JP5111282B2 - Electromagnetic band gap structure and printed circuit board - Google Patents

Description

  The present invention relates to an electromagnetic bandgap structure, and more particularly to an electromagnetic bandgap structure that shields signal transmission in a predetermined frequency band and a printed circuit board including the same.

  In recent years, commercially available electronic devices and communication devices have been increasingly reduced in size, thickness, and weight. This is closely related to recent trends in which mobility is important.

  Such electronic devices and communication devices include various electronic circuits (analog circuit and digital circuit) for realizing the functions and operations of the devices in a composite manner. .

  Usually, such an electronic circuit is mounted on a printed circuit board (PCB) to perform its function. Here, electronic circuits mounted on the printed circuit board generally have different operating frequencies.

  Therefore, in a printed circuit board on which various electronic circuits are mounted in a complex manner, the electromagnetic frequency (EM wave) due to the operating frequency of one electronic circuit and its harmonics component is normally transmitted to other electronic circuits. However, there are many noise problems caused by interference, that is, mixed signal problems. At this time, the transmitted noise can be broadly classified into radiation noise and conduction noise.

  Here, radiation noise can usually be easily reduced by covering the electronic circuit with a shielding cap. However, since conduction noise is transmitted through a signal transmission path inside the substrate, a noise reduction method can be found. was difficult. This conduction noise is indicated by reference numeral 150 in FIG.

  The conduction noise 150 will be described more specifically with reference to FIG. FIG. 1 is a cross-sectional view of a printed circuit board on which two electronic circuits having different operating frequencies are mounted. Although a printed circuit board 100 having a four-layer structure is shown in FIG. 1, various modifications such as a two-layer, six-layer, and eight-layer structure are possible in addition to the four-layer structure.

  Referring to FIG. 1, the printed circuit board 100 includes four metal layers 110 (110-1, 110-2, 110-3, 110-4) and a dielectric layer 120 (120) interposed between the metal layers. -1,120-2, 120-3). On the uppermost metal layer 110-1 of the printed circuit board 100, two electronic circuits 130 and 140 (hereinafter referred to as a first electronic circuit 130 and a second electronic circuit 140) having different operating frequencies are mounted. Has been. Two electronic circuits having different operating frequencies are, for example, a mobile communication terminal such as a mobile phone, a digital circuit functioning as a microprocessor, and an RF circuit (analog circuit) for transmitting and receiving RF signals. ).

  Here, assuming that the metal layer 110-2 is a ground layer and the metal layer 110-3 is a power layer, each ground terminal (ground) of the first electronic circuit 130 and the second electronic circuit 140 is assumed. pin) is electrically connected to the metal layer 110-2, and each power pin is electrically connected to the metal layer 110-3. Further, all the ground layers in the printed circuit board 100 and all the power supply layers are electrically connected to each other through vias (see 160 in FIG. 1).

  Here, when the first electronic circuit 130 and the second electronic circuit 140 have different operating frequencies, as shown in FIG. 1, for example, the operating frequency of the first electronic circuit 130 and its harmonics (harmonics) ) Conduction noise 150 due to the component is transmitted to the second electronic circuit 140, and prevents the second electronic circuit 140 from functioning correctly.

  Such a conduction noise problem becomes more difficult to solve as electronic devices become more complex and the operating frequency of digital circuits increases. In particular, a method using a bypass capacitor or a decoupling capacitor, which is a typical solution for conduction noise, is not a suitable solution for an electronic device using a high frequency band. is the current situation.

  In addition, these methods are used when a substrate having a complicated wiring structure in which various electronic circuits are provided on the same substrate, or when many active elements and passive elements are provided in a narrow area such as SIP (System in Package). There is also a problem that it is not a fundamental solution when an operating frequency in a high frequency band is required like a network board.

  In view of the problems of the prior art, the present invention provides an electromagnetic bandgap structure that can reduce noise at a specific frequency because it has a low bandgap frequency while having a small size, and a printed circuit board including the same. The purpose is to do.

  Another object of the present invention is to ensure high impedance and high inductance while having a small size, and easy design even when many active elements and passive elements are provided in a narrow area like SIP. An electromagnetic band gap structure and a printed circuit board including the same are provided.

