JP5012407B2 - Common mode current suppression filter using EBG material - Google Patents

Description

  The present invention relates to a common mode current suppression filter, and more specifically, a high-frequency noise current generated inside a printed circuit board is applied to a cable connected to the connector via a connector installed on the printed circuit board. The present invention relates to a common mode current suppression filter that suppresses propagation using an electromagnetic band gap (hereinafter referred to as “EBG”) material.

  In recent years, EBG materials have been developed with the development of technology, and for example, proposed to be used as a means for preventing electromagnetic interference between circuits caused by unnecessary electromagnetic waves radiated from a high-frequency circuit. Here, “EBG material” has a structure in which dielectrics or conductors are periodically arranged two-dimensionally or three-dimensionally in a broad sense, and the two-dimensional direction or three-dimensional direction of electromagnetic waves in a specific frequency band. A material or structure having a function of suppressing or greatly attenuating the propagation of.

  As one form of use of the EBG material, a high-impedance surface (hereinafter referred to as “HIS”) is disclosed in Patent Document 1 (US Pat. No. 6,262,495B1) and Patent Document 2 (US Pat. No. 6, 483, 481B1) and the like.

  17 to 19 show the structure of a conventional HIS, and FIG. FIG. 18 is a cross-sectional view of a conventional HIS described in FIG. FIG. 19 is a top view of a conventional HIS disclosed in FIG. The top view of the conventional HIS described in 3a is shown respectively.

  The conventional HIS 1 shown in FIG. 17 has the following structure. That is, the HIS 1 is configured by periodically arranging a plurality of conductor elements 4 having a thumbtack-like shape above the ground plane 5. Each of the conductor elements 4 includes a conductor piece 2 and a conductor column 3 having an upper end connected to the conductor piece 2. Each of the conductor elements 4 is electrically connected to the ground plane 5 at the lower end (that is, the other end of the conductor pillar 3). Each conductor piece 2 is disposed on the upper surface of the dielectric plate 6. The ground plane 5 is disposed on the lower surface of the dielectric plate 6. Each conductor pillar 3 passes through the dielectric plate 6 in the thickness direction and reaches the ground plane 5. Examples of the planar shape of the conductor piece 2 include a regular hexagon shown in FIG. 18 and a square shown in FIG.

  As shown in FIG. 20, the conventional HIS 1 shown in FIG. 17 has a series capacitance C generated between two adjacent thumbtack-like conductor elements 4 and a parallel generated from each conductor element 4 and the ground plane 5. The inductance L can be considered as a distributed constant circuit distributed two-dimensionally. In the HIS1, in the vicinity of the resonance frequency of the resonance circuit composed of the inductance L and the capacitance C, the impedance is increased to suppress the propagation of the surface current, and the bandwidth (bandgap bandwidth) in which the propagation of the surface current is suppressed. ) Is proportional to the reciprocal of the capacity C is disclosed in Patent Document 1 and the like.

  When the filter is configured by the HIS 1, the area occupied by the HIS 1 can be reduced by setting the size of each conductor piece 2 small while maintaining the product value of the series capacitance C and the parallel inductance L. Also, by setting the parallel inductance L of the HIS 1 large, it is possible to widen the band gap bandwidth of the filter.

  A method for increasing the parallel inductance L of the HIS 1 has already been disclosed. For example, FIG. 3 of Patent Document 3 (US Pat. No. 6,933,895 B2). 13 and Patent Document 4 (Japanese Patent Laid-Open No. 2006-253929), a dielectric having a two-layer structure between the conductor piece 2 and the ground plane 5 as in the HIS 1a shown in FIG. A plate, that is, a first dielectric plate 16 and a second dielectric plate 26 are arranged, and a plurality of conductor pieces 2 are periodically arranged on the upper first dielectric plate 16, and the lower second dielectric plate 26. A plurality of inductance elements 8 are periodically arranged on the top. Therefore, the inductance element 8 is located between the first dielectric plate 16 and the second dielectric plate 26. The ground plane 5 is formed on the lower surface of the second dielectric plate 26.

  The plurality of conductor pieces 2 and the plurality of inductance elements 8 are electrically connected to each other in a one-to-one manner by a plurality of first conductor columns 7 penetrating the first dielectric plate 16. The plurality of inductance elements 8 and the ground plane 5 are electrically connected by a plurality of second conductor columns 17 that penetrate the second dielectric plate 26.

  FIG. 22 shows an equivalent circuit diagram of the conventional HIS 1a shown in FIG. In the conventional HIS 1a, the parallel inductance L is increased as compared with the conventional HIS 1 shown in FIG. 17 by inserting and arranging the plurality of inductance elements 8 between the plurality of conductor pieces 2 and the ground plane 5 in this way. be able to.

  As the inductance element 8 used in the conventional HIS 1a, for example, the spiral coil 18 shown in FIG. 23 or the meander coil 28 shown in FIG. 24 can be used. However, other than these, for example, a surface acoustic wave resonator, a bulk acoustic wave resonator, or the like can be used as the inductance element 8.

  Examples in which the EBG material is applied as a countermeasure for the electromagnetic interference problem are disclosed in, for example, Patent Document 3 and Patent Document 5.

  In the technique disclosed in Patent Document 3, an EBG material is used for a ground plane in order to prevent interference between two antennas via a surface current.

  In the technique disclosed in Patent Document 5, an EBG material is used for a part of the inner wall of the casing. In the first place, when various functions are integrated in the high-frequency circuit inside the housing, unnecessary electromagnetic radiation is generated in the housing, and signals between each function interfere with each other, adversely affecting the characteristics of the entire high-frequency circuit. There is a problem of affecting. By using EBG material for the inner wall of the housing on the side facing the high-frequency circuit, unnecessary electromagnetic radiation in the housing can be prevented, so the characteristics of the high-frequency circuit change even when the inner wall of the housing is close to the high-frequency circuit. Without downsizing, the housing can be downsized.

One of the causes of electromagnetic interference, which has become a problem in recent years, is that high-frequency noise current generated inside the printed circuit board propagates to the cable connected to the connector via the connector installed on the printed circuit board. And unnecessary electromagnetic radiation generated from the cable. Conventionally, as a countermeasure against common mode noise for such a cable, for example, a shield technology such as covering a printed circuit board to which the cable is connected with a shield box, or mounting a connector with a metal cover for shielding at one end of the cable, etc. Is adopted.
US Pat. No. 6,262,495B1 (FIG. 1, 2a, 2b) US Pat. No. 6,483,481B1 (FIG. 2a, 3a) US Pat. No. 6,933,895 B2 (FIG. 13) JP 2006-253929 A (FIG. 1) JP 2004-22587 A (FIG. 1)

  The above-described conventional shielding technique used as a method for suppressing unnecessary electromagnetic radiation from the cable on the printed circuit board has a problem that the manufacturing cost is high. Such an electromagnetic radiation shield is preferably executed in a printed circuit board which is a source of high frequency noise. Therefore, when an electromagnetic radiation shielding method that can be realized in a printed circuit board is studied, a desired electromagnetic radiation shielding function can be obtained by arranging the conventional HIS 1 shown in FIG. 17 around the connector provided on the printed circuit board. It seems to be possible to realize a common mode current suppression filter having

  For example, in a printed circuit board having two or more conductor layers, a plurality of conductor pieces 2 are periodically arranged in a two-dimensional manner on a certain conductor layer and separated from the conductor layer by a dielectric plate 6. Another conductor layer is used as the ground plane 5, and a plurality of conductor pillars 3 that are electrically interconnected between each conductor piece 2 and the ground plane 5 are formed as through vias whose inner peripheral surfaces are covered with a conductive film. If it is formed using (through via hole), there is a possibility that a desired common mode current suppression filter can be realized.

