Test bench for evaluating noise suppression materials, noise suppression material evaluation system, and noise suppression material evaluation method

Abstract

This technology enables the evaluation of noise suppression material characteristics over a wide bandwidth. [Solution] The test bench for evaluating noise suppression members, according to the embodiment, has a bench body comprising a transmission line member to which measuring instruments for measuring transmission characteristics are connected at both ends, and a base member having a ground surface facing the transmission line member. The bench body has a first region located in the longitudinal center of the transmission line member, and a pair of second regions located on both sides of the first region in the longitudinal direction. The first line portion of the transmission line member included in the first region is arranged parallel to the ground surface at a distance from it and has a mounting portion to which the noise suppression member to be evaluated is attached. The pair of second line portions included in the pair of second regions of the transmission line member, and the base member are provided such that the impedance of the pair of second line portions gradually changes from both ends toward the first line portion.

Description

Technical Field

[0001] The present disclosure relates to a test bench for evaluating noise countermeasure members, a noise countermeasure member evaluation system, and a noise countermeasure member evaluation method.

Background Art

[0002] Conventionally, in order to suppress unnecessary electromagnetic waves radiated from electronic devices, cables, and harnesses, noise countermeasure members such as magnetic sheet members and ferrite cores may be used (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to evaluate the noise suppression effect of the above noise countermeasure member, for example, there is an evaluation method of a noise suppression sheet conforming to IEC62333-2. In this evaluation method, a noise suppression sheet to be evaluated is arranged on a microstrip line, and evaluation is performed based on the attenuation degree of noise excited in the microstrip line. However, the conditions are greatly different between the above method using a microstrip line and an actual machine using a harness, and there is a possibility that appropriate evaluation cannot be performed.

[0005] Also, for example, it is conceivable to take out only the harness, directly connect a measuring instrument to both ends of the harness, and evaluate the attenuation degree of noise excited in the harness. However, in such a method, there may be a case where broadband evaluation cannot be performed due to resonance according to the length of the harness.

[0006] Therefore, this disclosure aims to provide a technology that enables the evaluation of the characteristics of noise suppression materials over a wide bandwidth. [Means for solving the problem]

[0007] The test bench for evaluating noise suppression members, which is an embodiment of this design, comprises a bench body comprising a transmission line member to which measuring instruments for measuring transmission characteristics are connected at both ends, and a base member having a ground surface facing the transmission line member. The bench body comprises a first region located in the longitudinal center of the transmission line member, and a pair of second regions located on both sides of the first region in the longitudinal direction. The first line portion of the transmission line member included in the first region is arranged parallel to the ground surface at a distance from it and has a mounting portion to which the noise suppression member to be evaluated is attached. The pair of second line portions included in the pair of second regions of the transmission line member, and the base member, are provided such that the impedance of the pair of second line portions gradually changes from both ends toward the first line portion. [Effects of the Invention]

[0008] According to this disclosure, it becomes possible to evaluate the characteristics of noise suppression materials over a wide bandwidth. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an external view showing an example of a test bench for evaluating noise suppression components according to the first embodiment. [Figure 2] Figure 2 shows a partial top view and a partial front view of the evaluation test bench. [Figure 3] Figure 3 is a perspective view showing a test bench for evaluating the short-length configuration. [Figure 4] Figure 4 is an enlarged view of the main parts of the transmission line components; (a) shows the transmission line components when the evaluation test bench is in a long configuration, and (b) shows the transmission line components when the evaluation test bench is in a short configuration. [Figure 5]Figure 5 shows an example of a noise suppression component evaluation system. [Figure 6] Figure 6 is a flowchart showing an example of an evaluation method for noise suppression components using an evaluation test bench. [Figure 7] Figure 7 is a diagram illustrating an example of the de-embedding process in this embodiment. [Figure 8] Figure 8 is a front view of a test bench for evaluating noise suppression components according to the second embodiment. [Figure 9] Figure 9 shows a partial top view and a partial front view of a test bench for evaluating noise suppression members according to the third embodiment, where (a) is a top view showing a portion of the second region side of the evaluation test bench, and (b) is a front view of the portion corresponding to (a). [Figure 10] Figure 10 is a front view of a test bench for evaluating noise suppression components according to the fourth embodiment. [Figure 11] Figure 11 is a front view of a test bench for evaluating noise suppression members according to a modified example of the fourth embodiment. [Figure 12] Figure 12 is a cross-sectional view of the main part of a transmission line member composed of multiple rod-shaped members. [Figure 13] Figure 13 shows another modified example of a transmission line component. [Figure 14] Figure 14 shows an example of the passage characteristics according to the embodiment. [Figure 15] Figure 15 shows an example of the passage characteristics related to a comparative example. [Modes for carrying out the invention]

[0010] First, the details of the embodiment will be listed and explained. [Summary of the Embodiment]

[0011] (1) The test bench for evaluating noise countermeasure members according to the embodiment includes a bench body having a transmission line member to which measuring instruments for measuring passing characteristics are connected at both ends, and a base member having a ground plane facing the transmission line member. The bench body has a first region portion located at the longitudinal center of the transmission line member, and a pair of second region portions located on both sides in the longitudinal direction of the first region portion. The first line portion included in the first region portion of the transmission line member is arranged in parallel at an interval with respect to the ground plane, and has a mounting portion to which a noise countermeasure member to be evaluated is mounted. The pair of second line portions included in the pair of second region portions of the transmission line member, and the base member are provided such that the impedance of the pair of second line portions gradually changes from both ends toward the first line portion. According to the above configuration, since the impedance of the pair of second line portions is provided so as to gradually change from both ends toward the first line portion, if impedance matching can be achieved between both ends and the measuring instruments connected to this test bench, signal reflection at both ends is suppressed, and the occurrence of resonance between both ends is suppressed. Therefore, by dividing the passing characteristics of the pair of second line portions from the passing characteristics of the transmission line member and obtaining the passing characteristics in the first line portion, the characteristics of the noise countermeasure member mounted on the first line portion can be evaluated over a wide band.

[0012] (2) In the test bench for evaluating noise countermeasure members of (1) above, the impedance of the pair of second line portions determined by the pair of second line portions and the base member may gradually increase from both ends toward the first line portion. In this case, while achieving impedance matching between both ends and the measuring instruments connected to this test bench, impedance matching can be achieved between the end on the first line portion side and the first line portion in the pair of second line portions. Thereby, the characteristics of the noise countermeasure member mounted on the first line portion can be appropriately evaluated.

[0013] (3) In the test bench for evaluating the noise countermeasure member in (2) above, when the ground surface includes a pair of inclined surfaces included in the pair of second region portions, the intervals between the pair of inclined surfaces and the pair of second line portions may gradually widen from the both end portions toward the first region portion. In this case, the impedances of the pair of second line portions can be continuously and gently changed.

[0014] (4) In the test bench for evaluating the noise countermeasure member in (3) above, when the ground surface includes a central surface included in the first region portion and the transmission line member is parallel to the central surface, the pair of inclined surfaces may be inclined so as to be separated from the transmission line member from the both end portions toward the first region portion. In this case, it becomes easy to continuously and gently change the impedances of the pair of second line portions.

