each of the first and second stub-type resonators 91 and 92 is composed of a distributed constant line.

[0036] The first stub-type resonator 91 is connected in the middle of the first conductor portion 11. In FIG. 1, the portion of the first conductor portion 11 located between the connection point with the first stub-type resonator 91 and the second conductor portion 12 in terms of circuit configuration is indicated by reference numeral 11A, and the portion of the first conductor portion 11 located between the connection point with the first stub-type resonator 91 and the ground is indicated by reference numeral 11B.

[0037] The second stub-type resonator 92 is connected in the middle of the first conductor portion 21. In FIG. 1, the portion of the first conductor portion 21 located between the connection point with the second stub-type resonator 92 and the second conductor portion 22 in terms of circuit configuration is indicated by reference numeral 21A, and the portion of the first conductor portion 21 located between the connection point with the second stub-type resonator 92 and the ground is indicated by reference numeral 21B.

[0038] As will be described later, the shape of the first stub-type resonator 91 and the shape of the second stub-type resonator 92 are different from each other. In particular, in the present embodiment, the length of the first stub-type resonator 91 and the length of the second stub-type resonator 92 are different from each other.

[0039] Each of the first and second stub-type resonators 91 and 92 may be an open stub with one end open, or may be a short stub with one end connected to the ground. FIG. 1 shows an example in which the first and second stub-type resonators 91 and 92 are open stubs, respectively.

[0040] Next, referring to FIG. 2, other configurations of the filter 1 will be described. FIG. 2 is a perspective view showing the appearance of the filter 1.

[0041] The filter 1 further includes a laminate 50. The laminate 50 includes a plurality of stacked dielectric layers, a plurality of conductor layers formed on the plurality of dielectric layers, and a plurality of through holes. The first to third resonators 10, 20, 30 and the first and second stub-type resonators 91, 92 are integrated with the laminate 50. The first to third resonators 10, 20, 30 and the first and second stub-type resonators 91, 92 are configured using a plurality of conductor layers.

[0042] The laminate 50 has a first surface 50A and a second surface 50B located at both ends in the stacking 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. The side surfaces 50C and 50D face opposite sides, and the side surfaces 50E and 50F also face opposite sides. The side surfaces 50C to 50F are perpendicular to the first surface 50A and the second surface 50B.

[0043] Here, as shown in FIG. 2, the X direction, the Y direction, and the Z direction are defined. The X direction, the Y direction, and the Z direction are perpendicular to each other. In the present embodiment, one direction parallel to the stacking direction T is defined as the Z direction. Also, 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.

[0044] As shown in FIG. 2, 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 upper 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.

[0045] The planar shape of the laminate 50 when viewed from the Z direction, that is, the shape of the first surface 50A or the second surface 50B, is a shape that is long in one direction. In particular, in the present embodiment, the planar shape of the laminate 50 when viewed from the Z direction is a rectangular shape that is long in a direction parallel to the X direction.

[0046] The filter 1 further includes a plurality of terminals 111, 112, 113, 114, 115, 116 provided on the first surface 50A of the laminate 50. The terminal 111 extends in the Y direction in the vicinity of the side surface 50C. The terminal 112 extends in the Y direction in the vicinity of the side surface 50D. The terminals 113 to 116 are arranged between the terminal 111 and the terminal 112. The terminals 113 and 114 are arranged in this order in the X direction in the vicinity of the side surface 50E. The terminals 115 and 116 are arranged in this order in the X direction in the vicinity of the side surface 50F.

[0047] The terminal 111 corresponds to the first port 2, and the terminal 112 corresponds to the second port 3. Therefore, the first and second ports 2 and 3 are provided on the first surface 50A of the laminate 50. The terminals 113 to 116 are connected to the ground. Hereinafter, the terminal 111 is also referred to as the first terminal 111, the terminal 112 is also referred to as the second terminal 112, and the terminals 113 to 116 are also referred to as the ground terminals 113 to 116.

[0048] Next, with reference to FIGS. 3 to 5, an example of a plurality of dielectric layers and a plurality of conductor layers constituting the laminate 50 will be described. In this example, the laminate 50 has nine stacked dielectric layers. Hereinafter, these nine dielectric layers will be referred to as the first to ninth dielectric layers in order from the bottom. Also, the first to ninth dielectric layers are represented by reference numerals 51 to 59.

[0049] FIG. 3(a) shows the pattern formation surface of the first dielectric layer 51. Terminals 111, 112, 113, 114, 115, and 116 are formed on the pattern formation surface of the dielectric layer 51. Also, through holes 51T1, 51T2, 51T3, 51T4, 51T5, and 51T6 connected to the terminals 111, 112, 113, 114, 115, and 116, respectively, are formed in the dielectric layer 51.