  In this case, the area occupied by the HIS 1 functioning as a common mode current suppression filter can be reduced by forming each conductor piece 2 small while maintaining the product of the series capacitance C and the parallel inductance L in the conventional HIS 1.

  In addition, the band gap bandwidth of the common mode current suppression filter can be increased by increasing the parallel inductance L of the conventional HIS1. However, when trying to realize a wideband common mode current suppression filter having a desired bandgap bandwidth using HIS1, it is necessary to lengthen the conductor column 3 of HIS1 in order to increase the parallel inductance L. The thickness of the HIS 1 increases with the increase in the size, which is against the request for downsizing the filter.

  Therefore, in order to realize a small and wideband common mode current suppression filter using the HIS 1, the parallel inductance L is maintained while maintaining both the area of each conductor piece 2 and the distance from each conductor piece 2 to the ground plane 5. Need to be increased.

  Here, as a method of increasing the parallel inductance L, it is possible to adopt the structure of the conventional HIS 1a shown in FIG. However, in that case, a connection point 15 between each inductance element 8 and the corresponding first conductor column 7 and a connection point 25 between the inductance element 8 and the corresponding second conductor column 17 are electrically connected. Need to be separated. The reason is that if the first conductor column 7 and the second conductor column 17 are integrally formed using the through via, the connection point 15 and the connection point 25 are electrically short-circuited, and the parallel connection by the inductance element 8 is performed. This is because the inductance L is not increased. Therefore, the first conductor pillar 7 and the second conductor pillar 17 cannot be formed using the through via.

  A known build-up process can be used as a method of manufacturing a printed circuit board from which the first conductor pillar 7 and the second conductor pillar 17 in an electrically separated state can be obtained. However, the use of a build-up process raises the problem of increasing the manufacturing cost of the printed circuit board itself.

  Thus, in order to increase the parallel inductance L and increase the band gap bandwidth, it is not preferable to adopt the structure of the conventional HIS 1a shown in FIG. The parallel inductance L needs to be increased by other methods.

  The present invention has been made in consideration of the above points, and the object of the present invention is that a high frequency noise current generated inside the printed circuit board is connected to a connector installed on the printed circuit board. Propagating to a cable connected to the connector via the connector can suppress unnecessary electromagnetic radiation emitted from the cable, and can also propagate high-frequency noise current from the cable to the printed circuit board. An object of the present invention is to provide a common mode current suppression filter using an EBG material that can be suppressed and can be reduced in size to have no practical problem.

  Another object of the present invention is to provide a common mode current suppression filter using an EBG material that can obtain the above-described electromagnetic radiation suppression function over a wide band.

  Still another object of the present invention is to provide a common mode current suppression filter using an EBG material that can be mounted using an inexpensive multilayer printed circuit board.

  Other objects of the present invention which are not specified here will become apparent from the following description and the accompanying drawings.

(1) The common mode current suppression filter of the present invention includes:
A common mode current suppression filter provided on a printed circuit board having a connector on its surface,
A high-impedance surface (HIS) made of an electromagnetic bandgap material (EBG material) having a bandgap that prevents propagation of electromagnetic waves in a predetermined frequency band is formed in the periphery of the connector on the surface of the printed circuit board. And
The high impedance surface (HIS)
A plurality of first conductor pieces periodically disposed on a first conductor layer of the printed circuit board;
A ground plane formed in the second conductor layer of the printed circuit board;
A plurality of first pillars with conductors for electrically connecting each of the first conductor pieces and the ground plane;
Each of the first pleated conductor columns includes a first columnar conductor (for example, a through via with a conductive film) extending between the first conductor layer and the second conductor layer of the printed circuit board; A first fold conductor (for example, an inner layer fold conductor piece) attached to the first columnar conductor;
The thickness of the first pleated conductor is at least twice the skin depth in a desired bandgap frequency band.

  In the common mode current suppression filter of the present invention, as described above, a high impedance surface (HIS) made of an electromagnetic bandgap material (EBG material) is disposed around the connector on the surface of the printed circuit board. Thus, propagation of high-frequency noise current that occurs inside the printed circuit board and flows through the ground plane to the connector is suppressed. For this reason, unnecessary electromagnetic radiation emitted from the cable can be suppressed by propagating the high-frequency noise current to the cable connected to the connector via the connector.

  At the same time, since the propagation of the high-frequency noise current transmitted to the cable by unnecessary external electromagnetic waves from the connector to the ground plane is suppressed, the propagation of the high-frequency noise current from the cable to the printed circuit board is suppressed. Can also be suppressed.

  Therefore, it is possible to prevent the operating characteristics of the internal circuit of the printed circuit board from being affected by the high frequency noise current flowing through the ground plane.

  Furthermore, the high impedance surface includes a plurality of first conductor pieces periodically disposed on the first conductor layer of the printed circuit board, a ground plane formed on the second conductor layer of the printed circuit board, A plurality of first pleated conductor columns that electrically connect each of the first conductor pieces and the ground plane are provided. Each of the first pleated conductor columns includes a first columnar conductor extending between the first conductor layer and the second conductor layer of the printed circuit board, and a first columnar conductor mounted on the first columnar conductor. The first inner layer conductor conductor piece has a thickness that is at least twice the skin depth in the desired band gap frequency band. For this reason, the high-frequency noise current flowing through the ground plane formed on the second conductor layer of the printed circuit board bypasses the surface of each of the first inner layer fold conductor pieces, and the first conductor of the printed circuit board. It flows to the first conductor piece in the layer. Therefore, the magnetic flux generated in the current path by the high-frequency noise current is increased as compared with the conventional high impedance surface without the first inner layer conductor conductor piece. In general, since the parallel inductance of the high impedance surface is proportional to the magnetic flux generated therein, this means that the parallel inductance increases.

  In the common mode current suppression filter of the present invention, the parallel inductance can be increased without increasing the length of the through via (the pleated conductor pillar) of the printed circuit board for the above reasons. Can be made thinner. Further, if the first conductor piece is reduced in size in accordance with the increase in parallel inductance, the area occupied by the first conductor piece on the surface of the printed circuit board is reduced. Therefore, it is easy to downsize the common mode current suppression filter to a size that does not cause a problem in practice.