[0015] (5) In the test bench for evaluating the noise countermeasure member in (3) or (4) above, when the transmission line member is stretchable in the longitudinal direction and the base member includes a pair of base blocks having the pair of inclined surfaces and a ground plate having an arrangement surface on which the pair of base blocks are arranged along the longitudinal direction, the pair of base blocks may be configured to be able to select either a first arrangement in which they are separated from each other in the longitudinal direction with the first region portion interposed therebetween or a second arrangement in which they are closer to each other than the first arrangement as the arrangement on the arrangement surface. In this case, if the arrangement of the pair of base blocks is set to the second arrangement and the transmission line member is further shortened, the passing characteristics of the pair of second line portions to be divided from the passing characteristics of the transmission line member can be obtained. Therefore, the test bench for evaluating the noise countermeasure member can be used as a reference test bench for obtaining the passing characteristics of the pair of second line portions. As a result, there is no need to set up a separate reference test bench from the test bench used for evaluating noise suppression components. Furthermore, the pair of second line sections used when measuring the transmission line characteristics of the transmission line components and the pair of second line sections used when measuring the transmission line characteristics of the reference transmission line components can be made common, thereby further improving the measurement accuracy of the transmission characteristics of the first line section.

[0016] (6) In the noise suppression member evaluation test bench described in (5) above, if the transmission line member includes a rod-shaped member and a cylindrical member extending from at least one end of the rod-shaped member, the rod-shaped member may be inserted into the inner circumference of the cylindrical member so as to be movable in the axial direction while in contact with the cylindrical member. In this case, the transmission line members can be easily extended or retracted depending on the arrangement of the pair of base blocks. Furthermore, by having a portion of the transmission line members be made of cylindrical members, the rigidity of the transmission line members can be increased, and deflection occurring in the transmission line members can be suppressed.

[0017] (7) In the noise suppression member evaluation test bench described in (5) above, the transmission line member may include a first rod-shaped member having a length corresponding to the first line portion, and a pair of second rod-shaped members detachably connected to both ends of the first rod-shaped member and extending from both ends. In this case, the length of the transmission line member 4 can be extended or extended by the length of the first rod-shaped member by attaching the first rod-shaped member or by removing the first rod-shaped member and connecting the pair of second rod-shaped members together. This allows the transmission line member to be extended or extended according to the arrangement of the pair of base blocks. Furthermore, it becomes easier to make the cross-sectional contour shape and dimensions of the first rod-shaped member the same as those of the pair of second rod-shaped members, thereby making the cross-sectional contour shape of the transmission line member uniform along the longitudinal direction.

[0018] (8) Another embodiment from a different perspective is a noise suppression member evaluation system. This noise suppression member evaluation system includes the noise suppression member evaluation test bench described in (1) to (7) above, The system includes measuring instruments connected to both ends of the transmission line member.

[0019] (9) Another embodiment from a different perspective is a noise suppression member evaluation method. This noise suppression member evaluation method includes the steps of: using the noise suppression member evaluation test bench described in (1) above, measuring the passage characteristics of the transmission line member before and after mounting the noise suppression member to be evaluated to the mounting portion; using a reference test bench configured such that the ground plane includes a pair of inclined surfaces that are included in the pair of second regions by connecting the pair of second regions to each other, excluding the first region from the noise suppression member evaluation test bench, and measuring the reference passage characteristics of the reference transmission line member having the reference test bench, which includes only the pair of second line portions; and determining the passage characteristics of the first line portion based on the passage characteristics of the transmission line member before and after mounting and the reference passage characteristics.

[0020] [Details of the embodiment] Preferred embodiments will be described below with reference to the drawings. Furthermore, at least some of the embodiments described below may be combined in any way. [Regarding the first embodiment] [Regarding the test bench for evaluating noise suppression components] Figure 1 is an external view showing an example of a test bench for evaluating noise suppression components according to the first embodiment. This noise suppression material evaluation test bench 1 (hereinafter also simply referred to as evaluation test bench 1) is a test bench used to evaluate the noise suppression effect of noise suppression materials used in transmission lines such as cables and wire harnesses.

[0021] The evaluation test bench 1 comprises a bench body 2. The bench body 2 includes a transmission line member 4 and a base member 6. The transmission line member 4 is a long member made of a conductive metal such as copper, brass, or aluminum alloy. The cross-sectional contour shape of the transmission line member 4 is circular. This simulates the outer conductor of a coaxial cable, STP (Shielded Twisted Pair) cable, etc. The transmission line member 4 is attached to the base member 6.

[0022] In the following explanation, the three mutually orthogonal directions in each diagram will be referred to as the X, Y, and Z directions. Furthermore, one direction within the X direction will be designated as the X1 direction, and the opposite direction will be designated as the X2 direction. One direction within the Y direction will be designated as the Y1 direction, and the opposite direction will be designated as the Y2 direction. One direction within the Z direction will be designated as the Z1 direction, and the opposite direction will be designated as the Z2 direction. The Z1 direction is also called the upward direction, and the Z2 direction is also called the downward direction. The base member 6 has a rectangular shape when viewed from the Z1 direction. One of the four sides that make up the rectangular shape of the base member 6 is aligned with the X direction. The longitudinal direction of the transmission line member 4 is aligned with the X direction.

[0023] The upper surface of the base member 6 has a pair of retaining surfaces 7 and a ground surface 8. The pair of retaining surfaces 7 are surfaces that hold both ends of the transmission line member 4. The pair of retaining surfaces 7 are rectangular surfaces located at both ends in the X direction of the base member 6. The long sides of the pair of retaining surfaces 7 are aligned in the Y direction. The ground surface 8 is provided between the pair of retaining surfaces 7. The ground surface 8 is made up of a plate surface of a conductive plate such as an aluminum alloy. This conductive plate is grounded.

[0024] Both ends 4e of the transmission line member 4 are fixed to connection substrates 20 provided on a pair of holding surfaces 7. Therefore, the transmission line member 4 and the ground surface 8 face each other. The ground surface 8 includes a central surface 8a and a pair of inclined surfaces 8b. The central surface 8a is a rectangular surface located in the center of the ground surface 8 in the X direction. The central surface 8a is aligned with the XY plane. The central surface 8a is located on the Z2 direction (downward) side of the pair of retaining surfaces 7. Therefore, the transmission line member 4 and the central surface 8a are separated by a predetermined distance. The pair of inclined surfaces 8b are inclined downwards as they move from the pair of holding surfaces 7 toward the central surface 8a. Therefore, the pair of inclined surfaces 8b are inclined so as to move away from the transmission line member 4 from both ends 4e toward the central surface 8a. As a result, the ground surface 8 has a shape that is recessed downwards.

[0025] Here, the bench body 2 has a first region A1 and a pair of second regions A2 arranged along the X direction. The first region A1 is a region of the bench body 2 that is demarcated by an edge along the Y direction of the central surface 8a. Therefore, the first region A1 includes the central surface 8a and the first line portion 4a of the transmission line member 4 that is located on the central surface 8a. The first line portion 4a has a mounting portion 5. The mounting portion 5 is the portion to which the noise suppression member to be evaluated is attached. The first line portion 4a and the central surface 8a are approximately parallel.

