Wireless module and noise reduction method

Abstract

This wireless module is provided with: a circuit board having a substrate surface on which a circuit component serving as a noise source is provided; an antenna provided on an edge portion of the circuit board or around the circuit board; and at least one non-powered protruding conductor provided on the substrate surface and grounded. The distance between the protruding conductor and the noise source is shorter than the distance between the protruding conductor and the antenna.

Description

Wireless module and noise reduction method

[0001] This disclosure relates to a wireless module and a noise reduction method. This application claims priority to Japanese Application No. 2024-127822 filed on August 2, 2024, and incorporates by reference all of the contents of said Japanese application.

[0002] 2. Description of the Related Art In recent years, with the miniaturization of communication devices, a communication antenna is sometimes provided on a substrate on which a chip having a communication function is mounted (see, for example, Patent Document 1).

[0003] JP 2011-142542 A

[0004] A wireless module according to an embodiment includes a circuit board having a board surface on which circuit components that are noise sources are provided, an antenna provided on an edge of the circuit board or around the circuit board, and at least one grounded, unpowered protruding conductor provided on the board surface, wherein the distance between the protruding conductor and the circuit components is shorter than the distance between the protruding conductor and the antenna.

[0005] FIG. 1 is a perspective view showing an example of a wireless communication device. FIG. 2 is a plan view of a circuit board. FIG. 3 is a cross-sectional view of a main portion of the circuit board. FIG. 4 is a view showing a case where a first protruding conductor is arranged at a position deviated from the imaginary line L1. FIG. 5 is a partial perspective view showing an example of a wireless module according to a second embodiment. FIG. 6 is a partial perspective view showing an example of a wireless module according to a third embodiment. FIG. 7 is a partial perspective view showing an example of a wireless module according to a fourth embodiment. FIG. 8 is a partial perspective view showing an example of a wireless module according to a fifth embodiment. FIG. 9 is a partial perspective view showing an example of a wireless module according to a sixth embodiment. FIG. 10 is a partial perspective view showing an example of a wireless module according to a seventh embodiment. FIG. 11 is a diagram showing an example of a model used in a verification test. FIG. 12 is a diagram showing a portion of a model of Example 2. FIG. 13 is a diagram showing an example of the arrangement of protruding conductors in models of Examples 3, 4, and 5. FIG. 14 is a diagram showing a portion of models of Examples 6 and 7. FIG. 15 is a diagram showing a portion of a model of Example 8. FIG. 16 is a diagram showing a portion of a model of Example 9. FIG. 17 is a diagram showing a model of Example 10. FIG. 18 is a diagram showing a part of a model of Example 11. FIG. 19 is a diagram showing the frequency characteristics of S21 when the length of the protruding conductor is changed using Example 1. FIG. 20 is a diagram showing the frequency characteristics of S21 when the length of the protruding conductor is changed using Example 1. FIG. 21 is a diagram showing the frequency characteristics of S21 when the distance between the noise source and the protruding conductor is changed using Example 1. FIG. 22 is another diagram showing the frequency characteristics of S21 when the distance between the noise source and the protruding conductor is changed using Example 1. FIG. 23 is a diagram showing an image of an electromagnetic field distribution near a noise source. FIG. 24 is a diagram showing a radiation pattern of a noise source. FIG. 25 is a diagram showing a radiation pattern of a noise source. FIG. 26 is a diagram showing the frequency characteristics of S21 when the position of the protruding conductor is changed using Example 1. FIG. 27 is a diagram showing the frequency characteristics of S21 when the number of protruding conductors is changed. FIG. 28 is a diagram showing an image of an electromagnetic field distribution near a noise source. FIG. 29 is a diagram showing the frequency characteristics of S21 of Example 6. FIG. 30 is a diagram showing the frequency characteristics of S21 of Example 7. FIG. 31 is a diagram showing the frequency characteristics of S21 in the eighth embodiment.Fig. 32 is a diagram showing frequency characteristics of S21 in Example 9. Fig. 33 is a diagram showing frequency characteristics of S21 in Example 10. Fig. 34 is a diagram showing frequency characteristics of S21 in Example 11.

[0006] [Problem to be Solved by the Present Disclosure] A crystal oscillator that outputs a reference signal or the like is typically mounted on a circuit board of a communication device. The crystal oscillator is a circuit component that generates noise and is a noise source. The noise from the crystal oscillator may affect the transmission and reception of the antenna. For this reason, measures are taken to reduce the noise that reaches the antenna, such as mounting noise-reducing chip components on the circuit board or covering the peripheral circuit, including the noise source, with a shield cover.

[0007] However, these measures increase the cost of the product, so a simpler method of reducing the noise reaching the antenna is desired.

[0008] Effect of the Present Disclosure According to the present disclosure, it is possible to reduce noise reaching an antenna with a simple configuration.

[0009] First, the contents of the embodiment will be listed and explained.

[0010] (1) A wireless module according to an embodiment includes a circuit board having a board surface on which circuit components that are noise sources are mounted, an antenna mounted on an edge of the circuit board or around the periphery of the circuit board, and at least one grounded, non-powered protruding conductor mounted on the board surface. The distance between the protruding conductor and the circuit component is shorter than the distance between the protruding conductor and the antenna. According to the above configuration, the protruding conductor, which is positioned relatively close to the circuit component, resonates with noise from the circuit component. This resonance causes the noise to be absorbed and attenuated by the protruding conductor. As a result, noise reaching the antenna from the circuit component can be reduced with a simple configuration in which the protruding conductor is mounted near the circuit component.

[0011] (2) In the wireless module of (1), the protruding conductor may be disposed in a region between the circuit component and the antenna. In this case, the protruding conductor is disposed between the circuit component and the antenna. Therefore, the protruding conductor can absorb noise radiated from the circuit component toward the antenna, thereby effectively reducing noise reaching the antenna.

[0012] (3) In the wireless module of (1), when the at least one protruding conductor includes two or more protruding conductors, the two or more protruding conductors may be arranged to surround the circuit component. In this case, noise radiated from the circuit component toward the surroundings can be absorbed by the two or more protruding conductors, thereby more effectively reducing noise reaching the antenna.

[0013] (4) In the wireless module of (1) or (2), the protruding conductor may be provided on a passing line that is a straight line that passes through the circuit component and the antenna and minimizes the distance between the circuit component and the antenna. In this case, too, one or more protruding conductors can be disposed at a position sandwiched between the circuit component and the antenna, thereby more effectively reducing noise reaching the antenna.

[0014] (5) In the wireless module of any one of (1) to (4), the protruding conductor may have a base end connected to the substrate surface and connected to the ground conductor, and a tip end that is an electrically open end. In this case, the protruding conductor can be provided on the circuit board by connecting it to the substrate surface. Therefore, as long as there is at least space available to connect the base end, additional protruding conductors can be mounted on the circuit board even after many chips and circuits have been mounted on the circuit board.

[0015] (6) In the wireless module of (5), the protruding conductor may include a pin-shaped main body extending from the base end to the tip end. In this case, the space required for providing the protruding conductor on the substrate surface can be minimized. This makes it easier to mount additional protruding conductors on the circuit board after multiple chips and circuits have been mounted on it.

[0016] (7) In the wireless module of (5), the protruding conductor may include a main body having a spiral shape extending from the base end to the tip end in a direction intersecting the substrate surface. In this case, since the main body of the protruding conductor has a spiral shape, it is possible to keep the protruding height from the circuit board low while ensuring the length required for the protruding conductor.

[0017] (8) In the wireless module of (5), the protruding conductor may include a plate-shaped main body extending from the base end to the tip end. In this case, the protruding conductor has a larger width in a direction parallel to the board surface than, for example, a pin-shaped protruding conductor. Therefore, the protruding conductor can absorb noise while shielding it from the circuit components.

[0018] (9) In the wireless module of (6), the main body may have a protruding portion extending from the base end in a direction intersecting the board surface, and a horizontally extending portion extending from a tip of the protruding portion to the tip in a planar direction of the board surface. In this case, the horizontally extending portion can reduce the protruding height from the circuit board while ensuring a length required for the protruding conductor.

[0019] (10) In any one of the wireless modules (5) to (9), the length from the base end to the tip end of the protruding conductor may be 0.2 to 0.25 times the wavelength of the radio waves transmitted and received by the antenna. If the length of the protruding conductor is less than 0.2 or more than 0.25 times the wavelength of the radio waves transmitted and received by the antenna, the resonant frequency of the protruding conductor may be significantly different from the frequency of the radio waves transmitted and received by the antenna, and noise near the frequency of the radio waves transmitted and received by the antenna may not be effectively absorbed by the protruding conductor. By setting the length of the protruding conductor to be 0.2 to 0.25 times the wavelength of the radio waves transmitted and received by the antenna, noise near the frequency of the radio waves transmitted and received by the antenna is effectively absorbed by the protruding conductor.

[0020] (11) In the wireless module of (5), the protruding conductor may further include a rod-shaped main body extending from the base end to the tip end in a direction intersecting the substrate surface, and a plate-shaped conductor provided at an end of the main body on the tip end side. In this case, an appropriate capacitance component can be imparted to the tip end side of the protruding conductor, and the noise absorption effect can be maintained even if the length of the main body is shortened. As a result, the protruding conductor can be made smaller.

[0021] (12) In the wireless module of (1), the protruding conductor may have a first end connected to a first point on the substrate surface, a second end connected to a second point on the substrate surface different from the first point, and a rod-shaped main body connecting the first end and the second end. In this case, the protruding conductor protrudes from the first point and the second point and has a shape in which the protruding portions from both points are connected. Therefore, with one protruding conductor, the same effect as when two protruding conductors are provided protruding from one point on the substrate surface can be obtained.