  Another object of the present invention is to provide an electromagnetic bandgap structure that can solve the problem of mixed signals in an electronic device in which an RF circuit and a digital circuit are provided on the same substrate, for example, a mobile communication terminal. It is to provide a printed circuit board including the same.

  Other objects of the present invention will be easily understood through the following description.

  In order to achieve the above-described problems, according to an embodiment of the present invention, a dielectric layer, a plurality of conductive plates, and a stitching via that electrically connects the conductive plates and the conductive plates are provided. In addition, an electromagnetic bandgap structure is provided, wherein the stitching via penetrates the dielectric layer, and a portion of the stitching via is located on a different plane from the conductive plate.

  The stitching via includes a first via that penetrates the dielectric layer and has one end connected to one of two adjacent conductive plates, and two stitches that penetrate the dielectric layer and have one end adjacent to each other. A second via connected to the other one of the conductive plates, and a connection pattern having one end connected to the other end of the first via and the other end connected to the other end of the second via. Can do.

  The conductive layer may further include a conductive layer positioned at a distance from the conductive plate. Furthermore, the conductive layer may be provided with a clearance hole, and the connection pattern may be accommodated in the clearance hole.

  Here, the conductive plate may have a polygonal shape, a circular shape, or an elliptical shape. The conductive plates may have the same size or may be divided into a plurality of different size groups. The conductive plates may all be located on the same plane.

  According to another embodiment of the present invention, there is provided a printed circuit board including two electronic circuits having different operating frequencies, wherein a dielectric layer, a plurality of conductive plates, and an electric connection between the conductive plates and the conductive plates are provided. An electromagnetic bandgap structure including a stitching via to be electrically connected is disposed between the two electronic circuits, the stitching via penetrating the dielectric layer, and a portion of the stitching via is the conductive plate. A printed circuit board is provided which is located on a different plane.

  The stitching via includes a first via that penetrates the dielectric layer and has one end connected to one of two adjacent conductive plates, and two stitches that penetrate the dielectric layer and have one end adjacent to each other. A second via connected to the other one of the conductive plates, and a connection pattern having one end connected to the other end of the first via and the other end connected to the other end of the second via. it can.

  The conductive layer may further include a conductive layer positioned at a distance from the conductive plate. At this time, the conductive layer may be provided with a clearance hole, and the connection pattern may be accommodated in the clearance hole.

  Further, the conductive layer is any one of a ground layer and a power supply layer, and the conductive plate can be connected to the other one layer on the same plane. At this time, the conductive plate and the other one layer can be connected via the stitching via.

  Still further, the conductive plate may have a polygonal shape, a circular shape, or an elliptical shape. The conductive plates may have the same size or may be divided into a plurality of different size groups. The conductive plates may all be located on the same plane.

  According to another embodiment of the present invention, a printed circuit board including a signal layer and a ground layer, the dielectric layer, a plurality of conductive plates, and stitches for electrically connecting the conductive plates and the conductive plates. An electromagnetic bandgap structure including a via, and the stitching via penetrates the dielectric layer, a portion of the stitching via is located on a different plane from the conductive plate, and the conductive plate is A printed circuit board is provided that is connected on the same plane as the signal layer.

  Here, the conductive plate and the signal layer can be connected via the stitching via.

  The stitching via includes a first via that penetrates the dielectric layer and has one end connected to one of two adjacent conductive plates, and two conductive conductors that penetrate the dielectric layer and have one end adjacent to each other. A second via connected to the other one of the plates, and a connection pattern having one end connected to the other end of the first via and the other end connected to the other end of the second via. it can.

  Further, the semiconductor device may further include a conductive layer positioned with the dielectric layer separated from the conductive plate. At this time, the conductive layer may be provided with a clearance hole, and the connection pattern may be accommodated in the clearance hole. Here, the conductive layer may be a ground layer.

  Here, the conductive plate may have a polygonal shape, a circular shape, or an elliptical shape. The conductive plates may have the same size or may be divided into a plurality of different size groups. The conductive plates may all be located on the same plane. The conductive plates may be arranged in one or two rows along the signal transmission path.

