High frequency component mounting unit and high frequency component mounting method

Abstract

To eliminate the need for high accuracy of machining on metal plates and recesses in a high frequency component mounting unit in which a metal plate connected to a high frequency board is disposed in a recess inside a metal case.SOLUTION: The upper side of a metal plate 61 constitutes a horizontal plane and the underside of the metal plate 61 is tapered. More specifically, inclined faces 61A, 61B that would reduce thickness as it goes toward an end side on the underside are formed on the left and right end sides in the drawing, respectively. A bottom face 61C is formed in a region between the inclined face 61A and the inclined face 61B on the underside of the metal plate 61. The inside shape of a recess is formed to a shape corresponding to said shape of the underside of the metal plate 61. When accommodating the metal plate 61 in the recess, the inclined face 61A and an inclined face 10AA, the inclined faces 61B and 10AB, and the bottom face 61C and a bottom face 10AC face each other, respectively, thus realizing the structure shown in Figure 2.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a high-frequency component mounting unit having high-frequency components used in a transmission path of a high-frequency signal in a metal case, and a method for mounting the high-frequency components. [Background technology]

[0002] In particular, when high-frequency components (such as amplifiers) that operate on high-frequency band signals such as millimeter waves and quasi-millimeter waves are used in combination, multiple high-frequency components are mounted in a metal case that shields the entire unit. The structure of a high-frequency component mounting unit having such a configuration is described in Patent Document 1, for example.

[0003] Here, the high-frequency components are in the form of a high-frequency board mounted on the surface of an insulating substrate, and striplines that serve as paths (wiring) for transmitting signals are also formed on the surface of this substrate. A metal layer that serves as a GND is formed over the entire back side of this substrate, and this is then bonded to a metal plate, which is then fixed to the metal base that forms the bottom surface of the metal case. Within this metal case, multiple high-frequency components are arranged along the signal propagation direction, and various high-frequency circuits can be realized by connecting the striplines on adjacent substrates (high-frequency boards).

[0004] FIG. 6 is a top view showing a planar configuration of an example of such a high-frequency component mounting unit 900. Here, amplifying elements (high-frequency components) 21 to 23 that function in a high-frequency range are connected in series and installed in a rectangular box-shaped metal case 910 with an open top. Signals are input to and output from an input connector 31 and an output connector 32, respectively, to the metal case 910, and coaxial cables are connected to the input connector 31 and the output connector 32 from the outside. Here, the amplifying element 21 is mounted on a substrate 41, the amplifying element 22 on a substrate 42, and the amplifying element 23 on a substrate 43. Here, substrates 44 and 45 that do not mount active elements but function only as signal paths are also provided. All substrates are made of insulating materials, but strip lines 50 that serve as signal paths (wiring) are formed on the surfaces of the substrates 41, 44, and 45.

[0005] With this configuration, a high frequency signal input from input connector 31 is amplified by amplifying elements 21, 22, and 23 and output from output connector 32. Since metal case 910 is grounded, noise generated during this process is reduced, enabling stable operation. At this time, input connector 31 and board 41, board 41 and board 42, board 42 and board 44, board 44 and board 43, board 43 and board 45, and board 45 and output connector 32 are electrically connected by pin-shaped connection terminals 70, respectively.

[0006] Here, among the amplifying elements, amplifying element 21 plays a major role, and Fig. 7 is an exploded perspective view showing the surrounding structure in detail. As shown in the upper part of Fig. 7, amplifying element 21 is in the form of a high-frequency substrate 20 mounted on insulating substrate 41 having strip line 50 formed on its surface. A thin metal layer is formed on the entire back surface of substrate 41, and this metal layer is set to ground potential (GND), so that the ground potential in this high-frequency substrate 20 is ensured.

[0007] The back side of the high-frequency substrate 20 is bonded to a metal plate 961 with a conductive adhesive or the like (not shown), and the metal plate 961 is further bonded to the bottom surface of the metal case 910 with a conductive adhesive or the like (not shown). At this time, as shown in the figure, screws 80 can be further used to strengthen the bond between the high-frequency substrate 20 and the metal plate 961 and the bond between the metal case 910 and the metal plate 961. As a result, the back side of the substrate 41 is held at ground potential via the metal plate 961 and the metal case 910, and the amplification element 21 can amplify signals while suppressing the introduction of noise.