[0026] Furthermore, the pair of second regions A2 are regions of the bench body 2 that are demarcated by the edges of the pair of inclined surfaces 8b that are aligned in the Y direction. Thus, the pair of second regions A2 include the pair of inclined surfaces 8b and the pair of second line portions 4b of the transmission line member 4 that are located on the pair of inclined surfaces 8b. In this specification, of the pair of second regions A2, the second region A2 on the X2 direction side is referred to as second region A21, and the second region A2 on the X1 direction side is referred to as second region A22.

[0027] The base member 6 comprises a pair of base blocks 10 and a base plate 12. A pair of base blocks 10 are placed on the placement surface 12a of the base plate 12. The placement surface 12a is the upper surface of the base plate 12. The pair of base blocks 10 are arranged side by side on the placement surface 12a along the X direction.

[0028] Figure 2 shows a partial top view and a partial front view of the evaluation test bench 1. Figure 2(a) is a top view showing a portion of the second region A21 side of the evaluation test bench 1. Figure 2(b) shows a front view of the portion corresponding to (a). Figure 2(b) also shows the base plate 12 and the pair of base blocks 10 separated. Note that both base blocks 10 have the same configuration. Therefore, only the base block 10 on the X2 direction side will be described here.

[0029] In Figure 2, the base block 10 comprises a main body 16, a connecting substrate 20, and a pair of guide members 22. The main body 16 is a component formed from a conductive plate such as an aluminum alloy. The main body 16 is grounded. The main body 16 is placed on the placement surface 12a of the base plate 12. The upper surface of the main body 16 has an inclined surface 17a and a flat surface 17b. Plane 17b is a rectangular surface located at the end in the X2 direction. Plane 17b is a surface that lies along the XY plane. The inclined surface 17a is a surface that extends from the edge of the plane 17b on the X1 direction side. The inclined surface 17a is a surface that slopes downward as it moves from the plane 17b toward the central surface 8a. The edge of the inclined surface 17a on the X1 direction side intersects with the bottom edge 16a. Therefore, the edge of the main body 16 on the X1 direction side has an acute angle. The bottom edge 16a is the edge of the main body 16 on the Z2 direction side when the main body 16 is viewed from the front. The bottom edge 16a is parallel to the X direction. The plane 17b constitutes the holding surface 7 of the base member 6. The inclined surface 17a is the surface corresponding to the inclined surface 8b of the ground surface 8. Furthermore, the inclined surface 17a, which is the surface of the conductor plate, constitutes the inclined surface 8b included in the ground surface 8.

[0030] The connecting board 20 is fixed on the plane 17b. The connecting board 20 is located at the center of the plane 17b in the Y direction. The connecting board 20 has a board body 20a, a microstrip line 20b, and a connector 20c. The microstrip line 20b is provided on the substrate body 20a. The microstrip line 20b is a line made of a conductor such as copper. The substrate body 20a is a plate-shaped component made of a dielectric material. A conductive plate is provided on the lower surface (the surface facing the Z2 direction) of the substrate body 20a. The conductive plate is electrically connected to the main body 16 by contacting the plane 17b. Therefore, the conductive plate is grounded. Connector 20c is a coaxial connector for connecting measuring instruments such as network analyzers to measure transmission characteristics. Connector 20c is provided at the X2 direction end of the microstrip line 20b. The center conductor of connector 20c is connected to the microstrip line 20b. The outer conductor of connector 20c is connected to the conductor plate of the main board 20a. The end 4e of the transmission line member 4 is fixed to the X1 direction end of the microstrip line 20b. The end 4e is fixed to the microstrip line 20b and electrically connected, for example, by brazing, soldering, or the like.

[0031] The pair of guide members 22 are provided on both sides 16c of the main body 16 facing the Y direction. The pair of guide members 22 are provided on the portion of the side 16c corresponding to the plane 17b. The pair of guide members 22 are rectangular plate-shaped members formed of resin. The pair of guide members 22 are in contact with the side surface 12b of the base plate 12. Therefore, the pair of guide members 22 sandwich the base plate 12 along the Y direction. The pair of guide members 22 sandwich the base plate 12 to such an extent that the base block 10 can move in the X direction. In this way, the pair of guide members 22 guide the base block 10 to move along the base plate 12 while sliding in the X direction. In other words, the base block 10 is able to move along the base plate 12 while sliding in the X direction.

[0032] In Figure 2, the base plate 12 is a rectangular plate-shaped member. The long side of the base plate 12 of the evaluation test bench 1 is aligned with the X direction. The base plate 12 is a rectangular plate-shaped member formed from a conductive plate such as an aluminum alloy. The placement surface 12a of the base plate 12 is aligned with the XY plane. The base plate 12 is grounded.

[0033] As shown in Figures 2 and 1, the pair of base blocks 10 placed on the placement surface 12a are spaced apart from each other by the width dimension in the X direction of the central surface 8a. Therefore, the placement surface 12a is exposed on the central surface 8a. In other words, the central surface 8a included in the ground surface 8 is composed of the placement surface 12a of the base plate 12.

[0034] Here, the evaluation test bench 1 of this embodiment can also be used as a reference test bench, which is constructed by connecting a pair of second regions A2 to each other, excluding the first region A1. The reference test bench will be described later.

[0035] Specifically, the pair of base blocks 10 are movable along the X direction. Therefore, the arrangement of the pair of base blocks 10 on the placement surface 12a can be changed. The arrangement of the pair of base blocks 10 in this embodiment includes a first arrangement in which they are spaced apart from each other in the X direction with the first region A1 in between, and a second arrangement in which they are closer to each other in the X direction than in the first arrangement. The pair of base blocks 10 can be arranged on the placement surface 12a in either a first arrangement or a second arrangement.

[0036] When attaching noise suppression components to the transmission line component 4 and measuring the transmission characteristics, the pair of base blocks 10 are arranged in the first configuration. When using the evaluation test bench 1 as a reference test bench, the pair of base blocks 10 are arranged in the second configuration.

[0037] Furthermore, the relative positions of the connecting substrates 20 at both ends in the X direction are also changed depending on the arrangement of the pair of base blocks 10. Therefore, the total length of the transmission line member 4 is changed according to the arrangement of the pair of base blocks 10. When the pair of base blocks 10 are arranged in the first configuration, the transmission line member 4 is longer than when the pair of base blocks 10 are arranged in the second configuration. In the following explanation, the state of the evaluation test bench 1 when the pair of base blocks 10 are arranged in the first configuration is referred to as the long configuration, and the state of the evaluation test bench 1 when the pair of base blocks 10 are arranged in the second configuration is referred to as the short configuration.

[0038] Figures 1 and 2 show the test bench 1 for evaluating the long-length state. In the long-length configuration, the evaluation test bench 1 has, as described above, a first region A1 and a pair of second regions A2 located on both sides of the first region A1 in the X direction.

[0039] Figure 3 is a perspective view showing test bench 1 for evaluation in a shortened state. In Figure 3, the pair of base blocks 10 are moved from the first arrangement toward each other by the same distance and abutted together to form the second arrangement. The pair of base blocks 10 are slidable along the base plate 12 in the X direction. At this time, the positional displacement of the pair of base blocks 10 relative to the base plate 12 is suppressed by the pair of guide members 22.