  Since the electromagnetic bandgap structure according to the present invention has a small bandgap frequency while having a small size, noise at a specific frequency can be reduced. Thus, high impedance, high inductance, etc. are ensured, and the design is facilitated even when many active elements and passive elements are provided in a narrow area like SIP. In addition, the problem of mixed signals in an electronic device such as a mobile communication terminal in which an RF circuit and a digital circuit are provided in the same substrate can be solved.

  Since the present invention can be modified in various ways and have various embodiments, specific embodiments are illustrated in the drawings and described in detail. However, this should not be construed as limiting the invention to the specific embodiments, but is to be understood as including all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. In describing the present invention, when it is determined that the specific description of the known technology is not clear, the detailed description thereof will be omitted.

  Terms such as “first” and “second” are merely used to describe various components, and the components are not limited by the terms. The terms are only used to distinguish one component from another.

  For example, the first component in the scope of the present invention may be named as the second component, and similarly, the second component may be named as the first component. The term “and” / “or” includes any combination of a plurality of related description items or a plurality of related description items.

  When a component is described as being “coupled” or “connected” to another component, it may be directly coupled to or connected to another component, and in the middle It must be understood that the components of can also exist. On the other hand, when it is described that a certain component is “directly connected” or “directly connected” to another component, it should be understood that there is no other component in the middle.

  The terms used in the present application are merely used to describe particular embodiments, and are not intended to limit the present invention. A singular expression includes the plural expression unless it is explicitly expressed in a sentence. In this application, terms such as “comprising” or “having” specify the presence of a feature, number, step, action, component, part, or combination thereof as described in the specification, It should be understood that this does not pre-exclude the existence or additionality of one or more other features or numbers, steps, actions, components, parts, or combinations thereof.

  Unless otherwise defined, all terms used herein, including technical or scientific terms, are terms commonly understood by those having ordinary skill in the art to which this invention belongs. Have the same meaning. Terms such as those defined in commonly used dictionaries should be construed as having a meaning consistent with the contextual meaning of the related art and are ideal or defined unless explicitly defined in this application. Don't interpret it in an overly formal sense.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 2 is a three-dimensional perspective view illustrating an electromagnetic bandgap structure according to an embodiment of the present invention. 3A is a cross-sectional view showing the electromagnetic bandgap structure shown in FIG. 2, and FIG. 3B is a plan view showing an arrangement structure of the electromagnetic bandgap structure shown in FIG. In particular, FIG. 3a is a cross-sectional view taken along line AA 'of FIG. In the description of the electromagnetic band gap structure of the present invention, a case where a metal layer or a metal plate is used throughout will be described. However, this is not a metal, but other conductive materials. It will be apparent to those skilled in the art that a conductive layer or a conductive plate manufactured in (1) can be substituted for each.

  Referring to FIGS. 2 to 3b, an electromagnetic bandgap structure according to an embodiment of the present invention includes a plurality of metal plates 210a, 210b, and 210c, and a metal layer 220 positioned on a different plane from these metal plates. A stitching via 230 for electrically connecting two adjacent metal plates. Here, different planes can be referred to as planes having different heights.

  That is, the electromagnetic bandgap structure 200 shown in FIGS. 2 to 3b is a two-layer plane (planar) in which the metal layer 220 is a first layer and the plurality of metal plates 210a, 210b, and 210c are second layers. ) Has a structure. Here, a dielectric layer is interposed between the metal layer 220 and the plurality of metal plates 210a, 210b, and 210c.

  FIGS. 2 to 3b show only the components constituting the electromagnetic bandgap structure, that is, only the components of the two-layered electromagnetic bandgap structure including the stitching via, for convenience of illustration. However, this is also applicable to FIGS. 4a to 4c. Accordingly, the metal layer 220 and the metal plates 210a, 210b, and 210c shown in FIGS. 2 to 3b may be any two layers existing inside the multilayer printed circuit board. That is, at least one other metal layer can be further present under the metal layer 220, and at least one other metal layer can also be present above the metal plates 210a, 210b, and 210c. It is. Note that at least one other metal layer may be present between the metal layer 220 and the metal plates 210a, 210b, and 210c.