[0050] FIG. 3(b) shows the pattern formation surface of the second dielectric layer 52. A conductor layer 521 is formed on the pattern formation surface of the dielectric layer 52. Also, through holes 52T1, 52T2, 52T3, 52T4, 52T5, and 52T6 are formed in the dielectric layer 52. The through holes 51T1 and 51T2 formed in the dielectric layer 51 are connected to the through holes 52T1 and 52T2, respectively. The through holes 51T3 to 51T6 formed in the dielectric layer 51 and the through holes 52T3 to 52T6 are connected to the conductor layer 521.

[0051] FIG. 3(c) shows the pattern formation surface of the third dielectric layer 53. Conductor layers 531, 532, 533, and 534 are formed on the pattern formation surface of the dielectric layer 53. The conductor layer 532 is connected to the conductor layer 531. The conductor layer 534 is connected to the conductor layer 533. In FIG. 3(c), the boundaries between the conductor layer 531 and the conductor layer 532 and between the conductor layer 533 and the conductor layer 534 are indicated by dotted lines, respectively.

[0052] In addition, through holes 53T1, 53T2, 53T3, 53T4, 53T5, and 53T6 are formed in the dielectric layer 53. The through hole 52T1 formed in the dielectric layer 52 and the through hole 53T1 are connected to the conductor layer 532. The through hole 52T2 formed in the dielectric layer 52 and the through hole 53T2 are connected to the conductor layer 534. The through holes 52T3 to 52T6 formed in the dielectric layer 52 are respectively connected to the through holes 53T3 to 53T6.

[0053] Figure 4(a) shows the pattern formation surface of the fourth dielectric layer 54. A conductor layer 541 is formed on the pattern formation surface of the dielectric layer 54. In addition, through holes 54T1, 54T2, 54T3, 54T4, 54T5, 54T6, and 54T7 are formed in the dielectric layer 54. The through holes 53T1 to 53T6 formed in the dielectric layer 53 are respectively connected to the through holes 54T1 to 54T6. The through hole 54T7 is connected to the conductor layer 541.

[0054] Figure 4(b) shows the pattern formation surface of the fifth dielectric layer 55. A conductor layer 551 is formed on the pattern formation surface of the dielectric layer 55. In addition, through holes 55T1, 55T2, 55T7, and 55T8 are formed in the dielectric layer 55. The through holes 54T1, 54T2, and 54T7 formed in the dielectric layer 54 are respectively connected to the through holes 55T1, 55T2, and 55T7. The through holes 54T3 to 54T6 formed in the dielectric layer 54 and the through hole 55T8 are connected to the conductor layer 551.

[0055] Figure 4(c) shows the pattern formation surface of the sixth dielectric layer 56. Through holes 56T1, 56T2, 56T7, and 56T8 are formed in the dielectric layer 56. The through holes 55T1, 55T2, 55T7, and 55T8 formed in the dielectric layer 55 are respectively connected to the through holes 56T1, 56T2, 56T7, and 56T8.

[0056] FIG. 5(a) shows the pattern formation surface of the seventh dielectric layer 57. Conductor layers 571, 572, 573, and 574 are formed on the pattern formation surface of the dielectric layer 57. Each of the conductor layers 571 and 572 has a first end and a second end located on opposite sides of each other. The first end of the conductor layer 571 and the first end of the conductor layer 572 are connected to each other. In FIG. 5(a), the boundary between the conductor layer 571 and the conductor layer 572 is indicated by a dotted line. The through hole 56T1 formed in the dielectric layer 56 is connected to the vicinity of the second end of the conductor layer 571. The through hole 56T2 formed in the dielectric layer 56 is connected to the vicinity of the second end of the conductor layer 572.

[0057] The conductor layer 573 is connected in the middle of the conductor layer 571. The conductor layer 574 is connected in the middle of the conductor layer 572. In FIG. 5(a), the boundary between the conductor layer 571 and the conductor layer 573 and the boundary between the conductor layer 572 and the conductor layer 574 are each indicated by a dotted line.

[0058] Also, through holes 57T7 and 57T8 are formed in the dielectric layer 57. The through hole 56T7 formed in the dielectric layer 56 is connected to the through hole 57T7. The through hole 56T8 formed in the dielectric layer 56 and the through hole 57T8 are connected to the vicinity of the first end of the conductor layer 571 and the vicinity of the first end of the conductor layer 572.

[0059] FIG. 5(b) shows the pattern formation surface of the eighth dielectric layer 58. A conductor layer 581 is formed on the pattern formation surface of the dielectric layer 58. The conductor layer 581 has a first end and a second end located on opposite sides of each other. The through hole 57T7 formed in the dielectric layer 57 is connected to the vicinity of the first end of the conductor layer 581.

[0060] Also, a through hole 58T8 is formed in the dielectric layer 58. The through hole 57T8 formed in the dielectric layer 57 and the through hole 58T8 are connected to the vicinity of the second end of the conductor layer 581.