[0040] In the shortened state, the pair of base blocks 10 are butted together, so as shown in Figure 3, the first region A1 is removed and the pair of second regions A2 are connected to each other. Therefore, in the shortened state, the ground surface 8 includes only a pair of inclined surfaces 8b. The transmission line member 4 includes only a pair of second line portions 4b. The transmission line member 4 faces the ground surface 8, which includes only a pair of inclined surfaces 8b.

[0041] Figure 4 is an enlarged view of the main part of the transmission line component 4. Note that the dimensions of each part in Figure 4 are exaggerated for ease of understanding. The transmission line member 4 in this embodiment is configured to be expandable and contractible. The transmission line member 4 expands and contracts according to the state of the evaluation test bench 1. Figure 4(a) shows the transmission line member 4 when the evaluation test bench 1 is in its long configuration. The transmission line member 4 includes a rod-shaped member 30, a first cylindrical member 32, and a second cylindrical member 34. The rod-shaped member 30 and the cylindrical members 32 and 34 are made of conductive metals such as copper, brass, and aluminum alloy.

[0042] The rod-shaped member 30 includes the first track portion 4a. Therefore, the rod-shaped member 30 has a mounting portion 5. The mounting portion 5 is the outer circumferential surface of the first line portion 4a. The sheet-shaped noise suppression member T, which is the subject of evaluation, is wrapped around the mounting portion 5. Note that the subject of evaluation includes not only sheet-shaped noise suppression members but also ring-shaped noise suppression members such as ferrite cores.

[0043] The first cylindrical member 32 and the second cylindrical member 34 extend from both ends of the rod-shaped member 30. The end of the rod-shaped member 30 on the X2 direction side is inserted and fixed to the inner circumference of the first cylindrical member 32. The rod-shaped member 30 and the first cylindrical member 32 are in contact with each other and are electrically connected. The end of the first cylindrical member 32 on the X2 direction side is connected to the connection board 20 on the X2 direction side.

[0044] The end of the rod-shaped member 30 on the X1 direction side is inserted into the inner circumference of the second cylindrical member 34 so as to be movable in the axial direction. The rod-shaped member 30 and the second cylindrical member 34 are in contact with each other and are electrically connected. The end of the second cylindrical member 34 on the X1 direction side is connected to the connection board 20 on the X1 direction side. Therefore, the rod-shaped member 30 and the second cylindrical member 34 are relatively movable along the X direction. As a result, the transmission line member 4 can be easily extended and retracted according to the arrangement of the pair of base blocks 10. Furthermore, by having a portion of the transmission line member 4 composed of a cylindrical member, the rigidity of the transmission line member 4 can be increased, and deflection occurring in the transmission line member 4 can be suppressed.

[0045] Figure 4(b) shows the transmission line member 4 when the evaluation test bench 1 is in a shortened state. As shown in the figure, the portion that was the mounting part 5 is located on the inner circumference side of the second cylindrical member 34. In this way, the rod-shaped member 30 is partially housed on the inner circumference side of the second cylindrical member 34. As a result, the transmission line member 4 has a length appropriate for the shortened state. As shown in the figure, when the evaluation test bench 1 is in a shortened state, the transmission line member 4 includes only the pair of second line portions 4b.

[0046] In the long-length evaluation test bench 1, both ends 4e of the transmission line member 4 and the connector 20c are set to the reference impedance of the measuring instrument. This reference impedance is generally 50Ω.

[0047] Furthermore, the characteristic impedance of the first line portion 4a included in the first region A1 of the transmission line member 4 is set to a value higher than the reference impedance. Also, since the first line portion 4a and the central surface 8a are almost parallel, the characteristic impedance of the first line portion 4a is almost constant along the X direction. Furthermore, the characteristic impedance of the pair of second line portions 4b included in the pair of second region portions A2 of the transmission line member 4 is set to gradually increase from both ends 4e toward the first line portion 4a.

[0048] The characteristic impedance of the pair of second line sections 4b is achieved by the fact that the pair of inclined surfaces 8b are inclined so as to move away from the transmission line member 4 from both ends 4e toward the first region A1, as shown in Figures 1 and 2. In other words, the distance between the pair of inclined surfaces 8b and the pair of second track sections 4b gradually widens from both ends 4e toward the first region A1. This makes it possible to continuously and gradually change the characteristic impedance of the pair of second transmission line sections 4b.

[0049] For example, if the characteristic impedance of the first transmission line section 4a is 180Ω, then the characteristic impedance of the pair of second transmission line sections 4b will change gradually along the X direction between 50Ω and 180Ω.

[0050] [Regarding the evaluation method] The evaluation test bench 1 is used in combination with measuring instruments as a noise suppression component evaluation system. Figure 5 shows an example of a noise suppression component evaluation system. The noise suppression component evaluation system 100 includes an evaluation test bench 1 and a measuring instrument 38. The measuring instrument 38 is a measuring instrument capable of measuring the pass-through characteristics of the transmission line component 4. The measuring instrument 38 is, for example, a network analyzer. The measuring instrument 38 is connected to a pair of connectors 20c on both sides in the X direction. Thus, the measuring instrument 38 is connected to both ends 4e of the transmission line member 4 via the connection board 20.

[0051] The evaluation of the noise suppression component is performed by generating a transmission signal simulating common-mode noise between the transmission line component 4 and the base plate 12 using the measuring instrument 38, and then measuring the passage characteristics of the first line portion 4a of the transmission line component 4 at that time.

[0052] Figure 6 is a flowchart showing an example of an evaluation method for noise suppression component T using the evaluation test bench 1. In this evaluation method, first, the reference passage characteristics of the transmission line member 4 are measured using a short-length evaluation test bench 1 (step S1). This allows the reference transmission line component's reference transmission characteristics to be measured using a reference test bench. The reference passage characteristics represent the passage characteristics of only the pair of second line portions 4b included in the pair of second region portions A2.

[0053] The reference test bench is a test bench used solely for measuring reference transmission characteristics. The reference test bench has the same configuration as the evaluation test bench 1 in the short-length state, but does not have the function to change to the long-length state. Therefore, the ground surface of the reference test bench (corresponding to ground surface 8) is configured to include only a pair of inclined surfaces (corresponding to a pair of inclined surfaces 8b). The reference transmission line member of the reference test bench includes only a pair of second line sections (corresponding to a pair of second line sections 4b).

[0054] In this embodiment, the reference pass-through characteristics of the transmission line member 4 are measured using the evaluation test bench 1 in a short state. However, a separate reference test bench may be prepared and the reference pass-through characteristics may be measured using the reference test bench. Furthermore, the reference passthrough characteristics do not change depending on the object being evaluated. Therefore, once measured, the previously measured reference passthrough characteristics can be used in subsequent evaluations. If previously measured reference passthrough characteristics are used, step S1 is omitted.

[0055] Next, using the long-length evaluation test bench 1, the passage characteristics of the transmission line member 4 without the noise suppression member T and the passage characteristics of the transmission line member 4 with the noise suppression member T installed are measured (step S2).

