JP6867036B2 - Wireless communication device and noise suppression method - Google Patents

Description

The present invention relates to a wireless communication device and a noise suppression method, and more particularly to a wireless communication device applied to a portable wireless communication device such as a mobile phone, a smartphone, and a mobile router, and a noise suppression method in the wireless communication device.

In recent years, wireless communication devices have adopted connection interfaces having various clock frequencies and wireless communication technologies having various operating frequencies, and there is a strong demand for measures against noise interference between the connection interface and wireless communication devices. ing. For example, in recent years, with the increase in communication speed, USB3.0 (operating clock 2.5 GHz), wireless LAN (Local Area Network, 2412 MHz to 2484 MHz), Bluetooth (registered trademark) (2402 MHz to 2480 MHz), which are relatively high frequencies, have been used. ) Noise interference is a problem. The most effective noise countermeasure is to completely shield the noise transmission path, but in reality, it is difficult to make a completely shielded structure for various reasons such as mounting and manufacturing.

For example, even with the shield structure as shown in FIG. 11, it is difficult to suppress noise. FIG. 11 is a schematic diagram showing a noise reduction structure in the current technology. The noise generation source 106 shown in FIG. 11 is a power supply circuit of a DC / DC converter or the like, and a harmonic component of a switching frequency used in the power supply circuit is radiated as noise. The noise mainly propagates to the outside as radiation noise 110 and noise current 111.

In the case of the structure of FIG. 11, the shield 107 can shield the radiation noise 110 radiated directly from the noise source 106 directly into the space to some extent, and can reduce the influence of the shield 107 on the outside. it can. However, with respect to the noise current 111 flowing on the surface of the substrate 101, since it flows on the surface layer of the substrate 101, it flows out of the shield 107 along the surface layer of the substrate 101 through the gaps of the shield 107 and the like, and the noise is emitted to the periphery. This will deteriorate the wireless characteristics of the wireless communication device. That is, with the shield structure as shown in FIG. 11, the noise transmission path cannot be completely blocked.

In particular, when the switching frequency of a power supply circuit such as a DC / DC converter is close to the operating frequency for wireless communication, noise cannot be attenuated by a filter or the like, so it is difficult to take measures against noise radiated from the power supply circuit. For example, Japanese Patent Application Laid-Open No. 2016-171329 "Circuit board having a noise suppression structure" of Patent Document 1 proposes a technique for forming a resonator in which a slot line is looped, but from a power supply circuit It is difficult to completely suppress the outflow of noise.

Japanese Unexamined Patent Publication No. 2016-171329

As described above, in the current technology related to the present invention, noise countermeasures for wireless communication devices against noise radiated from power supply circuits and connection interfaces are still insufficient. That is, in the current technology, there is a problem to be solved regarding noise countermeasures for wireless communication devices.

(Purpose of this disclosure)
An object of the present disclosure is a wireless communication device and a noise suppression method capable of suppressing noise radiated from a noise source such as a power supply circuit or noise transmission such as a connection interface and improving wireless communication quality in view of such a problem. Is to provide.

In order to solve the above-mentioned problems, the wireless communication device and the noise suppression method according to the present invention mainly employ the following characteristic configurations.

(1) The wireless communication device according to the present invention is
A slit is formed on the substrate on which the component is mounted to block the electrical connection so as to surround at least one of the noise source and the noise transmission path, and at any plurality of positions of the slit. By mounting a conductive element that makes an electrical connection, the position is line-symmetric with respect to at least one of the noise source and the noise transmission path, and the operation for wireless communication is performed. It is characterized by forming two loop-shaped circuits that resonate with the frequency.

(2) The noise suppression method according to the present invention is
A slit is formed on the substrate on which the component is mounted to block the electrical connection so as to surround at least one of the noise source and the noise transmission path, and at any plurality of positions of the slit. By mounting a conductive element that makes an electrical connection, the position is line-symmetric with respect to at least one of the noise source and the noise transmission path, and the operation for wireless communication is performed. It is characterized by forming two loop-shaped circuits that resonate with the frequency.

According to the wireless communication device and the noise suppression method of the present invention, the following effects can be mainly obtained.