[0008] In this configuration, the state of contact between the high-frequency substrate 20 and the metal case 910 affects the signal transmission characteristics. For example, as described in Patent Document 1, in this configuration, if the metal plate 961 is warped, the transmission characteristics are significantly degraded. For this reason, the technology described in Patent Document 1 describes inserting a thin metal plate between the metal plate 961 and the bottom surface of the metal case 910, which is crushed when the metal plates are joined. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2002-76178 A DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0010] In the technology described in Patent Document 1, the deterioration of the transmission characteristics due to the deterioration of the accuracy of the positional relationship of the high-frequency board (metal plate) with respect to the metal case in the vertical direction is compensated for. On the other hand, as shown in Fig. 6, particularly when multiple high-frequency components are provided in the metal case, the accuracy of the positional relationship of the high-frequency board (metal plate) with respect to the metal case in the horizontal direction (direction in which the signal is transmitted) also affects the transmission characteristics.

[0011] Fig. 8 is a cross-sectional view taken along the line AA in Fig. 6, showing the structure inside the metal case 910. Here, the positional relationship inside the metal case 910 of the input connector 31, the substrate 41 (amplifying element 21), the metal plate 961, and the substrate 42 (amplifying element 22) is shown. In reality, there is insulation between the connection terminal 70 connected to the input connector 31 and the metal case 910, but the structure for this insulation is omitted. Also, the strip line 50 on the substrate 41 in Fig. 7 is omitted.

[0012] In particular, when mass-producing high-frequency component mounting units 900, it is required to determine the horizontal position of substrate 41 (high-frequency substrate 20) within metal case 910. To achieve this, it is effective to provide recess 910A for accommodating metal plate 961 in the bottom surface of metal case 910, as is commonly known, as shown in Figs. 7 and 8. Ideally, if the metal plate 961 is configured to fit within recess 910A, this position can be determined with high precision. Since metal plate 961 is usually plate-shaped (thin rectangular shape), recess 910A also has the same shape.

[0013] However, in reality, there is dimensional variation in the metal plate 961 and the recess 910A due to their processing accuracy, and if the metal plate 961 becomes longer than the width of the recess 910A, for example, the metal plate 961 (high frequency board 20) cannot be accommodated in the metal case 910. For this reason, the recess 910A and the metal plate 961 are actually set so that there is a gap between them as shown in region X in Fig. 8. That is, the metal plate 961 is actually set to be slightly shorter than the width of the recess 910A, and the metal plate 961 is designed to be loosely fitted into the recess 910A.

[0014] The results of investigating this effect through simple calculations will be described below. In Fig. 8, the gap between the left and right sides of metal plate 961 in recess 910A in the left-right direction in the figure (signal transmission direction) is L, and the depth of recess 910A is D. That is, it is assumed here that a gap with width L and depth D is formed on the left and right sides of metal plate 961. Depth D of recess 910A corresponds approximately to the thickness of metal plate 961, and is 3.8 mm here. The high-frequency board 20 is simply a line with a characteristic impedance of 50 Ω, and the VSWR (voltage standing wave ratio) was calculated when L was set to 0 to 0.3 mm.

[0015] FIG. 9 shows the results of calculations of the VSWR when the signal frequency is 5 to 15 GHz when L is 0 mm, 0.1 mm, 0.2 mm, and 0.3 mm. From these results, the smaller the gap width L between the metal plate 961 and the inner surface of the recess 910A along the signal transmission direction, the closer the VSWR is to 1 uniformly. Here, L=0 mm is an ideal case in which the VSWR is 1 regardless of the frequency, but as described above, it is difficult to achieve L=0 mm in reality. On the other hand, when L is larger than 0.1 mm, the VSWR significantly increases from 1. When there is a loose fit between the metal plate 961 and the recess 910A as described above, L can be 0.1 mm to 0.3 mm.

[0016] In other words, when the length of the recess 910A was used as a standard, if the metal plate 961 was longer than the ideal case, the metal plate 961 could not be accommodated in the recess 910A, and if the metal plate 961 was shorter than the ideal case, the transmission characteristics were significantly degraded. For this reason, high processing accuracy was required for the metal plate 961 and the recess 910A.

