JP2018121113A - Radio communication apparatus and noise suppression method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication apparatus capable of radiating a signal of frequency component for radio communication not containing noise component, by restraining inflow of a noise current to an antenna, even when the clock frequency of a connection interface becoming a noise source and the operation frequency for radio communication are close to each other.SOLUTION: In a radio communication apparatus 101 including an antenna 107 radiating radio wave with the operation frequency for radio communication and a connector 109 forming a connection interface for connection with an external circuit via a cable 110 on a board, first and second loop circuits are formed in loop, as a noise suppression circuit for suppressing outflow of the noise current from the connection interface to the antenna 107, at the positions of bilateral symmetry on the board with respect to the connector 109, and the first and second loop circuits are configured to resonate at the operation frequency for radio communication.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wireless communication device and a noise suppression method. In particular, the present invention relates to a wireless communication apparatus and a noise suppression method that can be suitably applied to portable devices such as a mobile phone, a smartphone, a mobile notebook PC (Personal Computer), and a mobile router.

  Recent wireless communication devices are equipped with connection interfaces having various clock frequencies and wireless communication units having various operating frequencies, and countermeasures against noise interference between the connection interface and the wireless communication unit are required. It has been. The most effective countermeasure is a polyhedron EBG that prevents the propagation of electromagnetic waves, as described in, for example, Japanese Patent Application Laid-Open No. 2013-243429 “Structural member and wireless communication apparatus provided with the structural member”. By applying a member having an (Electromagnetic Band Gap) structure, the noise transmission path is completely shielded. However, when a connection interface for connecting to an external circuit (device) is provided, it is actually difficult to provide such a shield for various reasons such as mounting and manufacturing.

  For filtering technology that suppresses frequencies other than a specific frequency, if the clock frequency of the connection interface is close to the operating frequency for wireless communication, noise from the connection interface that is the noise source should be attenuated. Therefore, it is difficult to realize effective noise interference countermeasures.

  In recent years, with the increase in the speed of wireless communication, the clock frequency of the connection interface and the operating frequency for wireless communication have been approaching. In particular, USB 3.0 (operation clock 2500 MHZ) that uses a relatively high frequency. Interference between a wireless communication unit such as a wireless LAN (Local Area Network, 2,412 MHz to 2,484 MHz) or Bluetooth (registered trademark) (2,402 MHz to 2,480 MHz) Yes.

JP 2013-243429 A

  As described above, in order to suppress noise emission, for example, as described in Patent Document 1, it is most effective to block the noise transmission path with a shield. However, in a normal wireless communication device such as a mobile phone, a smartphone, or a mobile notebook PC, the connector terminal mounted on the substrate is exposed in order to connect to a cable for connection to an external circuit (device). Therefore, the connector terminal serves as a noise radiation source for the antenna for wireless communication. In addition, the connector terminal has a problem that it is difficult to shield it completely in consideration of the manufacturing process. Furthermore, since the cable connected to the external circuit (device) can generally use a commercial product selected by the user, it is expected that the influence of noise will increase when the shield performance of the cable is low. Is done.

  As another noise suppression method other than the shield structure, for example, a method using a filter is also assumed. However, as described above, the clock frequency that is a noise source and the operating frequency for wireless communication are close to each other. However, it is difficult to reduce noise by using a filter.

(Object of the present invention)
The present invention has been made to solve such a problem, and even when the clock frequency of the connection interface serving as a noise source is close to the operating frequency for wireless communication, the noise current to the antenna It is an object of the present invention to provide a wireless communication apparatus and a noise suppression method that can suppress the inflow of noise and can radiate a signal of a frequency component for wireless communication that does not include a noise component.

  In order to solve the above-described problems, the wireless communication apparatus and the noise suppression method according to the present invention mainly adopt the following characteristic configuration.

(1) A wireless communication apparatus according to the present invention includes:
A wireless communication device having on a substrate an antenna that radiates radio waves at an operating frequency for wireless communication, and a connector that forms a connection interface for connecting to an external circuit via a cable,
With respect to the connector, a first loop circuit and a second loop circuit are provided as noise suppression circuits for suppressing the outflow of noise current from the connection interface to the antenna at symmetrical positions on the board. Formed in a loop,
In addition, each of the first loop circuit and the second loop circuit is configured to resonate at the operating frequency for wireless communication.