[0056] Subsequently, the pass-through characteristics of the first transmission line section 4a are calculated based on the pass-through characteristics of the transmission line members 4 before and after the installation of the noise suppression member T, and the reference transmission line member (step S3). In step S3, the pass characteristics of the first line section 4a before and after the installation of the noise suppression member T are calculated.

[0057] The calculation of the passage characteristics of the first track section 4a is performed by a processor or the like in the measuring instrument 38. Alternatively, the calculation in step S3 may be performed by an external computer that receives data from the measuring instrument 38.

[0058] In step S3, the processor performs de-embedding. Figure 7 is a diagram illustrating an example of the de-embedding process in this embodiment. First, the processor converts the frequency domain reference pass-through characteristics into a time domain function using an inverse Fourier transform or the like, then divides it to obtain two divided characteristics. This gives the pass-through characteristics for each of the pair of second transmission line sections 4b. Next, the processor converts the two division characteristics into the frequency domain and then determines their inverse characteristics.

[0059] The processor multiplies the two obtained inverse characteristics by the transmission line member 4's transmission line characteristics. This divides the transmission line member 4's transmission line characteristics by the transmission line characteristics of the pair of second line sections 4b, obtaining the transmission line characteristics of the first line section 4a. The processor calculates the pass-through characteristics of the first line section 4a before and after the installation of the noise suppression member T. Next, the transmission characteristics of the first line section 4a before and after the installation of the noise suppression member T are compared, and the characteristics of the noise suppression member T are evaluated based on the change in transmission characteristics with and without the noise suppression member T, and the frequency characteristics of the transmission characteristics (step S4).

[0060] According to the above configuration, the characteristic impedance of the pair of second transmission line sections 4b is set to gradually increase from both ends 4e towards the first transmission line section 4a, thereby suppressing signal reflection at both ends 4e and preventing the occurrence of resonance between both ends 4e. Therefore, by dividing the transmission line member 4's transmission line characteristics by the transmission line characteristics of the pair of second line sections 4b, the transmission line characteristics of the first line section 4a can be determined, and the characteristics of the noise suppression member T attached to the first line section 4a can be evaluated over a wide bandwidth.

[0061] In this embodiment, the pair of base blocks 10 of the evaluation test bench 1 are configured to allow selection of either a first arrangement on the placement surface 12a in which they are spaced apart from each other in the X direction with the first region A1 in between, or a second arrangement in which they are abutted against each other. Therefore, by setting the arrangement of the pair of base blocks 10 to the second arrangement and further shortening the transmission line member 4, the passage characteristics of the pair of second line portions 4b, which should be divided from the passage characteristics of the transmission line member 4, can be determined. Thus, the evaluation test bench 1 can be used as a reference test bench. As a result, there is no need to set up a separate reference test bench from the evaluation test bench 1. Furthermore, the pair of second line sections 4b used when measuring the passage characteristics of the transmission line member 4 and the pair of second line sections used when measuring the passage characteristics of the reference transmission line member can be made common, thereby further improving the measurement accuracy of the passage characteristics of the first line section 4a.

[0062] Furthermore, in this embodiment, the distance between the pair of inclined surfaces 8b and the pair of second transmission line portions 4b gradually widens from both ends 4e toward the first region A1, making it possible to continuously and gradually change the characteristic impedance of the pair of second transmission line portions 4b. This effectively suppresses the reflection of the input signal at both ends 4e, and further suppresses the occurrence of resonance between both ends 4e.

[0063] Furthermore, in this embodiment, the second arrangement of the pair of base blocks 10 is exemplified as a position where the pair of base blocks 10 are abutting against each other. However, in the second arrangement, the pair of base blocks 10 are only required to be closer to each other in the X direction than in the first arrangement, and a gap shorter than the distance of the first region A1 in the X direction may be provided between the pair of base blocks 10 in the second arrangement, or a spacer made of a rectangular plate-shaped conductive plate may be interposed. In this case, the position of the pair of base blocks 10 relative to the expandable transmission line member 4 can be easily adjusted by adjusting the dimensions of the spacer.

[0064] [Regarding the second embodiment] Figure 8 is a front view of the test bench 1 for evaluating noise suppression members according to the second embodiment. The evaluation test bench 1 of this embodiment differs from the first embodiment in that it does not have a pair of base blocks 10, the ground surface 8 has a planar shape that aligns with the XY plane, and a pair of second line portions 4b of the transmission line member 4 are inclined.

[0065] The evaluation test bench 1 of this embodiment does not have a pair of base blocks 10. Therefore, the ground surface 8 is composed of the entire surface 12a of the base plate 12. Furthermore, the transmission line component 4 is a single wire made of a conductive metal such as copper, brass, or aluminum alloy.

[0066] A pair of spacers 40 are interposed between the base plate 12 and the transmission line member 4. The pair of spacers 40 are provided corresponding to the pair of second regions A2. When viewed from the Z direction, the pair of spacers 40 have a rectangular shape corresponding to the shape of the pair of second regions A2. The pair of spacers 40 are made of a dielectric material such as resin. Each pair of spacers 40 has a lower surface 40a and an inclined surface 40b. The lower surface 40a is a surface that aligns with the XY plane. The lower surface 40a abuts against the placement surface 12a of the base plate 12.

[0067] The inclined surface 40b is the upper surface of the spacer 40. The inclined surface 40b slopes upward from the connection board 20 side toward the first region A1 side. The inclined surface 40b abuts against the transmission line member 4 over the entire X direction. As a result, the spacer 40 supports the transmission line member 4 from below.

[0068] The pair of spacers 40 support the transmission line member 4 such that the pair of second line portions 4b are inclined. Therefore, the pair of second line portions 4b are inclined along the pair of inclined surfaces 40b. In this embodiment, the example shows that the pair of spacers 40 are provided over the entire area of ​​the pair of second region portions A2, but as long as they can support the transmission line member 4, they do not need to be provided over the entire area of ​​the pair of second region portions A2, and may be provided only partially over the pair of second region portions A2. A space corresponding to the first region A1 is provided between the pair of spacers 40. This space is interposed between the first track section 4a and the ground surface 8. The height of the pair of spacers 40 on the side facing the first region A1 is the same. Therefore, the first transmission line portion 4a and the ground plane 8 are approximately parallel, and in this embodiment as well, the characteristic impedance of the first transmission line portion 4a is approximately constant along the X direction. Furthermore, as described above, the characteristic impedance of the first transmission line portion 4a is set to a value higher than the reference impedance.

[0069] Furthermore, the characteristic impedance of the pair of second transmission line sections 4b is set to gradually increase from both ends 4e toward the first transmission line section 4a. The characteristic impedance of the pair of second transmission line sections 4b is achieved by the fact that the pair of second transmission line sections 4b are inclined so as to move away from the ground plane 8 from both ends 4e toward the first region A1. This makes it possible to continuously and gradually change the characteristic impedance of the pair of second transmission line portions 4b in this embodiment as well. As a result, reflection of the input signal at both ends 4e is effectively suppressed, and the occurrence of resonance between both ends 4e is further suppressed.

