JP2012129271A - Noise suppression structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control noise current by being provided above a first power supply layer or a second power supply layer of a substrate.SOLUTION: A noise suppression structure includes at least two metal surfaces 111 and 113 provided separately from a first power supply layer or a second power supply layer. One end of the metal surface 111 is connected to the first power supply layer or the second power supply layer, and in addition, the metal surfaces 111 and 113 form a capacitance.

Description

  The present invention relates to a noise suppression structure. In particular, the present invention relates to a noise suppression structure that is provided on a first power supply layer or a second power supply layer of a substrate and controls a noise current.

  Wireless devices such as mobile phones and wireless personal computers have become widespread because of their convenience, and recently, they are becoming thinner and smaller, and more and more wireless systems are being installed.

  FIG. 14 shows an example of a known wireless utilization device 900. 14 (a) is a perspective view, FIG. 14 (b) is a view showing only the noise suppression structure 910, and FIG. 14 (c) is a lateral view thereof. The wireless device 900 includes at least an antenna unit 930 that transmits and receives radio waves for communication with a base station and the like, and a wireless circuit that processes a signal transmitted or received from the antenna unit 930 The unit 940 and the digital circuit unit 950 for processing a digital signal for data processing or the like are mounted on the printed circuit board 920.

  A ground layer 921 is disposed on the inner layer of the printed circuit board 920 and serves as a common ground for the wireless circuit unit 940 and the digital circuit unit 950.

  In addition, a noise suppression structure 910 is mounted on the printed circuit board 920 to suppress electromagnetic interference generated between the wireless circuit unit 940 and the digital circuit unit 950.

  In addition, a signal layer and a power supply layer are formed in the inner layer of the printed circuit board 920, and a pattern for transmitting a signal according to each purpose such as a digital signal and an analog signal is formed. The illustration is omitted here.

  In the wireless device 900, the wireless circuit unit 940 and the digital circuit unit 950 are mixed on the same printed circuit board 920 and are actually mounted with high density. Electromagnetic noise generated from 950 is mixed into the antenna unit 930 and the radio circuit unit 940, so that electromagnetic interference occurs and affects the reception characteristics of the antenna.

  That is, the digital circuit unit 950 handles a clock signal, a data bus signal, or the like whose fundamental wave is several tens of MHz or several hundreds of MHz. Of the noise in the high frequency band of such a signal, the reception band of the antenna (800 MHz band) If noise matching the 2 GHz band or the like is mixed into the antenna unit 930 or the wireless circuit unit 940, wireless characteristics such as antenna reception sensitivity are deteriorated.

  In addition, when the current from the antenna unit 930 is mixed into the digital circuit unit 950, mixing (mixing) of a transmission wave and a digital signal may occur, resulting in noise.

  As described above, in the wireless device 900, the current generated from the antenna unit 930, the wireless circuit unit 940, and the digital circuit unit 950 may behave like noise, and one circuit is connected via the common ground layer 921. From one part to the other circuit part.

  That is, mixing of noise current from the digital circuit unit 950 to the antenna unit 930 or the wireless circuit unit 940 and mixing of current from the antenna unit 930 or the wireless circuit unit 940 to the digital circuit unit 950 occurred.

  Electromagnetic interference due to noise mixing generated between the wireless circuit unit 940 and the digital circuit unit 950 as described above tends to become more prominent due to downsizing and thinning and mounting of a plurality of wireless systems. In order to ensure good communication quality, it has been desired to suppress electromagnetic interference between the radio circuit unit 940 and the digital circuit unit 950 to a lower level.

  Further, in the wireless device 900, since the use of multiple frequency bands has progressed due to the mounting of multiple wireless systems, a technique for varying the frequency for suppressing electromagnetic noise, such as fine-tuning the frequency for suppressing electromagnetic interference. Realization of was desired.

  In order to suppress electromagnetic interference, for example, Patent Document 1 proposes a configuration that focuses on a current flowing on a metal surface. In Patent Document 1, the noise suppression structure is disposed on the upper and lower layers of the metal surface (ground). However, since the configuration and principle of the upper and lower noise suppression structures are the same, the upper layer is the upper layer. Only the case where the noise suppression structure is provided will be described.