(2) The noise suppression method according to the present invention is:
A method for suppressing noise in a wireless communication apparatus having an antenna that radiates a radio wave at an operating frequency for wireless communication and a connector that forms a connection interface for connecting to an external circuit via a cable on a substrate,
A first loop circuit and a second loop circuit are each formed in a loop shape in order to suppress the outflow of noise current from the connection interface to the antenna at a symmetrical position on the board with respect to the connector. ,
In addition, each of the first loop circuit and the second loop circuit is configured to resonate at the operating frequency for wireless communication.

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

  That is, in the present invention, the first and second loop circuits for noise suppression are arranged at symmetrical positions with respect to a connector connected to an external circuit (device) as a connection interface via a cable. Even if the clock frequency of the connection interface that is a noise source and the operating frequency for wireless communication are close to each other, the noise level is reduced from the noise source to the antenna without reducing the waveform level of the signal of the connection interface. It is possible to reduce the noise current that flows out and to radiate a frequency component signal for wireless communication from which the noise component is suppressed from the antenna.

It is a block diagram which shows the structural example of the radio | wireless communication apparatus which concerns on the 1st Embodiment of this invention. It is a schematic diagram which shows the loop circuit of the loop shape arrange | positioned symmetrically regarding the unwanted current generation source of the radio | wireless communication apparatus shown in FIG. FIG. 3 is a circuit diagram showing an equivalent circuit of each of the first loop circuit and the second loop circuit shown in FIG. 2. It is a schematic diagram for demonstrating a mode that the unnecessary electric current of a radio | wireless communication apparatus at the time of applying the present technique relevant to this invention flows. 3 is a table showing circuit constant values of each element for simulating the noise radiation suppressing effect of the first and second loop circuits formed using each element of the wireless communication apparatus shown in FIG. 1. It is a graph which shows the simulation result of the noise radiation suppression effect in the case of the pattern 1 of FIG. FIG. 6 is a schematic diagram showing a current distribution at a frequency of 2442 MHz in the case of pattern 1 in FIG. 5. It is a graph which shows the simulation result of the noise radiation suppression effect in the case of the pattern 2 of FIG. FIG. 6 is a schematic diagram showing a current distribution at a frequency of 2442 MHz in the case of pattern 2 in FIG. 5. 6 is a graph showing a simulation result of the noise radiation suppression effect when the value of the circuit constant of each element of the wireless communication apparatus shown in FIG. 1 is changed from pattern 2 to pattern 3 in FIG. 5. It is a block diagram which shows the structural example of the radio | wireless communication apparatus which concerns on the 2nd Embodiment of this invention.

  Preferred embodiments of a wireless communication apparatus and noise suppression method according to the present invention will be described below with reference to the accompanying drawings. In addition, it is needless to say that the drawing reference numerals attached to the following drawings are added for convenience to each element as an example for facilitating understanding, and are not intended to limit the present invention to the illustrated embodiment. Yes.

(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 loop circuit having a loop shape composed of a plurality of elements or metal proximity portions and a slit portion of a substrate pattern is used as a noise suppression circuit for noise reduction to a wireless communication portion (antenna, antenna feeding portion). With regard to the transmission line of the source or noise, more specifically, regarding a connector which is a connection interface for connecting to an external circuit (device), the main feature is that two are arranged at symmetrical positions.

  Thus, in the wireless communication apparatus according to the present invention, even if the clock frequency of the connection interface, which is a noise source, is close to the operating frequency for wireless communication, measures such as a filter cannot be adopted. Even in such a case, it is possible to prevent the noise current from flowing out to the antenna without reducing the waveform level of the signal line of the connection interface serving as a noise source, and the frequency component of the signal for wireless communication can be reduced. It is possible to radiate from the antenna. That is, in the wireless communication apparatus according to the present invention, it is possible to reduce the interference wave radiated from the connection interface represented by USB (Universal Serial Bus) and improve the wireless communication quality.