  For example, the electromagnetic bandgap structure shown in FIGS. 2 to 3b is provided between any two metal layers constituting a power layer and a ground layer, respectively, in a multilayer printed circuit board to shield conduction noise. May be arranged. The same applies to the electromagnetic bandgap structure according to another embodiment shown in FIGS. 4a to 4c. In addition, since the conduction noise is not necessarily a problem only between the power supply layer and the ground layer, the electromagnetic bandgap structure shown in FIGS. 2 to 4c is provided between different layers in the multilayer printed circuit board. It can be disposed between any two ground layers or between any two power layers.

  The metal plates 210a, 210b, and 210c are located on the same plane and spaced apart by a predetermined distance. Here, the metal layer 220 and the metal plates 210a, 210b, and 210c are made of a material that can transmit a signal when power is supplied, for example, copper (Cu).

  The stitching via 230 electrically connects two adjacent metal plates, for example, 210b and 210c in FIG. However, the two metal plates 210b and 210c are not connected in the same layer, but the two metal plates 210b and 210c are connected via a layer different from the two metal plates 210b and 210c, that is, the metal layer 220 here. Let

  The stitching via 230 includes a first via 232, a connection pattern 234, and a second via 236. One end of the first via 232 is connected to the first metal plate 210 b and the other end is connected to one end of the connection pattern 234. One end of the second via 236 is connected to the second metal plate 210 c, and the other end is connected to the other end of the connection pattern 234. Via lands for connection to the first via 232 and / or the second via 236 may be formed at both ends of the connection pattern 234.

  Here, the stitching via 230 may be formed with a plating layer only on the inner walls of the first via 232 and the second via 236 for electrical connection between the metal plates, or the inside thereof may be conductive. The battery may be charged with a conductive material such as a conductive paste. It is obvious that the connection pattern 234 is also made of a conductive material such as metal.

  Two adjacent metal plates 210 b and 210 c are connected in series via a stitching via 230. That is, they are electrically connected in series in the order of the first metal plate 210b → stitching via 230 (first via 232 → connection pattern 234 → second via 236) → second metal plate 210c.

  The first metal plate 210b is connected to another adjacent metal plate 210a via a stitching via, and the second metal plate 210c is also connected to another adjacent metal plate (not shown) via a stitching via. If it does in this way, all the metal plates located in the 2nd layer have the effect of connecting in series via a stitching via.

  The metal layer 220 is provided with a clearance hole 225, and a connection pattern 234 is accommodated therein. In addition to the connection pattern 234, the clearance hole 225 can accommodate both via lands for facilitating connection with the first via 232 and / or the second via 236. Since there is the clearance hole 225, the stitching via 230 and the metal layer 220 can be electrically separated.

  Since the metal plates 210a, 210b, and 210c are connected through the stitching via 230, it is not necessary to form a pattern for connecting the metal plates 210a, 210b, and 210c in the second layer. For this reason, by reducing the size of the metal plates 210a, 210b, and 210c, the interval between the metal plates 210a, 210b, and 210c can be reduced, and the space between the metal plates 210a, 210b, and 210c can be reduced. There is an effect that the capacitance due to the gap can be increased.

  An equivalent circuit diagram of an electromagnetic bandgap structure having such a structure is shown in FIG.

  When the electromagnetic bandgap structure of FIG. 2 is applied to the equivalent circuit diagram of FIG. 3c, the inductance component L1 corresponds to the first via 232, the inductance component L2 corresponds to the second via 236, and the inductance component L3 is This corresponds to the connection pattern 234. C1 is a capacitance component due to the metal plates 210a and 210b and any other dielectric layer and metal layer located above the metal plates 210a and 210b, and C2 and C3 are the metal layer 220 located on the same plane with the connection pattern 234 as a reference. Capacitance component due to any other dielectric and metal layers located below it.

  With such an equivalent circuit diagram, the electromagnetic bandgap structure of FIGS. 2 to 3b functions as a band stop filter that shields a signal in a specific frequency band. That is, as can be seen from the equivalent circuit diagram of FIG. 3c, the signal (x) in the low frequency band and the signal (y) in the high frequency band pass through the electromagnetic bandgap structure, and the signal in the specific frequency band in the middle ( z1), (z2), and (z3) are shielded by an electromagnetic bandgap structure.