  If the band gap bandwidth may be narrowed, the size of the first conductor piece can be further reduced by increasing the series capacitance simultaneously with the parallel inductance, so that the common mode current suppression filter can be further reduced in size. Is possible. On the other hand, if the series capacitance is decreased in accordance with the increase of the parallel inductance, the band gap bandwidth can be increased accordingly, so that the electromagnetic radiation suppressing function described above can be obtained over a wide band.

  Furthermore, since the first pleated conductor post can be formed using the through via of the printed circuit board and the first inner layer crease conductor piece, it is not necessary to use an expensive build-up process. Therefore, it is possible to mount the common mode current suppression filter using an inexpensive multilayer printed circuit board.

  (2) In a preferred example of the common mode current suppression filter of the present invention, the first conductor piece is disposed on the front surface or inner layer of the printed circuit board, and the ground plane is the back surface of the printed circuit board or the first conductor piece. The first columnar conductor is formed using a through via extending from the back surface of the printed circuit board to the surface thereof.

(3) In another preferred example of the common mode current suppression filter of the present invention, a plurality of third conductor layers of the printed circuit board between the first conductor layer and the second conductor layer of the printed circuit board are provided. The second conductor pieces are periodically arranged,
Each of the second conductor pieces and the ground plane are electrically interconnected by a plurality of second pleated conductor posts,
Each of the second pleated conductor pillars includes a second pillar conductor (for example, a through via with a conductive film) extending between the third conductor layer and the second conductor layer of the printed circuit board, A second fold conductor (for example, an inner layer fold conductor piece) attached to the second columnar conductor;
The thickness of the second pleat conductor is at least twice the skin depth in a desired band gap frequency band,
The first layer conductor pieces and the second layer conductor pieces are arranged so as to partially overlap when viewed from above.

  (4) In still another preferred example of the common mode current suppression filter of the present invention, the first crease conductor of the first crease conductor column is centered on the corresponding first columnar conductor (for example, a through via). Further, it has a planar shape including a circle having a predetermined radius, and is arranged so as not to overlap with the other adjacent first crease conductors.

  (5) In still another preferred example of the common mode current suppression filter of the present invention, the first conductor pieces adjacent to each other are arranged in mesh with each other.

  (6) In still another preferred example of the common mode current suppression filter of the present invention, the first conductor piece and the first pleated conductor column are on a plurality of concentric circles or concentric arcs centered on the connector or in the vicinity thereof. It arrange | positions periodically along the moving radius of these concentric circles or concentric circular arcs.

  (7) In the example of (6), preferably, the second conductor piece and the second pleated conductor column are also arranged on a plurality of concentric circles or concentric arcs centered on the connector or the vicinity thereof. It arrange | positions periodically along the moving radius of a concentric circular arc.

  (8) In still another preferred example of the common mode current suppression filter of the present invention, each of the first conductor pieces has a substantially equal length of a side in contact with the other adjacent first conductor piece.

  (9) In still another preferred example of the common mode current suppression filter of the present invention, the dielectric plate of the printed circuit board is formed using an insulating magnetic material.

  According to the common mode current suppression filter of the present invention, (a) the high frequency noise current generated inside the printed circuit board is transmitted to the cable connected to the connector via the connector installed on the printed circuit board. Propagation can suppress unwanted electromagnetic radiation emitted from the cable, and can also suppress the propagation of high-frequency noise current from the cable to the printed circuit board. The size can be reduced to a small size, (b) the above-described electromagnetic radiation suppressing function can be obtained over a wide band, and (c) an inexpensive multilayer printed circuit board can be used for mounting. can get.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
1 to 5 show a common mode current suppression filter according to a first embodiment of the present invention formed on a printed circuit board. This common mode current suppression filter is configured using the HIS101.

  1 is a top view showing a common mode current suppression filter (HIS) according to a first embodiment of the present invention formed (mounted) on a printed circuit board, FIG. 2 is a partial sectional view thereof, and FIG. 3 is a partially enlarged view thereof. FIG. 4 is a top view, FIG. 4 is a perspective view of a conductor element used in the filter, and FIG.

  The common mode current suppression filter of the first embodiment shown in FIGS. 1 to 5 is configured by a HIS 101 formed on a printed circuit board 100. The HIS 101 is a form of EBG material having a structure in which dielectrics or conductors are periodically arranged two-dimensionally or three-dimensionally. HIS (EBG material) has a function of suppressing or greatly attenuating propagation of electromagnetic waves in a specific frequency band in a two-dimensional direction or a three-dimensional direction.

  The HIS 101 constituting the common mode current suppression filter of the first embodiment surrounds the three directions of the connector 108 around the connector 108 provided in the vicinity of one end portion of the surface of the printed circuit board 100. Is formed.

  As shown in FIGS. 1 to 3, the HIS 101 includes a plurality of conductor elements 104 periodically arranged on the printed circuit board 100, and these conductor elements 104 (that is, a first layer conductor piece 102 described later). The layout is a substantially U-shaped two-dimensional periodic arrangement as shown in FIG. The conductor element 104 does not exist in the direction in which the cable 109 connected to the connector 108 extends. A predetermined distance is provided between the conductor element 104 (ie, the HIS 101) and the connector 108, and thus the conductor element 104 (HIS 101) is separated from the connector 108. The planar shape of each conductor element 104 (first layer conductor piece 102) is square as clearly shown in FIG.

  The HIS 101 has a cross-sectional structure as shown in FIG. 2 and is formed using a conductor layer of the printed circuit board 100 and a dielectric plate.

  The printed circuit board 100 is configured by alternately arranging first to fifth conductor layers and first to fourth dielectric plates 106. The first conductor layer (uppermost conductor layer) on the surface of the printed circuit board 100 is formed with a plurality of first layer conductor pieces 102 arranged periodically, and the fifth conductor layer (lowermost layer) on the back surface thereof. The entire conductor layer is a ground plane 5. The second to fourth conductor layers arranged between the first layer conductor piece 102 and the ground plane 5 are respectively formed with conductor pieces, and these three conductor pieces are respectively inner layer fold conductor pieces 123. This corresponds to the “please conductor”.

  The printed circuit board 100 is further formed with a plurality of through vias 107 that penetrate the printed circuit board 100 in the thickness direction. Each through via 107 passes through the first to fifth conductor layers and the first to fourth dielectric plates 106, and extends from the front surface to the back surface of the printed circuit board 100. Openings are formed in the first conductor layer and the fifth conductor layer of the printed circuit board 100, respectively. Since the inner peripheral surface of each through via 107 is covered with a conductive film, each through via 107 can be said to be a through via with a conductive film. Each through via 107 with a conductive film corresponds to a “columnar conductor”.