(Configuration example of the first embodiment)
Next, a configuration example of the wireless communication apparatus according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration example in the vicinity of a connector of the wireless communication apparatus according to the first embodiment of the present invention, and shows a simplified simulation of a metal portion through which noise propagates. Note that the shape of the metal portion through which the noise propagates is not limited to the shape shown in FIG. 1, but the present invention can be applied, but here, the shape shown in FIG. 1 is shown as an example. Here, the connector is disposed on the board and constitutes a connection interface unit for connecting a circuit in the wireless communication device to an external circuit (device) via a cable.

  As shown in FIG. 1, an unnecessary current generation source 102, an element 103, an element 104, an element 105, and an element 106 that are noise sources are located near a connector 109 that is a connection interface installed on the board of the wireless communication apparatus 101. Is disposed on the substrate. Further, an antenna 107 and an antenna feeding point 108 that radiate radio waves of a frequency component for wireless communication are arranged at the end of the substrate outside the element 104 (that is, on the side opposite to the connector 109 side with respect to the element 104). In addition, a cable 110 for connecting to an external circuit (device) is connected to the connector 109.

  Here, the connector 109 of the connection interface and the circuit unit of the wireless communication apparatus 101 are electrically coupled to the element 103, the element 104, the element 105, the element 106, and the signal line of the connection interface, that is, the cable 110 portion. It is. Further, the GND (Ground) of the entire wireless communication apparatus 101 and the GND of the connection interface are separated. The reason for this is to prevent the occurrence of a fire or the like of the wireless communication apparatus 101 due to a failure of the AC adapter connected to supply power to the wireless communication apparatus 101 due to a short circuit between the power supply and GND. This is due to considerations.

  Note that the unnecessary current generation source 102 shown in FIG. 1 simulates a generation source of noise superimposed on the signal line of the connection interface, that is, the cable 110 and the connector 109.

  Further, the element 103, the element 104, the element 105, and the element 106 are electrical elements including capacitors and the like, and with respect to the connector 109, the element 103 and the element 104, and the element 105 and the element 106 are symmetrical on the substrate. It is arranged in the correct position. In other words, the element 103 and the element 104 are arranged so as to be symmetrical with respect to the unnecessary current generation source 102, and the element 105 and the element 106 are further arranged. The element 103 and the element 105 are connected in a loop by a slit formed as a pattern on the substrate. Similarly, the element 104 and the element 106 are connected in a loop by a slit formed as a pattern on the substrate. By such arrangement and connection of each element, a loop-shaped first loop circuit composed of the element 103 and the element 105 and a loop-shaped second loop circuit composed of the element 104 and the element 106 cause noise. With respect to the cable 110 of the source transmission line and the connector 109 of the noise source, that is, with respect to the unnecessary current generation source 102 of the noise radiation source, the state is arranged symmetrically.

  FIG. 2 is a schematic diagram showing loop-like loop circuits arranged symmetrically with respect to the unnecessary current generation source 102 of the wireless communication apparatus 101 shown in FIG. This loop-shaped loop circuit includes a first loop circuit 201 formed by the element 103, the element 105, and a slit on the substrate, and a second loop formed by the element 104, the element 106, and a slit on the substrate. The circuit 202 is used. FIG. 2 shows a state in which the first loop circuit 201 and the second loop circuit 202 are arranged symmetrically on the board with respect to the unnecessary current generation source 102, that is, the noise source connector 109. Yes. Here, for the first loop circuit 201 formed by the element 103, the element 105, and the slit on the substrate, the circuit constant values of the element 103 and the element 105 are set so as to resonate at the operating frequency for wireless communication. The circuit element including the slit adjusts the loop length of the first loop circuit 201. The same applies to the second loop circuit 202 formed by the element 104, the element 106, and the slit on the substrate.

  As a result, the first loop circuit 201 and the second loop circuit that are arranged in symmetrical positions with respect to the unnecessary current generation source 102 of the noise radiation source, that is, with respect to the noise transmission line cable 110 and the noise source connector 109. Since a vortex current is generated in 202 and the noise current flows in a vortex and circulates, it is suppressed that the noise current flows out to the surroundings. That is, the noise current from the unnecessary current generation source 102 of the noise radiation source circulates in each of the first loop circuit 201 and the second loop circuit 202, and the noise current flows outside the loop. There is a work that makes it difficult to leak.