[0022] (13) In the wireless module of (12), the length from the first end to the second end of the protruding conductor may be 0.4 to 0.5 times the wavelength of the radio waves transmitted and received by the antenna. If the length from the first end to the second end is less than 0.4 or more than 0.5 times the wavelength of the radio waves transmitted and received by the antenna, the resonant frequency of the protruding conductor may be significantly different from the frequency of the radio waves transmitted and received by the antenna, and noise near the frequency of the radio waves transmitted and received by the antenna may not be effectively absorbed by the protruding conductor. By setting the length of the protruding conductor to be 0.4 to 0.5 times the wavelength of the radio waves transmitted and received by the antenna, noise near the frequency of the radio waves transmitted and received by the antenna is effectively absorbed by the protruding conductor.

[0023] (14) In the wireless module of (5), the at least one protruding conductor may be plural, and the plural protruding conductors may include a first conductor and a second conductor, and the length from the base end to the tip end of the first conductor may be different from the length from the base end to the tip end of the second conductor. In this case, the resonant frequency of the first conductor is different from the resonant frequency of the second conductor. Therefore, when the antenna transmits and receives two radio waves of different frequencies, the resonant frequency of the first conductor and the resonant frequency of the second conductor can be set to values ​​corresponding to the two radio waves, so that noise for each of the two radio waves can be absorbed by the first conductor and the second conductor.

[0024] (15) In the wireless module of (14), when the antenna is capable of transmitting and receiving a first radio wave having a first wavelength and a second radio wave having a second wavelength different from the first wavelength, the length from the base end to the tip end of the first conductor may be 0.2 to 0.25 times the first wavelength, and the length from the base end to the tip end of the second conductor may be 0.2 to 0.25 times the second wavelength. In this case, noise near the frequency of the first radio wave transmitted and received by the antenna is effectively absorbed by the first conductor, and noise near the frequency of the second radio wave is effectively absorbed by the second conductor.

[0025] (16) Another embodiment is a noise reduction method for reducing noise reaching an edge of a circuit board of a wireless module or an antenna provided around the circuit board. The noise reduction method includes providing at least one grounded, parasitic protruding conductor on a board surface of the circuit board. A distance between the protruding conductor and a first circuit component on the board surface is shorter than a distance between the protruding conductor and the antenna.

[0026] [Details of the Embodiments] Preferred embodiments will now be described with reference to the drawings. Note that at least some of the embodiments described below may be combined in any manner. [Regarding the First Embodiment] FIG. 1 is a perspective view showing an example of a wireless communication device. This wireless communication device 1 includes, for example, a wireless LAN router capable of wireless LAN communication. The wireless communication device 1 includes a wireless module 2 according to the first embodiment and a housing 6.

[0027] The housing 6 accommodates the wireless module 2 therein. Note that part of the housing 6 is omitted in FIG. 1 . The wireless module 2 is fixed inside the housing 6. The housing 6 has legs 6a for installing the wireless communication device 1. Therefore, the wireless communication device 1 of this embodiment is installed and used indoors or outdoors. Note that the housing 6 may also be installed and used on a wall. In this case, the housing 6 may have installation holes that engage with protruding members protruding from the wall, instead of the legs 6a. The housing 6 may also have brackets for installing the wireless communication device 1 on an outdoor structure or vehicle. Note that the housing 6 may have brackets for fixing the wireless communication device 1 to a vehicle, such as an automobile or train, instead of the legs 6a. In this case, the wireless communication device 1 is installed and used inside the vehicle.

[0028] The wireless module 2 includes a circuit board 3 and an antenna 4. The circuit board 3 has a board surface 3a. The wireless module 2 further includes mounted components mounted on the circuit board 3. The mounted components are provided on the board surface 3a of the circuit board 3.

[0029] The circuit board 3 is, for example, a rectangular rigid board made of a dielectric material. The mounted components mounted on the circuit board 3 are components necessary for realizing the functions of the wireless communication device 1 (wireless module 2). The mounted components include a first circuit component and a second circuit component. The first circuit component is a circuit component that is a noise source. The second circuit component is a circuit component that generates less noise than the first circuit component. The second circuit component is arranged around the first circuit component. The first circuit component can be a noise source at least for the antenna 4. Furthermore, the second circuit component is not a noise source for the antenna 4.

[0030] The mounted components include a wireless chip 8, a crystal oscillator 10, a processing circuit chip 12, a LAN chip 13, a USB connector 14, and a plurality of LAN connectors 16. The mounted components also include other chip elements such as circuit chips, chip resistors, and chip coils.

[0031] The crystal oscillator 10 outputs a reference signal used for wireless communication. The crystal oscillator 10 is located in the center of the substrate surface 3a. The crystal oscillator 10 is included in the first circuit component, which is a noise source. The crystal oscillator 10 outputs a square wave (digital clock). This digital clock is supplied directly or after frequency division to the processing circuit chip 12 and the wireless chip 8 located around the crystal oscillator 10. The digital clock contains many harmonic components. Therefore, the digital clock is likely to become a noise source. However, because the wiring on the circuit board contains inductive components and capacitance components between the circuit board and ground, the harmonic components contained in the digital clock are reduced when the digital clock is transmitted to the surrounding area via the wiring. Furthermore, if a ferrite bead that blocks noise transmission is inserted in series with the wiring, the harmonic components contained in the digital clock can be further suppressed. In other words, the crystal oscillator 10 becomes a noise source by outputting a digital clock that contains many harmonic components. Furthermore, in the second circuit components around the crystal oscillator 10, the harmonic components contained in the digital clock are suppressed, so no significant noise is generated compared to the crystal oscillator 10. For this reason, the protruding conductors described below are positioned closer to the crystal oscillator 10 than the second circuit components.

[0032] It is also possible to generate a digital clock using a crystal unit and an oscillation circuit instead of the crystal oscillator 10. In such a configuration, noise may be generated from active elements (e.g., a C-MOS inverter) included in the oscillation circuit or from wiring around the crystal unit. In this case, the crystal unit and oscillation circuit can be treated as a single noise source. Furthermore, a crystal unit separate from the crystal oscillator 10 may be provided to generate carrier waves used in wireless communications. When the carrier wave is a sine wave, the carrier wave contains fewer harmonic components. For this reason, noise countermeasures should be applied to the crystal oscillator 10 rather than to the crystal unit that outputs a sine wave.

[0033] The USB connector 14 is an interface for connecting to an external device. The USB connectors 14 are arranged along the side edge of the circuit board 3. The USB connectors 14 are connectors that comply with USB 3.0 or higher standards. The USB connector 14 is included in the first circuit components that are noise sources. Noise generated by the USB connector 14 may affect reception by the antenna 4. The LAN chip 13 is a chip for performing LAN-related processing. The LAN chip 13 is also included in the first circuit components that are noise sources. Noise generated by the LAN chip 13 may affect reception by the antenna 4.

[0034] The wireless chip 8 is a chip that integrates functions for realizing wireless LAN communication. The wireless chip 8 constitutes a transceiver that transmits and receives wireless signals via the antenna 4. The wireless chip 8 is provided near the antenna 4. More specifically, the wireless chip 8 is provided on the substrate surface 3a, between the crystal oscillator 10 and the antenna 4. The processing circuit chip 12 includes a processor and the like. The processing circuit chip 12 has functions for controlling each part of the wireless communication device 1. The multiple LAN connectors 16 are connection interfaces with external devices. The LAN connectors 16, like the USB connector 14, are arranged along the side edge of the circuit board 3. The wireless chip 8, the processing circuit chip 12, and the multiple LAN connectors 16 are included in a second circuit component.

[0035] Like the mounted components, the antenna 4 is also provided on the board surface 3a of the circuit board 3. The antenna 4 is an antenna used for wireless LAN communication. The antenna 4 transmits radio waves to a terminal device with which the wireless communication device 1 performs wireless LAN communication, and receives radio waves from the terminal device. The antenna 4 includes an antenna board 4a and an antenna pattern 4b. The antenna board 4a is a rigid board made of a dielectric. The antenna board 4a is provided upright relative to the board surface 3a. The antenna board 4a is provided along the upper edge of the circuit board 3. The antenna pattern 4b is made of a conductor such as copper. The antenna pattern 4b is mounted on the board surface of the antenna board 4a. The antenna pattern 4b includes an antenna element 4b1 and a feed point 4b2. The elements included in the antenna pattern 4b form an inverted-F antenna. Therefore, the antenna 4 includes an inverted-F antenna.

[0036] The wireless module 2 of this embodiment further includes a first protruding conductor 20, a second protruding conductor 22, and a third protruding conductor 25. The first protruding conductor 20, the second protruding conductor 22, and the third protruding conductor 25 are provided on the board surface 3a of the circuit board 3. The first protruding conductor 20 is a protruding conductor provided near the crystal oscillator 10. The first protruding conductor 20 is provided between the crystal oscillator 10 and the antenna 4. The first protruding conductor 20 is provided so as to sandwich the wireless chip 8 between the first protruding conductor 20 and the antenna 4. In other words, the first protruding conductor 20 is provided at a position closer to the crystal oscillator 10 (first circuit component) than to the wireless chip 8 (second circuit component). The second protruding conductor 22 is a protruding conductor provided near the USB connector 14. Note that when a plurality of USB connectors 14 are provided, the second protruding conductor 22 is preferably provided near the USB connector 14 that is closest to the antenna 4 among the plurality of USB connectors 14.

[0037] The third protruding conductor 25 is a protruding conductor provided near the LAN chip 13. The third protruding conductor 25 is provided between the LAN chip 13 and the antenna 4. The third protruding conductor 25 is provided so as to sandwich the wireless chip 8 between itself and the antenna 4. In other words, the third protruding conductor 25 is provided at a position closer to the crystal oscillator 10 than the wireless chip 8.