  As shown in FIGS. 2 and 4, the three-layer inner fold conductor pieces 123 formed in the second to fourth conductor layers are arranged in a bowl shape around the corresponding through vias 107, and It is mechanically and electrically connected to the conductor film on the inner peripheral surface of the through via 107. The through via 107 and the three-layer inner pleated conductor piece 123 connected and integrated in this way constitute a pleated conductor column 103. The pleated conductor pillar 103 having such a configuration can be easily formed by forming a through via 107 in the printed circuit board 100 and plating a conductive film on the inner peripheral surface thereof. The upper end of the pleated conductor pillar 103 (through via 107) is mechanically and electrically connected to the corresponding first layer conductor piece 102 to form a thumbtack-like conductor element 104. The lower end of the pleated conductor pillar 103 (through via 107) is mechanically and electrically connected to the ground plane 5 (fifth conductor layer).

  In the HIS 101 of the first embodiment, the printed circuit board 100 includes the first layer conductor piece 102 in the uppermost first conductor layer, the inner layer conductor conductor piece 123 in the second to fourth conductor layers, and the lowermost layer. The ground plane 5 is provided in the fifth conductor layer, and the multi-layer structure has five conductor layers. However, the present invention is not limited to this, and the conductor layer has three or more conductor layers. A multilayer printed circuit board can be used as the printed circuit board 100.

  The thicknesses of the first layer conductor piece 102 and the inner layer conductor piece 123 of the conductor element 104 are both set to be twice or more the skin depth in the desired band gap frequency band. For example, when a copper plate is used as the conductor layer of the printed circuit board 100, the skin depth at 30 MHz is about 12 μm. Therefore, if the thickness of the copper plate used in the normal printed circuit board manufacturing process is 35 μm, at least Above 30 MHz, the condition that the thickness of the copper plate is at least twice the skin depth is satisfied. Even when a copper plate having a thickness of 15 μm is used, the condition that the thickness of the copper plate is twice or more the skin depth is satisfied at 100 MHz or higher.

  When the connector 108 provided on the printed circuit board 100 is electrically connected to the ground plane 5, when the cable 109 is connected to the connector 108, the ground portion of the cable 109 is electrically connected to the ground plane 5. Will be. Here, if the HIS 101 does not exist, the high frequency noise current I generated inside the printed circuit board 100 flows through the ground plane 5 and propagates to the cable 109 via the connector 108. However, since the HIS 101 in which a band gap appears in a desired frequency band is provided on the printed circuit board 100 in the periphery of the connector 108, the high-frequency noise current I flowing through the ground plane 5 is propagated to the connector 108. It is suppressed. For this reason, propagation of the high frequency noise current I to the cable 109 is also suppressed, and as a result, generation of unnecessary electromagnetic waves from the cable 109 can be suppressed.

  Further, when a high frequency noise current I flows through the ground portion of the cable 109 due to an external unnecessary electromagnetic wave, the high frequency noise current I propagates from the cable 109 to the ground plane 5 via the connector 108 in the same manner as described above. Is suppressed by.

  Therefore, it is possible to prevent a situation in which the circuit operation characteristics inside the printed circuit board 100 are affected by the high-frequency noise current I flowing through the ground plane 5.

  As described above, the HIS 101 has the inner layer fold conductor piece 123 having a thickness of twice or more the skin depth in a desired frequency band, so that the high frequency noise current I is as shown in FIG. As shown, the surface of each inner layer fold conductor piece 123 flows around in a meander shape. Assuming that the current path through which such a bypass current flows is 110, the magnetic flux generated in the current path 110 by the high-frequency noise current I flowing through the current path 110 increases as compared with the case where the inner layer fold conductor piece 123 is not provided. Generally, since the parallel inductance of the HIS is proportional to the magnetic flux Φ passing through it, the parallel inductance is increased in the HIS 101 of the first embodiment as compared with the case where the inner layer conductor conductor piece 123 is not provided.

  In the common mode current suppression filter according to the first embodiment, the HIS 101 having the above-described configuration is used. Therefore, the parallel inductance is increased without increasing the length of the through via 107 (the pleated conductor pillar) of the printed circuit board 100. Therefore, the printed circuit board 100 can be made thinner accordingly. In addition, since the series capacitance can be reduced in accordance with the increase in parallel inductance, the side length of the first conductor piece 102 can be shortened, and the first conductor piece 102 can be reduced in size. Become. As a result, the area where the first layer conductor piece 102 occupies the surface of the printed circuit board 100 is reduced. Therefore, it is easy to downsize the common mode current suppression filter to a size that does not cause a problem in practice.

  If it is desired to lower the bandgap frequency instead of narrowing the bandgap bandwidth, it can be realized by increasing the series capacitance simultaneously with the parallel inductance. Further, since the series capacitance per size of the same first layer conductor piece 102 is increased, the series capacitance can be obtained even if the first layer conductor piece 102 is further downsized. As a result, the common mode current suppression filter can be further reduced in size. On the other hand, if the series capacitance is decreased in accordance with the increase in parallel inductance, the band gap bandwidth can be increased accordingly, and thus the above-described electromagnetic radiation suppressing function can be obtained over a wide band.

  Furthermore, each creased conductor pillar 103 is formed using the through via 107 of the printed circuit board 100 and the inner crease conductor piece 123, so that it is not necessary to use an expensive build-up process. Therefore, it is possible to mount the common mode current suppression filter using an inexpensive multilayer printed circuit board.

  A part or all of the first to fourth dielectric plates 106 may be formed of an insulating high magnetic permeability material. In this case, there is an advantage that the parallel inductance is further increased.

(Modification of the first embodiment)
6 and 7 are diagrams showing examples of the planar shape of the inner layer fold conductor piece 123 used in the HIS 101 of the common mode current suppression filter of the first embodiment. FIG. 8 is a diagram showing a modification of the planar shape of the first layer conductor pieces 102 shown in FIG. 3, and FIG. 9 is an example of the layout (periodic arrangement) of the first layer conductor pieces 102 shown in FIG. FIG.

  In the HIS 101, the current path that the high-frequency noise current I bypasses depends on the layout (periodic arrangement) of the inner fold conductor pieces 123, and the high-frequency noise current I tends to concentrate on the shortest current path. For this reason, the high-frequency noise current I tends to flow in a concentrated manner at the shortest distance from the through via 107. Therefore, when the layout of the inner fold conductor piece 123 corresponding to the conductor fold is formed as shown in FIG. 6, a portion having a short distance and a long portion from the through via 107 are formed at the end of the inner layer fold conductor piece 123. The current concentrates at the end of the conductor piece 123 having a short distance from the through via 107, and the current concentration portion 120 is generated. As a result, the current path of the high-frequency noise current I is formed at the shortest distance from the through via 107.

