Sensor Module

Abstract

To provide a sensor module with good radiation characteristics.SOLUTION: The sensor module includes a metal member having a recess, a resin part embedded inside the recess, a radiating part provided inside the resin part and radiating radio waves, a wireless communication unit installed inside the resin part and connected to the radiating part, and a sensor connected to the wireless communication unit. The metal member is insulated from the radiating part by the resin part and functions as an unpowered element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a sensor module. [Background technology]

[0002] Conventionally, there has been a microstrip antenna consisting of a dielectric substrate sandwiched between a patch surface of a radiating conductor and a ground surface, characterized in that at least a part of the ground surface is folded so that its tip is at approximately the same height as the patch surface, the folded portion covers the side surface of the dielectric substrate, and the surface including the patch surface is configured so that the distance between the peripheral edge of the patch surface and the folded end of the ground surface is longer than the height of the folded portion of the ground surface (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-148840 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, conventional microstrip antennas are not designed with the assumption that they will be incorporated into a sensor module.

[0005] It is therefore an object of the present invention to provide a sensor module with good radiation characteristics. [Means for solving the problem]

[0006] The sensor module of an embodiment of the present invention includes a metal member having a recess, a resin part embedded in the recess, a radiating part provided inside the resin part and radiating radio waves, a wireless communication part provided inside the resin part and connected to the radiating part, and a sensor connected to the wireless communication part, and the metal member is insulated from the radiating part by the resin part and functions as a parasitic element. Effect of the Invention

[0007] A sensor module with good radiation characteristics can be provided. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a sensor module 100 according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA in FIG. [Diagram 3] FIG. 1 shows a multi-module 130. [Figure 4] 13 is a diagram showing frequency characteristics of the S11 parameter of the sensor module 100. FIG. [Diagram 5] 11 is a diagram showing a simulation result of the directivity of the sensor module 100. FIG. [Figure 6] FIG. 13 is a diagram showing a sensor module 100A according to a modified example of the embodiment. [Figure 7] FIG. 13 is a diagram showing a sensor module 100B1 according to a modified example of the embodiment. [Figure 8] FIG. 13 is a diagram showing a sensor module 100B2 according to a modified example of the embodiment. [Figure 9] FIG. 13 is a diagram showing a sensor module 100B3 according to a modified example of the embodiment. [Figure 10] FIG. 13 is a plan view showing a part of a sensor module 100C1 according to a modified example of the embodiment. [Figure 11] FIG. 13 is a plan view showing a portion of a sensor module 100C2 according to a modified example of the embodiment. [Figure 12]FIG. 13 is a plan view showing a portion of a sensor module 100C3 according to a modified example of the embodiment. [Figure 13] FIG. 13 is a plan view showing a portion of a sensor module 100C4 according to a modified example of the embodiment. [Figure 14] 13 is a diagram showing a cross section and a part of a sensor module 100D according to a modified example of the embodiment. FIG. [Figure 15] 15 is a modified example of the multi-module 130D shown in FIG. [Figure 16] 16 is a modified example of the multi-module 130D shown in FIG. [Figure 17] 13 is a diagram showing a cross section and a part of a sensor module 100E according to a modified example of the embodiment. FIG. [Figure 18] FIG. 13 is a diagram showing a sensor module 100F according to a modified example of the embodiment. [Figure 19] FIG. 13 shows a multi-module 130F. [Figure 20] FIG. 13 is a diagram showing frequency characteristics of the S11 parameter of the sensor module 100F. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment to which a sensor module of the present invention is applied will be described.

[0010] <Embodiment> Fig. 1 is a diagram showing a sensor module 100 according to an embodiment. Fig. 2 is a diagram showing a cross section taken along the line AA in Fig. 1. In the following description, an XYZ coordinate system is defined, and the XY plane view is referred to as a planar view. For convenience of explanation, the -Z direction side is referred to as the lower side or bottom, and the +Z direction side is referred to as the upper side or top, but these do not represent a universal vertical relationship.

[0011] The sensor module 100 includes metal members 110 (110A, 110B), a resin part 120, a multi-module 130, and a resin part 140. The sensor module 100 is a disc-shaped member.