[0038] Fig. 2 is a plan view of the circuit board 3. For ease of understanding, Fig. 2 shows only the antenna 4, the crystal oscillator 10, the USB connector 14, the first protruding conductor 20, and the second protruding conductor 22 among the components provided on the board surface 3a, and omits other components.

[0039] In the following description, the three mutually orthogonal directions in each figure are referred to as the X direction, Y direction, and Z direction. Also, as shown in FIG. 2, one of the X directions is referred to as the X1 direction, and the opposite direction of the X1 direction is referred to as the X2 direction. One of the Y directions is referred to as the Y1 direction, and the opposite direction of the Y1 direction is referred to as the Y2 direction. One of the Z directions is referred to as the Z1 direction, and the opposite direction of the Z1 direction is referred to as the Z2 direction. In this embodiment, the board surface 3a of the circuit board 3 is parallel to the XY plane. The board surface 3a faces the Z1 direction. Each side of the circuit board 3 is parallel to the X direction or the Y direction.

[0040] Fig. 3 is a cross-sectional view of a main part of the circuit board 3. Fig. 3 shows a cross section of a portion of the circuit board 3 where the first protruding conductor 20 is provided. Fig. 3 is taken along the X-Z cross section. Note that only the first protruding conductor 20 will be described here, but the second protruding conductor 22 also has a similar configuration to the first protruding conductor 20.

[0041] As shown in FIG. 3 , the first protruding conductor 20 protrudes from the board surface 3 a of the circuit board 3. The first protruding conductor 20 extends along the Z direction. The first protruding conductor 20 includes a conductor such as copper or an aluminum alloy. The first protruding conductor 20 has a pin-shaped main body 24. The main body 24 may be a pin-shaped conductive material, or a pin-shaped resin having a conductor coated on its surface. The main body 24 may also include a dielectric substrate and a strip-shaped conductor pattern formed on the dielectric substrate. In this case, the dielectric substrate on which the conductor pattern is formed is erected on the board surface 3 a so that the longitudinal direction of the conductor pattern is aligned with the Z direction.

[0042] The first protruding conductor 20 has a base end 20a and a tip end 20b. The main body 24 extends from the base end 20a to the tip end 20b. The base end 20a is connected to the board surface 3a of the circuit board 3. The circuit board 3 has a board main body 3p and a ground conductor 3g. The ground conductor 3g is a conductor pattern made of copper or the like provided on the back surface 3b of the circuit board 3. The ground conductor 3g is grounded. The back surface 3b is the surface of the circuit board 3 facing the Z2 direction, opposite the board surface 3a. The board main body 3p has a board main body surface 3p1 and a hole 3p2. The board main body surface 3p1 is the surface of the board main body 3p facing the Z1 direction. The hole 3p2 is a hole that penetrates the board main body 3p. The hole 3p2 opens to the board main body surface 3p1.

[0043] The base end 20a of the first protruding conductor 20 is inserted into the hole 3p2. In this way, the base end 20a is fixed to the substrate surface 3a. The base end 20a is electrically connected to the ground conductor 3g by brazing, soldering, or the like. Therefore, the first protruding conductor 20 is grounded. The tip end 20b of the first protruding conductor 20 is an electrically open end as shown in FIG. 3. Furthermore, the first protruding conductor 20 does not have a feeding point or the like. Therefore, the first protruding conductor 20 is a grounded, non-powered element.

[0044] As such, the first protruding conductor 20 has a base end 20a connected to the substrate surface 3a and a tip end 20b which is an open end, so that as long as there is at least space to connect the base end 20a, the first protruding conductor 20 can be additionally mounted even after a large number of chips and circuits have been mounted on the circuit board 3.

[0045] Furthermore, since the first protruding conductor 20 has a pin-shaped main body 24 extending from the base end 20 a to the tip end 20 b, it is possible to minimize the space required to provide the first protruding conductor 20 on the board surface 3 a. This makes it easier to mount additional first protruding conductors 20 after a large number of chips and circuits have been mounted on the circuit board 3.

[0046] As shown in Fig. 2, when the substrate surface 3a is viewed from above, the first protruding conductor 20 is located closer to the crystal oscillator 10 than the antenna 4. In Fig. 2, the longitudinal direction of the antenna 4 is parallel to the Y direction. The longitudinal direction of the antenna 4 is the direction in which the antenna element 4b1 of the antenna 4 extends. The antenna substrate 4a is also parallel to the Y direction.

[0047] In Figure 2, imaginary line L1 is a straight line on the substrate surface 3a that passes through the center point 10p of the crystal oscillator 10 and is perpendicular to the longitudinal direction of the antenna 4. The imaginary line L1 is perpendicular to the antenna 4. Therefore, the distance between the crystal oscillator 10 and the antenna 4 (antenna element 4b1) is minimum on the imaginary line L1. In Figure 2, the center of the first protruding conductor 20 is located on the imaginary line L1. In other words, the first protruding conductor 20 is provided on the imaginary line (passing line) L1 that passes through the crystal oscillator 10 and the antenna 4 and where the distance between the crystal oscillator 10 and the antenna 4 is minimum. The distance between the first protruding conductor 20 and the antenna 4 is also minimum on the imaginary line L1.

[0048] 2 , the distance s1 between the first protruding conductor 20 and the crystal oscillator 10 is the distance between the center of the first protruding conductor 20 and the center point 10p of the crystal oscillator 10. Furthermore, the distance w1 between the first protruding conductor 20 and the antenna 4 is the distance between the center of the first protruding conductor 20 and the feed point 4b2. In other words, the distance w1 is the distance when the distance between the first protruding conductor 20 and the antenna 4 is minimum. In this embodiment, the distance s1 is shorter than the distance w1. Therefore, the first protruding conductor 20 is located closer to the crystal oscillator 10 than the antenna 4.

[0049] Here, the crystal oscillator 10 is a first circuit component that is a noise source. Noise from the crystal oscillator 10 may affect reception by the antenna 4. In contrast, in this embodiment, the first protruding conductor 20, which is located relatively close to the crystal oscillator 10, resonates with noise from the crystal oscillator 10. This resonance causes the noise to be absorbed and attenuated by the first protruding conductor 20. As a result, with the simple configuration of locating the first protruding conductor 20 near the crystal oscillator 10, it is possible to reduce noise reaching the antenna 4 from the crystal oscillator 10. Note that the noise referred to here refers to electromagnetic waves radiated in conjunction with the operation of a first circuit component that is a noise source, such as the crystal oscillator 10, and includes electromagnetic waves in the frequency band of radio waves transmitted and received by the antenna 4.

[0050] If the distance s1 is shorter than the distance w1, noise can be reduced, but the distance s1 may be set to 0.2 times the distance w1 or less. If the distance s1 is greater than 0.2 times the distance w1, the distance between the crystal oscillator 10 and the protruding conductor 20 may be too great, which may reduce the noise absorption effect. By setting the distance s1 to 0.2 times the distance w1 or less, noise is effectively absorbed by the protruding conductor 20.

[0051] In the present embodiment, the first protruding conductor 20 is disposed on the imaginary line L1. However, the first protruding conductor 20 may be disposed at a position deviated from the imaginary line L1. FIG. 4 illustrates a case where the first protruding conductor 20 is disposed at a position deviated from the imaginary line L1. In FIG. 4 , distance w1 is the distance between the center of the first protruding conductor 20 and point 4r. Point 4r is the point where imaginary line L5 intersects with the antenna element 4b1. The imaginary line L5 is a straight line on the substrate surface 3a that passes through the center of the first protruding conductor 20 and is parallel to the X direction. In the case of FIG. 4 , the first protruding conductor 20 is also disposed at a position where distance s1 is shorter than distance w1. Therefore, the first protruding conductor 20 is disposed closer to the crystal oscillator 10 than the antenna 4. This allows the first protruding conductor 20 to absorb noise from the crystal oscillator 10 while suppressing the influence of the first protruding conductor 20 on the antenna 4.

[0052] Returning to FIG. 2 , the first protruding conductor 20 is preferably provided on the imaginary line L1, but may also be disposed in the region A1 between the crystal oscillator 10 and the antenna 4. Region A1 is the region surrounded by the pair of imaginary lines L2 and L3 and the antenna 4. The imaginary line L2 is a straight line on the substrate surface 3a that passes through a first end point 4p of the antenna 4 and a center point 10p of the crystal oscillator 10. The first end point 4p is the end point of the antenna element 4b1 on the Y1 direction side. The imaginary line L3 is a straight line on the substrate surface 3a that passes through a second end point 4q of the antenna 4 and a center point 10p of the crystal oscillator 10. The second end point 4q is the end point of the antenna element 4b1 on the Y2 direction side.

[0053] The first protruding conductor 20 is disposed in a position within the region A1 that satisfies the condition that the distance s1 is shorter than the distance w1. When the first protruding conductor 20 is disposed in the region A1, the first protruding conductor 20 is disposed between the crystal oscillator 10 and the antenna 4. Therefore, the first protruding conductor 20 can absorb noise radiated from the crystal oscillator 10 toward the antenna 4, and can effectively reduce the noise that reaches the antenna 4.

[0054] 3 , the length h from the base end 20a to the tip end 20b of the first projecting conductor 20 may be 0.2 to 0.25 times the wavelength of the radio waves transmitted and received by the antenna 4. In other words, the length h may be approximately ¼ of the wavelength of the radio waves transmitted and received by the antenna 4. If the length of the first projecting conductor 20 is less than 0.2 or more than 0.25 times the wavelength of the waves transmitted and received by the antenna 4, the resonant frequency of the first projecting conductor 20 will be significantly different from the frequency of the waves transmitted and received by the antenna 4, and noise generated by the crystal oscillator 10 that is close to the frequency of the waves transmitted and received by the antenna 4 may not be effectively absorbed by the first projecting conductor 20. By setting the length h to be 0.2 to 0.25 times the wavelength of the waves transmitted and received by the antenna 4, noise that is close to the frequency of the waves transmitted and received by the antenna 4 is effectively absorbed by the first projecting conductor 20.