[0061] FIG. 5(c) shows the pattern formation surface of the ninth dielectric layer 59. A conductor layer 591 is formed on the pattern formation surface of the dielectric layer 59. The through hole 58T8 formed in the dielectric layer 58 is connected to the conductor layer 591.

[0062] The laminate 50 shown in FIG. 2 is configured by laminating the first to ninth dielectric layers 51 to 59 such that the pattern formation surface of the first dielectric layer 51 becomes the first surface 50A of the laminate 50, and the surface opposite to the pattern formation surface of the ninth dielectric layer 59 becomes the second surface 50B of the laminate 50.

[0063] FIG. 6 shows the inside of the laminate 50 configured by laminating the first to ninth dielectric layers 51 to 59. As shown in FIG. 6, inside the laminate 50, a plurality of conductor layers and a plurality of through holes shown in FIGS. 3 to 5 are laminated.

[0064] Hereinafter, the correspondence between the components of the circuit of the filter 1 shown in FIG. 1 and the components inside the laminate 50 shown in FIGS. 3 to 5 will be described. First, the first resonator 10 will be described. The first conductor portion 11 is constituted by the conductor layer 571. The second conductor portion 12 is constituted by the conductor layer 531. The third conductor portion 13 is constituted by the conductor layer 532.

[0065] The conductor layer 532 (the third conductor portion 13) and the through holes 53T1, 54T1, 55T1, 56T1 connect the conductor layer 571 constituting the first conductor portion 11 and the conductor layer 531 constituting the second conductor portion 12. Further, the conductor layer 571 constituting the first conductor portion 11 is connected to the ground terminals 113 to 116 via the through holes 51T3 to 51T6, the conductor layer 521, the through holes 52T3 to 52T6, 53T3 to 53T6, the through holes 54T3 to 54T6, the conductor layer 551, and the through holes 55T8, 56T8.

[0066] Next, the second resonator 20 will be described. The first conductor portion 21 is constituted by the conductor layer 572. The second conductor portion 22 is constituted by the conductor layer 533. The third conductor portion 23 is constituted by the conductor layer 534.

[0067] The conductor layer 534 (the third conductor portion 23) and the through holes 53T2, 54T2, 55T2, 56T2 connect the conductor layer 572 constituting the first conductor portion 21 and the conductor layer 533 constituting the second conductor portion 22. Also, the conductor layer 572 constituting the first conductor portion 21 is connected to the ground terminals 113 to 116 via the through holes 51T3 to 51T6, the conductor layer 521, the through holes 52T3 to 52T6, 53T3 to 53T6, the through holes 54T3 to 54T6, the conductor layer 551, and the through holes 55T8, 56T8.

[0068] Next, the third resonator 30 will be described. The first conductor portion 31 is constituted by the conductor layer 581. The second conductor portion 32 is constituted by the conductor layer 541.

[0069] The conductor layer 581 constituting the first conductor portion 31 is connected to the ground terminals 113 to 116 via the through holes 51T3 to 51T6, the conductor layer 521, the through holes 52T3 to 52T6, 53T3 to 53T6, the through holes 54T3 to 54T6, the conductor layer 551, and the through holes 55T8, 56T8, 57T8.

[0070] Next, the first and second stub resonators 91, 92 will be described. The first stub resonator 91 is constituted by the conductor layer 573. The second stub resonator 92 is constituted by the conductor layer 574.

[0071] Next, the conductor parts 4 and 5 will be described. The conductor part 4 is composed of through-holes 51T1 and 52T1. The through-hole 51T1 is connected to the first terminal 111. The through-hole 52T1 is connected to the conductor layer 532 that constitutes the third conductor part 13 and is also connected to the conductor layer 571 that constitutes the first conductor part 11 via through-holes 53T1, 54T1, 55T1, and 56T1.

[0072] The conductor part 5 is composed of through-holes 51T2 and 52T2. The through-hole 51T2 is connected to the second terminal 112. The through-hole 52T2 is connected to the conductor layer 534 that constitutes the third conductor part 23 and is also connected to the conductor layer 572 that constitutes the first conductor part 21 via through-holes 53T2, 54T2, 55T2, and 56T2.

[0073] Next, with reference to FIGS. 2 to 8, the structural features of the filter 1 according to the present embodiment will be described. FIGS. 7 and 8 are perspective views showing a part inside the laminate 50. FIG. 7 mainly shows a plurality of conductor layers and a plurality of through-holes that constitute the first and second resonators 10 and 20 and the first and second stub resonators 91 and 92. FIG. 8 mainly shows a plurality of conductor layers and a plurality of through-holes that constitute the third resonator 30.

[0074] 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 at a position closer to the side surface 50C than the side surface 50D. As shown in FIG. 7, the first conductor part 11 (conductor layer 571) and the second conductor part 12 (conductor layer 531) of the first resonator 10 are disposed at different positions in the stacking direction T. The second conductor part 12 is disposed between the first surface 50A where a plurality of terminals 111 to 116 are disposed and the first conductor part 11.