FIG. 3 is a circuit diagram showing an equivalent circuit of each of the first loop circuit 201 and the second loop circuit 202 shown in FIG. 2, and a symmetrical positional relationship with respect to the unnecessary current generation source 102 which is a noise radiation source. Each loop length is also equal. In the equivalent circuit of FIG. 3, the capacitance of the equivalent capacitor C ₁ of the first loop circuit 201 and the capacitance of the equivalent capacitor C ₂ of the second loop circuit 202 are the same value, and the first loop circuit 201, Each of the two loop circuits 202 is set to a value that resonates at the operating frequency for wireless communication.

  With the configuration of the first embodiment shown in FIG. 1 as described above, it is possible to reduce noise with respect to a signal for wireless communication radiated from the antenna 107 without using a noise suppression method applying a shield or a filter. . Note that the number of elements included in each of the first loop circuit 201 and the second loop circuit 202 is two elements such as two elements 103 and 105 and two elements 103 and 105. The present invention is not limited to this case, and it goes without saying that an arbitrary number of elements may be used for each of the elements as long as the number is two or more that can form a loop circuit. .

  FIG. 4 is a schematic diagram for explaining a state in which an unnecessary current flows in the wireless communication device when the current technology related to the present invention is applied, and a configuration in the vicinity of the connector similar to the block configuration shown in FIG. Is shown. In the wireless communication apparatus 401 in the current technology shown in FIG. 4, unlike the case of FIG. 1, the noise radiation source unnecessary current generation source 102 is related, that is, the noise transmission line cable 110 and the noise source connector 109. The loop circuit by an element does not exist in the symmetrical position about. As a result, the noise current generated in the unwanted current generation source 102 of the noise radiation source, that is, the noise transmission line cable 110 and the noise source connector 109 is changed into the first current 402 and the second current as shown in FIG. As the current 403 of 2 is transmitted to the outer edge side of the substrate, it reaches the antenna 107 and affects the signal of the operating frequency for wireless communication. Furthermore, since the noise current also flows through the outer skin of the connected cable 110, the radiation noise from the cable 110 may also affect the signal of the operating frequency for wireless communication.

(Description of the effect of the first embodiment)
As described above, the wireless communication apparatus according to the first embodiment can achieve the following effects.

  FIG. 5 shows the noise emission of the first and second loop circuits formed using the elements 103, 104, 105, and 106 of the wireless communication apparatus 101 shown in FIG. 1 as the first embodiment. In order to simulate the suppression effect, it is a table showing the values of the circuit constants of the elements 103, 104, 105 and 106, and the values of the circuit constants of the elements 103, 104, 105 and 106, respectively. Is shown when pattern 1 and pattern 2 are changed. That is, in FIG. 5, the pattern 1 in which the element 103 and the element 104 are not provided and a capacitor of 100 pF is used for each of the element 105 and the element 106 is an example in which the first and second loop circuits are not formed. On the other hand, pattern 2 using a capacitor of 100 pF for each of the element 103, the element 104, the element 105, and the element 106 is an example in which the first and second loop circuits are formed.

  In the measurement method of the noise radiation suppression effect in this simulation, the amount of coupling between the unnecessary current generation source 102 and the antenna feeding point 108 is used, and the noise suppression effect increases as the value of the coupling amount decreases. To evaluate.

  The simulation results when using patterns 1 and 2 in FIG. 5 are shown in FIGS. Here, FIG. 6 is a graph showing the simulation result of the noise radiation suppression effect in the case of the pattern 1 of FIG. 5, and unlike the case shown in FIG. 2, the first loop circuit 201 and the second loop circuit are shown. The case where 202 is not formed is shown. FIG. 8 is a graph showing a simulation result of the noise radiation suppression effect in the case of the pattern 2 in FIG. 5, and shows a case where the first loop circuit 201 and the second loop circuit 202 in FIG. 2 are formed. Show. 6 and 8, the horizontal axis represents frequency, and the vertical axis represents the amount of coupling between the unnecessary current generation source 102 and the antenna feeding point 108.