[0055] Furthermore, as described above, the first protruding conductor 20 can be additionally mounted. That is, the first protruding conductor 20 can be provided on the board surface 3 a of the circuit board 3 on which the first protruding conductor 20 is not provided. This makes it possible to effectively reduce noise reaching the antenna 4.

[0056] As shown in FIG. 2 , the USB connector 14 is located on the Y2 direction side of the antenna 4. In FIG. 2 , the second end point 4q of the antenna 4 is the point on the antenna 4 closest to the USB connector 14. In FIG. 2 , an imaginary line L4 is a straight line on the substrate surface 3a that passes through the center point 14p of the USB connector 14 and the second end point 4q of the antenna 4. Therefore, the distance between the USB connector 14 and the antenna 4 is minimum on the imaginary line L4. In FIG. 2 , the center of the second protruding conductor 22 is located on the imaginary line L4. The second protruding conductor 22 is located on the imaginary line (passing line) L4 that passes through the USB connector 14 and the antenna 4 and where the distance between the USB connector 14 and the antenna 4 is minimum. Therefore, the distance between the second protruding conductor 22 and the antenna 4 is also minimum on the imaginary line L4. Note that the imaginary line L4 is a straight line on the substrate surface 3a.

[0057] 2 , the distance s2 between the second protruding conductor 22 and the USB connector 14 is the distance between the center of the second protruding conductor 22 and the center point 14p of the USB connector 14. Furthermore, the distance w2 between the second protruding conductor 22 and the antenna 4 is the distance between the center of the second protruding conductor 22 and the second end point 4q. In other words, the distance w2 is the distance when the distance between the first protruding conductor 20 and the antenna 4 is minimum. In this embodiment, the distance s2 is shorter than the distance w2. Therefore, the second protruding conductor 22 is located closer to the USB connector 14 than the antenna 4.

[0058] As described above, the USB connector 14 conforming to the USB 3.0 or higher standard is also a first circuit component that is a noise source, similar to the crystal oscillator 10. Noise from the USB connector 14 may affect reception by the antenna 4. In contrast, in this embodiment, the second protruding conductor 22, which is provided relatively close to the USB connector 14, which is the first circuit component, resonates with noise from the USB connector 14. This resonance causes the noise to be absorbed and attenuated by the second protruding conductor 22. As a result, similar to the first protruding conductor 20, the provision of the second protruding conductor 22 can reduce noise reaching the antenna 4 from the USB connector 14.

[0059] In this embodiment, the second protruding conductor 22 is arranged on the virtual line L4, but if the distance s2 is shorter than the distance w2, the second protruding conductor 22 may be arranged at a position away from the virtual line L4.

[0060] Although the second protruding conductor 22 is preferably provided on the imaginary line L4, the second protruding conductor 22 may be disposed in an area A2 between the USB connector 14 and the antenna 4. The area A2 is an area surrounded by the pair of imaginary lines L4, L6, and the antenna 4. As described above, the imaginary line L4 is a straight line passing through the second end point 4q and the center point 14p of the USB connector 14. The imaginary line L6 is a straight line on the board surface 3a passing through the first end point 4p and the center point 14p. The second protruding conductor 22 is disposed at a position within the area A2 that satisfies the condition that the distance s2 is shorter than the distance w2.

[0061] In this case as well, the second protruding conductor 22 is disposed between the USB connector 14 and the antenna 4. Therefore, the second protruding conductor 22 can absorb noise radiated from the USB connector 14 toward the antenna 4, and can effectively reduce the noise that reaches the antenna 4.

[0062] 2, the first protruding conductor 20 and the second protruding conductor 22 are described, but the third protruding conductor 25 provided near the LAN chip 13 is also arranged in the same configuration as the first protruding conductor 20 and the second protruding conductor 22. Therefore, the third protruding conductor 25 can absorb noise radiated from the LAN chip 13, and can effectively reduce noise reaching the antenna 4.

[0063] 5 is a partial perspective view showing an example of a wireless module 2 according to a second embodiment. This embodiment differs from the first embodiment in that a plurality of first protruding conductors 20 are provided around the periphery of the crystal oscillator 10.

[0064] 5, in this embodiment, four first protruding conductors 20 are provided. The four first protruding conductors 20 are arranged on a circle centered at the center point 10p of the crystal oscillator 10. The four first protruding conductors 20 are provided at positions in the X direction and at positions in the Y direction relative to the center point 10p.

[0065] 5, the four first protruding conductors 20 surround the periphery of the crystal oscillator 10. The four first protruding conductors 20 are provided so as to surround the crystal oscillator 10. This allows the four first protruding conductors 20 to absorb noise radiated from the crystal oscillator 10 toward the surroundings, thereby more effectively reducing noise reaching the antenna 4.

[0066] While the present embodiment illustrates an example in which four first protruding conductors 20 are provided, three or more first protruding conductors 20 may be provided. Furthermore, when the first protruding conductors 20 have a shape extending in a direction along the substrate surface 3 a, such as a plate shape as shown in a third embodiment described later, the multiple first protruding conductors 20 may surround the periphery of the crystal oscillator 10. In this case, the crystal oscillator 10 is located within an area on the substrate surface 3 a formed by connecting the ends of a pair of adjacent first protruding conductors 20 with a straight line. The end of the first protruding conductor 20 refers to the end of the first protruding conductor 20 in the direction along the substrate surface 3 a. In other words, when the crystal oscillator 10 is located within this area, the multiple first protruding conductors 20 surround the periphery of the crystal oscillator 10. Therefore, a pair of first protruding conductors 20 may surround the periphery of the crystal oscillator 10.

[0067] 6 is a partial perspective view showing an example of a wireless module 2 according to a third embodiment. This embodiment differs from the first embodiment in that one plate-shaped first protruding conductor 20 is provided.

[0068] The main body 24 of the first protruding conductor 20 of this embodiment has a rectangular plate shape extending from the base end 20a to the tip end 20b. This main body 24 may be formed from a conductive material in a plate shape, or may be formed from a resin plate having a plate shape coated with a conductor. The first protruding conductor 20 is provided at a predetermined distance on the X1 direction side of the crystal oscillator 10. Therefore, the distance (s1) between the first protruding conductor 20 and the crystal oscillator 10 is shorter than the distance (w1) between the first protruding conductor 20 and the antenna 4. The plate longitudinal direction of the first protruding conductor 20 is parallel to the Y direction. The plate lateral direction of the first protruding conductor 20 is parallel to the Z direction. The first protruding conductor 20 of this embodiment has a larger width in a direction parallel to the substrate surface 3a than, for example, a pin-shaped first protruding conductor. Therefore, the first protruding conductor 20 can block and absorb noise from the crystal oscillator 10.

[0069] 7 is a partial perspective view showing an example of a wireless module 2 according to a fourth embodiment. This embodiment differs from the first embodiment in that a plurality of first protruding conductors 20 are arranged in a row.

[0070] The multiple (seven in the illustrated example) first protruding conductors 20 are arranged in a row parallel to the Y direction on the X1 direction side of the crystal oscillator 10. The distance (s1) between each first protruding conductor 20 and the crystal oscillator 10 is shorter than the distance (w1) between the first protruding conductor 20 and the antenna 4.

[0071] Even when multiple first protruding conductors 20 are arranged in a row as in this embodiment, the multiple first protruding conductors 20 can absorb noise while blocking noise from the crystal oscillator 10.

[0072] 8 is a partial perspective view showing an example of a wireless module 2 according to a fifth embodiment. This embodiment differs from the first embodiment in that the first protruding conductors 20 have an L-shape.

[0073] 8, the main body 24 of the first protruding conductor 20 has a protruding portion 26 and a horizontally extending portion 28. The protruding portion 26 is a rod-shaped portion extending from the base end 20a along the Z1 direction intersecting the substrate surface 3a. The horizontally extending portion 28 is a rod-shaped portion extending along the XY plane from the tip of the protruding portion 26 to the tip end 20b. The horizontally extending portion 28 in this embodiment extends parallel to the Y direction. The first protruding conductor 20 in this embodiment is L-shaped by the protruding portion 26 and the horizontally extending portion 28.

[0074] The length from the base end 20 a to the tip end 20 b is the same as in the first embodiment. In this case, the horizontal extension portion 28 can ensure the required length of the first protruding conductor 20 while keeping the protruding height from the circuit board 3 low.

[0075] 9 is a partial perspective view showing an example of a wireless module 2 according to a sixth embodiment. This embodiment differs from the first embodiment in that the first protruding conductor 20 has a gate shape.

[0076] 9 , the first protruding conductor 20 has a first end 20c, a second end 20d, and a main body 30. The first end 20c is an end of the first protruding conductor 20 that is connected to a first point 3a1 on the substrate surface 3a. The second end 20d is an end of the first protruding conductor 20 that is connected to a second point 3a2 on the substrate surface 3a. The first point 3a1 is located on the X2 side of the crystal oscillator 10 and on the Y2 side of the crystal oscillator 10. The second point 3a2 is located on the X1 side of the crystal oscillator 10 and on the Y1 side of the crystal oscillator 10. The main body 30 is a rod-shaped member that connects the first end 20c and the second end 20d.