[0075] The first conductor portion 11 (conductor layer 571) includes a plurality of portions extending in a plurality of directions orthogonal to the stacking direction T. In particular, in the present embodiment, 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.

[0076] The shape of the second conductor portion 12 (conductor layer 531) is long in a direction intersecting the longitudinal direction of the laminate 50. In particular, in the present embodiment, the shape of the second conductor portion 12 (conductor layer 531) is a rectangular shape that is long in a direction parallel to the Y direction.

[0077] 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 at a position closer to the side surface 50D than the side surface 50C. As shown in FIG. 7, the first conductor portion 21 (conductor layer 572) and the second conductor portion 22 (conductor layer 533) of the second resonator 20 are disposed at different positions in the stacking direction T. The second conductor portion 22 is disposed between the first surface 50A on which the plurality of terminals 111 to 116 are disposed and the first conductor portion 21.

[0078] The first conductor portion 21 (conductor layer 572) includes a plurality of portions extending in a plurality of directions orthogonal to the stacking direction T. In particular, in the present embodiment, 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.

[0079] The shape of the second conductor portion 22 (conductor layer 533) is long in a direction intersecting the longitudinal direction of the laminate 50. In particular, in the present embodiment, the shape of the second conductor portion 22 (conductor layer 533) is a rectangular shape that is long in a direction parallel to the Y direction.

[0080] At least a part of the third resonator 30 is disposed between the first resonator 10 and the second resonator 20 when viewed from the Z direction. In particular, in the present embodiment, a part of the third resonator 30 is disposed between the first resonator 10 and the second resonator 20.

[0081] As shown in FIG. 8, 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 from each other in the stacking direction T. The second conductor portion 32 is arranged between the first surface 50A where the plurality of terminals 111 to 116 are arranged and the first conductor portion 31.

[0082] The first conductor portion 31 (conductor layer 581) includes a plurality of portions extending in a plurality of directions orthogonal to the stacking direction T. In particular, in the present embodiment, 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.

[0083] The first conductor portion 31 (conductor layer 581) has a shape that is asymmetric with respect to any XZ plane intersecting the first conductor portion 31 and also has a shape that is asymmetric with respect to any YZ plane intersecting the first conductor portion 31. Hereinafter, any XZ plane intersecting the first conductor portion 31 is referred to as a first virtual plane, and any YZ plane intersecting the first conductor portion 31 is referred to as a second virtual plane. The first virtual plane may intersect the center of the laminate 50 in a direction parallel to the Y direction. The second virtual plane may intersect the center of the laminate 50 in a direction parallel to the X direction.

[0084] The shape of the second conductor portion 32 (conductor layer 541) is a shape that is long in the longitudinal direction of the laminate 50. In particular, in the present embodiment, the shape of the second conductor portion 32 (conductor layer 541) is a rectangular shape that is long in a direction parallel to the X direction.

[0085] As shown in FIGS. 5(a) and 6, 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. As shown in FIGS. 5(a), 5(b) and 6, the first conductor portion 31 (conductor layer 581) of the third resonator 30 is arranged at a position different from that of the first conductor portions 11 and 21 in the stacking direction T. Also, a part of the first conductor portion 11 and a part of the first conductor portion 21 overlap the first conductor portion 31 when viewed from the Z direction. Also, the shape of the first conductor portion 31 is different from the shape of the first conductor portion 11 and the shape of the first conductor portion 21.

[0086] Also, as shown in FIGS. 3(c) and 6, 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 arranged at the same position in the stacking direction T. As shown in FIGS. 3(c), 4(a) and 6, the second conductor portion 32 (conductor layer 541) of the third resonator 30 is arranged at a position different from that of the second conductor portions 12 and 22 in the stacking direction T. Also, a part of the second conductor portion 12 and a part of the second conductor portion 22 overlap the second conductor portion 32 when viewed from the Z direction. Also, the shape of the second conductor portion 32 is different from the shape of the second conductor portion 12 and the shape of the second conductor portion 22.

[0087] As shown in FIG. 5, the shapes of the first stub-type resonator 91 (conductor layer 573) and the second stub-type resonator 92 (conductor layer 574) are different from each other. Specifically, the length of the first stub-type resonator 91 and the length of the second stub-type resonator 92 are different from each other. In the example shown in FIG. 5, the first stub-type resonator 91 is longer than the second stub-type resonator 92. The first stub-type resonator 91 includes 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 stub-type resonator 92 extends in a direction parallel to the X direction. Note that the widths of the first stub-type resonator 91 and the second stub-type resonator 92 are the same or substantially the same.

[0088] The first conductor portion 11 of the first resonator 10 includes a first connection portion to which the first stub-type resonator 91 is connected and a first non-connection portion other than the first connection portion. Specifically, the first connection portion is a portion 571a near the boundary with the conductor layer 573 indicated by the dotted line in the conductor layer 571 shown in FIG. 5(a). In FIG. 5(a), the approximate position of the portion 571a is indicated by an arrow. The first non-connection portion is the portion of the conductor layer 571 other than the portion 571a.