  On the other hand, when the layout of the inner layer conductor conductor piece 123 is as shown in FIG. 7, that is, the shortest distance from the through via 107 to the end of the inner layer conductor conductor piece 123 is larger than that in the layout shown in FIG. If it is made longer, the path for detouring the high-frequency noise current I becomes longer. Therefore, comparing the layouts shown in FIGS. 6 and 7, the parallel inductance is larger in the layout of FIG. 7 than in the layout of FIG.

  For this reason, in order to detour the high-frequency noise current I by a certain distance or more, a circle 111 having a radius of a certain distance or more from the through via 107 (columnar conductor) is assumed. What is necessary is just to set the layout of the inner-layer fold conductor piece 123 so that it is completely contained in the inner-layer fold conductor piece 123 and does not overlap with the adjacent inner-layer fold conductor piece 123.

  Needless to say, the layout of the conductor pieces 102 constituting the HIS 101 of the first embodiment is not limited to the square shown in the top view of FIG. For example, the regular hexagonal triangular lattice arrangement shown in FIG. 18 may be used. Further, the planar shape of the inner layer conductor conductor piece 123 is arbitrary, and may be a circle as shown in FIG. 3 or a polygon as shown in FIG.

  The band gap bandwidth may be narrowed, but when it is desired to further reduce the size of the first layer conductor piece 102 or to lower the band gap bandwidth than the square shape shown in FIG. It is also possible to increase the capacity C.

  For example, by adopting a form (interdigital structure) in which adjacent first layer conductor pieces 102a mesh with each other as shown in FIGS. 8 and 9, the two first layer conductor pieces 102a adjacent to each other in the gap region 131 are opposed to each other. The side to be processed can be lengthened, thereby increasing the series capacitance C. In this way, it is possible to increase the series capacitance C as well as increase the parallel inductance due to the pleated conductor pillar 103.

(Second Embodiment)
10 to 12 show a common mode current suppression filter according to a second embodiment of the present invention. FIG. 10 is a top view of the HIS constituting the common mode current suppression filter, FIG. 11 is a partial cross-sectional view taken along the line AA ′ in FIG. 10, and FIG. 12 is an exploded view of the HIS shown in FIG. It is sectional explanatory drawing shown.

  In the second embodiment, as shown in FIGS. 8 and 9, the parallel inductance L and the series capacitance C are provided without the adjacent first layer conductor pieces 102 engaging with each other (interdigital structure). It is an increase.

  As shown in FIGS. 10 and 11, the HIS 201 of the second embodiment includes a plurality of first conductor elements 204 periodically arranged on the printed circuit board and a plurality of periodically arranged on the board. The second conductor element 214 is provided. The layout of the conductor elements 204 and 214 (that is, first layer conductor pieces 202 and 212 described later) can be, for example, the two-dimensional periodic arrangement shown in FIG. As clearly shown in FIG. 10, the planar shapes of the conductor elements 204 and 214 (that is, first-layer conductor pieces 202 and 212 described later) are both square.

  The arrangement period of the first conductor element 204 and the second conductor element 214 is the same. The adjacent first layer conductor piece 202 and second layer conductor piece 212 partially overlap, and an overlapping region 251 is formed between them. The overlapping region 251 can be easily formed by disposing the periodic arrangement of the first conductor elements 204 with respect to the periodic arrangement of the second conductor elements 214 by shifting them by half a period in the vertical direction and the horizontal direction.

  The HIS 201 has a cross-sectional structure as shown in FIG. 11, and is formed using a conductor layer and a dielectric plate of a printed circuit board.

  Similar to the first embodiment, the printed circuit board is configured by alternately arranging the first to fifth conductor layers and the first to fourth dielectric plates 206. A plurality of first layer conductor pieces 202 arranged periodically are formed on the first conductor layer (uppermost conductor layer) on the surface of the printed circuit board. A plurality of second layer conductor pieces 212 arranged periodically are formed on the second conductor layer of the same printed circuit board adjacent to the first conductor layer with the first dielectric plate 206 interposed therebetween. The fifth conductor layer (lowest conductor layer) on the back surface of the printed circuit board is the ground plane 5 as a whole.

  The third to fourth conductor layers arranged between the second layer conductor piece 202 and the ground plane 5 are respectively formed with conductor pieces, and these two conductor pieces are respectively inner layer fold conductor pieces 223. This corresponds to the “please conductor”.

  The printed circuit board further includes a plurality of through vias 207 that penetrate the printed circuit board in the thickness direction. Each through via 207 passes through the first to fifth conductor layers and the first to fourth dielectric plates 206, and extends from the front surface to the back surface of the printed circuit board. Openings are respectively formed in the first conductor layer and the fifth conductor layer of the printed circuit board. Each through via 207 is a through via with a conductive film whose inner peripheral surface is covered with a conductive film. Each through via 207 with a conductive film corresponds to a “columnar conductor”.

  As shown in FIGS. 11 and 12, the two inner fold conductor pieces 223 formed in the third to fourth conductor layers are arranged in a bowl shape around the corresponding through via 207, and It is mechanically and electrically connected to the conductor film on the inner peripheral surface of the through via 207. The through via 207 and the two inner fold conductor pieces 223 connected and integrated in this way constitute the first crease conductor column 203 or the second crease conductor column 213. The through via 207 immediately below the first layer conductor piece 202 and the two-layer inner fold conductor piece 223 constitute a first pleated conductor column 203, and two through vias 207 immediately below the second layer conductor piece 212. The inner fold conductor piece 223 of the layer constitutes a second fold conductor column 213.

  In the first pleated conductor column 203, the upper end of the through via 207 is mechanically and electrically connected to the corresponding first layer conductor piece 202 to constitute a thumbtack-shaped first conductor element 204. The conductor does not exist in the location corresponding to the 2nd conductor layer of the conductor pillar 203 with the 1st crease. The lower end of the first pleated conductor column 203 (through via 207) is mechanically and electrically connected to the ground plane 5 (fifth conductor layer).

  In the second pleated conductor column 213, the portion corresponding to the second conductor layer of the through via 207 is mechanically and electrically connected to the corresponding second layer conductor piece 212, and the upper end of the through via 207 is It penetrates through the two-layer conductor piece 212 and reaches the surface of the same printed circuit board, and constitutes a top-like second conductor element 214. The conductor does not exist in the location corresponding to the 1st conductor layer of the conductor pillar 213 with the 2nd crease. The lower end of the second pleated conductor post 213 (through via 207) is mechanically and electrically connected to the ground plane 5 (fifth conductor layer).

  The first and second pleated conductor pillars 203 and 213 having such a configuration can be easily formed by forming a through via 207 on the printed circuit board and plating a conductive film on the inner peripheral surface thereof. can do.