[0077] The main body 30 has a first protrusion 32, a second protrusion 34, and a horizontal extension 36. The first protrusion 32 is a rod-shaped portion protruding in the Z1 direction from the first end 20c. The second protrusion 34 is a rod-shaped portion protruding in the Z1 direction from the second end 20d. The first protrusion 32 and the second protrusion 34 extend along the Z direction. Similar to the base end 20a of the first embodiment, the first end 20c and the second end 20d are electrically connected to the ground conductor 3g (FIG. 3) by brazing, soldering, or the like. Thus, both ends of the first protrusion conductor 20 are grounded. The horizontal extension 36 is a rod-shaped portion connecting the tip of the first protrusion 32 and the tip of the second protrusion 34. In this embodiment, the horizontal extension 36 extends parallel to the Y direction. The first protruding conductor 20 of this embodiment has a gate shape formed by the first protruding portion 32, the second protruding portion 34, and the horizontal extending portion 36.

[0078] In this embodiment, the first protruding conductor 20 has a shape in which the portions protruding from both the first point 3a1 and the second point 3a2 are connected. Therefore, a single protruding conductor can achieve the same effect as when two protruding conductors are provided protruding from one location on the board surface 3a. Furthermore, in this embodiment, the horizontal extension portion 36 can ensure the required length of the first protruding conductor 20 while keeping the protruding height from the circuit board 3 low.

[0079] The length from the first end 20c to the second end 20d of the first projecting conductor 20 may be 0.4 to 0.5 times the wavelength of the wave transmitted and received by the antenna 4. That is, the length from the first end 20c to the second end 20d of the first projecting conductor 20 may be approximately half the wavelength of the wave transmitted and received by the antenna 4. If the length of the first projecting conductor 20 is less than 0.4 or more than 0.5 times the wavelength of the wave transmitted and received by the antenna 4, the resonant frequency of the first projecting conductor 20 will be significantly different from the frequency of the wave transmitted and received by the antenna 4, and noise generated by the crystal oscillator 10 that is close to the frequency of the wave transmitted and received by the antenna 4 may not be effectively absorbed by the first projecting conductor 20. By setting the length h to be 0.4 to 0.5 times the wavelength of the wave transmitted and received by the antenna 4, noise that is close to the frequency of the wave transmitted and received by the antenna 4 is effectively absorbed by the first projecting conductor 20.

[0080] 10 is a partial perspective view showing an example of a wireless module 2 according to a seventh embodiment. This embodiment differs from the second embodiment in that the multiple first protruding conductors 20 include a first conductor 40 and a second conductor 42. The antenna 4 of the wireless module 2 according to this embodiment is capable of transmitting and receiving a first radio wave having a first wavelength, and is also capable of transmitting and receiving a second radio wave having a second wavelength longer than the first wavelength.

[0081] 10 , the plurality of first protruding conductors 20 include four first conductors 40 and four second conductors 42. The first conductors 40 and the second conductors 42 are arranged alternately around the periphery of the crystal oscillator 10. The length from the base end to the tip end of the first conductors 40 is different from the length from the base end to the tip end of the second conductors 42.

[0082] In this case, the resonant frequency of the first conductor 40 is different from the resonant frequency of the second conductor 42. Therefore, when the antenna 4 transmits and receives two radio waves with different frequencies, by setting the resonant frequency of the first conductor to a value corresponding to the first radio wave and the resonant frequency of the second conductor to a value corresponding to the second radio wave, it is possible to have the first conductor 40 and the second conductor 42 absorb noise for each of the two radio waves.

[0083] More specifically, the length of the first conductor 40 is 0.2 to 0.25 times the first wavelength, and the length of the second conductor 42 is 0.2 to 0.25 times the second wavelength. This allows noise near the frequency of the first radio wave transmitted and received by the antenna 4 to be effectively absorbed by the first conductor 40, and noise near the frequency of the second radio wave to be effectively absorbed by the second conductor 42.

[0084] [Verification Test] Next, a verification test conducted to verify the effects of this embodiment will be described. As a test method, a model of the antenna 4, the first protruding conductor 20, the noise source, and the circuit board 3 on which these were mounted was constructed, and the model was used to determine the effect of noise from the noise source on the antenna 4 by computer simulation. The frequency of the transmitted and received waves by the antenna 4 was set to a frequency band of 2.4 GHz to 2.5 GHz or a frequency band of 5 GHz to 5.5 GHz.

[0085] 11 is a diagram showing an example of a model used in the verification test. (a) in FIG. 11 shows a perspective view of the model, and (b) in FIG. 11 shows a side view of the model as viewed from the Y1 direction. On the substrate surface 3a of the model, the crystal oscillator 10 shown in each of the above embodiments was replaced with a noise source N, and an antenna 4 (antenna pattern 4b), a first protruding conductor 20 (hereinafter simply referred to as the protruding conductor 20), and the noise source N were arranged.

[0086] As shown in FIG. 11 , the antenna 4 is arranged along the Y direction. The noise source N is arranged on a virtual line L1. The virtual line L1 is a straight line parallel to the X direction and passing through the feed point 4b2. The distance w shown in (b) of FIG. 11 is set to 60 mm. The length n is set to 3 mm. The distance w is the distance between the noise source N and the antenna 4 along the X direction. The length n is the length of the noise source N in the Z direction. The distances s and h in FIG. 11 are set appropriately. The distance s is the distance between the noise source N and the protruding conductor 20 in the X-Y plane. The length h is the length from the base end to the tip end of the protruding conductor 20. The diameter of the protruding conductor 20 is set to 0.5 mm.

[0087] The above model was used to determine the pass characteristics from the noise source N to the antenna 4. The pass characteristics from the noise source N to the antenna 4 were determined as follows. That is, the frequency characteristics of S21, which is an S parameter when the feed point of the noise source N in the model is defined as port 1 and the feed point 4b2 of the antenna 4 is defined as port 2, were determined as the pass characteristics from the noise source N to the antenna 4. Regarding the influence of noise from the noise source N on the antenna 4, the frequency characteristics of S21 were determined for each of the examples shown below and compared for evaluation.

[0088] Example 1: A model including one protruding conductor 20 was constructed as a model for Example 1. In the model for Example 1, the position of the protruding conductor 20 may be on the virtual line L1 and on the X1 side of the noise source N as shown in FIG. 11 , or on the virtual line L1 and on the X2 side of the noise source N as shown in FIG. 2 . Example 1, in which the protruding conductor 20 is on the virtual line L1 and on the X2 side of the noise source N, corresponds to the first embodiment. Example 1, in which the protruding conductor 20 is on the virtual line L1 and on the X1 side of the noise source N, corresponds to a modified example of the first embodiment. Example 2: A model including two protruding conductors 20 was constructed as a model for Example 2. In Example 2, two protruding conductors 20 were provided on the virtual line L1 ( FIG. 11 ). The two protruding conductors 20 were provided on either side of the noise source N as shown in FIG. 12 . The distance s between the two protruding conductors 20 was 5 mm, and the length h was 25 mm. Example 3: A model including four protruding conductors 20 was constructed as a model of Example 3. The four protruding conductors 20 were provided around the noise source N as shown in (a) of FIG. 13 . The four protruding conductors 20 were provided at four points in the X and Y directions of the noise source N, respectively. The distance s between the four protruding conductors 20 was 5 mm, and the length h was 20 mm. Example 4: A model including eight protruding conductors 20 was constructed as a model of Example 3. The eight protruding conductors 20 were provided around the noise source N as shown in (b) of FIG. 13 . The eight protruding conductors 20 were provided at four points in the X and Y directions of the noise source N, as well as at midpoints between adjacent points among the four points. The distance s between the eight protruding conductors 20 was 5 mm, and the length h was 20 mm.

[0089] Example 5: A model including 12 protruding conductors 20 was constructed as a model for Example 5. The 12 protruding conductors 20 were arranged around the noise source N, as shown in (c) of FIG. 13 . The 12 protruding conductors 20 were arranged at four points in the X and Y directions of the noise source N, as well as at two points that divide the distance between adjacent points in the four directions into thirds. The distance s between the 12 protruding conductors 20 was 5 mm, and the length h was 20 mm. Example 6: A model including a protruding conductor 20 having a rectangular plate shape was constructed as a model for Example 6. The model for Example 6 corresponds to the third embodiment described above. As shown in (a) of FIG. 14 , the distance s between the protruding conductor 20 and the noise source N in the X direction was 5 mm, the longitudinal dimension b in the Y direction was 30 mm, and the length h was 20 mm. Example 7: A model including multiple protruding conductors 20 arranged in a row was constructed as a model for Example 7. The model of Example 7 corresponds to the fourth embodiment described above. As shown in (b) of FIG. 14 , this model includes eleven protruding conductors 20. The eleven protruding conductors 20 are arranged in a row along the Y direction. The distance x along the X direction between the row of protruding conductors 20 and the noise source N is 5 mm, the spacing c between adjacent pairs of protruding conductors 20 is 3 mm, and the length h of the eleven protruding conductors 20 is 20 mm. Example 8: A model including L-shaped protruding conductors 20 was constructed as the model of Example 8. The model of Example 8 corresponds to the fifth embodiment described above. As shown in (a) and (b) of FIG. 15 , the distance s is 5 mm, the length h of the protruding conductors 20 is 10 mm, and the longitudinal dimension j of the horizontal extension portion 28 is 10 mm. In addition, in the model of Example 8, as shown in (b) of FIG. 15 , the position and orientation of the protruding conductors 20 are set to the following four ways.Position P1: The protrusion 26 is located on a line extending from the noise source N in the X1 direction, and the orientation of the horizontal extension 28 is along the Y direction. Position P2: The protrusion 26 is located on a line extending from the noise source N in the Y1 direction, and the orientation of the horizontal extension 28 is along the X direction. Position P3: The protrusion 26 is located on a line extending from the noise source N in the X2 direction, and the orientation of the horizontal extension 28 is along the Y direction. Position P4: The protrusion 26 is located on a line extending from the noise source N in the Y2 direction, and the orientation of the horizontal extension 28 is along the X direction.