  As shown in FIG. 14, the known noise suppression structure 910 forms a metal surface 911 with respect to the ground layer 921 in order to suppress the current In flowing through the ground layer 921 of the printed circuit board 920, and ends of the metal surface 911. The short circuit surface 912 is formed. The length of the metal surface 911 is a resonator configuration set to λ / 4 (λ: wavelength) of a desired frequency. For this reason, the opening surface at the right end behaves electrically as an open end, and the input impedance has a high value.

  When the impedance is high, the current In flowing through the ground is difficult to flow, and mixing of electromagnetic noise from one side to the other side, that is, from the digital circuit unit 950 side to the wireless circuit unit 940 side is suppressed.

  As described above, the known noise suppression structure 910 includes the metal surface 911 so as to wrap the current flowing through the ground layer 921 of the printed circuit board 920, the short-circuit surface 912 at the terminal end, and the metal surface 911 serving as a transmission line. By adopting a resonator configuration in which the length is set to λ / 4 (λ: wavelength), the input impedance on the aperture surface side is set to a high value. Further, in such a noise suppression structure 910, it is difficult for the current from the line connected to the opening side to flow toward the line connected to the termination side, that is, electromagnetic noise is mixed from one to the other. It is suppressed.

Japanese Patent No. 3531621

  However, in the known noise suppression structure, since the metal surface serving as the transmission path is set to a length of λ / 4, the target frequency is fixed. With this structure, the noise suppression frequency can be varied. It was difficult. In addition, considering the application to small devices, it has been desired to reduce the size of the noise suppression structure.

  As described above, wireless devices have been equipped with a plurality of wireless systems, and a technique for changing the frequency for suppressing noise is required. However, although the known technology is effective for a single target frequency, it cannot be said that the frequency change is sufficient, and the noise suppression frequency can be changed while considering miniaturization. It has been desired to realize a noise suppression structure that can be used.

  In order to solve the above-mentioned problem, according to a first aspect of the present invention, there is provided a noise suppression structure provided on a first power supply layer or a second power supply layer of a substrate to control a noise current. It is composed of at least two metal surfaces spaced from one power supply layer or the second power supply layer, and one end of the metal surface is connected to the first power supply layer or the second power supply layer. At the same time, a capacitance is formed between the metal surfaces.

  In addition, as described above, the summary of the invention does not enumerate all necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.

  As is apparent from the above description, in the present invention, a capacitor is loaded on the open end of the metal surface forming the resonator, and the resonance frequency can be varied to enable noise suppression by the effect of the capacitor. Also, there is an advantage that downsizing can be realized as compared with a known structure.

It is a figure which shows an example of the noise suppression structure 110 which concerns on one Embodiment. It is a figure which shows the loading of a capacitor | condenser typically. It is a figure which shows the analysis result of the noise suppression structure 910 and the noise suppression structure 110 which concerns on one Embodiment of this invention. It is a figure which shows an example of the noise suppression structure 210 which concerns on other embodiment. It is a figure which shows an example of the noise suppression structure 310 which concerns on other embodiment. It is a figure which shows an example of the noise suppression structure 410 which concerns on other embodiment. It is a figure which shows an example of the noise suppression structure 510 which concerns on other embodiment. It is a figure which shows an example of the noise suppression structure 610 which concerns on other embodiment. It is a figure which shows the state which decomposed | disassembled the noise suppression structure. It is a figure which shows an example of the noise suppression structure 710 which concerns on other embodiment. It is a figure which shows the state which decomposed | disassembled the noise suppression structure 710. It is a figure which shows an example of the noise suppression structure 810 which concerns on other embodiment. It is a figure which shows the state which decomposed | disassembled the noise suppression structure. It is a figure which shows an example of the known radio | wireless utilization apparatus 900. FIG.

  Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the scope of claims, and are combinations of features described in the embodiments. Not all are essential to the solution of the invention.

  The printed board shown here is a multilayer printed board consisting of a plurality of layers, and an insulating dielectric material such as a glass epoxy material is embedded between each layer, but the illustration is omitted. is doing. In addition, since the via hole provided in the printed board has a configuration in which a conductive layer is formed around the air hole, the via hole penetrating the metal pattern is electrically connected to the metal pattern.