  The thicknesses of the first layer conductor piece 202 of the first conductor element 204, the second layer conductor piece 212 of the second conductor element 214, and the inner layer fold conductor piece 223 are all the skin depth in the desired band gap frequency band. Is set to more than twice. For example, when a copper plate is used as the conductor layer of the printed circuit board 100, the skin depth at 30 MHz is about 12 μm. Therefore, if the thickness of the copper plate used in the normal printed circuit board manufacturing process is 35 μm, at least Above 30 MHz, the condition that the thickness of the copper plate is at least twice the skin depth is satisfied. Even when a copper plate having a thickness of 15 μm is used, the condition that the thickness of the copper plate is twice or more the skin depth is satisfied at 100 MHz or higher.

  Since the common mode current suppression filter of the second embodiment includes the HIS 201 having the above configuration, the circuit operation characteristics inside the printed circuit board are the same for the same reason as described in the first embodiment. It is possible to prevent the situation of being affected by the high-frequency noise current I flowing through the ground plane 5, and it is easy to downsize to a size that does not cause a problem in practice, and an inexpensive multilayer printed circuit board is used. The effect that it can be mounted is obtained.

  In addition, since the HIS 201 of the second embodiment has the same configuration as the HIS 101 of the first embodiment, the parallel inductance is increased as compared with the case where the inner fold conductor piece 223 is not provided. Moreover, in the overlapping region 251 between the first conductor element 204 and the second conductor element 214, the first layer conductor piece 202 and the second layer conductor piece 212 have a structure facing each other through the dielectric plate 206. In the overlapping region 251, the adjacent first conductor element 204 and second conductor element 214 are capacitively coupled. Accordingly, the series capacitance is increased as compared with the HIS 101 of the first embodiment and its modification shown in FIGS. 1 to 9, and the series capacitance can be easily changed by changing the area of the overlapping region 251. It is possible to adjust to.

  Furthermore, the electromagnetic radiation suppression function described above can be obtained over a lower band by increasing the series capacitance. On the other hand, when the band gap bandwidth may be narrowed, the common mode current suppression filter can be further downsized.

  Note that the planar shapes of the first layer conductor pieces 202 and the second layer conductor pieces 212 constituting the HIS 201 are not limited to the square rectangular lattice arrangement shown in FIG. For example, a regular hexagonal triangular lattice arrangement may be used.

  Further, a part or all of the first to fourth dielectric plates 206 may be formed of an insulating high magnetic permeability material. In this case, there is an advantage that the parallel inductance is further increased.

(Third embodiment)
FIG. 13 is a top view of the HIS constituting the common mode current suppression filter of the third embodiment of the present invention.

  In the third embodiment, the conductor elements are not periodically arranged in a square lattice pattern or a triangular lattice pattern as in the first and second embodiments, but around a certain point 315 near the connector 108. The HIS 301 is configured by arranging conductor elements in a concentric arc shape.

  As shown in FIG. 13, the HIS 301 used in the third embodiment is formed around the connector 108 provided on the surface of the printed circuit board 100 so as to surround the three directions of the connector 108.

  The HIS 301 includes a plurality of conductor elements periodically arranged on the printed circuit board 100, and the layout of these conductor elements (that is, a first layer conductor piece 302 described later) is a connector as shown in FIG. This is a two-dimensional periodic arrangement in a sector area centered at 108. The conductor element does not exist in the direction in which the cable 109 connected to the connector 108 extends. A predetermined distance is provided between the conductor element (ie, HIS 301) and the connector 108, so that the conductor element 104 (HIS 301) is spaced from the connector 108. The planar shape of each conductor element (first layer conductor piece 302) is a sector shape, as clearly shown in FIG.

  The first conductor layer pieces 302 constituting each conductor element of the HIS 301 are periodically arranged on three concentric arcs around the point 315 in the vicinity of the connector 108, and a common radial direction of the concentric arcs. Are periodically arranged radially. In FIG. 13, fan-shaped first conductor layer pieces 302 are arranged at equal angular intervals along each of three arcs arranged at equal intervals in the radial method. The first conductor layer pieces 302 on the same arc have the same planar shape. The size of the first conductor layer pieces 302 arranged on the three arcs gradually increases according to the distance from the point 315. Reference numeral 307 indicates a through via, and reference numeral 323 indicates an inner layer conductor conductor piece.

  Other configurations of the conductor elements of the HIS 301 are the same as the conductor elements 104 of the HIS 101 of the first embodiment described above.

  In the absence of the HIS 301, a path where high-frequency noise current concentrates on the connector 108 from the printed circuit board 100 and the high-frequency noise current transmitted from the cable 109 propagates radially from the connector 108 to the ground plane of the printed circuit board 100. Is assumed. However, when the HIS 301 of the third embodiment is arranged in the vicinity of the connector 108 in the layout as shown in FIG. 13, the high-frequency noise current is efficiently suppressed, and at the same time, the high-frequency noise current transmitted to the cable 109 by an external unnecessary electromagnetic wave. Propagation to the printed circuit board 100 is also efficiently suppressed. Therefore, it is possible to prevent a situation in which the circuit operation characteristics inside the printed circuit board 100 are affected by the high frequency noise current flowing through the ground plane.

  Further, in the common mode current suppression filter of the third embodiment, the HIS 301 having the above-described configuration is used, so that the parallel inductance without increasing the length of the through via 307 (corrugated conductor pillar) of the printed circuit board 100. Therefore, the printed circuit board 100 can be made thinner accordingly. In addition, since the series capacitance can be reduced in accordance with the increase in parallel inductance, the side length of the first conductor piece 302 can be shortened, and the first conductor piece 302 can be reduced in size. Become. As a result, the area where the first layer conductor piece 302 occupies the surface of the printed circuit board 100 is reduced. Therefore, it is easy to downsize the common mode current suppression filter to a size that does not cause a problem in practice.

  If it is desired to lower the bandgap frequency instead of narrowing the bandgap bandwidth, it can be realized by increasing the series capacitance simultaneously with the parallel inductance. Further, since the series capacitance per size of the same first layer conductor piece 302 is increased, the first layer conductor piece can be obtained even if the first layer conductor piece 302 is further downsized. 302 can be reduced in size, and as a result, the common mode current suppression filter can be further reduced in size. On the other hand, if the series capacitance is decreased in accordance with the increase in parallel inductance, the band gap bandwidth can be increased accordingly, and thus the above-described electromagnetic radiation suppressing function can be obtained over a wide band.

  Furthermore, since each pleated conductor post 303 is formed using the through via 307 and the inner fold conductor piece 323 of the printed circuit board 100, it is not necessary to use an expensive build-up process. Therefore, it is possible to mount the common mode current suppression filter using an inexpensive multilayer printed circuit board.

  A part or all of the dielectric plate of the printed circuit board 100 may be formed of an insulating high magnetic permeability material. In this case, there is an advantage that the parallel inductance is further increased.

(Modification of the third embodiment)
FIG. 14 is a top view showing a modification of the first layer conductor piece 302 of the HIS 301 of the third embodiment, and FIG. 15 is a top view of the HIS 301a when the first layer conductor piece 302a shown in FIG. 14 is used. .