  First, FIG. 6 showing a simulation result in the case of the pattern 1 in which the first and second loop circuits are not formed will be described. In FIG. 6, the coupling amount between the unnecessary current generation source 102 and the antenna feeding point 108 at the frequency of 2442 MHz indicated by reference numeral 2 is a relatively large value of −35.696 dB. Therefore, the current distribution at this time is as shown in FIG. FIG. 7 is a schematic diagram showing a current distribution at a frequency of 2442 MHz in the case of the pattern 1 of FIG. In the case of the pattern 1 in FIG. 5, since the first and second loop circuits using the elements (capacitors) are not formed, the unnecessary current generation source 102 of the cable 110 or the connector 109 is used as shown in FIG. The flowing current flows out to the edge of the substrate as a noise current and reaches the antenna 107.

  On the other hand, as for the simulation result in the case of the pattern 2 forming the first and second loop circuits 201 and 202, as shown in FIG. 8, the unnecessary current generating source 102 at the frequency 2442 MHz shown in FIG. And the antenna feeding point 108 is −52.140 dB, which realizes a significant reduction of the coupling amount by 16 dB or more than in the case of FIG. FIG. 9 is a schematic diagram showing a current distribution at a frequency of 2442 MHz in the case of the pattern 2 of FIG. In the case of the pattern 2 in FIG. 5, as shown in FIG. 9, a loop current flows through the first and second loop circuits 201 and 202 using the elements (capacitors). It is possible to effectively suppress the current flowing out to the substrate outer edge side.

  As can be seen from the above simulation results, the wireless communication apparatus 101 according to the first embodiment has the following effects. That is, the wireless communication apparatus 101 according to the first embodiment includes loop-shaped first and second loop circuits 201 and 202 each including a plurality of elements (capacitors) and a slit formed in a loop shape as a substrate pattern. As the noise reduction circuit, a configuration in which the noise source or the noise transmission line is arranged symmetrically is adopted. Thus, even if the clock frequency of the connection interface that is a noise source and the operating frequency for wireless communication are close to each other, the waveform level of the signal line of the connection interface is reduced to reduce the noise level. Therefore, it is possible to effectively radiate a signal having a frequency component to be radiated as a radio signal from the antenna 107.

  The circuit constant value of each element (element 103, element 104, element 105, element 106) forming the first and second loop circuits 201, 202 is the loop length or the clock frequency of the connection interface of the noise source. It can be changed to any value according to the operating frequency for wireless communication. In the case of the pattern 2 in FIG. 5, the capacitances of the capacitors of the element 103, the element 104, the element 105, and the element 106 are set to 100 pF. However, in the case of setting different circuit constant values, FIG. Show.

  That is, FIG. 10 shows a simulation result of the noise emission suppression effect when the circuit constant values of the elements 103 and 104 of the wireless communication apparatus 101 shown in FIG. 1 are changed from the pattern 2 to the pattern 3 in FIG. Here, a case is shown in which the capacitance of the two capacitors of the element 103 and the element 104 is changed from 100 pF to 3 pF. FIG. 10A is a table showing circuit constant values of the elements 103, 104, 105, and 106 in the pattern 3, and FIG. 10B shows the pattern 3 in FIG. 10A. It is a schematic diagram which shows the electric current distribution in frequency 2,442MHz in the case of.

  In FIG. 10 showing the simulation result in the case of the pattern 3 forming the first and second loop circuits, the coupling amount between the unnecessary current generation source 102 and the antenna feeding point 108 at the frequency of 2442 MHz indicated by reference numeral 2. Is −63.734 dB, and a further reduction of the coupling amount of 11 dB or more is realized compared to −52.140 dB in the case of the pattern 2 shown in FIG. That is, as compared with the case of the pattern 1 in which the first and second loop circuits are not formed, the coupling amount is reduced by about 28 dB, and noise emission can be greatly suppressed.

  Further, not only in the case where the frequency is 2,442 MHz, but also in the frequency 2,400 MHz which is slightly lower than 2,442 MHz, and in the frequency 2,484 MHz which is slightly higher than 2,442 MHz, FIG. As shown by reference numerals 1 and 3 in the graphs of FIGS. 8 and 10, respectively, substantially the same effect can be obtained.

  The noise emission suppressing effect as described above is not only the adjustment of the circuit constant values (for example, the capacitance value of the capacitor) of the two elements of the element 103 and the element 104, but also the two elements of the element 105 and the element 106. It is also possible to adjust the circuit constant value (for example, the capacitance value of the capacitor) and the loop lengths of the first and second loop circuits 201 and 202 so as to obtain an appropriate effect. .