  FIG. 1 shows an example of a noise suppression structure 110 according to an embodiment. This shows a noise suppression structure 110 that suppresses a noise current in a printed circuit board of a wireless device. FIG. 1 (a) is a perspective view, and FIG. 1 (b) is a side view. 1C is a view of the metal surface 111 and the metal surface 113 constituting the noise suppressing structure 110 as viewed from above.

  The noise suppression structure 110 can vary the noise suppression frequency by forming a capacitance between the two metal surfaces 111 and 113. As a mounting position, it is disposed between the digital circuit unit and the wireless circuit unit in order to cut off the electromagnetic coupling between the wireless circuit unit and the digital circuit unit and prevent the mixing of both noise currents.

  The noise suppression structure 110 is formed on the ground layer 121 through which noise propagates, and the first metal surface 111 and the second metal surface 113 are located on the same plane. Short-circuit plate 112 is provided at the end of first metal surface 111, and ground pins 114 a and b (hereinafter collectively referred to as ground pin 114) are provided at both ends of second metal surface 113. Connected.

  The first metal surface 111 and the second metal surface 113 are arranged at a distance from each other at the end portion of the metal plate, and are not conductive in direct current. For this reason, both the metal surfaces 111 and 113 form a capacitor | condenser between the opposing edge parts, and come to have a capacitance.

  In this example, the first metal surface 111 and the second metal surface 113 form a comb-shaped pattern on a rectangular metal pattern. When actually mounted in a printed circuit board, both metal surfaces 111 and 113 are arranged in the same layer, and are arranged in a staggered manner so that the respective comb-shaped portions do not contact each other. By alternately mounting such comb-shaped shapes, capacitors formed between the comb-shaped portions of the first metal surface 111 and the comb-shaped portions of the second metal surface 113 are formed in a zigzag shape so as to follow the comb shape. Is done.

  Note that the short-circuit plate 112 actually has a plurality of via holes arranged in a row within the region. In the noise suppression structure 110, since the interval between adjacent via holes is set to a sufficiently small pitch with respect to the wavelength, it can be regarded as an electrically short-circuited state. Here, a plurality of such arranged in a narrow pitch is used. The via hole row is called a short-circuit plate 112. Further, since the noise suppression structure 110 is intended to suppress noise, it may be disposed on the power supply layer. However, here, the ground layer 121 is targeted, and a structure when mounted on the ground layer 121 is used. explain. Since the ground layer 121 applies a DC voltage to the power supply layer, it may be referred to as a second power supply layer. The original power supply layer is the first power supply layer, and the ground layer 121 is the second power supply layer. Although it may be handled as a power supply layer, the following description uses the expression ground layer 121.

  The noise suppression structure 110 can change a resonance frequency that enables noise suppression by a capacitor formed by two metal surfaces 111 and 113. The noise suppression structure 110 basically includes a resonator structure for setting a resonance frequency and a loaded capacitor structure for changing the resonance frequency. By loading the capacitor equivalently to the resonator, The resonance frequency can be varied (this also has an effect on the size reduction of the noise suppression structure 110).

  The basic principle of changing the frequency will be described below. Usually, the electric field in the λ / 4 type resonator has a distribution such that it takes a maximum at the open end and a minimum at the short-circuited end. That is, the electric field component is dominant compared to the magnetic field component in the vicinity of the open end, in other words, the electric field and the magnetic field have a relationship of electric field> magnetic field. The resonance frequency at this time is a frequency according to the quarter wavelength distribution formed by the electric field or magnetic field in the resonator.

  For this reason, when a capacitance component such as a capacitor is loaded near the open end, the electric field component is affected and its distribution changes. That is, the electrical length is equivalently changed and the resonance frequency is shifted. The present invention is characterized by a structure that realizes a variable resonance frequency and a reduction in size using such a principle to enable noise suppression.

  Considering the noise suppression structure 110, the first metal surface 111 and the short-circuit plate 112 are configured to form a resonator structure. That is, the first metal surface 111 acts as a transmission line having a resonance length, and the short-circuit plate 112 basically forms a short end of the resonator. The other end corresponding to the tip of the first metal surface 111 is not particularly treated, and acts as an open end when the first metal surface 111 has a resonance length of λ / 4 or the like. To do. At the open end, the electric field component is dominant compared to the magnetic field component, and the electric field strength is increased.