[0090] Example 9: As a model of Example 9, a model including a gate-shaped protruding conductor 20 was constructed. The model of Example 9 corresponds to the sixth embodiment described above. As shown in FIG. 16A, the length h of the protruding conductor 20 was 10 mm, and the longitudinal dimension j of the horizontal extension portion 28 was 20 mm. In the model of Example 9, the positions of the protruding conductor 20 were set to the following four positions. Position P11: A position where the horizontal extension portion 36 is arranged along the Y direction and is located on the X1 direction side of the noise source N. Position P12: A position where the horizontal extension portion 36 is arranged along the X direction and is located in the Y1 direction of the noise source N. Position P13: A position where the horizontal extension portion 36 is arranged along the Y direction and is located in the X2 direction of the noise source N. Position P14: A position where the horizontal extension portion 36 is arranged along the X direction and is located in the Y2 direction of the noise source N. Example 10: As a model of Example 10, a model was constructed in which the protruding conductor 20 had a pin-shaped main body portion and a plate-shaped conductor portion provided on the main body portion. The model of Example 10 corresponds to a modified example of the first embodiment described above. As shown in FIG. 17(a), the protruding conductor 20 includes a main body portion 50 and a plate-shaped conductor portion 52. The main body portion 50 is a pin-shaped member extending in the Z1 direction from the substrate surface 3a. The plate-shaped conductor portion 52 is provided at the end of the main body portion 50 located on the tip portion 20b side. The plate-shaped conductor portion 52 has a circular shape. The tip of the main body portion 50 is fixed to the center of the plate-shaped conductor portion 52. The plate-shaped conductor portion 52 is parallel to the substrate surface 3a. In this example, the provision of the plate-shaped conductor portion 52 provides an appropriate capacitance component to the tip end of the protruding conductor 20, thereby maintaining the noise absorption effect even when the length of the main body portion 50 is shortened. As a result, the protruding conductor 20 can be made smaller. The diameter r of the plate-shaped conductor portion 52 is 6 mm, the thickness of the plate-shaped conductor portion 52 is 0.5 mm, and the length h of the protruding conductor 20 is 10 mm. Example 11 A model was constructed for Example 11, in which the protruding conductor 20 had a spiral-shaped main body portion. The model for Example 11 corresponds to a modified example of the first embodiment described above. As shown in Fig. 18 , the protruding conductor 20 has a main body portion 54. The main body portion 54 has a spiral shape extending in the Z direction from the base end portion 20a to the tip end portion 20b.In this embodiment, the protruding conductor 20 has a spiral shape, which makes it possible to reduce the protruding height from the circuit board 3 while ensuring the required length of the protruding conductor 20. The diameter k of the main body 54 is 3.5 mm, and the length h of the protruding conductor 20 is 10 mm.

[0091] Comparative Example As a comparative example, a model was constructed in which the protruding conductor 20 included in the first embodiment was eliminated.

[0092] [Regarding the length h of the protruding conductor 20] Fig. 19 is a diagram showing the frequency characteristics of S21 when the length of the protruding conductor 20 is changed using Example 1. In Fig. 19, the horizontal axis represents frequency and the vertical axis represents S21. Here, a model was used in which the protruding conductor 20 was located on a line extending from the noise source N in the X1 direction. The distance s was set to 5 mm. The frequency of the transmitted and received waves by the antenna 4 was set to a frequency band from 2.4 GHz to 2.5 GHz. The length h was set to three values: 15 mm, 20 mm, and 25 mm.

[0093] In Figure 19, the solid line represents the graph for the comparative example, the dashed line represents the graph for length h = 15 mm, the broken line represents the graph for length h = 20 mm, and the dashed line represents the graph for length h = 25 mm. As shown in Figure 19, the frequency characteristics of the three examples 1 appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that noise in example 1, which is provided with the protruding conductor 20, is reduced compared to the comparative example. In particular, when the length h is 25 mm, noise reduction of about 10 dB is observed compared to the comparative example in the frequency band of the waves transmitted and received by the antenna 4.

[0094] When the length h = 25 mm, if the frequency of the waves transmitted and received by the antenna 4 is 2.4 GHz, the length h is 0.2 times the wavelength of the waves transmitted and received by the antenna 4. Also, if the frequency of the waves transmitted and received by the antenna 4 is 2.5 GHz, the length h is 0.21 times the wavelength of the waves transmitted and received by the antenna 4.

[0095] Fig. 20 is a diagram showing the frequency characteristics of S21 in Example 1. In Fig. 20, the horizontal axis represents frequency, and the vertical axis represents S21. Here, a model was used in which the protruding conductor 20 was located on a line extending from the noise source N in the X1 direction. The distance s was set to 5 mm. The frequency of the transmission and reception waves of the antenna 4 was set to a frequency band from 5 GHz to 5.5 GHz. The length h was set to 12.7 mm.

[0096] In Fig. 20, the solid line indicates the graph for the comparative example, and the dashed line indicates the graph for length h = 12.7 mm. As shown in Fig. 20, the frequency characteristics of Example 1, which is provided with the protruding conductor 20, appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that the noise of Example 1, which is provided with the protruding conductor 20, is reduced compared to the comparative example.

[0097] When the length h = 12.7 mm, if the frequency of the waves transmitted and received by the antenna 4 is 5 GHz, the length h is 0.21 times the wavelength of the waves transmitted and received by the antenna 4. Also, if the frequency of the waves transmitted and received by the antenna 4 is 5.5 GHz, the length h is 0.23 times the wavelength of the waves transmitted and received by the antenna 4.

[0098] From the results of Figures 19 and 20, it can be seen that by setting the length h to be greater than or equal to 0.2 times and less than or equal to 0.25 times the wavelength of the wave transmitted and received by the antenna 4, noise from the noise source N can be effectively absorbed by the protruding conductor 20.

[0099] [Regarding the distance s between the protruding conductor 20 and the noise source N] Fig. 21 is a diagram showing the frequency characteristics of S21 when the distance s between the noise source N and the protruding conductor 20 is changed using Example 1. In Fig. 21, the horizontal axis represents frequency and the vertical axis represents S21. Here, a model was used in which the protruding conductor 20 was located on a line extending from the noise source N in the X1 direction. The length h was set to 20 mm. The frequency of the waves transmitted and received by the antenna 4 was set to a frequency band from 2.4 GHz to 2.5 GHz. The distance s was set to two values: 5 mm and 10 mm.

[0100] In Fig. 21, the solid line represents the graph for the comparative example, the dotted line represents the graph for the distance s = 5 mm, and the dashed line represents the graph for the distance s = 10 mm. As shown in Fig. 21, the frequency characteristics of the two examples 1 provided with the protruding conductor 20 appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. Furthermore, the frequency characteristics of example 1 with distance s = 5 mm appear lower than the frequency characteristics of example 1 with distance s = 10 mm over a wide frequency band. This shows that example 1 with distance s = 5 mm has a greater noise reduction effect than example 1 with distance s = 10 mm.

[0101] Fig. 22 is another diagram showing the frequency characteristics of S21 when the distance s between the noise source N and the protruding conductor 20 is changed using Example 1. In Fig. 22, the horizontal axis represents frequency and the vertical axis represents S21. Here, a model was used in which the protruding conductor 20 was located on a line extending from the noise source N in the X2 direction. In other words, the protruding conductor 20 was located between the noise source N and the antenna 4. The length h was set to 20 mm. The frequency of the waves transmitted and received by the antenna 4 was set to a frequency band from 2.4 GHz to 2.5 GHz. The distance s was set to three values: 5 mm, 15 mm, and 25 mm.

[0102] In Figure 22, the solid line represents the graph for the comparative example, the dashed line represents the graph for distance s = 5 mm, the dashed line represents the graph for distance s = 15 mm, and the two-dot chain line represents the graph for distance s = 25 mm. As shown in Figure 22, the frequency characteristics of Example 1 when distance s = 15 mm and Example 1 when distance s = 25 mm appear higher than the frequency characteristics of the comparative example over a wide frequency band. This result indicates that Example 1 when distance s = 15 mm and Example 1 when distance s = 25 mm may not be able to achieve a noise reduction effect. Note that the frequency characteristics of Example 1 when distance s = 5 mm appear lower than the frequency characteristics of Example 1 when distance s = 10 mm over a wide frequency band.

[0103] 21 and 22, it can be said that the noise reduction effect of the protruding conductor 20 can be appropriately obtained by setting the distance s to approximately 12 mm or less. In other words, the distance s should be set to 0.2 times or less the distance w between the noise source N and the antenna 4. This allows the noise reduction effect of the protruding conductor 20 to be appropriately obtained.

[0104] [Electromagnetic field distribution and radiation pattern near noise source] Fig. 23 is a diagram showing an image of the electromagnetic field distribution near noise source N. Fig. 23 shows an image of the electromagnetic field distribution when the model is viewed from the Y1 direction side. Note that the portion where the electromagnetic field intensity appears higher on the Z2 direction side of circuit board 3 is the electromagnetic field distribution generated by the power supply line of noise source N, and is not related to the test this time.

[0105] (a) in Fig. 23 is an image diagram of the electromagnetic field distribution of the comparative example. (b) in Fig. 23 is an image diagram of the electromagnetic field distribution of Example 1. The distance s is 5 mm, and the length h is 25 mm. (c) in Fig. 23 is an image diagram of the electromagnetic field distribution of Example 2.