  In an exemplary embodiment of the present invention, the metal plates 210 a, 210 b, and 210 c may be located on the same plane as other metal layers that are distinguished from the metal layer 220. Therefore, in the present invention, the leftmost metal plate 210a can be connected to another metal layer that is distinguished from the metal layer 220 through the stitching via.

  If the metal layer 220 is a power supply layer, the other metal layers are ground layers, and if the metal layer 220 is a ground layer, the other metal layers are power supply layers.

  Alternatively, the metal layer 220 serves as a ground layer, the other metal layer serves as a signal layer and transmits a signal in a predetermined direction, and the metal plate 210a, 210b and 210c and the stitching via 230 can be arranged to reduce noise of a specific frequency included in the transmitted signal.

  Referring to FIGS. 2 to 3b, metal plates 210a, 210b, and 210c are arranged in a row, and two stitching vias are connected to each metal plate. However, in another embodiment, the metal plates may be arranged in an mxn (where m and n are natural numbers) matrix, and adjacent metal plates may be connected via stitching vias. In this case, each metal plate serves as a path for connecting other adjacent metal plates, and can be connected to at least two stitching vias. That is, the connection form shown in FIGS. 2 to 3b is only an example, and if a closed loop in which all the metal plates are electrically connected to each other can be formed, the stitching via is provided. Any connection method between the metal plates may be applied. Hereinafter, various embodiments according to the shape and arrangement of metal plates will be described with reference to the drawings.

  FIG. 5 is a plan view showing an arrangement structure of an electromagnetic band gap structure having a rectangular metal plate, and FIG. 6 is a plan view showing an arrangement structure of an electromagnetic band gap structure having a triangular metal plate. FIG. 7 is a plan view showing a band-like arrangement structure of the electromagnetic band gap structure.

  The metal plate can have various shapes such as a polygonal shape such as a hexagon, a circular shape or an elliptical shape in addition to the quadrangular shape and the triangular shape shown in FIGS.

  Further, as shown in FIGS. 5 and 6, metal plates connected by stitching vias can be arranged on the whole substrate, and as shown in FIG. 7, metal plates connected by stitching vias are substrates. It can also be arranged in only a part of.

  The metal plate is connected to two stitching vias as shown in FIG. 2 and can be connected to two other metal plates adjacent to each other. As shown in FIG. Once connected, it can be connected to four adjacent metal plates. Further, as shown in FIG. 6, it is connected to three stitching vias and can be connected to three adjacent metal plates.

  In this case, the metal plate arranged in the path from the signal source to the signal transmission point is prevented from being disconnected by the stitching via. That is, the metal plates are arranged in two rows, and all the metal plates having stitching vias adjacent to each metal plate can be connected, or the metal plates can be connected in a zigzag shape.

  8 and 9 are plan views showing an arrangement structure of electromagnetic bandgap structures formed of a plurality of metal plates of different sizes.

  As described above, all the metal plates connected by the stitching vias may have the same size, or may have different sizes as shown in FIGS. That is, the metal plates can be divided into a plurality of different sized groups.

  Referring to FIG. 8, relatively large large metal plates B and relatively small small metal plates C are alternately arranged, and each metal plate is connected to an adjacent metal plate by a stitching via. That is, both the large metal plate B and the small metal plate C are connected to adjacent metal plates by four stitching vias.

  Referring to FIG. 9, a relatively large large metal plate D and relatively small small metal plates E1, E2, E3, E4 are arranged. The small metal plates E1, E2, E3, E4 are arranged in 2 × 2 so that they occupy almost the same area as the large metal plate D as a whole. The small metal plates E1, E2, E3, E4 are connected to adjacent metal plates via four stitching vias. And since the large metal plate D has eight adjacent small metal plates, it is connected to the adjacent small metal plates via eight stitching vias.

  As described above, even when metal plates having different sizes are arranged in combination, signal transmission corresponding to a specific frequency can be blocked and noise can be reduced.

  Hereinafter, an electromagnetic bandgap structure according to another embodiment of the present invention will be described with reference to FIGS. 4A to 4C, the description overlapping with the description of FIGS. 2 to 3B will be omitted, and the characteristics of each embodiment will be mainly described. Briefly described. This is because the electromagnetic bandgap structure according to each embodiment of FIGS. 4a to 4c adopts the same technical principle as the electromagnetic bandgap structure of FIGS. 2 to 3b, except for some differences. Because. 4A to 4C, the same reference numerals are assigned to the corresponding components for convenience of comparison with FIGS. 2 to 3B.