  On the other hand, the second metal surface 113 and the ground pins 114a and 114b at both ends of the second metal surface 113 serve as a capacitor structure loaded on the resonator. That is, when this loaded capacitor structure composed of the second metal surface 113 and the ground pin 114 is close to the open end of the resonator, the open end is primarily dominated by the electric field component. Electric field coupling occurs between the first metal surface 111 forming the resonator (comb portion) and the end of the second metal surface 113 forming the structure (comb portion). Therefore, a capacitor having a relatively high degree of coupling is formed in a region where the first metal surface 111 and the second metal surface 113 are opposed to each other. Moreover, since the opposing comb-shaped portions are mounted so as to be alternately inserted, the capacitor is formed in a zigzag shape along the comb shape, and the capacitance tends to increase. Since one end of the second metal surface 113 is grounded to the ground layer 121 by the ground pin 114, the formed capacitor is grounded to the ground layer 121.

  FIG. 2 schematically shows the loading of the capacitor. In the noise suppression structure 110, a capacitor is loaded on the tip of the first metal surface 111 that forms a resonator, and is grounded to the ground layer 121. The capacitor at this time is generated by the first metal surface 111 and the second metal surface 113 facing each other with a gap therebetween.

  The noise suppression structure 110 has a configuration in which a capacitor is loaded at the tip of the resonator. Therefore, when the capacitance component due to the capacitor is added near the open end, the electrical length is equivalently changed, and as a result, the resonance frequency is changed.

  FIG. 3 shows analysis results of a known noise suppression structure 910 and a noise suppression structure 110 according to an embodiment of the present invention. The calculation assumes a model in which a noise suppression structure is arranged between two metal plates consisting of the ground layer and power supply layer of the printed circuit board, and the S parameter (transmission characteristics) when the noise suppression structure is mounted on the ground layer. : S21) was determined. In this analysis, the result of the known noise suppression structure 910 is also shown for comparison, but the dimensions of the known noise suppression structure 910 and the noise suppression structure 110 according to an embodiment of the present invention are the same. That is, the dimension of the metal surface 911 in the known noise suppression structure 910, the dimension of the noise suppression structure 110 according to an embodiment of the present invention (the dimension obtained by adding the first metal surface 111 and the second metal surface 113), and the like. The conditions in the calculation were analyzed as the same model.

  The known noise suppression structure 910 resonates near 7 GHz where the S21 characteristic is minimized, and it can be seen that noise suppression is possible at this frequency. In contrast, in the noise suppression structure 110 according to an embodiment of the present invention, the resonance frequency is shifted to around 5 GHz, and it can be seen that the noise suppression frequency can be controlled to the low frequency side.

  From another viewpoint, when suppressing noise at a frequency of 5 GHz, the known noise suppression structure 910 resonates at a quarter wavelength, so that the length La (at 7 GHz) of the metal surface 911 at 7 GHz is reached. On the other hand, the length Lb (at 5 GHz) at 5 GHz needs to be long because it has a low frequency. On the other hand, the noise suppression structure 110 according to the embodiment of the present invention may have the same length La as that at 7 GHz even when the frequency is as low as 5 GHz. In comparison, downsizing is possible.

  As described above, the noise suppression structure 110 is configured such that a capacitor is loaded on the open ends of the metal surfaces 111 and 113 forming the resonator, and the resonance frequency can be varied by the effect of the capacitor. In addition, there is an advantage that downsizing can be realized as compared with the known noise suppression structure 910.

  FIG. 4 shows an example of a noise suppression structure 210 according to another embodiment. 4A is a perspective view, and FIG. 4B is a view when viewed from the side.

  In the noise suppression structure 210, the first metal surface 211 and the second metal surface 213 are provided with notches at the end portions of a rectangular shape, and the respective recesses and projections are inserted when mounting. It is not configured. In the noise suppression structure 110, the ends of the first metal surface 111 and the second metal surface 113 have a comb shape. However, the noise suppression structure according to the present invention includes the first metal surface and the second metal surface. Since the capacitor is formed at the end of the capacitor, a notch is formed in a part of the metal surfaces 211 and 213 as in the noise suppression structure 210, and the capacitor is disposed by facing each other. It may be formed.