[0070] In this embodiment, a reference test bench separate from the evaluation test bench 1 is provided, and the reference pass-through characteristics are determined by the reference test bench. Furthermore, if the transmission line member 4 is detachable into a first line portion 4a and a pair of second line portions 4b, and the pair of second line portions 4b are configured to be connectable to each other, the evaluation test bench 1 of this embodiment can be used as a reference test bench.

[0071] [Regarding the third embodiment] Figure 9 shows a partial top view and a partial front view of the noise suppression member evaluation test bench 1 according to the third embodiment. Figure 9(a) is a top view showing a portion of the second region A21 side of the evaluation test bench 1. Figure 9(b) shows a front view of the portion corresponding to (a).

[0072] The evaluation test bench 1 of this embodiment differs from the second embodiment in that the transmission line member 4 has a line member 46 and a pair of line substrates 44. In other respects, it is the same as the second embodiment.

[0073] The pair of line substrates 44 are provided corresponding to the pair of second regions A2. Each of the pair of line substrates 44 has a substrate body 44a and a conductor line 44b. The conductor line 44b is provided on the substrate body 44a. The conductor line 44b is a line made of a conductor such as copper. The end of the conductor line 44b on the connecting substrate 20 side is connected to the microstrip line 20b of the connecting substrate 20. The end of the conductor line 44b on the first region A1 side is connected to the line member 46. The conductor line 44b constitutes the second line portion 4b. The substrate body 44a is a plate-shaped component made of a dielectric material. The lower surface of the substrate body 44a is in contact with the inclined surface 40b of the spacer 40. Therefore, the substrate body 44a and the spacer 40 are interposed between the conductor line 44b and the ground surface 8. A pair of track boards 44 are placed on the inclined surfaces 40b of a pair of spacers 40, connecting the connecting board 20 and the track members 46.

[0074] The track member 46 is a wire made of a conductive metal such as copper, brass, or aluminum alloy. The track member 46 constitutes the first track section 4a. The track member 46 connects a pair of track boards 44 on a pair of spacers 40. The track member 46 and the ground plane 8 are substantially parallel, and in this embodiment as well, the characteristic impedance of the track member 46 (first track section 4a) is substantially constant along the X direction.

[0075] The characteristic impedance of the pair of conductor lines 44b (second line portion 4b) is set to gradually increase from both ends 4e toward the line member 46. The characteristic impedance of the pair of conductor lines 44b is achieved by the fact that the pair of conductor lines 44b are inclined so as to move away from the ground from both ends 4e toward the first region A1. This makes it possible to continuously and gradually change the characteristic impedance of the pair of conductor lines 44b in this embodiment as well.

[0076] [Regarding the fourth embodiment] Figure 10 is a front view of the test bench 1 for evaluating noise suppression members according to the fourth embodiment. The evaluation test bench 1 of this embodiment differs from the first embodiment in that it does not have a pair of base blocks 10, the ground surface 8 has a planar shape that aligns with the XY plane, and a pair of second line portions 4b of the transmission line member 4 have a tapered shape. Note that Figure 10 shows the shapes of each part in an exaggerated manner for ease of understanding.

[0077] In this embodiment, the first line portion 4a of the transmission line member 4 has a cylindrical shape along the X direction. On the other hand, the pair of second line portions 4b of the transmission line member 4 have a tapered shape. The pair of second line portions 4b have a tapered shape that narrows from the connecting substrate 20 toward the first line portion 4a.

[0078] In this embodiment, since the pair of second line portions 4b have a tapered shape, the distance between the ground surface 8 and the pair of second line portions 4b gradually widens from both ends 4e toward the first region A1. As a result, the characteristic impedance of the pair of second line sections 4b is set to gradually increase from both ends 4e toward the line member 46. Therefore, in this embodiment as well, it is possible to continuously and gradually change the characteristic impedance of the pair of conductor lines 44b.

[0079] Figure 11 is a front view of the test bench 1 for evaluating noise suppression members according to a modified example of the fourth embodiment. This modified example differs from the third embodiment in that each of the pair of second line portions 4b has a tapered tapered portion 4b1 and a cylindrical straight portion 4b2, and that a pair of base blocks 50 are provided in a part of the pair of second region portions A2.

[0080] The straight section 4b2 includes the end portion 4e. The straight section 4b2 extends from the connecting substrate 20 to the middle of the second region A2. The tapered section 4b1 connects the tip of the straight section 4b2 on the first track section 4a side to the first track section 4a. The tapered section 4b1 has a tapered shape that narrows from the straight section 4b2 towards the first track section 4a.

[0081] As shown in Figure 11, the second region A2 of this embodiment includes a tapered region A3 and a straight region A4. The tapered region A3 corresponds to the tapered section 4b1. The straight region A4 corresponds to the straight section 4b2.

[0082] In this modified example, the ground surface 8 includes a central surface 8a and a pair of inclined surfaces 8b. The central surface 8a is a portion included in the first region A1 of the ground surface 8. The pair of inclined surfaces 8b are portions included in the pair of second region A2. Each of the pair of inclined surfaces 8b includes a flat portion 8b1 and an inclined portion 8b2. The inclined portion 8b2 is the upper surface of the pair of base blocks 50.

[0083] Each of the pair of base blocks 50 has a main body 52, a conductor plate 54, and a connecting board 20. The main body portion 52 is a component formed from resin, wood, or the like. The lower surface 52a of the main body portion 52 abuts against the placement surface 12a of the base plate 12. The upper surface of the main body portion 52 has an inclined surface 53a and a flat surface 53b. Plane 53b is a rectangular surface located at the end in the X2 direction. A connecting substrate 20 is provided on plane 53b. The inclined surface 53a is provided on the X1 direction side of the plane 53b. The inclined surface 53a is a surface that slopes downward as it moves from the plane 53b toward the central surface 8a. The edge of the inclined surface 53a on the X1 direction side intersects with the bottom surface 52a. Therefore, the edge of the main body portion 52 on the X1 direction side has an acute angle shape. The inclined surface 53a is the surface corresponding to the inclined portion 8b2 of the ground surface 8.

[0084] The conductor plate 54 is provided so as to be attached along the inclined surface 53a. The conductor plate 54 is a component made of an aluminum alloy plate or the like, and is grounded. The plate surface of the conductor plate 54 facing upwards constitutes the inclined portion 8b2 included in the ground surface 8.

[0085] In this embodiment, in the straight region A4, the inclined portion 8b2 is inclined so as to move away from the transmission line member 4 from the end portion 4e toward the first region A1. Therefore, the distance between the ground surface 8 and the second line portion 4b gradually widens from both ends 4e toward the first region A1. Furthermore, in the tapered region A3, because the tapered portion 4b1 has a tapered shape, the distance between the ground surface 8 and the second track portion 4b gradually widens from both ends 4e toward the first region A1. Therefore, the distance between the ground surface 8 and the second track section 4b in the second region A2 as a whole gradually widens from both ends 4e toward the first region A1. As a result, the characteristic impedance of the pair of second line sections 4b is set to gradually increase from both ends 4e toward the line member 46. Therefore, in this modified example as well, it is possible to continuously and gradually change the characteristic impedance of the pair of conductor lines 44b.