By providing a slit and a conductive element on the circuit board on which the components of the wireless communication device are mounted, the position is line-symmetric with respect to the noise source and the noise transmission path, and is used for wireless communication. Two loop-shaped circuits that resonate with the operating frequency of the above are formed and arranged so as to surround the noise source and the noise transmission path. Therefore, the noise current from the noise source and the noise transmission path can be circulated by flowing as a loop-shaped (vortex) current in each of the loop-shaped circuits, and the noise current flows out of each of the loop-shaped circuits. It can be deterred. Therefore, it is possible to suppress the noise radiated from the wireless communication device and improve the wireless communication quality of the wireless communication device.

It is a schematic diagram which shows an example of the circuit board which mounts the circuit element which comprises the wireless communication apparatus which concerns on this invention. It is explanatory drawing explaining the loop-shaped circuit formed by the slit and the element arranged on the circuit board of the wireless communication apparatus shown in FIG. It is an equivalent circuit of the loop-shaped circuit shown in FIG. It is explanatory drawing which shows the state of the noise current which flows out on a circuit board in the present technology. It is a schematic diagram which shows another example different from FIG. 1 of the circuit board of the wireless communication apparatus which concerns on this invention. It is explanatory drawing explaining the loop-shaped circuit formed by four elements arranged on the circuit board of the wireless communication apparatus shown in FIG. It is explanatory drawing which shows the state of the noise current which flows out on a circuit board when a loop-shaped circuit is not formed unlike FIG. It is a table which shows the setting example of four elements having conductivity set for evaluating the noise suppression effect in the wireless communication device of FIG. It is a graph which shows the simulation result of the noise suppression effect in the wireless communication apparatus of FIG. 5 when the 1st pattern of FIG. 8 is applied. It is a graph which shows the simulation result of the noise suppression effect in the wireless communication device of FIG. 5 when the 2nd pattern of FIG. 8 is applied. It is a schematic diagram which shows the noise reduction structure in the present technology.

Hereinafter, preferred embodiments of the wireless communication device and the noise suppression method according to the present invention will be described with reference to the accompanying drawings. It goes without saying that the drawing reference reference numerals attached to the following drawings are added to each element for convenience as an example for assisting understanding, and the present invention is not intended to be limited to the illustrated embodiment. No.

(Features of the present invention)
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. In the present invention, a slit is formed around a noise source or a noise transmission path that will be formed on a substrate on which a component of a wireless communication device is mounted, and an element having conductivity is formed in the slit. It is mounted so as to straddle it, and it is at a position that is line symmetric (for example, left-right symmetry, vertically symmetric, etc.) with respect to the noise source and the noise transmission path, and each resonates with the operating frequency for wireless communication. The main feature is that the structure forms two loop-shaped circuits. Therefore, a spiral current is generated in each loop-shaped circuit due to the noise current from the noise source or the like, and the current circulates in each loop-shaped circuit, and the noise current is generated outside each loop-shaped circuit. The effect of making it difficult for the current to flow out can be obtained.

Therefore, for example, even when the harmonic component of the switching frequency of the power supply circuit such as a DC / DC converter, which is a noise source, and the operating frequency for wireless communication are close to each other and it is difficult to take measures by a filter or the like, the DC / DC converter is used. It is possible to suppress noise radiated from a power supply circuit such as a DC converter and improve the wireless communication quality of the wireless communication device. Further, it is possible to obtain the effect that only the frequency component that interferes with the radio characteristics can be filtered without reducing the waveform level of the signal line of the connection interface.

(Embodiment of the present invention)
Next, an example of an embodiment relating to the wireless communication device according to the present invention will be described. FIG. 1 is a schematic view showing an example of a circuit board on which a circuit element constituting the wireless communication device according to the present invention is mounted. FIG. 1A is a cross-sectional view seen from the side and FIG. 1B is a top surface. The cross-sectional view seen from is shown.