  In order to obtain desired characteristics, the first metal surface 211 and the second metal surface 213 are arranged by adjusting the step size of the respective metal surfaces 211 and 213 and the gap size when facing each other. That's fine.

  The noise suppression structure 210 is different from the noise suppression structure 110 in the shape of the first metal surface 211 and the second metal surface 213, but the operating principle is the same, and resonance that enables noise suppression by the effect of the capacitor. The frequency can be varied, and the size can be reduced as compared with the known noise suppression structure 910.

  Since the noise suppression structure according to the present invention is characterized in that a capacitor is formed at the ends of the first metal surface and the second metal surface, the first metal surface and the second metal surface are flush with each other. You may arrange | position to the upper layer and the lower layer rather than arrange | positioning.

  FIG. 5 shows an example of a noise suppression structure 310 according to still another embodiment. FIG. 4A is a perspective view, and FIG. 4B is a surface when viewed from the side.

  In the noise suppression structure 310, a rectangular metal pattern is used for the first metal surface 311 and the second metal surface 313, and the first metal surface 311 and the second metal surface 313 are arranged in upper and lower layers so that the end portions of the metal surfaces 311 and 313 overlap each other. ing. In the case of the noise suppression structure 310, a region where the two metal surfaces 311 and 313 overlap through an insulating layer mainly forms a capacitor.

  In the noise suppression structure 310, a second metal surface 311 that functions as a loaded capacitor structure is disposed on the upper layer side of the first metal surface 311 that forms the transmission path of the resonator. In the noise suppression structure 110 and the noise suppression structure 210, the capacitor is formed in the horizontal direction in the same plane. However, like the noise suppression structure 310, the two metal surfaces 311 and 313 are arranged vertically, and the capacitor is arranged in the vertical direction. You may form in.

  FIG. 6 shows an example of a noise suppression structure 410 according to still another embodiment. As shown in FIG. 6, the first metal surface 411 and the second metal surface 413 may be turned upside down, and the second metal surface 413 may be disposed below the first metal surface 411.

  FIG. 7 shows an example of a noise suppression structure 510 according to still another embodiment. In the noise suppression structures 110 to 410, the second metal surface forming the loaded capacitor structure is grounded to the same ground layer as the first metal surface. However, as shown in FIG. It may be grounded. In FIG. 7, the ground layer 522 located at the uppermost layer is made transparent so that the configuration of the noise suppression structure 510 disposed between the ground layers 521 and 522 is easy to see.

  As described in the noise suppression structure 110, the noise suppression structure 510 forms a capacitance when the second metal surface 513 comes close to the tip portion of the first metal surface 511 forming the resonator. Even if the metal surface 513 is connected to the second ground layer 522 via the ground pins 514a and 514b, the operating principle does not change, and the first metal surface 511 and the tip end of the second metal surface 513 are not affected. Capacitance is formed, and the effect can be exerted without any effect.

  FIG. 8 shows an example of a noise suppression structure 610 according to still another embodiment. FIG. 8A regarding the noise suppression structure 610 is a perspective view, and FIG. 8B is a view when viewed from the side. FIG. 9 shows a state where the noise suppression structure 610 is disassembled.

  The noise suppression structure 610 has a common ground layer 621, and the same noise suppression structures 610a and 610b shown as the noise suppression structure 110 are arranged on the upper side and the lower side of the ground layer 621 so as to sandwich the ground layer 621. . That is, the first noise suppression structure 610a is formed above the ground layer 621, and the second noise suppression structure 610b is formed below the ground layer 621.

  The noise suppression structure 610 uses a noise suppression structure of the same principle as the noise suppression structure 110, but the noise suppression structure 610 is shown as the noise suppression structure 110 in consideration of mounting on an actual printed circuit board. Via holes 615a to 615p (hereinafter collectively referred to as via holes 615) are used instead of the short-circuit plate 112 and the ground pin 114, and via holes 615 are formed on the metal surfaces 611 and 613 and the ground surface 621 so as to correspond thereto. A via-hole connection hole 616 for electrical connection is formed.

