KR100871346B1 - Electromagnetic bandgap structure and printed circuit board - Google Patents

Abstract

An electromagnetic bandgap structure and a printed circuit board are provided to obtain a low bandgap frequency while having a small size. A first dielectric layer is laminated on a first metal layer(320a). A mush type structure(330) includes a metal plate(332) laminated on the first dielectric layer and a via(334) of which one end is connected to the metal plate. A second dielectric layer(320b) is laminated on the metal plate and the first dielectric layer. The other end(334b) of the via is positioned in a hole(350) formed in the first metal layer and is connected to the first metal layer through the metal line. The other end of via is connected to a via land(360) positioned in the hole. The metal line(340) connects the via land and the first metal layer.

Description

Electromagnetic bandgap structure and printed circuit board

1 is a cross-sectional view of a printed circuit board including an analog circuit and a digital circuit.

2 is a cross-sectional view of an electromagnetic bandgap structure that solves the mixed signal problem between analog and digital circuits in accordance with the prior art.

3 is a plan view showing a metal plate arrangement structure of the electromagnetic bandgap structure shown in FIG.

4 is a perspective view of the electromagnetic bandgap structure shown in FIG.

FIG. 5 is an equivalent circuit diagram of the electromagnetic bandgap structure shown in FIG. 2. FIG.

6 is a three-dimensional perspective view of an electromagnetic bandgap structure that solves the mixed signal problem between analog and digital circuits in accordance with one embodiment of the present invention.

7 is a plan view showing the arrangement of the electromagnetic bandgap structure shown in FIG.

FIG. 8 is a result of computer simulation using the electromagnetic bandgap structure shown in FIG. 6 and the electromagnetic bandgap structure according to the prior art.

9 is a three-dimensional perspective view of an electromagnetic bandgap structure that solves the mixed signal problem between analog and digital circuits in accordance with another embodiment of the present invention.

10 is a plan view showing the arrangement of the electromagnetic bandgap structure shown in FIG.

11 is a result of computer simulation using the electromagnetic bandgap structure shown in Figure 9 and the electromagnetic bandgap structure according to the prior art.

<Description of the symbols for the main parts of the drawings>

300, 400: electromagnetic bandgap structure

310a, 310b: metal layer

320a, 320b: dielectric layer

330: mushroom structure

332: metal plate 334: via

340: metal wire

345: spiral metal wire

350: hall

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board, and more particularly, to an electromagnetic bandgap structure and a printed circuit board which solve a mixed signal problem between an analog circuit and a digital circuit.

Recently, as mobility is important, various devices such as mobile communication terminals, PDAs (Personal Digital Assistants), notebook computers, and DMB (Digital Multimedia Broadcasting) devices capable of wireless communication are being released.

These devices include printed circuit boards that consist of a combination of analog circuits (eg RF circuits) and digital circuits for wireless communication.

1 is a cross-sectional view of a printed circuit board including an analog circuit and a digital circuit. Although the printed circuit board 100 having a four-layer structure is illustrated, a printed circuit board having various structures, such as two layers and six layers, is also applicable. Here, it is assumed that the analog circuit is an RF circuit.

The printed circuit board 100 may include a metal layer 110-1, 110-2, 110-3, 110-4, hereinafter abbreviated as 110, and a dielectric layer stacked between the metal layer 110. (120) (divided into 120-1, 120-2, and 120-3), a digital circuit 130 mounted on the uppermost metal layer 110-1, and an RF circuit 140.

Assuming that the metal layer 110-2 is a ground layer and the metal layer 110-3 is a power layer, a via connected between the ground layer 110-2 and the power layer 110-3. Current flows through the 160, and the printed circuit board 100 performs a predetermined operation or function.

Here, the electromagnetic wave (EM wave) 150 due to the operating frequency of the digital circuit 130 and the harmonics components are transmitted to the RF circuit 140 to generate a mixed signal problem. The mixed signal problem means that electromagnetic waves in the digital circuit 130 interfere with the correct operation of the RF circuit 140 because they have a frequency in the frequency band in which the RF circuit 140 operates. For example, when the RF circuit 140 receives a signal of a predetermined frequency band, since the electromagnetic wave 150 including the signal in the frequency band is transmitted from the digital circuit 130, the accurate signal within the corresponding frequency band may be lost. Reception can be difficult.