[0089] The current density at the center frequency of the passband of the filter 1 (band-pass filter) in the first connection portion (portion 571a) is large higher than the current density at the center frequency of the passband of the filter 1 (band-pass filter) in the first non-connection portion. That is, the first stub-type resonator 91 is connected to the portion where the current density is the highest or its vicinity in the first conductor portion 11.

[0090] The first conductor portion 21 of the second resonator 20 includes a second connection portion to which the second stub-type resonator 92 is connected and a second non-connection portion other than the second connection portion. Specifically, the first connection portion is a portion 572a near the boundary with the conductor layer 574 indicated by the dotted line in the conductor layer 572 shown in FIG. 5(a). In FIG. 5(a), the approximate position of the portion 572a is indicated by an arrow. The second non-connection portion is the portion of the conductor layer 572 other than the portion 572a.

[0091] The current density at the center frequency of the passband of the filter 1 (band-pass filter) in the second connection portion (portion 572a) is large higher than the current density at the center frequency of the passband of the filter 1 (band-pass filter) in the second non-connection portion. That is, the second stub-type resonator 92 is connected to the portion where the current density is the highest or its vicinity in the first conductor portion 21.

[0092] As described above, in the present embodiment, the first conductor portion 11 and the second conductor portion 12 of the first resonator 10 are arranged at different positions from each other in the stacking direction T. Thereby, according to the present embodiment, it becomes possible to arrange the first conductor portion 11 and the second conductor portion 12 overlapping each other. Thereby, according to the present embodiment, compared with the case where the first conductor portion 11 and the second conductor portion 12 are formed in the same dielectric layer and arranged at the same position in the stacking direction T, the area for arranging the first resonator 10 can be substantially reduced.

[0093] The above description of the first resonator 10 also applies to the second and third resonators 20 and 30. From these facts, according to the present embodiment, the filter 1 can be miniaturized.

[0094] Also, in the present embodiment, a part of the first conductor portion 11 of the first resonator 10 and a part of the first conductor portion 21 of the second resonator 20 overlap the first conductor portion 31 of the third resonator 30 when viewed from the Z direction, and a part of the second conductor portion 12 of the first resonator 10 and a part of the second conductor portion 22 of the second resonator 20 overlap the second conductor portion 32 of the third resonator 30 when viewed from the Z direction. Also by this, according to the present embodiment, the filter 1 can be miniaturized.

[0095] Also, in the present embodiment, each of the first conductor portions 11, 21, and 31 includes a plurality of portions extending in a plurality of different directions from each other. Thereby, according to the present embodiment, compared with the case where each of the first conductor portions 11, 21, and 31 extends in one direction, the area for arranging each of the first conductor portions 11, 21, and 31 can be substantially reduced.

[0096] Also, in the present embodiment, the conductor layer 591 is connected to the ground terminals 113 to 116 via the through-holes 51T3 to 51T6, the conductor layer 521, the through-holes 52T3 to 52T6, 53T3 to 53T6, the through-holes 54T3 to 54T6, the conductor layer 551, and the through-holes 55T8, 56T8, 57T8, 58T8. The first to third resonators 10, 20, 30 are disposed between the conductor layer 521 and the conductor layer 591. Each of the conductor layers 521 and 591 overlaps with the first to third resonators 10, 20, 30 when viewed from the Z direction. The conductor layers 521 and 591 function as shields.

[0097] Also, in the present embodiment, the first conductor portion 11 of the first resonator 10 has a larger impedance than the second conductor portion 12 of the first resonator 10. The first stub-type resonator 91 is electrically connected to the first conductor portion 11 having a large impedance. In particular, in the present embodiment, the first stub-type resonator 91 is connected to the portion where the current density is the largest in the first conductor portion 11. Thus, according to the present embodiment, spurious can be controlled while suppressing the influence of the first stub-type resonator 91 on the fundamental resonance of the first resonator 10.

[0098] The above description of the first resonator 10 and the first stub-type resonator 91 also applies to the second resonator 20 and the second stub-type resonator 92. According to the present embodiment, spurious can be controlled while suppressing the influence of the second stub-type resonator 92 on the fundamental resonance of the second resonator 20.

[0099] Next, the results of the first simulation showing that the absolute value of the attenuation amount (hereinafter referred to as the pass attenuation amount) can be increased in a wide frequency band on the high-frequency side of the passband by the first and second stub resonators 91 and 92 will be described. First, the models of the first to third comparative examples and the model of the example used in the first simulation will be described. The model of the first comparative example is the model of the filter of the first comparative example. FIG. 9 is a circuit diagram showing the circuit configuration of the filter of the first comparative example. FIG. 10 is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer in the laminate of the filter of the first comparative example. The configuration of the filter of the first comparative example is substantially the same as the configuration of the filter 1 according to the present embodiment, except that the first and second stub resonators 91 and 92 and the conductor layers 573 and 574 formed in the dielectric layer 57 of the laminate 50 are not provided.