  In the noise suppression structure 610, the first noise suppression structure 610a includes a first metal surface 611, a second metal surface 613, via holes 615a to 615f arranged in an array, and further via holes 23g and h. .

  In the first metal surface 611, via hole connection holes 616a to 616f are formed at the same positions as the via holes 615a to f, and the second metal surface 613 is also connected to the via holes 615g and h at the same positions as the via holes 615g and h. Holes 616g and h are provided respectively. The via hole connection holes 616a to 616f are arranged in an array. Similarly, in the ground layer 621, via hole connection holes 619a to 619f are provided at the same positions as the via holes 615a to f, and via hole connection holes 619g and h are provided at the same positions as the via holes 615g and h.

  On the other hand, the second noise suppression structure 610b includes a third metal surface 617, a fourth metal surface 618, and via holes 615i to 615p.

  Similarly to the first noise suppression structure 610a, the second noise suppression structure 610b has via hole connection holes 616i to 616n at the same positions as the via holes 615i to n on the third metal surface 617, and the fourth metal surface. 618 is provided with via hole connection holes 616o and p at the same positions as the via holes 615o and p, respectively.

  The first metal surface 611 is connected to the ground layer 621 through via holes 615a to 615f, and the second metal surface 613 is connected to the ground layer 621 through via holes 615g and h. Similarly, the third metal surface 617 and the fourth metal surface 618 are connected to the ground layer 621 through the via holes 615i to 615n and the via holes 615o and p, respectively.

  That is, in the noise suppression structure 610, the via holes 615a to 615f are connected to the via hole connecting holes 616a to 616f formed on the first metal surface 611 and the via hole connecting holes 619a to 619f formed on the ground layer 621. However, this is because each via hole 615 alone conducts via the via hole connection hole 616. Therefore, the via holes 615i to 615n are similarly connected to the via hole connecting holes 616i to n and the via hole connecting holes 619a to f, and the via holes 615o are similarly connected to the via hole connecting holes 616o at the same positions. And it is connected to the via hole connecting hole 619g and becomes conductive. Similarly, the via hole 615p is connected to the via hole connecting hole 616p and the via hole connecting hole 619h at the same position, and becomes conductive.

  In the noise suppression structure 610, the distance between the via holes 615a to 615f and the via holes i to n is sufficiently small with respect to the wavelength of the target frequency and arranged at a narrow pitch. Therefore, the first noise suppression structure 610 a and the second noise suppression structure 610 b arranged above and below the ground layer 621 may be equivalently equivalent to the structure of the noise suppression structure 110. The principle of operation is shown.

  Therefore, in the case of the noise suppression structure 610 as well, the resonance frequency that enables noise suppression can be varied by the effect of the capacitor, and the size can be reduced as compared with the known noise suppression structure 910. Since they are arranged in the upper and lower layers, a further suppressing effect can be expected for suppressing noise flowing through the ground layer 621.

  FIG. 10 shows an example of a noise suppression structure 710 according to still another embodiment. FIG. 10A regarding the noise suppression structure 710 is a perspective view, and FIG. 10B is a view when viewed from the side. FIG. 11 shows a state where the noise suppression structure 710 is disassembled.

  The noise suppression structure 710 is obtained by arranging the noise suppression structure 510 above and below the ground layer. The basic structure arranged above and below is the same as that of the noise suppression structure 510, but the target ground layer of the via hole 715 is different, and the via holes 715g and h connected to the second metal surface 713 are ground layers disposed on the upper layer side. The via holes 715o and p connected to the layer 722 and connected to the fourth metal surface 718 are connected to the ground layer 723 arranged on the lower layer side. Since the principle of operation is the same, the noise suppression structure 710 is particularly effective in a multilayer printed circuit board having a plurality of ground layers.

  FIG. 12 shows an example of a noise suppression structure 810 according to still another embodiment. 12A is a perspective view, and FIG. 12B is a view when viewed from the side. FIG. 13 shows a state where the noise suppression structure 810 is disassembled. In FIG. 13, the noise suppression structure 810b below the ground layer 821 is not shown, and only the noise suppression structure 810a above is shown.

  The noise suppression structure 810 uses the metal surface of the noise suppression structure 310 or the noise suppression structure 410, and connects the via holes 815g and h to the upper ground layer 822 like the noise suppression structure 710, and connects the via holes 815o and p to the lower layer side. It is connected to the ground layer 823, and such a structure is also effective.