As shown in FIG. 1A, a shield 107 having a shape that covers the noise source 106 in order to shield the radiated noise from the noise source 106 of the power supply circuit such as a DC / DC converter mounted on the substrate 101. Is mounted in the shield mounting area 104 on the substrate 101. The shield mounting area 104 on the substrate 101 on which the shield 107 is mounted has two slits 102 formed on the inner peripheral side and the outer peripheral side of the shield mounting area 104 to provide various circuit components including a noise source 106. The component mounting area 105 inside the board 101 to be mounted is electrically separated from the outer peripheral side of the board 101 on which the antenna element and the antenna feeding point are mounted. The shield 107 is connected to the GND in the inner layer of the substrate 101 by vias.

FIG. 1B is a cross-sectional view taken from the upper surface side with the shield 107 removed. As shown in FIG. 1 (B), two rectangular slits 102, one inside and one outside, formed on the substrate 101 are formed so as to double surround the noise source 106, and the noise source 106 is formed. The shield 107 is arranged so as to sandwich the shield mounting area 104 on which the shield 107 is mounted. Therefore, as described above, the shield mounting area 104 is in a state of being electrically cut off from the component mounting area 105 inside the board 101 and the antenna feeding point 202 on the outer peripheral side of the board 101.

However, regarding the space between the component mounting area 105 and the shield mounting area 104, four conductive elements (for example, a capacitor or the like) of the element 121, the element 122, the element 123, and the element 124 arranged so as to straddle the inner slit 102. It is electrically connected on the surface layer of the substrate 101 by the capacitive element). Since the two rectangular slits 102 are formed so as to connect each other at the central positions of the upper side and the lower side, the left and right regions of the shield mounting area 104 are electrically cut off. .. Further, the antenna element 201 is mounted on the outer peripheral end of the substrate 101 (the upper left end of FIG. 1A) via the antenna feeding point 202.

FIG. 2 is an explanatory diagram illustrating a loop-shaped circuit formed by the slit 102 and the elements 121, 122, 123, 124 arranged on the circuit board of the wireless communication device shown in FIG. As shown in FIG. 2, the four conductive elements 122, 123, and 124 arranged so as to straddle the inner slit 102 formed in the substrate 101 are in any direction of the noise source 106. Two loop-shaped circuits for flowing noise current in a loop shape (vortex shape) are formed at positions that are line-symmetrical with respect to the above (for example, left-right symmetry in the case of FIG. 2).

That is, a loop circuit 301 is formed by the component mounting area 105, the shield mounting area 104, the element 121, and the element 123 on the left side of the noise generation source 106 in FIG. 2, and on the right side of the noise generation source 106 in FIG. A loop-shaped circuit 302 is formed by the component mounting area 105, the shield mounting area 104, the element 122, and the element 124. As described above, the shield mounting area 104 is electrically cut off by the pattern of the slits 102 arranged at the center positions of the upper side and the lower side, so that the loop-shaped circuit is not formed at the vertically symmetrical positions. ..

Here, for each of the loop-shaped circuit 301 and the loop-shaped circuit 302, the loop length and the values of the elements (element 121, element 122, element 123, element 124) are set in advance so as to resonate with the frequency used for wireless communication. It is necessary to design and decide. Further, the loop-shaped circuit 301 and the loop-shaped circuit 302 need to be arranged so as to be line-symmetrical (left-right symmetric in the case of FIG. 2) with respect to an arbitrary direction of the noise source 106. With such a structure, as shown in FIG. 2, the loop-shaped circuit 301 and the loop in which the noise current 103 generated from the noise source 106 is formed at positions symmetrical with respect to the noise source 106. It can be circulated by being generated as a loop-shaped (vortex-shaped) current in the shaped circuit 302.

Therefore, it is possible to suppress the noise current 103 from flowing out to the outside of the slit 102 formed on the substrate 101, and it is possible to suppress the radiation of noise to the periphery. Furthermore, even if the noise current 103 has a frequency component close to the operating frequency for wireless communication, it is possible to suppress the radiation of noise due to the noise current 103. It can also be used in combination with noise countermeasures using a shield 107 or a filter.