[0012] The metal member 110 is an example of a first metal member, and includes a metal member 110A and a metal member 110B. Hereinafter, the combination of the metal member 110A and the metal member 110B will be referred to as the metal member 110.

[0013] The metal member 110A is a metal annular member, and has a groove 111A recessed in an annular shape from the top surface, and a through hole 112A penetrating in the vertical direction at the center in a plan view. The groove 111A is an example of a recess, and has an outer inner circumferential surface 111A1, an inner inner circumferential surface 111A2, and a bottom surface 111A3. The metal member 110A is made of a metal, such as stainless steel, iron, aluminum, or tungsten, for example.

[0014] The metal member 110B is an example of a second metal member, and is a thin, annular member. The outer diameter of the metal member 110B is smaller than the inner diameter of the cylindrical inner circumferential surface 111A1 of the groove portion 111A of the metal member 110A. The metal member 110B has a through hole 111B that penetrates in the vertical direction at the center. The size of the opening of the through hole 111B is equal to the size of the opening of the through hole 112A, and the centers of the through hole 111B and the through hole 112A are aligned in a plan view.

[0015] The end of the inner circumference side of the metal member 110B is fixed to the upper end 113A of the inner circumference of the metal member 110A, and is disposed on the resin part 120 provided inside the groove part 111A of the metal member 110A. The metal member 110B is configured to cover the inner circumference side part of the groove part 111A with a flange. As shown in FIG. 2, the flange realized by the metal member 110B faces from the radial inside to the outside of the groove part 111A, and forms an annular slit 115 between the upper end of the inner circumference surface 111A1 on the outside of the groove part 111A of the metal member 110A and the outer circumference end of the metal member 110B. The metal member 110B is made of a metal such as stainless steel, iron, aluminum, or tungsten, for example.

[0016] The resin part 120 is embedded entirely inside the groove 111A of the metal member 110A. The resin part 120 also covers and encases the multi-module 130, preventing the multi-module 130 from directly contacting the metal members 110A and 110B. The resin part 120 may be any resin that can be filled into the groove 111A, and may be, for example, a sealing resin containing an epoxy resin.

[0017] The multi-module 130 is a module having multiple functions, and has, for example, a communication function and a sensor function. The communication function is realized by a radiation unit and a wireless communication unit of the multi-module 130. For example, the sensor function is realized by a strain sensor (strain gauge), an accelerometer, a thermometer, etc.

[0018] As an example, the multi-module 130 has a thin plate shape and is embedded inside the resin part 120. As an example, the multi-module 130 is arranged in an upright state with the radiating part facing up near the cylindrical inner circumferential surface 111A1 on the outer side of the groove part 111A of the metal member 110A. Details of the multi-module 130 will be described later with reference to FIG. 3.

[0019] The resin portion 140 is embedded entirely inside the through hole 112A of the metal member 110A. The resin portion 140 may be any resin capable of filling the through hole 112A, and may be, for example, a sealing resin containing an epoxy resin.

[0020] In the sensor module 100 having such a configuration, an annular slit 115 is formed between an upper end of an inner circumferential surface 111A1 on the outer side of the groove portion 111A of the metal member 110A and an outer circumferential end of the metal member 110B. The length of one circumference of the slit 115 is set to the electrical length of one wavelength at the frequency (communication frequency) of the radio wave radiated from the radiating portion of the multi-module 130. More specifically, the length of one circumference at the upper end of the inner circumferential surface 111A1 located at the outermost position in the radial direction of the slit 115 is set to the electrical length of one wavelength at the communication frequency of the multi-module 130.

[0021] The length of one revolution at the outer circumferential end of metal member 110B located at the radially innermost position of slit 115 may be set to the electrical length of one wavelength at the communication frequency of multi-module 130. In addition, the length of one revolution of slit 115 between the upper end of inner circumferential surface 111A1 located at the radially outermost position of slit 115 and the outer circumferential end of metal member 110B located at the radially innermost position of slit 115 may be set to the electrical length of one wavelength at the communication frequency of multi-module 130.

[0022] In the sensor module 100, by having the above-mentioned slit 115, the radio waves radiated from the radiating portion of the multi-module 130 resonate in the metal members 110A and 110B and are radiated to the outside of the sensor module 100. At this time, the metal members 110A and 110B function as parasitic elements.