The mixed signal problem is difficult to solve as the operating frequency of the digital circuit 130 increases as the electronic device becomes complicated and becomes more complicated.

The decoupling capacitor method, which is a typical solution of power noise, is not an appropriate solution at high frequencies. Therefore, a study of a structure that blocks high frequency noise between RF circuits and digital circuits is required.

2 is a cross-sectional view of an electromagnetic bandgap structure for solving a mixed signal problem between an analog circuit and a digital circuit according to the prior art, and FIG. 3 is a plan view showing a metal plate arrangement structure of the electromagnetic bandgap structure shown in FIG. 4 is a perspective view of the electromagnetic bandgap structure shown in FIG. 2, and FIG. 5 is an equivalent circuit diagram of the electromagnetic bandgap structure shown in FIG. 2.

The electromagnetic bandgap structure 200 may include a first metal layer 210-1, a second metal layer 210-2, a first dielectric layer 220a, a second dielectric layer 220b, a metal plate 232, and the like. Via 234 is included.

The first metal layer 210-1 and the metal plate 232 are connected through the via 234, and the metal plate 232 and the via 234 form a mushroom type structure 230 (FIG. 4).

When the first metal layer 210-1 is a ground layer The second metal layer 210-2 is a power layer, and when the first metal layer 210-1 is a power layer, the second metal layer is a power layer. 210-2 becomes a ground layer.

That is, by repeatedly arranging the mushroom structure 230 formed of the metal plate 232 and the via 234 between the ground layer and the power layer (see FIG. 3), a band gap that does not pass a signal included in a specific frequency band It has a (bandgap) structure.

Functions that do not pass signals in a particular frequency band include resistance (R _E , R _P ), inductance (L _E , L _P ), capacitance (C _E , C _P , C _G ) And the conductance (G _P , G _E ) components, which are expressed by approximating an equivalent circuit as shown in FIG. 5.

BACKGROUND OF THE INVENTION Representative electronic devices in which digital circuits and RF circuits are implemented and used on the same substrate are mobile communication terminals. In order to solve the mixed signal problem in the mobile communication terminal, noise shielding is required in the region of 0.8 to 2.0 GHz, which is an operating frequency of the RF circuit, and the size of the mushroom structure must be small to be used in the mobile communication terminal. However, when using the above-described electromagnetic bandgap structure there is a problem that does not satisfy both at the same time.

As the size of the mushroom-shaped structure decreases, the bandgap frequency at which the noise is shielded increases, so that the above-described mobile communication terminal is not effective in the 0.8-2.0 GHz region of the operating frequency of the RF circuit.

Accordingly, the present invention provides an electromagnetic bandgap structure and a printed circuit board having a small size and a low bandgap frequency.

The present invention also provides an electromagnetic bandgap structure and a printed circuit board that solve the mixed signal problem in an electronic device (for example, a mobile communication terminal, etc.) in which an RF circuit and a digital circuit are implemented in the same substrate.

The present invention also provides an electromagnetic bandgap structure and a printed circuit board which do not pass noise of a specific frequency.

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

According to one aspect of the present invention, an electromagnetic bandgap structure is provided that prevents signal transmission in a predetermined frequency band.

The electromagnetic bandgap structure includes a first metal layer; A first dielectric layer stacked on the first metal layer; A mushroom structure comprising a metal plate stacked on the first dielectric layer and vias connected at one end to the metal plate; A second dielectric layer stacked on the metal plate and the first dielectric layer; And a second metal layer stacked on the second dielectric layer, wherein the other end of the via is located in a hole formed in the first metal layer and is connected to the first metal layer through a metal wire.

Here, the other end of the via may be connected to a via land located in the hole, and the metal line may connect the via land to the first metal layer.

The hole may accommodate the via and the metal wire.

In addition, the mushroom structure may be a plurality between the first metal layer and the second metal layer.

The metal wire may have a straight line connecting the other end of the via to the first metal layer, or the metal wire may have a spiral structure surrounding the other end of the via.

In addition, it is possible to prevent electromagnetic wave transmission in a predetermined frequency band by using an inductance connected in series between the metal plate and the first metal layer corresponding to the via.