FIG. 3 is an equivalent circuit of the loop-shaped circuit 301 and the loop-shaped circuit 302 shown in FIG. 2, FIG. 3 (A) shows an equivalent circuit of the loop-shaped circuit 301, and FIG. 3 (B) is a loop-shaped circuit. The equivalent circuit of the circuit 302 is shown. The case where each of the conductive elements 121, 122, 123, and 124 is a capacitive element is shown. As shown in FIG. 3, the noise current 103 circulates in a loop shape (vortex shape) in each of the loop-shaped circuit 301 and the loop-shaped circuit 302 formed symmetrically with respect to the noise source 106. On the other hand, in the case of a circuit board in the current technology which does not have the structure as shown in FIG. 1, the noise current as shown in FIG. 4 spreads over a wide range and flows on the circuit board.

FIG. 4 is an explanatory diagram showing a state of noise current flowing out on a circuit board in the current technology, and as an embodiment of the present invention, slits 102 and elements 121, 122, 123, 124 as shown in FIG. 1 are provided. The case where it is not arranged on the circuit board is shown. In the case of the current circuit board structure as shown in FIG. 4, the loop-shaped circuits 301 and 302 formed by the slit 102 and the conductive elements 121, 122, 123 and 124 as shown in FIG. 2 are not formed.

Therefore, as shown in FIG. 4, the noise current generated by the noise source 106 flows to the surface layer of the substrate 101 like the noise current 401, the noise current 402, the noise current 403, and the noise current 404, and the noise current of the substrate 101. It flows out to the end and reaches the antenna feeding point 202 of the antenna element 201. Therefore, even if the noise source 106 is covered with the shield 107, it is not possible to prevent the noise from being radiated to the outside, and even if a filter is used, it is close to the operating frequency for wireless communication. Since the noise current cannot be suppressed, the radiation of noise cannot be prevented.

In FIG. 1, the structure is such that slits 102 are provided on the inner peripheral side and the outer peripheral side of the shield mounting area 104, respectively, but the values of the elements 121, 122, 123, and 124 (in the case of a capacitive element, the capacitance). By adjusting the value) and the loop lengths of the loop-shaped circuits 301 and 302, it is possible to eliminate the need for the slits arranged on the outer peripheral side of the shield mounting area 104. Further, by forming a loop between the inner wall of the shield 107 and the elements 121, 122, 123, 124, it is possible to reduce the outflow of noise current to the outer wall of the shield 107.

Next, regarding the wireless communication device according to the present invention, another embodiment different from the above-described embodiment will be described. FIG. 5 is a schematic view showing another example different from FIG. 1 of the circuit board of the wireless communication device according to the present invention, and is not the noise generation source 106 in the case of FIG. 1 described above, but a connection interface with the outside. This describes a case where there is a noise transmission path that forms an unnecessary emission source in an element in the vicinity of the connector by mounting the above connector.

In the wireless communication device shown in FIG. 5, an antenna element 201 and an antenna feeding point 202 are mounted on the substrate 101A at an end (in the case of FIG. 5, the lower left end of the substrate 101A), and harmonics and low harmonics are observed. In the form of forming an unnecessary emission source 106A that generates unnecessary noise components such as waves and harmonics, the connection interface with the outside is provided in the vicinity of the unnecessary emission source 106A (in the case of FIG. 5, a nearly horizontal proximity position). A connector 505 is mounted, and a cable 506 for electrically connecting to another device is connected to the connector 505. Here, as shown by the dotted line, a noise transmission path 106B for transmitting a noise current is formed between the cable 506 and the connector 505, which serve as a connection interface with the outside, and the unnecessary emission source 106A. It has become.

Therefore, as shown in FIG. 5, a slit 102A is formed on the substrate 101A so as to surround the connector 505 as a noise countermeasure for the noise transmission path 106B leading to the unnecessary emission source 106A, and the connector of the substrate 101A is formed. The electrical connection between the mounting area and the area where the unnecessary emission source 106A is mounted is cut off. Further, four conductive elements 501, 502, 503, and 504 are mounted so as to straddle the slit 102A.