  As shown in FIG. 13, the planar shape of the first layer conductor piece 302 of the HIS 301 used in the third embodiment is different in the lengths of the adjacent sides of the two adjacent first conductor layer pieces 302. . For this reason, there exists a difficulty that the value of series capacity | capacitance will differ. On the other hand, in the first layer conductor piece 302a of FIG. 14, both sides of the four corners are cut obliquely to form an octagon, and thereby the four sides L1, L2, L3 of the first layer conductor piece 302a. , L4 lengths are substantially equal to each other.

  When the first conductor layer small pieces 302a having the planar shape as shown in FIG. 14 are arranged in the same layout as in FIG. 13 and the HIS 301a is configured, it becomes as shown in FIG. 14, and the adjacent first layer conductor small pieces 302a face each other. The lengths of the sides to be made are almost equal to each other. As a result, it is possible to obtain an effect that the series capacitances of the HIS 301a can be made substantially equal.

(Fourth embodiment)
FIG. 16 is a top view showing the HIS of the common mode current suppression filter of the fourth embodiment of the present invention.

  In the fourth embodiment, like the third embodiment (see FIG. 13), the conductor element 104 in the first embodiment (see FIGS. 1 and 2) is replaced with a certain point 315 in the vicinity of the connector 108. Rather than configuring the HIS 301 by concentrically arranging the centers as a center, the first conductor elements 204 and the second conductor elements 214 in the second embodiment are arrayed concentrically around a point 415 near the connector 108. Thus, the HIS 401 is configured.

  As shown in FIG. 16, the HIS 401 used in the fourth embodiment is formed around the connector 108 provided on the surface of the printed circuit board so as to surround the three directions of the connector 108.

  The HIS 401 includes a plurality of first conductor elements 404 and a plurality of second conductor elements 414 periodically arranged on a printed circuit board, and these conductor elements 404 and 414 (that is, a first layer conductor piece 402 described later). As shown in FIG. 16, the layout of the second layer conductor pieces 412) is a two-dimensional periodic arrangement in a sector area centered on the connector 108. Conductive elements 404 and 414 are not present in the direction in which the cable connected to connector 108 extends. A predetermined spacing is provided between the conductor elements 404 and 414 (ie, HIS 401) and the connector 108, and thus the conductor elements 404 and 414 (HIS 401) are spaced from the connector 108.

  The planar shape of each of the first conductor element 404 and the second conductor element 414 (the first layer conductor piece 402 and the second layer conductor piece 412) is shown in FIG. It is an octagon that is dropped. This is because, as in the first layer conductor piece 302a shown in FIGS. 14 and 15, the lengths of the opposing sides of the adjacent first layer conductor pieces 402 are made substantially equal to each other, and the adjacent second layer conductor pieces This is because the lengths of the opposite sides of 412 are made substantially equal to each other, and the series capacitance of the HIS 401 is made substantially equal.

  The first conductor layer pieces 402 constituting the first conductor element 404 of the HIS 401 are periodically arranged on a plurality of concentric arcs around the point 415 in the vicinity of the connector 108, and the common motion of these concentric arcs is It is periodically arranged radially in the radial direction. In FIG. 16, fan-shaped first conductor layer pieces 402 are arranged at equal angular intervals along each of a plurality of arcs arranged at equal intervals in the radial method. The first conductor layer pieces 402 on the same arc have the same planar shape. The size of the first conductor layer pieces 402 arranged on the plurality of arcs gradually increases according to the distance from the point 415. Reference numeral 407 denotes a through via, and reference numeral 423 denotes an inner layer conductor conductor piece.

  The layout of the second conductor element 414 is the same as that of the first conductor element 404, but is offset from the first conductor element 404 by a predetermined distance. For this reason, the adjacent first layer conductor piece 402 and second layer conductor piece 412 partially overlap, and an overlapping region 451 is formed between them. The overlapping region 451 is formed by disposing the periodic arrangement of the first conductor elements 404 with respect to the periodic arrangement of the second conductor elements 414 while being shifted by a half period in the circumferential direction and the radial direction, respectively.

  Other configurations of the first conductor element 404 and the second conductor element 414 are the same as those of the first conductor element 204 and the second conductor element 214 of the HIS 201 of the second embodiment described above, respectively.

  When the HIS 401 of the fourth embodiment is arranged in the vicinity of the connector 108 in the layout as shown in FIG. 16, the high-frequency noise current is efficiently suppressed, and at the same time, the high-frequency noise current transmitted to the cable 109 by the external unnecessary electromagnetic wave is printed. Propagation to the circuit board is also efficiently suppressed. Therefore, it is possible to prevent a situation in which the circuit operation characteristics inside the printed circuit board are affected by the high frequency noise current flowing through the ground plane.

  Further, in the common mode current suppression filter of the fourth embodiment, the HIS 401 having the above-described configuration is used. Therefore, the parallel inductance is reduced without lengthening the through via 407 (the conductor pillar with crease) of the printed circuit board. The printed circuit board can be made thinner accordingly. Further, since the series capacitance can be reduced in accordance with the increase in parallel inductance, the overlapping region 451 can be reduced in size, and the first layer conductor piece 402 and the second layer conductor piece 412 can be reduced in size. Become. As a result, the area occupied by the first layer conductor piece 402 and the second layer conductor piece 412 on the surface of the printed circuit board is reduced. Therefore, it is easy to downsize the common mode current suppression filter to a size that does not cause a problem in practice.

  If it is desired to lower the bandgap frequency instead of narrowing the bandgap bandwidth, it can be realized by increasing the series capacitance simultaneously with the parallel inductance. In addition, by adopting a structure in which the series capacitance per size of the same first layer conductor piece 402 is increased, the series capacitance can be gained even if the first layer conductor piece 402 and the second layer conductor piece 412 are further miniaturized. Therefore, the first layer conductor piece 402 and the second layer conductor piece 412 can be downsized, and as a result, the common mode current suppression filter can be further downsized. On the other hand, if the series capacitance is decreased in accordance with the increase in parallel inductance, the band gap bandwidth can be increased accordingly, and thus the above-described electromagnetic radiation suppressing function can be obtained over a wide band.

  Further, each pleated conductor post is formed using the through via 407 and the inner crease conductor piece 423 of the printed circuit board, so that it is not necessary to use an expensive build-up process. Therefore, it is possible to mount the common mode current suppression filter using an inexpensive multilayer printed circuit board.

  A part or all of the dielectric plate of the printed circuit board may be formed of an insulating high magnetic permeability material. In this case, there is an advantage that the parallel inductance is further increased.

(Modification)
The first to fourth embodiments show preferred examples of the present invention. Therefore, it goes without saying that the present invention is not limited to these embodiments, and various modifications are possible. For example, in the first to fourth embodiments, a plurality of first layer conductor pieces occupy a substantially U-shaped or arc-shaped region on the printed circuit board so as to surround the connector. It is not limited to. The shape of the occupied area of the plurality of first layer conductor pieces can be arbitrarily changed as necessary.