  First, referring to FIG. 4a, an electromagnetic bandgap structure 200 according to another embodiment of the present invention electrically connects a plurality of metal plates 210a, 210b, 210c and two adjacent metal plates. And stitching vias 230 to be connected to each other. That is, it can be seen that the electromagnetic band gap structure of FIG. 4a does not include the metal layer 220 of the electromagnetic band gap structure of FIGS.

  As described above, the electromagnetic band gap structure including the stitching via according to the present invention does not necessarily include a metal layer below the region where the stitching via and the metal plate are located. This is because the position where the connection pattern 234 of the stitching via 230 is formed need not be a portion where the metal layer exists.

  That is, when an arbitrary metal layer exists on the same plane corresponding to the position where the connection pattern 234 is formed, the connection pattern 234 is formed on the metal layer 220 on the same plane as shown in FIGS. This is because it is manufactured in a form of being accommodated in the formed clearance hole 225, but there may be a case where a separate metal layer does not exist at the position where the connection pattern 234 is formed, as shown in FIG. 4a. Of course, in FIG. 4a, there is a dielectric layer below the metal plate.

  Referring to FIG. 4b, an electromagnetic bandgap structure according to another embodiment of the present invention is upside down as compared to FIGS. 2 to 3b. That is, FIGS. 2 to 3b have a laminated structure in which the metal layer 220 forms a lower layer, the metal plates 210a, 210b, and 210c form an upper layer, and a dielectric layer is interposed between them. In the opposite structure, that is, the metal plates 210a, 210b, 210c form a lower layer, the metal layer 220 forms an upper layer, and a dielectric layer is interposed therebetween. In such a case, it is needless to say that the noise shielding effect as described above can be similarly expected.

  Referring to FIG. 4c, an electromagnetic bandgap structure according to another embodiment of the present invention is formed by removing the upper metal layer 220 from the electromagnetic bandgap structure having the stacked structure of FIG. 4b. The reason for this has been described with reference to FIG.

  As described above, the electromagnetic bandgap structure of the present invention can have various forms and laminated structures. In all the drawings described above, the metal plates are all shown to be stacked on the same plane, but the metal plates are not necessarily stacked on the same plane. At this time, when all of the metal plates are not laminated on one plane, it has a structure of two or more layers, which increases the number of layers. However, the electromagnetic band gap structure of the present invention is used as a multilayer printed circuit. This will not be a design disadvantage if it is placed in the board.

  Moreover, in all the drawings described above, a method of electrically connecting two adjacent metal plates with stitching vias is adopted, but two metal plates connected via one stitching via are used. However, they are not necessarily adjacent. In addition, although it is illustrated that one metal plate is connected to another metal plate via one stitching via, the number of stitching vias that connect two metal plates is illustrated. It is self-evident that there are no particular restrictions.

  Also, in FIGS. 2 to 4c, only three metal plates are shown for convenience of drawing illustration and to help a clear understanding of the present invention, and another one adjacent to one metal plate and In addition, the other one metal plate is electrically connected to each other through one stitching via, that is, the case where two adjacent cells are connected with respect to one cell as an example is illustrated. It ’s just that. That is, the electromagnetic bandgap structure according to each embodiment of the present invention may have various shapes on a part of the substrate (particularly, refer to FIG. 7) or on the whole substrate, as described above with reference to FIGS. They can be arranged in size and arrangement, and those skilled in the art will clearly understand this throughout the specification.

  FIG. 10 is a frequency characteristic graph of an electromagnetic bandgap structure according to an embodiment of the present invention. A simulation model of an electromagnetic bandgap structure including a stitching via is formed, and the result of analysis using a scattering parameter is shown.

  When -50 dB is used as a reference, a stop band that cuts off a signal transmitted through the electromagnetic bandgap structure is formed in a region where the frequency of the signal corresponds to about 2.8 to 7.5 GHz. Can be confirmed.

  Such a stop band frequency band appropriately suits various conditions such as the size of the electromagnetic band gap structure, the thickness of each component, the dielectric constant of the dielectric layer, the arrangement form, the shape, size, and number of metal plates. Clearly, it can be designed to have the desired frequency band by adjusting.