[0017] The present invention has been made in view of the above circumstances, and has an object to solve the above problems. [Means for solving the problem]

[0018] The present invention is a high-frequency component mounting unit comprising: a substrate having a high-frequency component mounted on its front side; a metal plate joined to the substrate on the back side of the substrate; and a metal case having a recess on its internal bottom surface for internally fixing the high-frequency component by accommodating the metal plate, and transmitting a high-frequency signal internally along one direction in a horizontal plane via the high-frequency component, wherein the recess comprises a recess-side bottom surface on the bottom side, and a recess-side inclined surface inclined from the horizontal plane so as to rise from the recess-side bottom surface toward the end side in the one direction, and the metal plate comprises a metal plate-side bottom surface facing the recess-side bottom surface and parallel to the recess-side bottom surface, and a metal plate-side inclined surface facing the recess-side inclined surface and parallel to the recess-side inclined surface, and the metal plate is accommodated in the recess within the metal case with the recess-side inclined surface and the metal plate-side inclined surface abutting each other. The recess-side inclined surface and the metal plate-side inclined surface may be formed on both end sides in the one direction, respectively. The bottom surface of the recess and the bottom surface of the metal plate may be in contact with each other via a conductive material. The present invention also relates to a method for mounting a high-frequency component on a front side of a substrate and mounting the component in a metal case, the method comprising the steps of: transmitting a high-frequency signal internally within the metal case via the high-frequency component along one direction in a horizontal plane; joining a metal plate to the substrate on the back side of the substrate; forming a recess for accommodating the metal plate on a bottom surface within the metal case; providing in the recess a recess-side bottom surface on the bottom side and a recess-side inclined surface at an end side in the one direction, the recess being inclined from the horizontal plane so as to rise from the recess-side bottom surface toward the end side; providing in the metal plate a metal-plate-side bottom surface facing the recess-side bottom surface and parallel to the recess-side bottom surface, and a metal-plate-side inclined surface facing the recess-side inclined surface and parallel to the recess-side inclined surface; and accommodating the metal plate in the recess with the recess-side inclined surface and the metal-plate-side inclined surface abutting each other within the metal case. Effect of the Invention

[0019] In a high-frequency component mounting unit in which a metal plate connected to a high-frequency board is provided in a recess in a metal case, high machining precision is not required for the metal plate and the recess. [Brief description of the drawings]

[0020] [Figure 1] The VSWR (Voltage Standing Wave Ratio) of a conventional high-frequency component mounting unit was calculated for each gap width, assuming the depth of the gap formed between the metal plate and the recess is 0.8 mm. [Diagram 2] 11 is a partial cross-sectional view showing the structure inside a metal case in a high-frequency component mounting unit according to an embodiment when the length of a metal plate is ideal. FIG. [Diagram 3] 4 is a partial cross-sectional view of a metal plate and a metal case in the high-frequency component mounting unit according to the embodiment. FIG. [Figure 4] 11 is a partial cross-sectional view showing the structure inside the metal case in the high-frequency component mounting unit according to the embodiment when the length of the metal plate is longer than the ideal length. FIG. [Diagram 5] 13 is a partial cross-sectional view showing the structure inside a metal case in a modified example of the high-frequency component mounting unit according to the embodiment when the length of the metal plate is ideal. FIG. [Figure 6] 1 is a top view showing a planar configuration of an example of a high-frequency component mounting unit. FIG. [Figure 7] FIG. 11 is a partial exploded perspective view showing a configuration of an example of a conventional high-frequency component mounting unit. [Figure 8] 1 is a partial cross-sectional view showing the structure inside a metal case in an example of a conventional high-frequency component mounting unit. [Figure 9] The VSWR in a conventional high-frequency component mounting unit was calculated for each gap width, assuming that the depth of the gap formed between the metal plate and the recess is 3.8 mm. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Next, a specific embodiment of the present invention will be described, in which a method for suppressing deterioration of transmission characteristics caused by a gap between the metal plate and the recessed portion even if the metal plate and the recessed portion have dimensional variations as described above will be described.

[0022] 9 shows the L dependency of VSWR when the width L of the gap formed between both ends of metal plate 961 in the signal propagation direction and the inner surface of recess 910A is set to 0 to 0.3 mm and the height (depth) D is set to 3.8 mm. Here, FIG. 1 shows the result of calculating the same characteristics as in FIG. 9 when the depth D of the gap (depth of recess 910A) in FIG. 8 is set to 0.8 mm, which is shallower than the case of FIG. 9. From this result, even if L is the same, it is possible to reduce the deterioration of the transmission characteristics (VSWR) by reducing the depth (depth of the gap) D of recess 910A.

[0023] 7 and 8, the depth of the recess 910A corresponds to the thickness of the metal plate 961. In this case, the thickness of the metal plate 961 is several mm, which is thicker than the 0.8 mm used in the calculation of Fig. 1. For this reason, it is not preferable to make the recess shallow in this way, for example.