  While the noise suppression structure according to the present invention has been described above, the structure may be used in various ways depending on the application.

  In the noise suppression structures 110 to 810, the example in which the noise suppression structure is disposed on the ground layer has been described. However, if the metal pattern propagates noise, it may be used other than the ground layer. Even if applied to it, it will be effective.

  Further, for example, in the noise suppression structure 110, the ground pins 114a and 114b are connected to the ground layer 121 on the second metal surface 113. In the present invention, a capacitor is provided on the first metal surface 111 forming the resonator. Since it is sufficient that the resonance frequency can be varied by being loaded, the ground pins 114a and 114b may be deleted if a capacitance that can be varied is obtained.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

110 Noise suppression structure 111 First metal surface 112 Short-circuit plate 113 Second metal surface 114 Ground pin 121 Ground layer 210 Noise suppression structure 211 First metal surface 212 Short-circuit plate 213 Second metal surface 214 Ground pin 221 Ground layer 310 Noise suppression structure 311 First metal surface 312 Short plate 313 Second metal surface 314 Ground pin 321 Ground layer 410 Noise suppression structure 411 First metal surface 412 Short plate 413 Second metal surface 414 Ground pin 421 Ground layer 510 Noise suppression structure 511 First metal surface 512 Short-circuit plate 513 Second metal surface 514 Ground pin 521 Ground layer 522 Ground layer 610 Noise suppression structure 611 First metal surface 613 Second metal surface 615 Via hole 616 For via hole connection Hole 617 third metal surface 618 fourth metal 619 Via hole connection hole 621 Ground layer 710 Noise suppression structure 711 First metal surface 713 Second metal surface 715 Via hole 716 Via hole connection hole 717 Third metal surface 718 Fourth metal surface 719 Via hole connection hole 721 Ground Layer 722 ground layer 723 ground layer 810 noise suppression structure 811 first metal surface 813 second metal surface 815 via hole 816 via hole connection hole 817 third metal surface 818 fourth metal surface 819 via hole connection hole 821 ground layer 822 Ground layer 823 Ground layer

Claims (9)

A noise suppression structure for controlling a noise current provided on the first power supply layer or the second power supply layer of the substrate,
It is composed of at least two metal surfaces spaced apart from the first power supply layer or the second power supply layer, and one end of the metal surface is the first power supply layer or the second power supply layer. The noise suppression structure is characterized in that a capacitance is formed between the metal surfaces.   The noise suppression structure according to claim 1, wherein an insulator is disposed between the metal plates and is non-contact in direct current.   3. The noise suppression according to claim 1, wherein the first power supply layer or the second power supply layer is a power supply layer to which direct current power is supplied or a ground layer that acts as a ground in the substrate. Construction.   The two metal surfaces are a first metal surface and a second metal surface having a comb structure on a flat plate, and one end of each of the first metal surface and the second metal surface is connected through a connecting portion. The comb structure connected to the first power supply layer or the second power supply layer and located at one end on the opposite side of the first power supply layer or the second power supply layer enters each other with the comb portions facing each other alternately. The noise suppression structure according to any one of claims 1 to 3, wherein the noise suppression structure is non-contact.   The noise suppression structure according to any one of claims 1 to 3, wherein the metal surface has a shape in which a notch is provided in a part of a rectangular shape.   4. The noise suppression structure according to claim 1, wherein a capacitor is formed by arranging the two metal surfaces in an upper layer and a lower layer. 5.   A first filter provided above the first power supply layer or the second power supply layer and a second filter provided below the ground layer are the first power supply layer or the second filter. The noise suppression structure according to claim 3, wherein the power supply layers are arranged so as to be sandwiched in common.   The first power supply layer or the second power supply layer is disposed in a multilayer printed circuit board having at least three layers in the substrate, and the first filter is located between the upper layer and the intermediate layer. The noise suppression structure according to claim 7, wherein the second filter is located between the intermediate layer and the lower layer.   The first metal surface is connected to the first power supply layer, and the second metal surface is connected to an upper layer or a lower layer of the power supply layer. Noise suppression structure.

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