[0023] The length of one circumference of the slit 115 as described above does not have to be strictly the electrical length of one wavelength at the communication frequency of the multi-module 130. For example, the resin part 120 is disposed in the groove 111A of the metal member 110A, and the resin part 140 is disposed in the through hole 112A. The multi-module 130 is disposed inside the resin part 120. In this way, when the impedance characteristics change due to the arrangement of the resin part 120, the multi-module 130, and the resin part 140 on the metal member 110, the length of one circumference of the slit 115 may be adjusted to be slightly shorter or longer than the electrical length of one wavelength at the communication frequency of the multi-module 130 so that the impedance of the slit 115 is matched. The purpose of setting the length of one circumference of the slit 115 to the electrical length of one wavelength at the frequency (communication frequency) of the radio wave radiated from the radiation part of the multi-module 130 includes the adjustment of the length of the slit 115 in this way.

[0024] Furthermore, the sensor module 100 may not include the resin part 140. In this case, the sensor module 100 is an annular module rather than a disk-shaped module. Furthermore, the sensor module 100 may not include the resin part 140, and may have a configuration in which the metal member 110 completely fills the through-hole 112A.

[0025] Fig. 3 is a diagram showing the multi-module 130. The XYZ coordinate system shown in Fig. 3 corresponds to the XYZ system shown in Figs.

[0026] As an example, the multi-module 130 includes a substrate 131, ground layers 132A and 132B, an antenna element 133, matching circuits 134A and 134B, and a chip 135, as shown in FIGS.

[0027] The substrate 131 is, for example, a wiring substrate conforming to the FR-4 (Flame Retardant type 4) standard. The substrate 131 may also be a flexible substrate realized by a polyimide film or the like. The substrate 131 is disposed parallel to the YZ plane.

[0028] As shown in Fig. 3(A), a ground layer 132A is provided on approximately 2 / 3 of the surface of the substrate 131 on the -X side in the -Z direction. An antenna element 133 is provided on approximately 1 / 3 of the surface of the substrate 131 on the -X side in the +Z direction. The ground layer 132A and the antenna element 133 are spaced apart. As shown in Fig. 3(B), a ground layer 132B is provided on the entire surface of the substrate 131 on the +X side.

[0029] The ground layers 132A and 132B are, for example, copper foil. A chip 135 is mounted on the top (−X direction side) of the ground layer 132A. The ground layers 132A and 132B are connected by a via or the like that penetrates the substrate 131 in the thickness direction (X direction).

[0030] The antenna element 133 is an example of a radiating portion, and extends in the Z direction at the center in the Y direction of about 1 / 3 of the surface on the +Z direction side of the -X direction side of the substrate 131. The antenna element 133 is produced by patterning copper foil, for example. The antenna element 133 is a microstrip line type radiating element because there is a ground layer 132B on the back surface of the substrate 131. The antenna element 133 has a feeding point 133A1 near the ground layer 132A.

[0031] The matching circuits 134A and 134B are, for example, inductors or capacitors. One end of the matching circuits 134A and 134B is connected to the antenna element 133, and the other end is connected to the ground layer 132B on the opposite side of the substrate 131 through a via (not shown). The matching circuits 134A and 134B are provided to achieve impedance matching of the antenna element 133. By using the matching circuits 134A and 134B, a wavelength shortening effect can be obtained.

[0032] The chip 135 has a wireless communication unit 135A, a sensor 135B, and a battery 135C. The wireless communication unit 135A and a power supply point 133A of the antenna element 133 are connected by a core wire of a coaxial cable (not shown), for example, and the antenna element 133 is supplied with power through the core wire. A shield wire of the coaxial cable is connected to the ground layers 132A and 132B.

[0033] Examples of the sensor 135B include a strain sensor (strain gauge), an accelerometer, and a thermometer. The sensor 135B outputs detection data indicating the strain, acceleration, temperature, and the like of the metal member 110 to the wireless communication unit 135A. The detection data is carried by radio waves output from the wireless communication unit 135A, radiated from the antenna element 133, and radiated to the outside of the sensor module 100 by the metal member 110 functioning as a parasitic element.