According to another aspect of the present invention, there is provided a printed circuit board comprising an analog circuit and a digital circuit to prevent signal transmission of a predetermined frequency band from the digital circuit to the analog circuit.

The printed circuit board includes a first metal layer; A first dielectric layer stacked on the first metal layer; A mushroom structure comprising a metal plate stacked on the first dielectric layer and vias connected at one end to the metal plate; A second dielectric layer stacked on the metal plate and the first dielectric layer; And a second metal layer stacked on the second dielectric layer, the electromagnetic bandgap structure disposed between the analog circuit and the digital circuit, wherein the other end of the via is located in a hole formed in the first metal layer, and through a metal wire. It is connected to the first metal layer.

Here, the first metal layer may be either a ground layer or a power layer, and the second metal layer may be the other.

The analog circuit may be an RF circuit including an antenna for receiving a radio signal from the outside.

The other end of the via may be connected to a via land located in the hole, and the metal line may connect the via land to the first metal layer.

The hole may accommodate the via and the metal wire.

In addition, the mushroom structure may be a plurality between the first metal layer and the second metal layer.

The metal wire may have a straight line connecting the other end of the via to the first metal layer, or the metal wire may have a spiral structure surrounding the other end of the via.

In addition, it is possible to prevent electromagnetic wave transmission in a predetermined frequency band by using an inductance connected in series between the metal plate and the first metal layer corresponding to the via.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

Terms such as first and second may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

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

FIG. 6 is a three-dimensional perspective view of an electromagnetic bandgap structure for solving a mixed signal problem between an analog circuit and a digital circuit according to an embodiment of the present invention, and FIG. 7 illustrates an arrangement structure of the electromagnetic bandgap structure shown in FIG. 8 is a plan view illustrating a computer simulation using the electromagnetic bandgap structure shown in FIG. 6 and the electromagnetic bandgap structure according to the prior art.

According to an embodiment, the electromagnetic bandgap structure 300 may include a mushroom structure 330 including a metal plate 332 and vias 334, a first metal layer 310a, a second metal layer 310b, and a first dielectric layer ( 320a) and a second dielectric layer 320b. Here, the mushroom structure 330 includes a metal plate 332 of a predetermined size, and a via 334 having one end 334a connected to the metal plate 332 and the other end 334b connected to the first metal layer 310a. It is configured by.

The first metal layer 310a and the metal plate 332 are connected through the via 334. More specifically, the other end 334b of the via 334 is connected to the via land 360, and the via land 360 is connected to the first metal layer 310a through the metal line 340 or without the via 334. The other end 334b) is connected to the first metal layer 310a through the metal line 340.

The dielectric layer 320 is stacked between the first metal layer 310a and the second metal layer 310b. The dielectric layer 320 is divided into a first dielectric layer 320a and a second dielectric layer 320b according to the formation time based on the metal plate 332.

The first metal layer 310a, the second metal layer 310b, the metal plate 332, and the via 334 are made of a metal material (for example, copper (Cu), etc.) to which power is supplied to which a signal can be transmitted. .

The first dielectric layer 320a and the second dielectric layer 320b may be formed of the same dielectric material or a dielectric material having the same or different dielectric constants.

When the first metal layer 310a is a ground layer, the second metal layer 310b is a power layer, and when the first metal layer 310a is a power layer, the second metal layer 310b is a ground layer. to be. That is, the first metal layer 310a and the second metal layer 310b are formed of a ground layer and a power supply layer adjacent to each other with the dielectric layer 320 interposed therebetween.

The metal plate 332 is illustrated as having a square shape, but may have various shapes such as polygons, circles, and ellipses.

A hole 350 is formed in the first metal layer 310a to accommodate the other end 334b of the via 334 and the metal wire 340.

The method of forming the electromagnetic bandgap structure 300 is as follows.

The first metal layer 310a is stacked. The metal line 340 connecting the hole 350 and the first metal layer 310a and the via 334 is patterned. When the via land 360 is required, the via land 360 is also patterned together. Patterning uses a method of masking, exposure, etching, development, etc., which is generally used when forming a circuit pattern on a printed circuit board, and thus a detailed description thereof will be omitted.