  The printed circuit board according to an embodiment of the present invention may be SIP.

  A signal layer and a ground layer are present in the printed circuit board. Here, noise is generated due to a high operating frequency of the signal transmitted along the signal layer. In this case, the electromagnetic band gap structure described above is employed to reduce noise having a specific frequency.

  The ground layer is a metal layer, and a metal plate is disposed on the same plane as the signal layer with a certain distance therebetween. Each metal plate is connected via a stitching via. The first via and the second via of the stitching via are connected to a connection pattern formed in the ground layer. The connection pattern is accommodated in the clearance hole so as not to contact the ground layer.

  The metal plates are arranged in one or two rows along the signal transmission path on the signal layer. The metal plates are connected by stitching vias so that signals are transmitted without interruption from the signal source to the signal transmission point.

  A printed circuit board according to another embodiment of the present invention includes two electronic circuits (assumed to be a digital circuit and an analog circuit in this example) having different operating frequencies. At this time, the electromagnetic band gap structure described above is disposed between the analog circuit and the digital circuit.

  That is, the electromagnetic band gap structure is arranged so that the electromagnetic wave transmitted from the digital circuit to the analog circuit always passes through the electromagnetic band gap structure. For this purpose, the electromagnetic bandgap structure may be arranged in a closed curve around the analog circuit, and the electromagnetic bandgap structure may be arranged in a closed curve around the digital circuit. Further, the electromagnetic bandgap structure may be arranged over the whole or a part of the printed circuit board from the digital circuit to the analog circuit.

  In each layer constituting the printed circuit board, an electromagnetic band gap structure is arranged between the power supply layer and the ground layer.

  Any one of the ground layer and the power supply layer becomes a metal layer. And a metal plate is arrange | positioned on the same plane as another one layer spaced apart by fixed distance. Each metal plate is connected through a stitching via. The first via and the second via of the stitching via are connected to a connection pattern formed in the metal layer. The connection pattern is accommodated in the clearance hole so as not to contact the metal layer.

  Since the electromagnetic bandgap structure described above is disposed inside, the printed circuit board used by providing both the analog circuit and the digital circuit has a specific frequency among the electromagnetic waves transmitted from the digital circuit to the analog circuit. Transmission of electromagnetic waves in the region can be prevented.

  That is, despite the small size of the structure, the above-described mixed signal problem can be solved by suppressing the transmission of electromagnetic waves in a specific frequency region corresponding to noise in the analog circuit.

  Although the present invention has been described with reference to the preferred embodiments, those skilled in the art can use the invention without departing from the spirit and scope of the present invention described in the claims. It will be understood that the present invention can be variously modified and changed.

It is sectional drawing of the printed circuit board containing an analog circuit and a digital circuit. 1 is a three-dimensional perspective view of an electromagnetic bandgap structure according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the electromagnetic bandgap structure shown in FIG. 2. FIG. 3 is a plan view showing an arrangement structure of the electromagnetic bandgap structure shown in FIG. 2. FIG. 3 is an equivalent circuit diagram showing the electromagnetic bandgap structure shown in FIG. 2. 3 is a three-dimensional perspective view of an electromagnetic bandgap structure according to another embodiment of the present invention. FIG. FIG. 6 is a perspective view of an electromagnetic bandgap structure according to another embodiment of the present invention. FIG. 6 is a perspective view of an electromagnetic bandgap structure according to another embodiment of the present invention. It is a top view which shows the arrangement structure of the electromagnetic band gap structure which has a square metal plate. It is a top view which shows the arrangement structure of the electromagnetic band gap structure which has a triangular metal plate. It is a top view which shows the strip | belt-shaped arrangement | sequence structure of an electromagnetic band gap structure. It is a top view which shows the arrangement | sequence structure of the electromagnetic band gap structure formed with the metal plate of a several different size group. It is a top view which shows the arrangement | sequence structure of the electromagnetic band gap structure formed with the metal plate of a several different size group. 5 is a frequency characteristic graph of an electromagnetic bandgap structure according to an embodiment of the present invention.