[0034] The battery 135C supplies power to the wireless communication unit 135A and the sensor 135B. The battery 135C may be a secondary battery that can be charged by wireless power supply, or a replaceable button battery. Instead of the battery 135C, power may be supplied to the wireless communication unit 135A and the sensor 135B from an external power supply device using a wired cable.

[0035] The multi-module 130 may have the configurations shown in Figs. 3C and 3D. For example, as shown in Fig. 3C, the other ends of the matching circuits 134A and 134B may be connected to ground elements 132C and 132D provided on both sides of the antenna element 133. The ground elements 132C and 132D are lines extending from the end sides of the ground layer 132A on the +Z direction side on both sides of the antenna element 133. In this case, as shown in Fig. 3D, the ground layer 132B may be provided in about 2 / 3 of the surface on the +X direction side of the substrate 131 on the -Z direction side, similar to the ground layer 132A. That is, the ground layer 132B may not overlap the antenna element 133.

[0036] In the above-described multi-module 130, the antenna element 133 is provided directly below the slit 115, facing the slit 115 (in the +Z direction), and a current flows in the antenna element 133 in the +Z direction. The antenna element 133 is provided in the vicinity of the slit 115. "In the vicinity of the slit 115" means that the antenna element 133 is close enough to the slit 115 that electromagnetic field coupling between the antenna element 133 and the slit 115 occurs. By obtaining electromagnetic field coupling between the antenna element 133 and the slit 115, the metal member 110 having the slit 115 functions as a parasitic element.

[0037] The length of one circumference of slit 115 is set to the electrical length of one wavelength at the communication frequency of multi-module 130. Furthermore, substrate 131 is provided such that the -X direction in which antenna element 133 is provided faces the inside of groove portion 111A.

[0038] Therefore, the radio waves radiated from the antenna element 133 resonate in the slits 115 and are radiated to the outside of the metal member 110 .

[0039] Fig. 4 is a diagram showing frequency characteristics of the S11 parameter of the sensor module 100. Fig. 4 shows results obtained in an electromagnetic field simulation in the case where the communication frequency of the multi-module 130 is set to 2.62 (GHz) as an example.

[0040] As shown in Figure 4, the value of the S11 parameter was approximately -30 dB at 2.62 GHz, indicating that resonance occurred at 2.62 GHz. It was also found that a wide band with extremely low reflection of less than -10 dB was obtained around 2.62 GHz. The gain was 2.501 dBi.

[0041] In addition, when the communication frequency of the multi-module 130 was set to 2.40 (GHz) as an example, a gain of 0.971 (dBi) was obtained in a sensor module 100 of the same size, and a wide band was obtained centered around 2.40 (GHz) in the frequency characteristics of the S11 parameter.

[0042] Fig. 5 is a diagram showing the results of a simulation of the directivity of the sensor module 100. Fig. 5(A) and (B) show the directivity in the XY plane and the YZ plane when the communication frequency of the multi-module 130 is set to 2.41 (GHz) as an example. As shown in Fig. 5(A), it was found that a substantially uniform directivity was obtained in the XY plane, and as shown in Fig. 5(B), it was found that the radiation to the upper side was slightly stronger in the YZ plane.

[0043] 5(C) and (D) show the directivity in the XY plane and the YZ plane when the communication frequency of the multi-module 130 is set to 2.62 (GHz) as an example. As shown in FIG. 5(C), it was found that a substantially uniform directivity was obtained in the XY plane, and as shown in FIG. 5(D), it was found that the radiation to the upper side was slightly stronger in the YZ plane. It was found that substantially the same tendency was obtained at 2.41 (GHz) and 2.62 (GHz).

[0044] As described above, the sensor module 100 has good radiation characteristics because the multi-module 130 is disposed inside the resin part 120 in the groove part 111A of the metal member 110 and the metal member 110 having the slit 115 functions as a parasitic element.

[0045] Therefore, it is possible to provide a sensor module 100 with good radiation characteristics.

[0046] Furthermore, since the antenna element 133 is disposed facing the slit 115, resonance is likely to occur in the slit 115, and it is possible to provide a sensor module 100 with better radiation characteristics.