(Configuration example of the second embodiment)
Next, a configuration example of a wireless communication apparatus according to the second embodiment of the present invention will be described. In the first embodiment, the first loop circuit 201 arranged symmetrically with respect to the noise transmission line cable 110 and the noise source connector 109, that is, the unnecessary current generation source 102 of the noise radiation source, Each of the two loop circuits 202 is formed by using, for example, a combination of the element 103 and the element 104 and a combination of the element 105 and the element 106 made of a capacitor. On the other hand, in the second embodiment, instead of using the combination of the element 103 and the element 104 and the combination of the element 105 and the element 106, a pair of conductive metals are arranged close to each other. A case where each of the first loop circuit and the second loop circuit is formed using the metal approaching portion will be described.

  FIG. 11 is a block diagram showing a configuration example of a wireless communication apparatus according to the second embodiment of the present invention, in which loop-shaped first and second loop circuits arranged symmetrically with respect to the unnecessary current generation source 102 Is also shown at the same time.

  As shown in FIG. 11, in the vicinity of the connector 109 serving as a connection interface installed on the substrate of the wireless communication device 301, an unnecessary current generation source 102 serving as a noise source, a metal approaching unit 302, a metal approaching unit 303, An approaching part 304 and a metal approaching part 305 are arranged on the substrate. Furthermore, an antenna 107 and an antenna feeding point 108 that radiate radio waves having a frequency component for wireless communication are disposed at the end of the board outside the metal approaching portion 303 (that is, opposite to the connector 109 side). The connector 109 is connected with a cable 110 for connecting to an external circuit (device). That is, the wireless communication device 301 of FIG. 11 uses a metal approaching portion 302, a metal approaching portion 303, instead of the elements 103, 104, 105, and 106 in the wireless communication device 101 of FIG. 1 of the first embodiment. The metal approaching part 304 and the metal approaching part 305 are used.

  Here, the connector 109 of the connection interface and the circuit unit of the wireless communication apparatus 301 are electrically coupled to the metal approach unit 302, the metal approach unit 303, the metal approach unit 304, the metal approach unit 305, and the connection interface. The signal line, that is, the cable 110 portion.

  Further, as described above, the metal approaching portion 302, the metal approaching portion 303, the metal approaching portion 304, and the metal approaching portion 305 are a pair of conductive metals that face each other and are arranged close to each other. The metal approaching part 302 and the metal approaching part 303, and the metal approaching part 304 and the metal approaching part 305 are arranged at symmetrical positions on the substrate. That is, the metal approaching part 302 and the metal approaching part 303 are arranged so that the positional relationship is symmetrical with respect to the unnecessary current generation source 102, and further, the metal approaching part 304 and the metal approaching part 305 are arranged. Then, the metal approaching portion 302 and the metal approaching portion 304 are connected in a loop shape by a slit formed as a pattern on the substrate to form a first loop circuit 306, and the metal approaching portion 303 and the metal approaching portion 303 A second loop circuit 307 is formed by connecting the approaching portion 305 in a loop shape with a slit formed in a loop shape as a pattern on the substrate.

  As a result, the first loop circuit 306 including the metal approaching part 302 and the metal approaching part 304 and the loop-like second loop circuit 307 including the metal approaching part 303 and the metal approaching part 305 transmit noise. With respect to the line cable 110 and the noise source connector 109, that is, with respect to the unnecessary current generation source 102 of the noise radiation source, the circuit is placed symmetrically. Here, in the first loop circuit 306 formed by the metal approaching part 302, the metal approaching part 304, and the slit on the substrate, the metal approaching part 302, the metal approaching so as to resonate at the operating frequency for wireless communication. The distance between the pair of metals in each of the portions 304 and the loop length of the loop circuit 306 are adjusted. The same applies to the second loop circuit 307 formed by the metal approaching portion 303, the metal approaching portion 305, and the slit on the substrate.