The first dielectric layer 320a is stacked on the first metal layer 310a. Thereafter, a via 334 penetrating the first dielectric layer 320a is formed through a drilling process so that the metal plate 332 and the first metal layer 310a to be stacked on the first dielectric layer 320a are electrically connected.

After the formation of the via 334, a plating process is performed such that a plating layer is formed on an inner wall of the via for electrical connection between the metal plate 332 and the first metal layer 310a. Depending on the plating process, the center portion of the inside of the via is empty, and a plating layer may be formed only on the inner wall of the via, or the inside of the via may be filled. When the central portion of the interior of the via is empty, the central portion may be filled with dielectric material or air. The formation of such vias is obvious to those skilled in the art, and detailed descriptions thereof will be omitted.

One end 334a of the via 334 is connected to the metal plate 332, and the other end 334b of the via 334 is connected to the first metal layer 310a.

Thereafter, the second dielectric layer 320b and the second metal layer 310b are sequentially stacked to form the electromagnetic bandgap structure 300.

In the mushroom structure 330 including the metal plate 332 and the via 334, one or more may be formed between the first metal layer 310a and the second metal layer 310b. The metal plates 332 of the plurality of mushroom-like structures 330 may be disposed on the same plane or on different planes between the first metal layer 310a and the second metal layer 310b. In addition, although the via 334 of the mushroom structure 330 faces the first metal layer 310a in FIG. 6, the via 334 may face the second metal layer 310b.

In addition, the vias 334 of the plurality of mushroom-like structures 330 all face the first metal layer 310a or the second metal layer 310b, or the vias 334 of some mushroom-like structures 330 are first The vias 334 of the remaining mushroom-like structure 330 may face toward the second metal layer 310b.

Referring to FIG. 7, an arrangement structure of a hole 350, a metal wire 340, and the like, in which the mushroom structure 330 is arranged at a predetermined interval on the first metal layer 310a is illustrated. The mushroom structure 330 is repeatedly formed to more effectively shield a signal in a frequency domain corresponding to an operating frequency range of an analog circuit (for example, an RF circuit) among electromagnetic waves traveling from a digital circuit to an analog circuit. It is possible.

In the mushroom structure 330, the capacitance value C _E between the metal plate 332 and the second metal layer 310b may be neglected by forming the metal wire 340 on the first metal layer 310a connected to the via 334. Decreases as finely as possible. In addition, the inductance value L _E connected in series between the metal plate 332 and the first metal layer 310a may be sufficiently secured to correspond to the via 334 and the metal wire 340. Therefore, even if the size of the mushroom-like structure 330 can be reduced without increasing the band gap frequency. The bandgap frequency refers to a frequency at which transmission of electromagnetic waves from one side of the electromagnetic bandgap structure 300 to the other side is suppressed. In the embodiment of the present invention, the 0.8 to 2.0 GHz region, which is an operating frequency region in the RF circuit of the mobile communication terminal, corresponds to the band gap frequency region.

8 shows the results of computer simulations using the electromagnetic bandgap structure 200 according to an embodiment of the present invention and the electromagnetic bandgap structure 200 according to the prior art.

Referring to FIG. 8, the structure size (ie, the size of the metal plate 232) of the conventional electromagnetic bandgap structure 200 is 49 mm 2 (7 × 7) (see 810), and 324 mm 2 (18 × 18). Is shown (see 820).

If the structure size is 49 mm2 (7x7) (see 810), the frequency with a noise level of -50 dB or less is 2.8 GHz or more.

When the structure size is 324 mm2 (18x18) (see 820), the frequency with noise level below -50 dB is 0.6-1.4 GHz, and the frequency with the lowest noise level is 1 GHz.

That is, in the case of the conventional electromagnetic bandgap structure 200, the noise must be shielded by placing a bandgap frequency in an area of 0.8 to 2.0 GHz, which is an operating frequency of an RF circuit used in a mobile communication terminal. (18 × 18) (see 820).

However, in the case of the electromagnetic bandgap structure according to the embodiment of the present invention, when the structure size (that is, the size of the metal plate 332) is 49 mm2 (7 × 7) (see 830), the noise level is −. The frequency below 50 dB is 0.8-1.2 GHz and the frequency with the lowest noise level is 1 GHz.