[0047] Furthermore, since the antenna element 133 is disposed in the vicinity of the slit 115, electromagnetic field coupling is obtained between the antenna element 133 and the slit 115, making it easier for resonance to occur in the slit 115, and a sensor module 100 with better radiation characteristics can be provided.

[0048] Furthermore, since the multi-module 130 having the substrate 131, the ground layers 132A and 132B, the antenna element 133, the matching circuits 134A and 134B, and the chip 135 is disposed inside the resin portion 120, the manufacturing process is easy.

[0049] Furthermore, when the sensor module 100 does not include the resin part 140 and is a circular module in which the resin part 140 is hollow, a member can be inserted into the through hole 112A. In this case, the sensor module 100 may measure the distortion, acceleration, temperature, etc. of the member inserted into the through hole 112A.

[0050] In the above, the metal member 110 has a circular slit 115. However, the slit 115 may have a rectangular or polygonal ring shape in a plan view, and the groove 111A may also have a rectangular or polygonal ring shape in a plan view. A polygonal ring shape refers to, for example, a triangle or a polygon having five or more corners (pentagon or more).

[0051] 2, a configuration has been described in which the flange realized by the metal member 110B faces from the radially inner side to the outer side of the groove portion 111A, and an annular slit 115 is formed between the upper end of the inner circumferential surface 111A1 on the outer side of the groove portion 111A of the metal member 110A and the outer circumferential end of the metal member 110B. In this case, the multi-module 130 is disposed so that the antenna element 133 is located directly below the slit 115.

[0052] However, the size of the metal member 110B in the radial direction may be increased, and the outer peripheral end of the metal member 110B may be attached to the upper end of the inner peripheral surface 111A1 on the outer peripheral side of the groove portion 111A of the metal member 110A. In this case, the flange realized by the metal member 110B faces inward from the outer side in the radial direction of the groove portion 111A, and a ring-shaped slit 115 is formed between the upper end of the inner peripheral surface 111A2 on the inner side of the groove portion 111A of the metal member 110A and the inner peripheral end of the metal member 110B. In this case, the multi-module 130 may be disposed near the inner peripheral surface 112A2 so that the antenna element 133 is located directly below the slit 115.

[0053] In the above, the metal member 110 has the metal members 110A and 110B. However, the metal member 110 may be modified as shown in FIG.

[0054] Fig. 6 is a diagram showing a sensor module 100A according to a modified example of the embodiment. The sensor module 100A has a configuration in which the metal member 110B is removed from the sensor module 100 shown in Figs. 1 and 2. In this case, the multi-module 130 may be provided in the resin part 120 in the groove 111A, as shown by the dashed line, near the inner peripheral surface 111A1 on the inside, near the inner peripheral surface 111A2 on the outside, or near the bottom surface 111A3. When provided near the bottom surface 111A3, the substrate 131 (see Fig. 3) may be arranged parallel to the bottom surface 111A3 and the antenna element 133 may be arranged to face upward (+Z direction).

[0055] In the above, the metal member 110A is annular and has an annular groove 111A, but may have a configuration as shown in Fig. 7 to Fig. 9. Fig. 7 to Fig. 9 are diagrams showing sensor modules 100B1 to 100B3 according to modified examples of the embodiment. Fig. 7(A) to Fig. 9(A) show the sensor modules 100B1 to 100B3 in plan view, and Fig. 7(B) to Fig. 9(B) show cross sections taken along the lines B1-B1, B2-B2, and B3-B3 in Fig. 7(A) to Fig. 9(A), respectively.

[0056] The sensor module 100B1 shown in FIGS. 7A and 7B includes metal members 110A1 and 110B1, a resin part 120B, and a multi-module 130. The metal member 110A1 is a cylindrical member having no upper surface, and has a recess 111D. The recess 111D is cylindrical. The resin part 120B is embedded inside the recess 111D. The resin part 120B is cylindrical. The metal member 110B1 is an annular member, and is disposed on the resin part 120. A slit 115B1 is formed between the opening at the upper end of the recess 111D of the metal member 110A1 and the outer circumferential end of the metal member 110B1. The multi-module 130 is disposed directly below the slit 115B1.

[0057] The sensor module 100B1 configured as above operates in the same manner as the sensor module 100 shown in FIGS.