[0024] For this reason, in the high-frequency component mounting unit or the high-frequency component mounting method according to the embodiment of the present invention, the cross-sectional shape of the metal plate and the corresponding recess is shaped so that the depth of the gap is substantially shallow. Here, as described above, there is manufacturing variation in the dimensions of the metal plate, etc., and even if there is variation in the length of the metal plate, etc., the substantial width L of the gap is not increased and the substantial depth D is kept small. For this reason, even if there is variation in the length of the metal plate and the recess, when the metal plate is accommodated in the recess, deterioration of the transmission characteristics due to this variation is unlikely to occur.

[0025] Fig. 2 is a cross-sectional view corresponding to Fig. 8, showing a cross section of a portion of this high-frequency component mounting unit 1. Here, as in the case of Fig. 8, an input connector 31, an amplifying element (high-frequency component) 21, a substrate 41, a metal plate 61, a substrate 42 (amplifying element 22), a metal case 10, and a connection terminal 70 are provided. As in Fig. 8, the structure for insulation between the connection terminal 70 connected to the input connector 31 and the metal case 10 and the strip line on the substrate 41 are omitted.

[0026] FIG. 3 is a cross-sectional view showing the shape of the metal case 10 and the metal plate 61 before assembly, corresponding to FIG. 2. Here, the metal plate 961 is a normal plate (a rectangular shape thin in the height direction), and its upper and lower surfaces each form a horizontal plane (horizontal plane), whereas the upper surface side of this metal plate 61 forms a horizontal plane like the metal plate 961, but the lower surface side of the metal plate 61 is tapered. Specifically, on the lower surface side, an inclined surface (metal plate side inclined surface) 61A and an inclined surface (metal plate side inclined surface) 61B that decrease in thickness toward the end side are formed on the left and right end sides in the figure. In the region between the inclined surface 61A and the inclined surface 61B on the lower surface of the metal plate 61, a bottom surface (metal plate side bottom surface) 61C that is a horizontal plane like the bottom surface of the metal plate 961 is formed. Both the inclined surfaces 61A and 61B are formed as flat surfaces, and the horizontal plane is inclined as shown in the figure. For this reason, although FIG. 2 shows a cross section at one point along the signal propagation direction, inclined surfaces 61A, 61B and bottom surface 61C are each formed perpendicular to the plane of the paper, and therefore their shapes are uniform across the range of the width of metal plate 61 in the direction perpendicular to the plane of the paper.

[0027] The shape of the inner surface of the recess 10A corresponds to the shape of the lower surface of the metal plate 61. That is, an inclined surface (metal case side inclined surface) 10AA rising toward the left at the left end side in FIG. 2, an inclined surface (metal case side inclined surface) 10AB rising toward the right at the right end side is formed, and a bottom surface (metal case side bottom surface) 10AC, which is a horizontal surface, is formed between them. The inclination angle of the inclined surface 10AA from the horizontal and the inclination angle of the inclined surface 61A from the horizontal, and the inclination angle of the inclined surface 10AB from the horizontal and the inclination angle of the inclined surface 61B from the horizontal are each equal. As a result, when the metal plate 61 is accommodated in the recess 10A, the inclined surface 61A and the inclined surface 10AA, the inclined surface 61B and the inclined surface 10AB, and the bottom surface 61C and the bottom surface 10AC face each other, and the structure shown in FIG. 2 is realized.

[0028] 2 shows an ideal case in which the length of the bottom surface 61C of the metal plate 61 and the length of the bottom surface 10AC of the metal case 10 (recess 10A) in the left-right direction (signal propagation direction) are equal. In this case, as shown in the figure, the inclined surfaces 61A, 61B, and bottom surface 61C on the metal plate 61 side are in surface contact with the inclined surfaces 10AA, 10AB, and bottom surface 10AC on the metal case 10 (recess 10A) side. In this case, the area X corresponding to the gap between the metal plate 961 and the inner surface of the recess 910A in FIG. 7 is negligibly small compared to the case of FIG. 7, and in particular the height D of the gap is small. For this reason, the deterioration of the transmission characteristics in this case is extremely small.

[0029] On the other hand, Fig. 4 shows a situation similar to that of Fig. 2, in which bottom surface 61C of metal plate 61 is slightly longer than bottom surface 10AC of metal case 10 (recess 10A) in the left-right direction. Here, the illustration of screws 80 is omitted. In this case, a gap is formed between bottom surface 61C and bottom surface 10AC, but the situation in which inclined surfaces 61A, 61B and inclined surfaces 10AA, 10AB are in surface contact remains the same as in Fig. 2. On the other hand, the gap in region X is small as in Fig. 2, and in particular, the height D is even smaller.