Here, the element 501 and the element 502 are arranged so as to sandwich the side surface of the connector 505 at the end of the substrate 101A, and with respect to the noise transmission path 106B between the connector 505 and the unnecessary emission source 106A. It is mounted at a position that is line-symmetrical (vertical symmetry in the case of FIG. 5). Further, the element 503 and the element 504 are arranged inside the substrate 101A in the vicinity of the back surface of the connector 505, and are line-symmetrical with respect to the noise transmission path 106B between the connector 505 and the unnecessary emission source 106A. In the case of FIG. 5, it is mounted at a position that is vertically symmetrical).

The GND (earth) of the opposite device connected to the wireless communication device via the cable 506 is electrically disconnected, and the wireless communication device is caused by a malfunction of the cable 506 or the opposite device such as the AC adapter. It is configured so that the power supply of the communication device and the GND are not short-circuited.

Further, as shown in FIG. 6, the loop-shaped circuit 601 is formed by the element 501, the element 503, and the slit 102A, and the loop-shaped circuit 602 is formed by the element 502, the element 504, and the slit 102A. FIG. 6 is an explanatory diagram illustrating a loop-shaped circuit formed by the four elements 501, element 503, element 504, and element 502 arranged on the circuit board of the wireless communication device shown in FIG. In any of the loop circuits, as in the case of FIG. 1, the values of each element 501, element 503, element 504, and element 502 (capacity in the case of a capacitive element) so as to resonate with the operating frequency of wireless communication. It is necessary to design the value) and loop length in advance. Further, it is also necessary that the two loop-shaped circuits 601 and the loop-shaped circuit 602 are formed at positions that are line-symmetrical (vertically symmetrical in the example of FIG. 6) with respect to the unnecessary emission source 106A and the noise transmission path 106B. is there.

With such a structure, as shown in FIG. 6, as shown in FIG. 6, the noise current 103A flows out on the substrate 101A as the noise current 103A flowing in the noise transmission path 106B between the unnecessary emission source 106A and the cable 506 or the connector 505 which is the connection interface. Even if it does, it is allowed to flow as a loop-shaped (vortex-shaped) current into the loop-shaped circuit 601 and the loop-shaped circuit 602 formed at positions line-symmetrical (vertically symmetrical in the example of FIG. 6) with respect to the noise transmission path 106B. Can be circulated.

Therefore, it is possible to suppress the noise current 103A from flowing out to the outside of the slit 102A formed on the substrate 101A, and it is possible to suppress the radiation of noise to the periphery. On the other hand, when the structure as shown in FIG. 5 is not provided, for example, the noise current as shown in FIG. 7 will widely flow on the circuit board.

FIG. 7 is an explanatory diagram showing the state of the noise current flowing out on the circuit board when the loop-shaped circuit is not formed unlike FIG. 5, and is an explanatory diagram showing the state of the noise current flowing out on the circuit board. Of the 502, 503 and 504, the case where the elements 503 and 504 are mounted but the elements 501 and 502 are not mounted on the circuit board is shown. In the case of the circuit board structure as shown in FIG. 7, the loop-shaped circuits 601, 602 by the slit 102A and the conductive elements 501, 502, 503, 504 as shown in FIG. 6 are not formed. ..

Therefore, as shown in FIG. 7, the current flowing between the unnecessary emission source 106A and the cable 506 or the connector 505 which is the connection interface is the noise current 701 and the noise current 702 of the surface layer of the substrate 101A and the connector 505. After flowing out to the surface layer, it further flows out to the outer peripheral portion of the substrate 101A and reaches the antenna feeding point of the antenna element mounted on the end portion of the substrate 101A. Therefore, it is not possible to prevent the radiation of noise from the antenna element. Furthermore, since the noise flows out to the outer skin of the connected cable 506, noise is radiated from the cable 506.

(Explanation of the effect of the embodiment)
As described in detail above, the following effects can be obtained in the present embodiment. By providing a slit and a conductive element on the circuit board on which the components of the wireless communication device are mounted, the position is line-symmetric with respect to the noise source and the noise transmission path, and is used for wireless communication. Two loop-shaped circuits (for example, symmetrical loop-shaped circuits 301 and 302 in the case of FIG. 1 and vertically symmetrical loop-shaped circuits 601, 602 in the case of FIG. 5) are formed in a state of resonating with the operating frequency of the above. It is arranged so as to surround the noise source and the noise transmission path. Therefore, the noise current from the noise source and the noise transmission path can be circulated by flowing as a loop-shaped (vortex) current in each of the loop-shaped circuits, and the noise current flows out of each of the loop-shaped circuits. It can be deterred. Therefore, it is possible to suppress the noise radiated from the wireless communication device and improve the wireless communication quality of the wireless communication device.