[0100] The model of the second comparative example is the model of the filter of the second comparative example. FIG. 11 is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer 57 in 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 in the present embodiment. In FIG. 11, the boundary between the conductor layer 571 and the conductor layer 575 is indicated by a dotted line. In the filter of the second comparative example, the first stub resonator 91 is constituted by the conductor layer 575. The other configuration of the filter of the second comparative example is the same as the configuration of the filter 1 according to the present embodiment.

[0101] In particular, in the model of the second comparative example, the shape of the first stub resonator 91 (conductor layer 575) is the same as the shape of the second stub resonator 92 (conductor layer 574). That is, the first stub resonator 91 extends in a direction parallel to the X direction.

[0102] The model of the third comparative example is the model of the filter of the third comparative example. FIG. 12 is an explanatory diagram showing the pattern formation surface of the seventh dielectric layer 57 in 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 in the present embodiment. In FIG. 12, the boundary between the conductor layer 572 and the conductor layer 576 is indicated by a dotted line. In the filter of the third comparative example, the second stub type resonator 92 is constituted by the conductor layer 576. Other configurations of the filter of the third comparative example are the same as those of the filter 1 according to the present embodiment.

[0103] In particular, in the model of the third comparative example, the shape of the second stub type resonator 92 (conductor layer 576) is the same as the shape of the first stub type resonator 91 (conductor layer 573). That is, the second stub type resonator 92 includes two portions extending in a direction parallel to the X direction and one portion extending in a direction parallel to the Y direction.

[0104] The model of the example is the model of the filter 1 according to the present embodiment. In the simulation, in each of the models of the first to third comparative examples and the model of the example, the impedance ratio in each of the first and second resonators 10 and 20 was set to 0.106, and the impedance ratio in the third resonator 30 was set to 0.094.

[0105] In the first simulation, each of the models of the first to third comparative examples and the model of the example was designed to function as a band-pass filter. Then, the passing attenuation characteristics of each of the comparative example models and the example model were obtained.

[0106] FIG. 13 is a characteristic diagram showing the passing attenuation characteristics of the model of the first comparative example. FIG. 14 is a characteristic diagram showing the passing attenuation characteristics of the model of the second comparative example. FIG. 15 is a characteristic diagram showing the passing attenuation characteristics of the model of the third comparative example. FIG. 16 is a characteristic diagram showing the passing attenuation characteristics of the model of the example. In each of FIGS. 13 to 16, the horizontal axis represents frequency, and the vertical axis represents attenuation amount.

[0107] As shown in FIGS. 13 to 16, in both the models of the first to third comparative examples and the model of the example, a plurality of spurs are generated on the high-frequency side of the passband. The frequencies of each of the plurality of spurs are different from each other in the models of the first to third comparative examples and the model of the example. As described above, in the model of the first comparative example, the first and second stub-type resonators 91 and 92 are not provided. In the models of the second to third comparative examples and the model of the example, the shapes of the first and second stub-type resonators 91 and 92 are different from each other. The results of the first simulation shown in FIGS. 13 to 16 indicate that the first and second stub-type resonators 91 and 92 can control a plurality of spurs.

[0108] Further, when comparing the model of the first comparative example (FIG. 13) with the model of the second comparative example (FIG. 14), in both the model of the first comparative example and the model of the second comparative example, a peak where the pass attenuation amount becomes relatively small exists in the frequency band of 17 to 18 GHz. In the model of the second comparative example, the minimum value of the pass attenuation amount at the above peak is slightly larger than that of the model of the first comparative example.

[0109] Also, in the model of the third comparative example (FIG. 15), a peak where the pass attenuation amount becomes relatively small exists in the frequency band of 14 to 18 GHz. Focusing on the above peak and the frequency band in its vicinity in each of the models of the first to third comparative examples, in the model of the third comparative example, the pass attenuation amount is larger than that in the models of the first and second comparative examples. On the other hand, focusing on the frequency band of 24 to 31 GHz in each of the models of the first to third comparative examples, in the model of the third comparative example, the pass attenuation amount is smaller than that in the models of the first and second comparative examples.

[0110] Also, in the model of the embodiment (FIG. 16), there is a peak where the passing attenuation amount becomes relatively small in the frequency band of 14 to 16 GHz. Focusing on the above-mentioned peak and the frequency band in its vicinity in each of the models of the first and second comparative examples and the model of the embodiment, the passing attenuation amount in the model of the embodiment is larger than that in the models of the first and second comparative examples. Also, focusing on the frequency band of 27 to 31 GHz in each of the models of the third comparative example and the model of the embodiment, the passing attenuation amount in the model of the embodiment is smaller than that in the model of the third comparative example.