[0058] 8A and 8B, the sensor module 100B2 has a configuration in which the metal member 110B1 of the sensor module 100B1 shown in Fig. 7A and 7B is replaced with metal members 110B21 and 110B22 arranged concentrically. The metal member 110B21 is a disk-shaped member arranged on the central side in a plan view, and the metal member 110B22 is an annular member arranged on the outer side in a plan view.

[0059] A slit 115B2 is formed between the upper opening of the recess 111D of the metal member 110A1 and the outer circumferential edge of the metal member 110B22. The multi-module 130 is disposed directly below the slit 115B2 as indicated by the solid line.

[0060] The sensor module 100B2 configured in this way operates in the same manner as the sensor module 100 shown in Figures 1 and 2. Note that the multi-module 130 may be provided below the slit between the metal members 110B21 and 110B22 as indicated by the dashed line.

[0061] 9A and 9B, the sensor module 100B3 has a configuration in which the metal members 110B21 and 110B22 of the sensor module 100B2 shown in Fig. 8A and 8B are changed to metal members 110B31 and 110B32. The metal member 110B31 is smaller than the metal member 110B21 in a plan view, and the metal member 110B32 is the same as the metal member 110B22.

[0062] The sensor module 100B3 configured in this way operates in the same manner as the sensor module 100 shown in Figures 1 and 2. Note that the multi-module 130 may be provided below the slit between the metal members 110B31 and 110B32 as indicated by the dashed lines.

[0063] 10 is a plan view showing a part of a sensor module 100C1 according to a modification of the embodiment, which corresponds to the part surrounded by the dashed line C shown in FIG.

[0064] The sensor module 100C1 shown in Fig. 10 is disposed inside the resin part 120 so that the substrate 131 of the multi-module 130 is parallel to the XY plane. The position of the multi-module 130 in Fig. 10 is one of three positions of the multi-module 130 shown by dashed lines in Fig. 6, which is a position that is lower inside the resin part 120 and parallel to the XY plane.

[0065] In this manner, the multi-module 130 may be disposed within the resin part 120, and the antenna element 133 may be disposed so as to be parallel to the Y direction. In this case, a current flows through the antenna element 133 in the -Y direction (a direction perpendicular to the width direction of the slit 115) (see the arrow in FIG. 10).

[0066] 11 is a plan view showing a part of a sensor module 100C2 according to a modified example of the embodiment. The part shown in FIG 11 corresponds to the part surrounded by the dashed line C shown in FIG 1, similar to FIG 10.

[0067] 10, the orientation of the multi-module 130 of the sensor module 100C2 is changed, and the antenna element 133 is parallel to the X direction. In this case, a current flows in the antenna element 133 in the +X direction (the width direction of the slit 115) as shown by the arrow.

[0068] Fig. 12 is a plan view showing a part of a sensor module 100C3 according to a modified example of the embodiment. The part shown in Fig. 12 corresponds to the part surrounded by the dashed line C shown in Fig. 1, similar to Figs.

[0069] 10, the substrate 131 is parallel to the XZ plane, and the antenna element 133 faces the +Z direction. In this case, a current flows in the antenna element 133 in the +Z direction.

[0070] Fig. 13 is a plan view showing a part of a sensor module 100C4 according to a modified example of the embodiment. The part shown in Fig. 13 corresponds to the part surrounded by the dashed line C shown in Fig. 1, similar to Figs.

[0071] 13, the substrate 131 is parallel to the YZ plane, and the antenna element 133 faces the +Z direction. In this case, a current flows in the antenna element 133 in the +Z direction.

[0072] 14 is a diagram showing a cross section and a part of a sensor module 100D according to a modified example of the embodiment. The cross section of the sensor module 100D shown on the left side of FIG.

[0073] 14, in multi-module 130D, substrate 131 is parallel to the YZ plane, antenna element 133 extends in the Z direction, and pin 133B is added to the tip. Pin 133B stands up in the -X direction.

[0074] In such a sensor module 100D, the current flowing in the +X direction through the antenna element 133 is excited in the -X direction by the pin 133B at the tip.

[0075] Fig. 15 is a modified example of the multi-module 130D shown in Fig. 14. In Fig. 15, the pins 133B are oriented in the +X direction along the side surface of the substrate 131 at the end of the substrate 131 in the +Z direction.