[0086] Furthermore, in this modified example, by providing a pair of base blocks 50, the impedance change near both ends 4e can be made more gradual compared to the fourth embodiment. That is, in the fourth embodiment, both ends 4e need to be spaced relatively far from the ground plane 8. In contrast, in this modified example, the pair of base blocks 50 allows the pair of inclined sections 8b2 to be brought closer to both ends 4e. This makes the impedance change near both ends 4e more gradual.

[0087] [Regarding variations, etc.] In the first embodiment, the fourth embodiment, and the modification of the fourth embodiment, examples were given in which a space is left between the transmission line member 4 and the ground surface 8 to separate them. However, a spacer made of a dielectric material may be interposed between the transmission line member 4 and the ground surface 8. By interposing a spacer, it is possible to suppress the transmission line member 4 from bending downward due to gravity. Alternatively, instead of a spacer, the transmission line member 4 may be supported by being suspended from above with a thread or the like made of an insulating material such as resin. In this case as well, it is possible to suppress the transmission line member 4 from bending downward due to gravity.

[0088] Furthermore, in the first embodiment, an example was given in which the transmission line member 4 is made extendable and retractable by combining the rod-shaped member 30 and the second cylindrical member 34. However, by combining multiple rod-shaped members, the length of the transmission line member 4 can also be made to correspond to both the long-length evaluation test bench 1 and the short-length evaluation test bench 1. Figure 12 is a cross-sectional view of the main part of the transmission line member 4, which is composed of multiple rod-shaped members. Note that the dimensions of each part in Figure 12 are exaggerated for ease of understanding. Figure 12 shows a cross-section along the X direction.

[0089] The transmission line member 4 in this example has a first rod-shaped member 60 and a pair of second rod-shaped members 62 and 63. Of the pair of second rod-shaped members 62 and 63, the second rod-shaped member 62 is connected to the X2 direction side of the first rod-shaped member 60. The second rod-shaped member 63 is connected to the X1 direction side of the first rod-shaped member 60. The first rod-shaped member 60 has a length corresponding to the first track section 4a. The pair of second rod-shaped members 62 and 63 have lengths corresponding to the pair of second track sections 4b. The pair of second rod-shaped members 62 and 63 extend from both ends of the first rod-shaped member 60.

[0090] The end face of the first rod-shaped member 60 on the X2 direction side has a projection 60a. The end face of the first rod-shaped member 60 on the X1 direction side has a hole 60b. The end face of the second rod-shaped member 62 on the X1 direction side has a hole 62a. The projection 60a of the first rod-shaped member 60 is inserted into the hole 62a. In this way, the first rod-shaped member 60 and the second rod-shaped member 62 are detachably connected. The end face of the second rod-shaped member 63 on the X2 direction side has a projection 63a. The projection 63a is inserted into the hole 60b of the first rod-shaped member 60. In this way, the first rod-shaped member 60 and the second rod-shaped member 63 are detachably connected.

[0091] The transmission line member 4 with the above configuration can have the first rod-shaped member 60 attached or the first rod-shaped member 60 removed and the pair of second rod-shaped members 62 and 63 connected to each other. Therefore, the length of the transmission line member 4 can be extended or retracted by the length of the first rod-shaped member 60. This allows the transmission line member 4 to be extended or retracted according to the arrangement of the pair of base blocks 10.

[0092] Furthermore, as in the first embodiment, when the rod-shaped member 30 and the cylindrical members 32 and 34 are combined, the outer diameter of the rod-shaped member 30 and the outer diameter of the cylindrical members 32 and 34 are different. However, with the above-described configuration of the transmission line member 4, it becomes easy to make the cross-sectional contour shape and dimensions of the first rod-shaped member 60 the same as the cross-sectional contour shape and dimensions of the pair of second rod-shaped members 62 and 63, and the cross-sectional contour shape of the transmission line member 4 can be made uniform along the longitudinal direction.

[0093] Furthermore, in the first rod-shaped member 60 of the transmission line member 4 with the above configuration, an example was given in which the end face on the X2 direction side has a projection 60a and the end face on the X1 direction side has a hole 60b. However, both end faces of the first rod-shaped member 60 may have projections or both end faces may have holes. In this case, the end faces of the pair of second rod-shaped members 62 and 63 are provided with projections or holes, depending on the end face of the first rod-shaped member 60.

[0094] Furthermore, the above configuration exemplifies a case where a pair of second rod-shaped members 62 and 63 have lengths corresponding to a pair of second track sections 4b. However, the lengths of the pair of second rod-shaped members 62 and 63 may be shorter than the lengths of the pair of second track sections 4b. In this case, two first rod-shaped members 60 of different lengths are used. When the evaluation test bench 1 is used in its long configuration, the longer first rod-shaped member 60 is used. When the evaluation test bench 1 is used in its short configuration, the shorter first rod-shaped member 60 is used.

[0095] Furthermore, although the above embodiments illustrate the case where the cross-sectional contour shape of the transmission line member 4 is circular, the cross-sectional contour shape of the transmission line member 4 may also be a polygon such as a quadrilateral or hexagon. In this case, connection to the connection board 20 becomes easier. Furthermore, as shown in Figure 13, the two wires 66 constituting the UTP (Unshielded Twisted Pair) may be connected to the microstrip line 20b and used as a transmission line component 4.

[0096] Furthermore, in the first embodiment, an example was given in which the main body portion 16 of the pair of base blocks 10 is formed of a conductive plate. However, the main body portion 16 may be formed of resin or the like. In this case, a conductive metal film or a conductive metal plate is provided on the inclined surface 17a of the main body portion 16. As a result, the inclined surface 17a can constitute an inclined surface 8b included in the ground surface 8. Furthermore, although the above embodiments illustrate the case where the base plate 12 is formed from a conductive plate, the base plate 12 may also be formed from resin or the like. In this case, a conductive metal film or conductive metal plate is provided on the placement surface 12a of the base plate 12. This allows the placement surface 12a to constitute a part of the ground surface 8.

[0097] Furthermore, in the above embodiments, examples were given in which the characteristic impedance of the pair of second transmission line portions 4b is provided to gradually increase from both ends 4e toward the first transmission line portion 4a. However, if impedance matching is achieved between both ends 4e and measuring instruments, and impedance matching is achieved between the end of the pair of second transmission line portions 4b on the first transmission line portion 4a side and the first transmission line portion 4a, the impedance may change in the longitudinal direction of the pair of second transmission line portions 4b, such as the impedance becoming partially constant or decreasing. Furthermore, although the above embodiments show the case where the impedance of the first transmission line portion 4a is higher than the impedance of the measuring instrument, the characteristics of the noise suppression member T attached to the first transmission line portion 4a can be evaluated over a wide bandwidth even when the impedance of the first transmission line portion 4a is lower than the impedance of the measuring instrument.