This is shown in Table 1 below.

That is, when the electromagnetic bandgap structure according to an embodiment of the present invention has the same bandgap frequency as the electromagnetic bandgap structure 200 according to the prior art, its size can be reduced by 1/6 or more (324 mm 2) → 49 mm2).

In addition, even in the case of the same structure size it can be seen that the bandgap frequency is lower than 1/2 (2.8 GHz → 1 GHz).

FIG. 9 is a three-dimensional perspective view of an electromagnetic bandgap structure for solving a mixed signal problem between an analog circuit and a digital circuit according to another embodiment of the present invention, and FIG. 10 illustrates an arrangement structure of the electromagnetic bandgap structure shown in FIG. FIG. 11 is a plan view illustrating a computer simulation using the electromagnetic bandgap structure shown in FIG. 9 and the electromagnetic bandgap structure according to the prior art.

Hereinafter, the same parts as the electromagnetic bandgap structure 300 described above with reference to FIGS. 6 to 8 with respect to the electromagnetic bandgap structure 400 according to another embodiment will be omitted and detailed descriptions will be made based on differences.

The electromagnetic bandgap structure 400 according to another embodiment may include a mushroom-like structure 330 including a metal plate 332 and vias 334, a first metal layer 310a, a second metal layer 310b, and a first dielectric layer ( 320a) and a second dielectric layer 320b. Here, the mushroom structure 330 includes a metal plate 332 of a predetermined size, and a via 334 having one end 334a connected to the metal plate 332 and the other end 334b connected to the first metal layer 310a. It is configured by.

6 to 8, the metal line 345 of the electromagnetic bandgap structure 300 according to the present exemplary embodiment has a straight shape compared to the metal line 340 of the electromagnetic bandgap structure 300 according to the exemplary embodiment. It has a spiral structure. Since the metal wire 345 has a spiral structure, the inductance value connected in series between the first metal layer 310a and the metal plate 332 may be sufficiently secured.

The first metal layer 310a is formed with a hole 350 that can accommodate both the spiral metal wire 345 and the other end 334b of the via 334 (or additionally, up to the via land 360). The inner wall of the hole 350 is spaced apart from the metal wire 345 by a predetermined distance, and only both ends of the spiral metal wire 345 are electrically connected to the first metal layer 310a and the via 334.

9 to 10 illustrate a spiral structure in which the metal wire 345 is wound around the via 334 1.5 times, the skilled person should understand that the scope of the present invention is not limited to the number of windings of the spiral structure.

Computer simulation results using the electromagnetic bandgap structure 200 according to another embodiment of the present invention and the electromagnetic bandgap structure 200 according to the related art are shown in FIG. 11.

Referring to FIG. 11, the structure size (ie, the size of the metal plate 232) of the conventional electromagnetic bandgap structure 200 is 4 mm 2 (2 × 2) (see 1110), and 81 mm 2 (9 × 9). (See 1120) is shown.

When the structure size is 4 mm2 (2x2) (see 1110), frequencies with a noise level of -50 dB or less are at least 7.5 GHz.

When the structure size is 81 mm2 (9x9) (see 1120), the frequency with a noise level of -50 dB or less is 0.9 to 2.4 GHz, and the frequency with the smallest noise level is 1.3 GHz.

That is, in the case of the conventional electromagnetic bandgap structure 200, the noise must be shielded by placing a bandgap frequency within a range of 0.8 to 2.0 GHz, which is an operating frequency of an RF circuit used in a mobile communication terminal. (9x9) (see 1120).

However, in the case of the electromagnetic bandgap structure according to another embodiment of the present invention, when the structure size (that is, the size of the metal plate 332) is 4 mm 2 (2 × 2) (see 1130), the noise level is −. The frequency below 50 dB is 1.3-1.7 GHz and the frequency with the lowest noise level is 1.5 GHz.

This is shown in Table 2 below.

That is, when the electromagnetic bandgap structure according to another embodiment of the present invention has the same bandgap frequency as the electromagnetic bandgap structure 200 according to the prior art, the size can be reduced by 1/20 or more (81 mm 2) → 4 mm 2) can be confirmed.