[0030] In the structure of FIG. 8, when the metal plate 961 is longer than the recess 910A, the metal plate 961 (high-frequency substrate 20) cannot be accommodated in the recess 910A. Therefore, a gap is set between the metal plate 961 and the inner surface of the recess 910A, which causes deterioration of the transmission characteristics. In contrast, in the structure of FIG. 2, even if the length of the metal plate 61 is longer than the ideal case (FIG. 2), the high-frequency substrate 20 can be accommodated in the recess 10A with the inclined surfaces abutting each other, and at least a deep gap is not formed, so that the transmission characteristics do not deteriorate due to this gap. Therefore, even if the processing accuracy (dimensional accuracy) of the metal plate 61 or the recess 10A is poor, the deterioration of the transmission characteristics caused by this can be suppressed. Alternatively, the deterioration of the transmission characteristics is less likely to occur when the length of the metal plate 61 or the recess 10A is from the ideal case (when the length of the bottom surface 61C is equal to the bottom surface 10AC) to the case where the length of the metal plate 61 is slightly longer than this or the recess 10A is slightly shorter than this. This widens the tolerance for machining accuracy of the metal plate 61 and the recess 10A.

[0031] Also, by bonding bottom surface 61C and bottom surface 10AC with a conductive adhesive or by interposing a thin sheet of conductive resin material between them, the gap between bottom surface 61C and bottom surface 10AC in the state shown in Fig. 4 can be filled with a conductive material. Even if there is a possibility of deterioration of the transmission characteristics due to this gap, this can be suppressed. Alternatively, if metal plate 61 is fixed to recess 10A (metal case 10) with screws 80, electrical connection therebetween can also be achieved with screws 80, so the same is true.

[0032] It is not impossible to use a conductive adhesive or a conductive resin material sheet in the same way for the gaps of width L and depth D formed on the left and right sides in the conventional structure shown in Figure 8. However, since the gaps formed in this case are close to the amplifying elements and the like on the upper side of the board, there is a risk that the amplifying elements and the like may be adversely affected by them, making this practical application difficult. In the above configuration, the problematic gaps are formed on the bottom side, so the amplifying elements and the like are not affected by the conductive adhesive, and various conductive materials can be easily used to fill the gaps.

[0033] In the above-described high-frequency component mounting unit 1, the inclined surfaces of the metal plate 61 and the recess 10A are provided on both the left and right sides in the left-right direction (signal propagation direction) in Fig. 2 etc., but such an inclined surface may be provided only on one side. Fig. 5 shows the structure of a high-frequency component mounting unit 2 which is such a modified example of the high-frequency component mounting unit according to the embodiment of the present invention, in correspondence with Fig. 2.

[0034] In this case, the lower surface side of the metal plate 161 is tapered only on the right side in the figure. Specifically, the side surface on the left side of the metal plate 161 in the figure is a side surface (metal plate side side) 161A which is a vertical surface, and only the right side of the metal plate 161 is provided with an inclined surface (metal plate side inclined surface) 161B similar to the above. The area on the lower surface side of the metal plate 161 other than the inclined surface 161B is a bottom surface (metal plate side bottom surface) 161C which is a horizontal surface. Correspondingly, the inner surface of the recess 110A is also formed with a side surface (metal case side side) 110AA corresponding to the side surface 161A, an inclined surface (metal case side inclined surface) 110AB corresponding to the inclined surface 161B, and a bottom surface (metal case side bottom surface) 110AC corresponding to the bottom surface 161C.

[0035] FIG. 5 shows an ideal case in which the length of the bottom surface 161C of the metal plate 161 and the length of the bottom surface 110AC of the metal case 110 (recess 110A) in the left-right direction (signal propagation direction) are equal. In this case, as shown in the figure, the side surface 161A, inclined surface 161B, and bottom surface 161C on the metal plate 61 side are in surface contact with the side surface 110AA, inclined surface 110AB, and bottom surface 110AC on the metal case 110 (recess 110A) side. In this case, the gap in the right-side region X1 is similar to the case in FIG. 2 and is smaller than the conventional case (FIG. 8). On the other hand, the gap in the left-side region X2 is not formed because the side surface 161A and the side surface 110AA are in surface contact with each other. Therefore, similar to the structure in FIG. 2, the deterioration of the transmission characteristics is extremely small in this case.