[0106] As shown in (b) of Figure 23, in Example 1, the protruding conductors 20 resonate, the noise from the noise source N is absorbed, and the range of noise in the X-Y plane is reduced. (c) of Figure 23 is similar to (b) of Figure 23. In Example 2, the two protruding conductors 20 resonate, the noise from the noise source N is absorbed, and the range of noise in the X-Y plane is reduced. In Example 2, the range of noise is smaller than in Example 1.

[0107] 24 and 25 are diagrams showing the radiation pattern of noise source N. FIG. 24 shows the radiation pattern when viewed from the Y2 direction on the X-Z plane. FIG. 24 shows the radiation pattern in a coordinate system based on the X axis along the X1 direction, the Y axis along the Y1 direction, and the Z axis along the Z1 direction. The origin of this coordinate system is the position of noise source N on substrate surface 3a. FIG. 24 shows the gain for elevation angles θ ranging from -180° to 180° when azimuth angle Φ = 0°. Elevation angle θ is the angle with respect to the Z axis. Azimuth angle Φ is the angle with respect to the X axis. Therefore, in FIG. 24, the direction of elevation angle θ = -90° is the direction facing antenna 4, and elevation angle θ = 90° is the opposite direction to antenna 4. In FIG. 24, the solid line indicates the vertical polarization component, and the dashed-dotted line indicates the horizontal polarization component.

[0108] The diagram on the left side of Fig. 24 shows the radiation pattern of the comparative example shown in Fig. 23. The diagram on the right side of Fig. 24 shows the radiation pattern of Example 1 shown in Fig. 23. In Fig. 24, when the gain of the vertical polarization component in the directions of elevation angles θ = -90° and 90° is compared between the comparative example and Example 1, the gain of Example 1 is smaller than the gain of Comparative Example 1. Furthermore, the gain of Example 1 is smaller than the gain of Comparative Example 1 in the range of elevation angles θ = -90° to 0° and in the range of elevation angles θ = 0° to 90°.

[0109] Figure 25 shows the radiation pattern when viewed from the Z1 direction on the XY plane. Figure 25 also shows the radiation pattern using the same coordinate system as Figure 24. Figure 25 shows the gain in the range of azimuth angles Φ = -180° to 180° when the elevation angle θ = 90°. Therefore, in Figure 25, the direction of azimuth angle Φ = 180° (-180°) is the direction facing the antenna 4. In Figure 25, the solid line indicates the vertical polarization component, and the dashed dotted line indicates the horizontal polarization component.

[0110] The diagram on the left in Fig. 25 shows the radiation pattern of the comparative example shown in Fig. 23. The diagram on the right in Fig. 25 shows the radiation pattern of Example 1 shown in Fig. 23. In Fig. 25, when the gain of the vertical polarization component is compared between the comparative example and Example 1, the gain of Example 1 is smaller than the gain of Comparative Example 1. Over the entire range of azimuth angles Φ = -180° to 180°, the gain of Example 1 is smaller than the gain of Comparative Example 1. Therefore, even in the direction toward antenna 4, the gain of Example 1 is smaller than the gain of Comparative Example 1.

[0111] 24 and 25, it can be seen that the range of noise from the noise source N on the substrate surface 3a is reduced by the protruding conductor 20.

[0112] [Regarding the position of the protruding conductor 20 relative to the noise source N] Fig. 26 is a diagram showing the frequency characteristics of S21 when the position of the protruding conductor 20 is changed using Example 1. In Fig. 26, the horizontal axis represents frequency and the vertical axis represents S21. Here, the position of the protruding conductor 20 was set in the following four ways. Position P21: Position on a line extending from the noise source N in the X1 direction Position P22: Position on a line extending from the noise source N in the Y1 direction Position P23: Position on a line extending from the noise source N in the X2 direction Position P24: Position on a line extending from the noise source N in the Y2 direction

[0113] For each of positions P21 to P24, the length h was set to 20 mm and the distance s was set to 5 mm.

[0114] 26, the thick solid line is the graph for the comparative example, the dotted line is the graph for position P21, the dashed line is the graph for position P22, the two-dot dashed line is the graph for position P23, and the thin solid line is the graph for position P24. As shown in Fig. 26, the frequency characteristics of the four working examples 1 provided with the protruding conductor 20 appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. In particular, the frequency characteristics at position P23 appear lower than the frequency characteristics of the other three working examples 1.

[0115] The protruding conductor 20 of Example 1 at position P23 is provided between the noise source N and the antenna 4. From this result, it can be seen that by disposing the protruding conductor 20 between the noise source N and the antenna 4, the noise reaching the antenna 4 can be effectively reduced.

[0116] [Regarding the number of protruding conductors 20] Figure 27 is a diagram showing the frequency characteristics of S21 when the number of protruding conductors 20 is changed. In Figure 27, the horizontal axis represents frequency and the vertical axis represents S21. Here, by using Examples 1, 3, 4, and 5, the number of protruding conductors 20 was set to four values: 1, 4, 8, and 12. The protruding conductors 20 in Example 1 were provided on a straight line extending from the noise source N in the X1 direction. In Example 1, the distance s was 5 mm and the length h was 25 mm.

[0117] 27, the thick solid line is the graph for the comparative example, the dotted line is the graph for Example 1 (1 conductor), the dashed line is the graph for Example 3 (4 conductors), the two-dot dashed line is the graph for Example 4 (8 conductors), and the thin solid line is the graph for Example 5 (12 conductors). As shown in Fig. 27, the frequency characteristics tend to appear lower as the number of protruding conductors 20 increases.

[0118] FIG. 28 is a diagram showing an image of the electromagnetic field distribution near the noise source N. FIG. 28 shows an image of the electromagnetic field distribution when the model is viewed from the Z1 direction side. (a) in FIG. 28 is an image of the electromagnetic field distribution of the comparative example. (b) in FIG. 28 is an image of the electromagnetic field distribution of Example 1. (c) in FIG. 28 is an image of the electromagnetic field distribution of Example 3. (d) in FIG. 28 is an image of the electromagnetic field distribution of Example 4. (e) in FIG. 28 is an image of the electromagnetic field distribution of Example 5. As shown in FIG. 28, it can be seen that the greater the number of protruding conductors 20, the smaller the range of noise in the X-Y plane tends to be.

[0119] 27 and 28 show that providing a plurality of protruding conductors 20 so as to surround the noise source N can more effectively reduce noise reaching the antenna 4. Also, from Fig. 27 and 28 it can be seen that the greater the number of protruding conductors 20 surrounding the noise source N, the greater the noise reduction effect.

[0120] [Regarding the protruding conductor 20 having a rectangular plate shape] Fig. 29 is a diagram showing the frequency characteristics of S21 of Example 6. In Fig. 29, the horizontal axis represents frequency and the vertical axis represents S21. In Fig. 29, the solid line represents the graph of the comparative example, and the two-dot chain line represents the graph of Example 6. As shown in Fig. 29, the frequency characteristics of Example 6 having the protruding conductor 20 having a rectangular plate shape appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that the noise of Example 6 is reduced compared to the comparative example.

[0121] [Regarding Multiple Protruding Conductors 20 Arranged in a Row] Figure 30 is a diagram showing the frequency characteristics of S21 of Example 7. In Figure 30, the horizontal axis represents frequency and the vertical axis represents S21. In Figure 30, the solid line represents the graph of the comparative example, and the two-dot chain line represents the graph of Example 7. As shown in Figure 30, the frequency characteristics of Example 7, which has multiple protruding conductors 20 arranged in a row, appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that the noise of Example 7 is reduced compared to the comparative example.

[0122] [Regarding the L-shaped protruding conductor 20] Fig. 31 is a diagram showing the frequency characteristics of S21 in Example 8. In Fig. 31, the horizontal axis represents frequency and the vertical axis represents S21. In Fig. 31, the thick solid line represents the graph for the comparative example, the one-dot chain line represents the graph for position P1, the dashed line represents the graph for position P2, the two-dot chain line represents the graph for position P3, and the thin solid line represents the graph for position P4.

[0123] As shown in Figure 31, the frequency characteristics of the four examples 8 having the L-shaped protruding conductor 20 appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that the noise of the example 8 is reduced compared to the comparative example. In particular, the frequency characteristics at position P3 appear lower than the frequency characteristics of the other three examples 8. The protruding conductor 20 of the example 8 at position P3 is disposed between the noise source N and the antenna 4. This result shows that even with an L-shaped protruding conductor 20, by disposing it between the noise source N and the antenna 4, the noise reaching the antenna 4 can be effectively reduced.

[0124] [Regarding the gate-shaped protruding conductor 20] Fig. 32 is a diagram showing the frequency characteristics of S21 in Example 9. In Fig. 32, the horizontal axis represents frequency and the vertical axis represents S21. In Fig. 32, the thick solid line represents the graph for the comparative example, the one-dot chain line represents the graph for position P11, the dashed line represents the graph for position P12, the two-dot chain line represents the graph for position P13, and the thin solid line represents the graph for position P14.

[0125] As shown in Figure 32, the frequency characteristics of the four examples 9 having gate-shaped protruding conductors 20 appear lower than the frequency characteristics of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. This shows that the noise of the example 9 is reduced compared to the comparative example. In particular, the frequency characteristics at position P13 appear lower than the frequency characteristics of the other three examples 9. The protruding conductor 20 of the example 9 at position P13 is disposed between the noise source N and the antenna 4. This result shows that even with the gate-shaped protruding conductor 20, by disposing it between the noise source N and the antenna 4, the noise reaching the antenna 4 can be effectively reduced.

[0126] [Regarding the protruding conductor 20 having a plate-shaped conductor portion at its tip] Fig. 33 is a diagram showing the frequency characteristics of S21 in Example 10. In Fig. 33, the horizontal axis represents frequency and the vertical axis represents S21. Here, the position of the protruding conductor 20 was set to four positions (positions P21, P22, P23, and P24) similar to those of the protruding conductor 20 in Fig. 26.