[0076] In such a multi-module 130D, the current flowing in the +X direction through the antenna element 133 is excited by the pin 133B at the tip.

[0077] Fig. 16 is a modified example of the multi-module 130D shown in Fig. 15. In Fig. 16, the pins 133B are longer and protrude beyond the surface on the +X direction side of the substrate 131. When such pins 133B are used, the coupling with the slits 115 is stronger.

[0078] Fig. 17 is a diagram showing a cross section and a part of a sensor module 100E according to a modified example of the embodiment. As shown in the cross section on the left side of Fig. 17, a multi-module 130E of the sensor module 100E is provided so that a substrate 131 is parallel to the XY plane.

[0079] 17, the antenna element 133E of the multi-module 130E extends in the +Y direction from a feed point 133E1 to a bent portion 133E2, and extends in the +X direction from the bent portion 133E2 to a tip portion 133E3. The tip portion 133E3 is provided directly below the slit 115 indicated by the dashed line.

[0080] In such a sensor module 100E, radio waves emitted from the tip 133E3 of the antenna element 133E are efficiently emitted from the slit 115. In addition, since the bent antenna element 133E is included, the impedance characteristics change compared to when the antenna element 133E is not bent due to the change in the direction of the current relative to the slit 115. Therefore, by changing the direction in which the antenna element 133E extends, it is possible to change the direction of the current relative to the slit 115 without changing the arrangement of the multi-module 130E, and the options for achieving impedance matching between the antenna element 133E and the slit 115 can be expanded.

[0081] Also, the section from the feed point 133E1 to the bent portion 133E2 of the multi-module 130E may be arranged to face the +Z direction. In this case as well, the direction of the section from the feed point 133E1 to the bent portion 133E2 and the section from the bent portion 133E2 to the tip portion 133E3 changes with respect to the slit 115. Therefore, the impedance characteristics change as the direction of the current changes with respect to the slit 115, and the options for impedance matching between the antenna element 133E and the slit 115 can be expanded.

[0082] As shown in Figures 10 to 13, by changing the arrangement of the multi-module 130, it is possible to change the direction of the current relative to the slit 115, thereby expanding the options for achieving impedance matching between the antenna element 133 and the slit 115.

[0083] Furthermore, as shown in Figures 14 to 17, by changing the shape of antenna elements 133, 133E, this is possible without changing the arrangement of multi-modules 130D, 130E or changing the direction of current relative to slit 115, thereby expanding the options for achieving impedance matching between antenna elements 133, 133E and slit 115.

[0084] Since the radiation efficiency of multi-modules 130D and 130E improves as the antenna elements 133, 133E are closer to the slit 115, by changing the shape of antenna elements 133, 133E as shown in Figures 14 to 17, it becomes possible to change the direction of current relative to slit 115 even when multi-module 130 is placed vertically (see Figures 12 and 13), thereby expanding the options for achieving impedance matching between antenna elements 133, 133E and slit 115.

[0085] 18 is a diagram showing a sensor module 100F according to a modified example of the embodiment. The sensor module 100F includes metal members 110 (110A, 110B), a resin part 120, a multi-module 130F, and a resin part 140. The sensor module 100F is a disc-shaped member.

[0086] Fig. 19 is a diagram showing a multi-module 130F. As shown in Fig. 19, the multi-module 130F has a substrate 131, a ground layer 132F, an antenna element 133F, matching circuits 134F1 and 134F2, a feed line 136, and pads 137A, 137B, and 137C.

[0087] An antenna element 133F, matching circuits 134F1 and 134F2, a feed line 136, and pads 137A, 137B, and 137C are provided on the surface of the substrate 131 facing the -X direction. A ground layer 132F is provided on the surface of the substrate 131 facing the +X direction.

[0088] The ground layer 132F is, for example, a copper foil. A chip similar to the chip 135 (see FIG. 3A) is mounted on the surface of the ground layer 132F, but is not shown in FIG. The ground layer 132F is provided in a portion that overlaps the feeding point 133F1, the feeding line 136, and the pads 137A, 137B, and 137C of the antenna element 133F in a plan view.