[0111] As understood from the results of the first simulation shown in FIGS. 13 to 16, according to this embodiment, the spurious generated on the high-frequency side of the passing band can be controlled by the first and second stub-type resonators 91 and 92. Also, as understood from the results of the first simulation shown in FIGS. 14 to 16, according to this embodiment, by making the shape of the first stub-type resonator 91 different from the shape of the second stub-type resonator 92, the passing attenuation amount can be increased in a wide frequency band on the high-frequency side of the passing band.

[0112] Next, the results of a second simulation showing that the passing attenuation amount (absolute value of the attenuation amount) can be increased on the high-frequency side of the passing band by the shape of the first conductor portion 31 of the third resonator 30 will be described. First, the model of the fourth comparative example used in the second simulation will be described. The model of the fourth comparative example is the model of the filter of the fourth comparative example.

[0113] FIG. 17 is an explanatory diagram showing a pattern formation surface of the eighth dielectric layer in the filter laminate of the fourth comparative example. In the filter of the fourth comparative example, a conductor layer 1581 is formed on the eighth dielectric layer 58 instead of the conductor layer 581 in the present embodiment. In the filter of the fourth comparative example, the first conductor portion 31 of the third resonator 30 is constituted by the conductor layer 1581 shown in FIG. 17. In the filter of the fourth comparative example, the first conductor portion 31 (conductor layer 1581) has a shape symmetric with respect to the YZ plane intersecting the center of the laminate 50 in the direction parallel to the X direction. Other configurations of the filter of the fourth comparative example are substantially the same as those of the filter 1 according to the present embodiment.

[0114] FIG. 18 is a characteristic diagram showing the pass attenuation characteristics of the model of the fourth comparative example. In FIG. 18, the horizontal axis represents frequency and the vertical axis represents attenuation amount. In the model of the fourth comparative example, a peak where the pass attenuation amount becomes relatively small exists in the frequency band of 15 to 18 GHz. When paying attention to the above-mentioned peak and the frequency band in the vicinity thereof in each of the model of the fourth comparative example and the model of the example (see FIG. 16), the pass attenuation amount is smaller in the model of the fourth comparative example than in the example.

[0115] As described above, in the present embodiment, the first conductor portion 31 (conductor layer 581) has an asymmetric shape. As understood from the results of the second simulation, according to the present embodiment, by making the first conductor portion 31 have an asymmetric shape, the pass attenuation amount can be increased on the high-frequency side of the pass band.

[0116] [Second Embodiment] Next, with reference to FIG. 19, an Second embodiment of the present invention will be described. FIG. 19 is a circuit diagram showing the filter circuit configuration according to the present embodiment.

[0117] The filter 1 according to this embodiment is different from the first embodiment in the following points. The filter 1 according to this embodiment includes a fourth resonator 40. The fourth resonator 40 is arranged between the second resonator 20 and the third resonator 30 in terms of circuit configuration. In this embodiment, the first to fourth resonators 10, 20, 30, 40 are configured such that the first resonator 10 and the third resonator 30 are adjacent to each other in terms of circuit configuration and are electromagnetically coupled, the third resonator 30 and the fourth resonator 40 are adjacent to each other in terms of circuit configuration and are electromagnetically coupled, and the second resonator 20 and the fourth resonator 40 are adjacent to each other in terms of circuit configuration and are electromagnetically coupled. In FIG. 19, the curve marked with the symbol K13 represents the electric field coupling between the first resonator 10 and the third resonator 30, the curve marked with the symbol K34 represents the magnetic field coupling between the third resonator 30 and the fourth resonator 40, and the curve marked with the symbol K24 represents the electric field coupling between the second resonator 20 and the fourth resonator 40.

[0118] The configuration 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 having 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 connected to the ground. Also, each of the first conductor portion 41 and the second conductor portion 42 is a distributed constant line. In particular, in this embodiment, 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 width larger than that of the first conductor portion 41.

[0119] Similar to the first to third resonators 10, 20, 30, the fourth resonator 40 is a stepped impedance resonator composed of a distributed constant line with a small width and a distributed constant line with a large width.

[0120] Although not shown, the first conductor portion 41 and the second conductor portion 42 of the fourth resonator 40 are arranged at different positions from each other in the stacking direction T, similar to the first conductor portion 31 and the second conductor portion 32 of the third resonator 30. The first conductor portion 31 and the first conductor portion 41 may be arranged at the same position in the stacking direction T, or may be arranged at different positions in the stacking direction T. Similarly, the second conductor portion 32 and the second conductor portion 42 may be arranged at the same position in the stacking direction T, or may be arranged at different positions in the stacking direction T.

[0121] In the present embodiment, at least a part of the third resonator 30 and at least a part of the fourth resonator 40 are arranged between the first resonator 10 and the second resonator 20 when viewed from the Z direction (see FIG. 2).