[0127] In Figure 33, the thick solid line represents the graph for the comparative example, the dotted line represents the graph for position P21, the dashed line represents the graph for position P22, the two-dot dashed line represents the graph for position P23, and the thin solid line represents the graph for position P24. As shown in Figure 33, the frequency characteristics of the four examples 10 appear lower than those of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. In particular, the frequency characteristics at position P23 appear lower than those of the other three examples 10. The protruding conductor 20 of example 10 at position P23 is located between the noise source N and the antenna 4. From the above results, it can be seen that even if the length of the main body 50 is shortened, the noise absorption effect of the plate-like conductor 52 can be maintained, and the protruding conductor 20 can be made smaller.

[0128] [Regarding the spiral-shaped protruding conductor 20] Fig. 34 is a diagram showing the frequency characteristics of S21 in Example 11. In Fig. 34, the horizontal axis represents frequency and the vertical axis represents S21. Here, the protruding conductor 20 was set to four positions (positions P21, P22, P23, and P24) similar to those of the protruding conductor 20 in Figs. 26 and 33.

[0129] In Figure 34, the thick solid line represents the graph for the comparative example, the dotted line represents the graph for position P21, the dashed line represents the graph for position P22, the two-dot dashed line represents the graph for position P23, and the thin solid line represents the graph for position P24. As shown in Figure 34, the frequency characteristics of the four examples 11 appear lower than those of the comparative example over a wide frequency band including the frequency band of the waves transmitted and received by the antenna 4. In particular, the frequency characteristics at position P23 appear lower than those of the other three examples 10. The protruding conductor 20 of example 10 at position P23 is provided between the noise source N and the antenna 4. From the above results, it can be seen that by forming the protruding conductor 20 in a spiral shape, the required length of the protruding conductor 20 can be secured, maintaining the noise absorption effect, while keeping the protruding height of the protruding conductor 20 low.

[0130] [Others] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. For example, in the above-described embodiments and examples, the antenna 4 is provided on the edge of the circuit board 3. However, the antenna 4 may be provided around the periphery of the circuit board 3 or may be disposed opposite the circuit board 3.

[0131] In addition, in the above-described embodiments and examples, the protruding conductors are perpendicular to the substrate surface. However, the protruding conductors may protrude obliquely from the substrate surface as long as they protrude from the substrate surface.

[0132] In the above-described embodiments and examples, the first circuit components that are noise sources are exemplified as crystal oscillators, USB connectors, and LAN chips. However, the first circuit components also include DDR (Double Data Rate) SDRAMs. Therefore, when a DDR SDRAM is mounted on the board surface 3 a, providing a protruding conductor near the DDR SDRAM as in the above-described embodiments can reduce noise reaching the antenna.

[0133] Furthermore, in the above-described embodiments and examples, the antenna 4 includes an inverted-F antenna. However, the antenna 4 may include other monopole antennas, such as an inverted-L antenna, or a dipole antenna. Furthermore, in the above-described embodiments, the antenna 4 includes an antenna substrate 4a and an antenna pattern 4b. However, the antenna 4 may be formed of a metal plate erected on the substrate surface 3a. In this case, the antenna 4 may include an inverted-F antenna, an inverted-L antenna, or a dipole antenna by providing a predetermined shape for the metal plate. Furthermore, when the antenna 4 is fixed to the housing 6, the antenna 4 may include a dipole antenna (including a modified dipole antenna) provided on the inner surface of the housing 6. Furthermore, the antenna 4 may be configured to have an antenna pattern on the substrate surface 3a. In this case, the antenna 4 may include an inverted-F antenna, an inverted-L antenna, or a dipole antenna by providing a predetermined shape for the antenna pattern on the substrate surface 3a.

[0134] Furthermore, in the above-described embodiments, a single-layer circuit board 3 having a ground conductor portion 3g on the back surface 3b has been illustrated. However, the circuit board 3 may be configured using a multilayer board having the ground conductor portion 3g on an inner layer. When the circuit board 3 is configured using a multilayer board, the first circuit component and the second circuit component may be mounted on both the board surface 3a and the back surface 3b. The protruding conductor is provided on the surface on which the first circuit component is mounted. Therefore, when the first circuit component is mounted on both the board surface 3a and the back surface 3b, the protruding conductor is provided on both the board surface 3a and the back surface 3b. When the first circuit component is mounted only on the back surface 3b, the protruding conductor is provided on the back surface 3b.

[0135] The scope of the present invention is defined by the claims, not by the meaning described above, and is intended to include all modifications within the scope and meaning equivalent to the claims.

[0136] 1 Wireless communication device 2 Wireless module (transmitter / receiver) 3 Circuit board 3a Board surface 3a1 First point 3a2 Second point 3b Back surface 3g Ground conductor portion 3p Board body 3p1 Board body surface 3p2 Hole portion 4 Antenna 4a Antenna board 4b Antenna pattern 4b1 Antenna element 4b2 Feeding point 4p First end point 4q Second end point 4r Point 6 Housing 6a Leg portion 8 Wireless chip 10 Crystal oscillator (circuit component) 10p Center point 12 Processing circuit chip 13 LAN chip 14 USB connector (circuit component) 14p Center point 16 LAN connector 20 First protruding conductor (protruding conductor) 20a Base end portion 20b Tip end portion 20c First end portion 20d Second end portion 22 Second protruding conductor (protruding conductor) 24 Main body portion 25 Third protruding conductor (protruding conductor) 26 Protruding portion 28 Lateral extension portion 30 Main body portion 32 First protruding portion 34 Second protruding portion 36 Lateral extension portion 40 First conductor 42 Second conductor 50 Main body portion 52 Plate-shaped conductor portion 54 Main body portion N Noise source A1 Area A2 Area L1 Virtual line (passing line) L2 Virtual line L3 Virtual line L4 Virtual line L5 Virtual line L6 Virtual line P1 Position P11 Position P12 Position P13 Position P14 Position P2 Position P21 Position P22 Position P23 Position P24 Position P3 Position P4 Position b Dimension c Spacing h Length j Longitudinal dimension k Diameter n Length r diameter s distance s1 distance s2 distance w distance w1 distance w2 distance x distance

Claims

1. A wireless module comprising: a circuit board having a board surface on which circuit components that are noise sources are mounted; an antenna mounted on the edge of the circuit board or around the periphery of the circuit board; and at least one unpowered protruding conductor mounted on the board surface and grounded, wherein the distance between the protruding conductor and the circuit components is shorter than the distance between the protruding conductor and the antenna.

2. The wireless module according to claim 1, wherein the protruding conductor is disposed in the region between the circuit component and the antenna.

3. The wireless module according to claim 1, wherein the at least one protruding conductor includes two or more protruding conductors, and the two or more protruding conductors are arranged to surround the circuit component.

4. A wireless module according to claim 1 or 2, wherein the protruding conductor is provided on a passing line that is a straight line that passes through the circuit component and the antenna and minimizes the distance between the circuit component and the antenna.

5. A wireless module according to any one of claims 1 to 4, wherein the protruding conductor has a base end connected to the substrate surface and to a ground conductor, and a tip end that is an electrically open end.

6. The wireless module according to claim 5, wherein the protruding conductor includes a pin-shaped main body portion extending from the base end to the tip end.

7. The wireless module according to claim 5, wherein the protruding conductor includes a main body portion having a spiral shape extending from the base end to the tip end in a direction intersecting the substrate surface.

8. The wireless module according to claim 5, wherein the protruding conductor includes a plate-shaped main body portion extending from the base end portion to the tip end portion.

9. A wireless module as described in claim 6, wherein the main body portion has a protruding portion extending from the base end portion in a direction intersecting the substrate surface, and a horizontal extending portion extending from the tip of the protruding portion to the tip end portion in the planar direction of the substrate surface.

10. A wireless module as claimed in any one of claims 5 to 9, wherein the length from the base end to the tip end of the protruding conductor is 0.2 times or more and 0.25 times or less the wavelength of the radio waves transmitted and received by the antenna.

11. A wireless module as described in claim 5, wherein the protruding conductor further comprises a rod-shaped main body portion extending from the base end to the tip end in a direction intersecting the substrate surface, and a plate-shaped conductor portion provided at the end of the main body portion on the tip end side.

12. A wireless module as described in claim 1, wherein the protruding conductor has: a first end portion connected to a first point on the substrate surface; a second end portion connected to a second point on the substrate surface different from the first point; and a rod-shaped main body portion connecting the first end portion and the second end portion.

13. A wireless module according to claim 12, wherein the length from the first end to the second end of the protruding conductor is 0.4 times or more and 0.5 times or less the wavelength of the radio waves transmitted and received by the antenna.

14. A wireless module as described in claim 5, wherein the at least one protruding conductor is plural, the plural protruding conductors include a first conductor and a second conductor, and the length from the base end to the tip end of the first conductor is different from the length from the base end to the tip end of the second conductor.

15. A wireless module as described in claim 14, wherein the antenna is capable of transmitting and receiving a first radio wave having a first wavelength and is also capable of transmitting and receiving a second radio wave having a second wavelength different from the first wavelength, the length from the base end to the tip end of the first conductor is 0.2 to 0.25 times the first wavelength, and the length from the base end to the tip end of the second conductor is 0.2 to 0.25 times the second wavelength.

16. A noise reduction method for reducing noise reaching the edge of a circuit board of a wireless module or an antenna provided around the circuit board, comprising the step of providing at least one grounded, non-powered protruding conductor on the surface of the circuit board, wherein the distance between the protruding conductor and a noise-source circuit component provided on the surface of the board is shorter than the distance between the protruding conductor and the antenna.

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