Here, for example, the effect when the four conductive elements 501, element 502, element 503, and element 504 as shown in FIG. 5 are mounted on the substrate 101A and noise suppression measures are taken by the loop-shaped circuits 601, 602. An example of the result of simulation evaluation will be described.

First, FIG. 8 is a table showing a setting example of four conductive elements 501, element 502, element 503, and element 504 set for evaluating the noise suppression effect in the wireless communication device of FIG. 5, and is a simulation. Two patterns used for evaluation are shown.

In the first pattern of FIG. 8, the element 501 and the element 502 are not mounted on the side surface of the connector 505 at the end of the substrate 101A shown in FIG. 5, and the capacitance value is 100 pF on the back surface side of the connector 505 inside the substrate 101A. It is a pattern in which the element 503 and the element 503 are mounted. That is, the first pattern is an implementation example similar to the case shown in FIG. 7, and is a case where the loop-shaped circuit 601 and the loop-shaped circuit 602 as shown in FIG. 6 are not formed. Further, the second pattern is an element 501 and an element 502 mounted on the side surface of the connector 505 at the end of the substrate 101A shown in FIG. 5, and an element 503 and an element mounted on the back surface side of the connector 505 inside the substrate 101A. Each of the 503 is a pattern implemented as an element having a capacitance value of 100 pF. That is, the second pattern is a case where the loop-shaped circuit 601 and the loop-shaped circuit 602 as shown in FIG. 6 are formed.

Further, the simulation evaluation of the noise suppression effect is performed by measuring the coupling amount between the unnecessary emission source 106A and the antenna feeding point 202, and the smaller the coupling amount, the larger the noise suppression effect. It means that.

FIG. 9 is a graph showing a simulation result of the noise suppression effect in the wireless communication device of FIG. 5 when the first pattern of FIG. 8 is applied. The horizontal axis shows the frequency for wireless communication, and the vertical axis shows the frequency for wireless communication. Indicates the amount of coupling between the unwanted emission source 106A and the antenna feeding point 202. Here, in the case of the first pattern, as described above, the loop-shaped circuit 601 and the loop-shaped circuit 602 are not formed. For example, as shown in the evaluation point 2 of FIG. 9, for wireless communication. When 2442 MHz is used as the operating frequency, the coupling amount is as large as −35.696 dB.

That is, the current distribution in the case of the first pattern is the same as that in the case of FIG. 7 in which the loop-shaped circuit 601 and the loop-shaped circuit 602 are not formed, and the noise current 701 and the noise current 702 are set as the noise current 701 of the substrate 101A. It flows out to the periphery and reaches the antenna feeding point 202 at the end of the substrate 101A. Therefore, noise is radiated to the surroundings.

Next, the simulation evaluation result in the case of the second pattern will be described with reference to FIG. FIG. 10 is a graph showing a simulation result of the noise suppression effect in the wireless communication device of FIG. 5 when the second pattern of FIG. 8 is applied, and as in the case of FIG. 9, the horizontal axis is for wireless communication. The frequency is shown, and the vertical axis shows the amount of coupling between the unwanted emission source 106A and the antenna feeding point 202.

In the case of the second pattern, as described above, the loop-shaped circuit 601 and the loop-shaped circuit 602 are formed, and unlike the graph of FIG. 9, for example, as shown in the evaluation point 2 of FIG. When 2442 MHz is used as the operating frequency for wireless communication, the coupling amount is -52.14 dB, which is a significantly small value. In other words, it is shown that the noise emission of about 16 dB can be suppressed in the case of the second pattern in which the loop-shaped circuit is formed as in the case of the first pattern in which the loop-shaped circuit is not formed.