[0122] Also, in the present embodiment, a part of the first conductor portion 11 of the first resonator 10 may overlap the first conductor portion 31 of the third resonator 30 when viewed from the Z direction. In this case, a part of the first conductor portion 21 of the second resonator 20 may overlap the first conductor portion 41 of the fourth resonator 40 when viewed from the Z direction.

[0123] Also, in the present embodiment, a part of the second conductor portion 12 of the first resonator 10 may overlap the second conductor portion 32 of the third resonator 30 when viewed from the Z direction. In this case, a part of the second conductor portion 22 of the second resonator 20 may overlap the second conductor portion 42 of the fourth resonator 40 when viewed from the Z direction.

[0124] The filter 1 according to the present embodiment further includes a third stub-type resonator 93 electrically connected to the first conductor portion 31 of the third resonator 30 and a fourth stub-type resonator 94 electrically connected to the first conductor portion 41 of the fourth resonator 40. Each of the third and fourth stub-type resonators 93 and 94 is a distributed constant line.

[0125] The third stub-type resonator 93 is connected in the middle of the first conductor portion 31. In FIG. 19, among the first conductor portion 31, the portion located between the connection point with the third stub-type resonator 93 in terms of circuit configuration and the second conductor portion 32 is indicated by reference numeral 31A, and the portion located between the connection point with the third stub-type resonator 93 in terms of circuit configuration and the ground is indicated by reference numeral 31B.

[0126] The fourth stub-type resonator 94 is connected in the middle of the first conductor portion 41. In FIG. 19, among the first conductor portion 41, the portion located between the connection point with the fourth stub-type resonator 94 in terms of circuit configuration and the second conductor portion 42 is indicated by reference numeral 41A, and the portion located between the connection point with the fourth stub-type resonator 94 in terms of circuit configuration and the ground is indicated by reference numeral 41B.

[0127] The third and fourth stub-type resonators 93, 94 are used, for example, to control spurious signals generated in a frequency region higher than the passband. The third and fourth stub-type resonators 93, 94 may each be an open stub with one end open, or a short stub with one end connected to the ground.

[0128] Other configurations, operations, and effects in this embodiment are the same as those in the first embodiment.

[0129] Note that the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the number and configuration of the resonators are not limited to those shown in each embodiment, and any configuration that satisfies the claims may be used. The number of resonators may be one, two, or five or more.

Explanation of Reference Numerals

[0130] 1... Filter, 2... First port, 3... Second port, 4, 5... Conductor parts, 10... First resonator, 11... First conductor part, 12... Second conductor part, 13... Third conductor part, 20... Second resonator, 21... First conductor part, 22... Second conductor part, 23... Third conductor part, 30... Third resonator, 31... First conductor part, 32... Second conductor part, 50... Stacked body, 50A... First surface, 50B... Second surface, 50C to 50F... Side surfaces, 91... First stub-type resonator, 92... Second stub-type resonator, 111... First terminal, 112... Second terminal, 113 to 116... Ground terminals.

Claims

1. A first resonator and a second resonator each including 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 formed of a distributed constant line and electrically connected to the first conductor portion of the first resonator, a second stub-type resonator formed of a distributed constant line and electrically connected to the first conductor portion of the second resonator, wherein the shape of the first stub-type resonator and the shape of the second stub-type resonator are different from each other. A filter characterized by this.

2. The filter according to claim 1, wherein the length of the first stub-type resonator and the length of the second stub-type resonator are different from each other.

3. The filter according to claim 1 or 2, wherein each of the first conductor portion and the second conductor portion is a distributed constant line.

4. The filter according to any one of claims 1 to 3, which is a band-pass filter that selectively passes signals of frequencies within a predetermined passband.

5. The filter according to any one of claims 1 to 4, wherein the impedance ratio, which is the ratio of the impedance of the second conductor portion to the impedance of the first conductor portion in each of the first resonator and the second resonator, is 0.3 or less.

6. The filter according to any one of claims 1 to 5, wherein the first conductor portion of the first resonator and the first conductor portion of the second resonator each include a plurality of portions extending in a plurality of different directions from each other.

7. Furthermore, it includes a laminate including a plurality of laminated dielectric layers, The filter according to any one of claims 1 to 6, wherein the first resonator, the second resonator, the first stub-type resonator, and the second stub-type resonator are integrated with the laminate.

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

9. The filter according to claim 8, further comprising a plurality of through holes connecting the first conductor portion and the second conductor portion of each of the first resonator and the second resonator.

10. The filter according to claim 8 or 9, wherein 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. **Claim 11** The filter according to any one of claims 8 to 10, wherein 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. **Claim 12** Furthermore, the filter according to any one of claims 1 to 11, further comprising a third resonator arranged between the first resonator and the second resonator in terms of circuit configuration. **Claim 13** The third resonator includes a third conductor portion and a fourth conductor portion having an impedance smaller than that of the third conductor portion. The filter according to claim 12, wherein the third conductor portion has an asymmetric shape.

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