[0036] On the other hand, when the metal plate 161 is slightly longer than that in FIG. 5 as in FIG. 4, the situation where no gap is formed in the left region X2 remains unchanged, and the situation where the inclined surface 161B and the inclined surface 110AB are in surface contact with each other in the right region X1 as in FIG. 4 also remains unchanged. As in FIG. 4, a gap is formed between the bottom surface 161C and the bottom surface 110AC, but the adverse effect of this gap on the transmission characteristics is small, or if there is an adverse effect, this gap can be easily filled. Therefore, even in this case, the deterioration of the transmission characteristics due to the possible accuracy (dimensional accuracy) of the metal plate 161 and the metal case 110 (recess 110A) is suppressed.

[0037] In the configurations of Figures 2 and 5, these structures are formed uniformly in the direction of the paper, that is, each inclined surface, each bottom surface, etc. are formed as a flat surface perpendicular to the paper surface. However, when the inclined surfaces and bottom surfaces of the metal plate side and the recessed portion (metal case) side face each other and abut against each other, each inclined surface and each bottom surface in Figures 2 and 5 do not necessarily have to be perpendicular to the paper surface. Also, each inclined surface and each bottom surface do not necessarily have to be configured as a flat surface.

[0038] Similarly, in the above configuration, the upper surface of the metal plate (the surface to which the high-frequency substrate is bonded) is flat, but the configuration of this upper surface is arbitrary as long as it does not adversely affect the transmission characteristics. The same is true for the configuration other than the shape of the inner surface of the recess in the metal case, which is set appropriately depending on the configuration of the high-frequency element placed inside.

[0039] The present invention has been described above based on the embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components, and that such modifications are also within the scope of the present invention. [Explanation of symbols]

[0040] 1, 2, 900 High frequency component mounting unit 10, 110, 910 Metal case 10A, 110A, 910A recess 10AA, 10AB, 110AB Inclined surface (Metal case side inclined surface) 10AC, 110AC bottom (metal case bottom) 20 High Frequency Board 21, 22, 23 Amplifying element (high frequency component) 31 Input Connector 32 Output Connector 41~45 Board 50 Stripline 61, 161, 961 metal plate 61A, 61B, 161B Slanted surface (slanted surface on metal plate side) 61C, 161C bottom (metal plate side bottom) 70 Connection terminal 110AA Side (Metal case side) 161A Side (metal plate side side)

Claims

1. A board with high-frequency components mounted on the front side, a metal plate joined to the substrate on a rear surface side of the substrate; a metal case having a recess on an inner bottom surface for accommodating the metal plate and fixing the high frequency component therein, and for transmitting a high frequency signal inside the metal case in one direction within a horizontal plane via the high frequency component; A high-frequency component mounting unit comprising: The recess includes a recess-side bottom surface on the bottom side and a recess-side inclined surface inclined from a horizontal plane so as to rise from the recess-side bottom surface toward the end side in the one direction, the metal plate includes a metal plate side bottom surface facing the recess side bottom surface and parallel to the recess side bottom surface, and a metal plate side inclined surface facing the recess side inclined surface and parallel to the recess side inclined surface, a metal plate housed in the recess with the recess-side inclined surface and the metal plate-side inclined surface abutting against each other within the metal case;

2. 2. The high-frequency component mounting unit according to claim 1, wherein the recess-side inclined surface and the metal plate-side inclined surface are formed on both end sides in the one direction, respectively.

3. 3. The high frequency component mounting unit according to claim 1, wherein a bottom surface of the recess side and a bottom surface of the metal plate side are in contact with each other via a conductive material.

4. A method for mounting a high-frequency component, comprising mounting the high-frequency component on a front side of a substrate and mounting the component in a metal case, the method comprising the steps of: A high-frequency signal is transmitted internally in one direction within a horizontal plane through the high-frequency component within the metal case; A metal plate is joined to the substrate on the rear surface side of the substrate; a recess for accommodating the metal plate is formed on a bottom surface inside the metal case; The recess has a bottom surface on the bottom side and an inclined surface on the end side in the one direction, the inclined surface being inclined from a horizontal plane so as to rise from the bottom surface toward the end side, The metal plate is provided with a metal plate-side bottom surface that faces the recess-side bottom surface and is parallel to the recess-side bottom surface, and a metal plate-side inclined surface that faces the recess-side inclined surface and is parallel to the recess-side inclined surface, a metal plate that is accommodated in the recess in the metal case with the recess-side inclined surface and the metal plate-side inclined surface abutting against each other,

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