That is, as shown in FIG. 6, the current distribution in the case of the second pattern flows as a loop-shaped (vortex-shaped) current through the loop-shaped circuit 601 and the loop-shaped circuit 602 formed on the substrate 101A, and loops. This means that the outflow to the outside of the shaped circuit 601 and the looped circuit 602 is suppressed.

The configuration of a preferred embodiment of the present invention has been described above. However, it should be noted that such embodiments are merely exemplary of the invention and do not limit the invention in any way. Those skilled in the art can easily understand that various modifications can be made according to a specific application without departing from the gist of the present invention.

101 Board 101A Board 102 Slit 102A Slit 103 Noise current 103A Noise current 104 Shield mounting area 105 Parts mounting area 106 Noise source 106A Unnecessary emission source 106B Noise transmission path 107 Shield 110 Radiation noise 111 Noise current 121 Element 122 Element 123 Element 124 Element 201 Antenna element 202 Antenna feeding point 301 Loop circuit 302 Loop circuit 401 Noise current 402 Noise current 403 Noise current 404 Noise current 501 Element 502 Element 503 Element 504 Element 505 Connector 506 Cable 601 Loop circuit 602 Loop circuit 701 Noise Current 702 Noise current

Claims (10)

A slit is formed on the substrate on which the component is mounted to block the electrical connection so as to surround at least one of the noise source and the noise transmission path, and at any plurality of positions of the slit. By mounting a conductive element that makes an electrical connection, the position is line-symmetric with respect to at least one of the noise source and the noise transmission path, and the operation for wireless communication is performed. Two loop-shaped circuits that resonate with the frequency are formed by different elements.
The slit includes a first slit that surrounds at least one of the noise source and the noise transmission path, and a second slit that further surrounds the first slit.
The first slit and the second slit are formed in the first region and the second slit so that the first region and the second region in which the two loop-shaped circuits are formed are electrically cut off. It is connected to the second area,
A wireless communication device characterized by the fact that. By adjusting the loop length of each of the loop-shaped circuits and the value of the conductive element, each of the loop-shaped circuits can be made to resonate with an arbitrary operating frequency for wireless communication. The wireless communication device according to claim 1. The wireless communication device according to claim 1 or 2 , wherein a capacitive element is used as the conductive element. Any of claims 1 to 3 , wherein a shield that shields noise radiation is mounted on the substrate, and the position where the slit is formed is arranged on the inner peripheral side of the shield mounting area on which the shield is mounted. The wireless communication device described in Crab. Claims 1 to 4 , wherein as a connection interface for connecting to an external device, a connector is provided at an end portion of the substrate, and a position for forming the slit is arranged so as to surround the connector. The wireless communication device according to any one. Interrupting the electrical connection so as to surround at least one of formed on a substrate for mounting a component noise source and noise transmission path, at least one of the noise source and the noise transmission path To mount a conductive element that forms a slit including a first slit that surrounds the first slit and a second slit that further surrounds the first slit , and that makes an electrical connection at any plurality of positions of the slit. The elements differ from each other in two loop-shaped circuits that are line-symmetrical with respect to at least one of the noise source and the noise transmission path and that resonate with the operating frequency for wireless communication. Formed by
The first slit and the second slit are set in the first region and the second slit so that the first region and the second region in which the two loop-shaped circuits are formed are electrically cut off. Connect to and from the second area,
A noise suppression method characterized by this. By adjusting the loop length of each of the loop-shaped circuits and the value of the conductive element, each of the loop-shaped circuits can be made to resonate with an arbitrary operating frequency for wireless communication. The noise suppression method according to claim 6. The noise suppression method according to claim 6 or 7 , wherein a capacitive element is used as the conductive element. Any of claims 6 to 8 , wherein a shield that shields noise radiation is mounted on the substrate, and a position for forming the slit is arranged on the inner peripheral side of the shield mounting area on which the shield is mounted. The noise suppression method described in Crab. Claims 6 to 9 , wherein as a connection interface for connecting to an external device, a connector is provided at an end portion of the substrate, and a position for forming the slit is arranged so as to surround the connector. The noise suppression method according to any one.

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