[0098] [Regarding verification tests] Next, we will describe the verification tests conducted on the effectiveness of the evaluation test bench 1. As for the test method, a model of the evaluation test bench 1 described in the first embodiment was constructed, and the passage characteristics of the evaluation test bench 1 were determined by computer simulation using this model. The passage characteristics were determined by a method similar to the evaluation method of the first embodiment. That is, a model of the evaluation test bench 1 in a short state was constructed, and the reference passage characteristics were determined using this model. The passage characteristics of the first track section 4a of the evaluation test bench 1 were then determined using the passage characteristics of the evaluation test bench 1 in a long state and the reference passage characteristics. For transmission characteristics, the S-parameter S21 of the transmission line member 4 was measured in a bandwidth from 0 to 10 GHz when noise was excited from one of the connectors 20c of the transmission line member 4.

[0099] As an example, we determined the pass-through characteristics with and without the noise suppression component installed. Furthermore, as a comparative example, a model of a comparative test bench was constructed in which the evaluation test bench 1 of the first embodiment did not have the pair of inclined surfaces 8b, and the transmission line member 4 and the ground surface 8 were parallel. The pass characteristics of the comparative example were determined using this comparative model. In the comparative example as well, the pass characteristics were determined before and after the installation of the noise suppression member.

[0100] Figure 14 shows an example of the pass-through characteristics according to the embodiment. The horizontal axis of Figure 14 represents frequency. The vertical axis of Figure 14 shows the absolute value in decibels of S21, which is the pass-through characteristic of the first transmission line section 4a of the evaluation test bench 1. In Figure 14, the dashed line shows the pass-through characteristics when the noise suppression member is not installed. The solid line shows the pass-through characteristics when the noise suppression member is installed.

[0101] As shown in Figure 14, it can be seen that when the noise suppression component is not installed, noise passes through the entire measured bandwidth. On the other hand, it can be seen that when the noise suppression component is installed, the noise is significantly attenuated compared to when the noise suppression component is not installed. In other words, the solid line in Figure 14 shows the frequency characteristics of the noise suppression component. By measuring the frequency characteristics of S21, it can be seen that the characteristics of noise suppression materials can be evaluated over a wide bandwidth.

[0102] Figure 15 shows an example of the pass-through characteristics for a comparative example. The horizontal axis in Figure 15 represents frequency. The vertical axis in Figure 15 represents the absolute value in decibels of S21, which is the pass-through characteristic of the first transmission line section 4a of the evaluation test bench 1. In Figure 15, the dashed line shows the pass-through characteristics without the noise suppression member installed. The solid line shows the pass-through characteristics with the noise suppression member installed.

[0103] As shown in Figure 15, in the comparative example, resonance occurs in the transmission line member 4, making it difficult to evaluate over a wide bandwidth. A comparison of the embodiment with the comparative example clearly shows that resonance in the transmission line member 4 is suppressed in the embodiment. As a result, the characteristics of the noise suppression member can be appropriately evaluated over a wide bandwidth.

[0104] 〔others〕 It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not in the sense described above, and is intended to include the meaning and scope of equivalents of the claims, and all modifications within that scope. [Explanation of Symbols]

[0105] 1. Test bench for evaluating noise suppression components 2 Bench body 4. Transmission line components 4a 1st track section 4b 2nd track section 4b1 Tapered section 4b2 Straight section 4e end 5. Mounting part 6 Base member 7 Holding surface 8 Ground surface 8a central plane 8b Slope 8b1 Flat part 8b2 Slope 10 base blocks 12 base plate 12a Placement surface 12b Side 16 Main body 16a Bottom edge 16c side 17a Slope 17b plane 20 connection boards 20a Main board 20b Microstrip Tracks 20c connector 22 Guide member 30 Rod-shaped member 32 First cylindrical member 34 Second cylindrical member 38 Measuring Instruments 40 Spacers 40a Bottom side 40b Slope 44 Track board 44a Main board 44b Conductor line 46 Track components 50 base blocks 52 Main body 52a Bottom side 53a Slope 53b plane 54 Conductor plate 60 First rod-shaped member 60a Protrusion 60b hole 62 Second rod-shaped member 62a hole 63 Second rod-shaped member 63a protrusion 66 Electric wire 100 Noise Suppression Material Evaluation System A1 1st area A2, A21, A22 2nd area part A3 Tapered Region A4 straight area T Noise suppression component

Claims

1. The bench body comprises a transmission line member to which measuring instruments for measuring transmission characteristics are connected at both ends, and a base member having a ground surface facing the transmission line member. The bench body has a first region located in the longitudinal center of the transmission line member, and a pair of second regions located on both sides of the first region in the longitudinal direction. The first line portion included in the first region of the transmission line member is arranged parallel to the ground plane at a distance from it and has a mounting portion to which the noise suppression member to be evaluated is attached. The pair of second line portions included in the pair of second regions of the transmission line member, and the base member, are arranged such that the impedance of the pair of second line portions gradually changes from both ends toward the first line portion. Test bench for evaluating noise suppression components.

2. The impedance of the pair of second line sections and the pair of second line sections determined by the base member gradually increases from both ends toward the first line section. A test bench for evaluating noise suppression components according to claim 1.

3. The ground surface includes a pair of inclined surfaces included in the pair of second regions, The distance between the pair of inclined surfaces and the pair of second track sections gradually widens from both ends toward the first region. A test bench for evaluating noise suppression members according to claim 2.

4. The ground surface includes the central surface included in the first region, The transmission line member is parallel to the central plane, The pair of inclined surfaces are inclined so as to be spaced apart from the transmission line member from both ends toward the first region. A test bench for evaluating noise suppression members according to claim 3.

5. The aforementioned transmission line member is expandable and contractible in the longitudinal direction. The base member is A pair of base blocks having the pair of inclined surfaces, The pair of base blocks are arranged along the longitudinal direction, and the ground plate has an arrangement surface, The pair of base blocks are configured to be arranged on the arrangement surface in either a first arrangement in which they are spaced apart from each other in the longitudinal direction with the first region in between, or a second arrangement in which they are closer to each other than in the first arrangement. A test bench for evaluating noise suppression members according to claim 4.

6. The aforementioned transmission line member is A rod-shaped member and The rod-shaped member includes a cylindrical member extending from at least one end of the rod-shaped member, The rod-shaped member is inserted into the inner circumference of the cylindrical member so as to be movable in the axial direction, while in contact with the cylindrical member. A test bench for evaluating noise suppression members according to claim 5.

7. The aforementioned transmission line member is A first rod-shaped member having a length corresponding to the first track section, Includes a pair of second rod-shaped members detachably connected to both ends of the first rod-shaped member and extending from both ends. A test bench for evaluating noise suppression members according to claim 5.

8. A test bench for evaluating noise suppression members according to any one of claims 1 to 7, Includes measuring instruments connected to both ends of the transmission line member. Noise suppression material evaluation system.

9. A step of using the noise suppression member evaluation test bench described in claim 1 to measure the pass characteristics of the transmission line member before and after the installation of the noise suppression member to be evaluated on the mounting portion, Using a reference test bench configured such that the ground plane includes a pair of inclined surfaces included in the pair of second regions, by removing the first region from the noise suppression member evaluation test bench and connecting the pair of second regions to each other, the reference transmission line member having the reference test bench, which includes only the pair of second line portions, is measured. The step includes determining the passage characteristics of the first line portion based on the passage characteristics of the transmission line members before and after installation, and the reference passage characteristics. Evaluation method for noise suppression materials.

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