It is a top view of HIS which comprises the common mode current suppression filter of 1st Embodiment of this invention. It is sectional drawing of HIS which comprises the common mode current suppression filter of 1st Embodiment of this invention. It is a partial expanded top view of HIS which comprises the common mode current suppression filter of 1st Embodiment of this invention. It is a perspective view of the conductor element which comprises HIS of the common mode current suppression filter of 1st Embodiment of this invention. It is a section explanatory view showing the current path of the high frequency noise current in HIS of the common mode current suppression filter of a 1st embodiment of the present invention. It is a top view for demonstrating the current concentration in the inner layer crease conductor piece of the common mode current suppression filter of the first embodiment of the present invention. It is a top view which shows the modification of the inner layer crease conductor piece of the common mode current suppression filter of 1st Embodiment of this invention. It is a top view which shows the modification of the 1st layer conductor piece of the common mode current suppression filter of 1st Embodiment of this invention. It is a top view which shows an example of HIS comprised by the 1st layer conductor piece shown in FIG. It is a top view of HIS which comprises the common mode current suppression filter which is 2nd Embodiment of this invention. It is a fragmentary sectional view in alignment with the AA 'line of FIG. It is the fragmentary sectional explanatory view which decomposed | disassembled and showed HIS shown in FIG. 11 for every component. It is a top view of HIS which comprises the common mode current suppression filter of 3rd Embodiment of this invention. It is a top view which shows the modification of the 1st layer conductor piece used by HIS of the common mode current suppression filter of 3rd Embodiment of this invention. It is a top view which shows an example of HIS comprised by the 1st layer conductor piece shown in FIG. It is a top view of HIS which comprises the common mode current suppression filter of 4th Embodiment of this invention. It is sectional drawing which shows an example of the conventional HIS. It is a top view which shows an example of the layout of the conductor piece of the conventional HIS shown in FIG. It is a top view which shows the other example of the layout of the conductor piece of the conventional HIS shown in FIG. FIG. 18 is an equivalent circuit diagram of the conventional HIS shown in FIG. 17. It is sectional drawing which shows the other example of the conventional HIS. FIG. 22 is an equivalent circuit diagram of the conventional HIS shown in FIG. 21. It is a top view at the time of using a spiral coil as an inductance element in the conventional HIS shown in FIG. It is a top view at the time of using a meander coil as an inductance element in the conventional HIS shown in FIG.

Explanation of symbols

1, 1a Conventional HIS
2 Conductor Piece 3 Conductor Column 4 Conductor Element 5 Ground Plane 6 Dielectric Plate 7 First Conductor Column 8 Inductance Element 15 Connection Point 16 between Inductance Element and First Conductor Column 16 First Dielectric Plate 17 Second Conductor Column 18 Spiral Coil 25 Connection point 26 between inductance element and second conductor pillar 26 Second dielectric plate 28 Meander coil 100 Printed circuit board 101, 201, 301, 301a, 401 HIS of the present invention
102, 102 a, 202, 302, 302 a, 402 First-layer conductor piece 103 Corrugated conductor pillar 104 Conductor element 106, 206 Dielectric plate 107, 207, 307, 407 Through via 106 Dielectric plate 108 Connector 109 Cable 110 Current path 111 circle 120 current concentrating portion 123, 223, 323, 423 inner layer fold conductor piece 131 gap region 203, 403 first fold conductor column 204, 404 first conductor element 212, 412 second layer conductor piece 213, 413 second fold Conductor pillars 214, 414 Second conductor elements 251, 451 Overlapping regions 315, 415 Arc center

Claims (9)

A high-impedance surface made of an electromagnetic bandgap material having a bandgap that prevents propagation of electromagnetic waves in a predetermined frequency band is provided at a peripheral portion of the connector on the surface of the printed circuit board and the connector on the surface of the printed circuit board. Formed,
The high impedance surface is located in the first conductor layer of the printed circuit board , and a plurality of periodically disposed first conductor pieces;
And the ground plane at least partially disposed in the different second located in the conductor layer, opposite said plurality of first conductive piece region and said first conductor layer,
Each of the first conductor pieces and the first pleated conductor column that electrically connects the ground plane;
Each of the first pleated conductor columns includes a first columnar conductor extending between the first conductor layer and the second conductor layer of the printed circuit board, and a first columnar conductor mounted on the first columnar conductor. 1 pleated conductor and
The common mode current suppression filter according to claim 1, wherein the thickness of the first fold conductor is at least twice the skin depth in a desired band gap frequency band.

The first conductor piece is disposed on a front surface or an inner layer of the printed circuit board, the ground plane is disposed on a back surface of the printed circuit board or an inner layer different from the first conductor piece, and the first columnar conductor is disposed on the printed circuit board. The common mode current suppression filter according to claim 1, wherein the common mode current suppression filter is formed using a through via extending from the back surface of the circuit board to the surface thereof.
A plurality of second conductor pieces are periodically arranged on the third conductor layer of the printed circuit board between the first conductor layer and the second conductor layer of the printed circuit board,
Each of the second conductor pieces and the ground plane are electrically interconnected by a plurality of second pleated conductor posts,
Each of the second pleated conductor columns includes a second columnar conductor extending between the third conductor layer and the second conductor layer of the printed circuit board, and a second columnar conductor attached to the second columnar conductor. 2 pleated conductors,
The thickness of the second fold conductor is at least twice the skin depth in a desired band gap frequency band, and the first conductor piece and the second conductor piece partially overlap when viewed from above . The common mode current suppression filter according to claim 1 or 2, wherein
The first crease conductor of the first crease conductor column has a planar shape including a circle centered on the corresponding first columnar conductor and having a predetermined radius, and is adjacent to each other. The common mode current suppression filter according to claim 1, wherein the common mode current suppression filter is disposed so as not to overlap the first fold conductor.
The common mode current suppression filter according to any one of claims 1 to 4, wherein the first conductor pieces adjacent to each other are arranged in mesh with each other.
The first conductor piece and the first pleated conductor column are periodically arranged on a plurality of concentric circles or concentric arcs centered on the connector or in the vicinity thereof, along the radius of the concentric circles or concentric arcs. The common mode current suppression filter according to any one of claims 1 to 5.
The second conductor piece and the second pleated conductor column are also periodically arranged on a plurality of concentric circles or concentric arcs centered on the connector or in the vicinity thereof, along the radius of the concentric circles or concentric arcs. The common mode current suppression filter according to claim 3 .
The common mode current suppression filter according to any one of claims 1 to 7, wherein each of the first conductor pieces has a substantially equal side length in contact with the other adjacent first conductor piece.
The common mode current suppression filter according to claim 1, wherein the dielectric plate of the printed circuit board is formed using an insulating magnetic material.

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