  That is, the first loop circuit 306 and the second loop circuit 307 are formed as symmetrical current loop circuits, and are set to resonate at a specific frequency, that is, an operating frequency for wireless communication. Therefore, when the frequency of the noise current from the unnecessary current generation source 102 of the noise radiation source, that is, the noise transmission line cable 110 or the noise source connector 109 is close to the specific frequency, the first It flows in the loop circuit 306 and the second loop circuit 307 in a vortex and is prevented from flowing out of the first loop circuit 306 and the second loop circuit 307, that is, to the outer edge side of the substrate. Therefore, even in a configuration that does not use an element as in the first embodiment, such as the wireless communication device 301 having a metal approaching portion as shown in FIG. Can be suppressed.

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

DESCRIPTION OF SYMBOLS 101 Wireless communication apparatus 102 Unwanted current generation source 103 Element 104 Element 105 Element 106 Element 107 Antenna 108 Antenna feeding point 109 Connector 110 Cable 201 First loop circuit 202 Second loop circuit 301 Wireless communication apparatus 302 Metal approach part 303 Metal approach Unit 304 metal approach unit 305 metal approach unit 306 first loop circuit 307 second loop circuit 401 wireless communication device 402 first current 403 second current

Claims (10)

A wireless communication device having on a substrate an antenna that radiates radio waves at an operating frequency for wireless communication, and a connector that forms a connection interface for connecting to an external circuit via a cable,
As a noise suppression circuit for suppressing the outflow of noise current from the connection interface to the antenna at a symmetrical position on the board with respect to the connector, the first loop circuit and the second loop circuit are respectively looped. Formed into a shape,
And each of said 1st loop circuit and said 2nd loop circuit is comprised so that it may resonate in the operating frequency for said radio | wireless communication. The radio | wireless communication apparatus characterized by the above-mentioned.   Each of the first loop circuit and the second loop circuit includes a plurality of electrical elements and a slit formed in a loop shape as a pattern on the substrate at a symmetrical position on the substrate with respect to the connector. The wireless communication apparatus according to claim 1, wherein the wireless communication apparatus is arranged and connected.   The wireless communication apparatus according to claim 2, wherein a capacitor is used as the electrical element for forming each of the first loop circuit and the second loop circuit.   Each of the first loop circuit and the second loop circuit includes a plurality of metal approaching portions each having a configuration in which a pair of conductive metals are arranged close to each other at symmetrical positions on the substrate with respect to the connector. The wireless communication device according to claim 1, wherein a slit formed in a loop shape is arranged and connected as a pattern on the substrate.   By adjusting the loop length of each of the first loop circuit and the second loop circuit, the value of the circuit constant of the electrical element, or the distance between a pair of metals of the metal approaching portion, the first loop circuit 5. The wireless communication apparatus according to claim 2, wherein the resonance frequency of each of the second loop circuits can be adjusted to an arbitrary value. A method for suppressing noise in a wireless communication device having on a substrate an antenna that radiates a radio wave at an operating frequency for wireless communication and a connector that forms a connection interface for connecting to an external circuit via a cable,
A first loop circuit and a second loop circuit are each formed in a loop shape in order to suppress the outflow of noise current from the connection interface to the antenna at a symmetrical position on the board with respect to the connector. ,
And each of said 1st loop circuit and said 2nd loop circuit is comprised so that it may resonate in the operating frequency for said radio | wireless communication. The noise suppression method characterized by the above-mentioned.   Each of the first loop circuit and the second loop circuit includes a plurality of electrical elements and a slit formed in a loop shape as a pattern on the substrate at a symmetrical position on the substrate with respect to the connector. The noise suppression method according to claim 6, wherein the noise suppression method is arranged and connected.   The noise suppression method according to claim 7, wherein a capacitor is used as the electrical element for forming each of the first loop circuit and the second loop circuit.   Each of the first loop circuit and the second loop circuit includes a plurality of metal approaching portions each having a configuration in which a pair of conductive metals are arranged close to each other at symmetrical positions on the substrate with respect to the connector. 7. The noise suppressing method according to claim 6, wherein a slit formed in a loop shape is arranged and connected as a pattern on the substrate.   By adjusting the loop length of each of the first loop circuit and the second loop circuit, the value of the circuit constant of the electrical element, or the distance between a pair of metals of the metal approaching portion, 10. The noise suppression method according to claim 7, wherein the resonance frequency of each of the loop circuit and the second loop circuit can be adjusted to an arbitrary value.

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