[0089] The antenna element 133F is an example of a radiation portion, and extends in an L-shape from a feeding point 133F1 to a tip 133F2. The antenna element 133F is produced by patterning a copper foil, for example. The feeding point 133F1 of the antenna element 133F overlaps with the ground layer 132F, and the feeding point 133F1 is a microstrip line. The feeding point 133F1 is connected to the feeding line 136 via a matching circuit 134F1, and is connected to the pad 137A via a matching circuit 134F2.

[0090] The matching circuits 134F1 and 134F2 are, for example, inductors or capacitors. The matching circuits 134F1 and 134F2 are provided to achieve impedance matching of the antenna element 133F. By using the matching circuits 134F1 and 134F2, a wavelength shortening effect can be obtained.

[0091] The power supply line 136 to which the matching circuit 134F1 is connected overlaps with the ground layer 132F to form a microstrip line. The power supply line 136 is connected to the wireless communication unit of the chip by a core of a coaxial cable (not shown). The antenna element 133F is fed with power from the wireless communication unit via the power supply line 136. The pads 137A, 137B, and 137C are connected to the ground layer 132F via vias 137A1, 137B1, and 137C1, respectively.

[0092] Fig. 20 is a diagram showing frequency characteristics of the S11 parameter of the sensor module 100F. Fig. 20 shows results obtained in an electromagnetic field simulation in the case where the communication frequency of the multi-module 130F is set to 2.45 (GHz) as an example.

[0093] As shown in Figure 20, the value of the S11 parameter is approximately -25 dB at 2.45 GHz, indicating that resonance occurs at 2.45 GHz. It was also found that a wide band with extremely low reflection of less than -10 dB was obtained around 2.45 GHz.

[0094] As shown in Figures 18 and 19, by arranging a multi-module 130F and having an L-shaped antenna element 133F, it is possible to change the direction of the current relative to the slit 115, thereby expanding the options for achieving impedance matching between the antenna element 133F and the slit 115.

[0095] The above describes an exemplary embodiment of a sensor module of the present invention. However, the present invention is not limited to the specifically disclosed embodiment, and various modifications and changes are possible without departing from the scope of the claims. [Explanation of symbols]

[0096] 100, 100A, 100B1, 100B2, 100B3, 100C1, 100C2, 100C3, 100D, 100E, 100F Sensor Module 110, 110A, 110B, 110A1, 110B1, 110B21, 110B22, 110B31, 110B32 Metallic parts 120, 120B Resin part 130, 130D, 130E, 130F Multi-Module 131 Substrate 133, 133E, 133F Antenna Elements 135 Chips 135A Wireless Communication Unit 135B Sensor

Claims

1. A metal member having a recess; A resin portion embedded in the recess; a radiation portion provided inside the resin portion and configured to radiate radio waves; a wireless communication unit provided inside the resin portion and connected to the radiation unit; A sensor connected to the wireless communication unit; Including, the metal member is insulated from the radiating portion by the resin portion and functions as a parasitic element, The metal member further has a slit having a circular ring shape, a rectangular ring shape, or a polygonal ring shape in a plan view, The recess communicates with the slit.

2. The sensor module according to claim 1 , wherein the metal member and the resin portion have a through hole passing through a center thereof in a plan view.

3. The metal member is a first metal member having the recess; a second metal member that is held in the resin portion provided inside the first metal member and that forms the circular, rectangular, or polygonal annular slit between the second metal member and an opening of the recess of the first metal member; The sensor module of claim 1 , further comprising:

4. The sensor module according to claim 3 , wherein the second metal member and the resin portion have a through hole passing through a center thereof in a plan view.

5. the first metal member is disk-shaped, The recess is annular, 5. The sensor module according to claim 3, wherein the second metal member is annular, and an annular slit is formed on an outer circumferential side or an inner circumferential side of the annular recess.

6. The sensor module according to claim 1 , wherein the radiation portion is provided inside the resin portion and facing the slit.

7. The sensor module according to claim 1 , wherein the radiation portion is provided in the vicinity of the slit.

8. The resin portion further includes a substrate provided inside the resin portion, The sensor module according to claim 1 , wherein the emitting portion, the wireless communication portion, and the sensor are mounted on the substrate.

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