Explanation of symbols

200 Electromagnetic Band Gap Structure 210a, 210b, 210c Metal Plate 220 Metal Layer 225 Clearance Hole 230 Stitching Via

Claims (19)

A dielectric layer; at least three conductive plates; an adjacent conductive plate; a stitching via that electrically connects the conductive plates; and a conductive layer positioned at a distance from the conductive plate to the dielectric layer. ,
The stitching via is
A first via penetrating the dielectric layer and connected to one of two adjacent conductive plates;
A second via passing through the dielectric layer and connected to the other one of the two adjacent conductive plates;
One end connected to the other end of the first via, seen including a connection pattern to the other end is connected to the other end of the second via, the,
The conductive layer is provided with a clearance hole,
The electromagnetic bandgap structure , wherein the connection pattern is accommodated in the clearance hole . The electromagnetic bandgap structure according to claim 1, wherein the conductive plate has a polygonal shape, a circular shape, or an elliptical shape. Wherein the conductive plate, electromagnetic bandgap structure according to claim 1 or claim 2, characterized in that each have the same size. Wherein the conductive plate, according to claim 1 or electromagnetic bandgap structure according to claim 2, characterized in that it is divided into groups of different sizes. The electromagnetic bandgap structure according to any one of claims 1 to 4 , wherein the conductive plates are located on the same plane. A printed circuit board including two electronic circuits having different operating frequencies,
A dielectric layer; at least three or more conductive plates; an adjacent conductive plate; a stitching via that electrically connects between the conductive plates; and a conductive layer positioned at a distance from the conductive plate to the dielectric layer. An electromagnetic bandgap structure is disposed between the two electronic circuits;
The stitching via is
A first via penetrating the dielectric layer and connected to one of two adjacent conductive plates;
A second via passing through the dielectric layer and connected to the other one of the two adjacent conductive plates;
One end connected to the other end of the first via, seen including a connection pattern to the other end is connected to the other end of the second via, the,
The conductive layer is provided with a clearance hole,
The printed circuit board , wherein the connection pattern is accommodated in the clearance hole . The printed circuit board according to claim 6 , wherein the conductive layer is one of a ground layer and a power supply layer, and the conductive plate is connected on the same plane as the other layer. . The printed circuit board according to claim 7 , wherein the conductive plate is connected to the other layer through the stitching via. The printed circuit board according to any one of claims 6 to 8 , wherein the conductive plate has a polygonal shape, a circular shape, or an elliptical shape. Wherein the conductive plate, printed circuit board according to 1, wherein any one of claims 6 to 9, characterized in that each have the same size. Wherein the conductive plate, printed circuit board according to any one of claims 6 to 9, characterized in that it is divided into groups of different sizes. Wherein the conductive plate, printed circuit board according to any one of claims 6 to 11, characterized in that located on the same plane. A printed circuit board including a signal layer and a ground layer,
A dielectric layer; at least three or more conductive plates; an adjacent conductive plate; a stitching via that electrically connects between the conductive plates; and a conductive layer positioned at a distance from the conductive plate to the dielectric layer. An electromagnetic bandgap structure is arranged,
The stitching via is
A first via penetrating the dielectric layer and connected to one of two adjacent conductive plates;
A second via passing through the dielectric layer and connected to the other one of the two adjacent conductive plates;
A connection pattern having one end connected to the other end of the first via and the other end connected to the other end of the second via,
The conductive layer is provided with a clearance hole,
The connection pattern is accommodated in the clearance hole;
The printed circuit board, wherein the conductive plate is connected on the same plane as the signal layer through the stitching via. The printed circuit board according to claim 13 , wherein the conductive layer is a ground layer. Wherein the conductive plate is polygonal, circular or printed circuit board according to claim 13 or claim 14 characterized in that it has an elliptical shape. Wherein the conductive plate, printed circuit board according to any one of claims 13 to claim 15, characterized in that it is arranged in one row or two rows along the signal transmission path. Wherein the conductive plate, printed circuit board according to one of claims claim 13 to claim 16, characterized in that each have the same size. Wherein the conductive plate, printed circuit board according to any one of claims 13 to claim 16, characterized in that it is divided into groups of different sizes. The printed circuit board according to any one of claims 13 to 18, wherein the conductive plates are located on the same plane.

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