In addition, the bandgap frequency is 1/5 or more low (7.5 GHz to 1.5 GHz) even when having the same structure size.

The printed circuit board according to the embodiment of the present invention includes an analog circuit and a digital circuit. The analog circuit may be an RF circuit such as an antenna that receives a radio signal (RF signal) from the outside.

In the printed circuit board, the electromagnetic bandgap structures 300 and 400 shown in FIGS. 6 and 7, 9 and 10 are disposed between the analog circuit and the digital circuit. That is, electromagnetic band gap structures 300 and 400 are disposed between the RF circuit 140 and the digital circuit 130 of the printed circuit board shown in FIG. 1.

The electromagnetic bandgap structures 300 and 400 are disposed such that electromagnetic waves transmitted from the digital circuit 140 to the RF circuit 130 necessarily pass through the electromagnetic bandgap structures 300 and 400. That is, the electromagnetic bandgap structures 300 and 400 may be arranged in the form of closed curves around the RF circuit 130, or the electromagnetic bandgap structures 300 and 400 may be arranged in the form of closed curves around the digital circuit 140.

Alternatively, electromagnetic bandgap structures 300 and 400 may be disposed in all printed circuit boards from the digital circuit 140 to the RF circuit 130.

Since the above-described electromagnetic bandgap structures 300 and 400 are disposed therein, a printed circuit board in which an analog circuit and a digital circuit are simultaneously implemented and used is a specific frequency region (for example, electromagnetic waves transmitted from a digital circuit to an analog circuit). 0.8 ~ 2.0 GHz) can prevent the transmission of electromagnetic waves.

That is, despite the small structure size, it is possible to solve the mixed signal problem described above by preventing the transmission of electromagnetic waves in a specific frequency region corresponding to noise in the RF circuit.

As described above, the electromagnetic bandgap structure and the printed circuit board according to the present invention may have a small size but a low bandgap frequency.

In addition, there is an effect of solving a mixed signal problem in an electronic device (for example, a mobile communication terminal, etc.) in which an RF circuit and a digital circuit are implemented in the same substrate.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art to which the present invention pertains without departing from the spirit and scope of the present invention as set forth in the claims below It will be appreciated that modifications and variations can be made.

Claims (16)

A first metal layer; A first dielectric layer stacked on the first metal layer; A mushroom structure comprising a metal plate stacked on the first dielectric layer and vias connected at one end to the metal plate; A second dielectric layer stacked on the metal plate and the first dielectric layer; And A second metal layer laminated on the second dielectric layer, The other end of the via is located in the hole formed in the first metal layer, the electromagnetic bandgap structure, characterized in that connected to the first metal layer through a metal wire. The method of claim 1, And the other end of the via is connected to a via land located in the hole, and the metal line connects the via land and the first metal layer. The method of claim 1, And the hole receives the via and the metal wire. The method of claim 1, The mushroom-shaped structure is an electromagnetic bandgap structure, characterized in that there is a plurality between the first metal layer and the second metal layer. The method of claim 1, The metal line is an electromagnetic bandgap structure, characterized in that the straight line connecting the other end of the via and the first metal layer. The method of claim 1, And the metal wire has a spiral structure surrounding the other end of the via. The method of claim 1, Electromagnetic bandgap structure, characterized in that it is possible to prevent electromagnetic wave transmission in the shielding target frequency band by using an inductance connected in series between the metal plate and the first metal layer corresponding to the via. In a printed circuit board comprising an analog circuit and a digital circuit, A first metal layer; A first dielectric layer stacked on the first metal layer; A mushroom structure comprising a metal plate stacked on the first dielectric layer and vias connected at one end to the metal plate; A second dielectric layer stacked on the metal plate and the first dielectric layer; And An electromagnetic bandgap structure comprising a second metal layer stacked on the second dielectric layer, disposed between the analog circuit and the digital circuit, The other end of the via is located in the hole formed in the first metal layer, the printed circuit board, characterized in that connected to the first metal layer through a metal wire. The method of claim 8, And the first metal layer is either a ground layer or a power layer, and the second metal layer is the other. The method of claim 8, The analog circuit is a printed circuit board, characterized in that the RF circuit including an antenna for receiving a wireless signal from the outside. The method of claim 8, And the other end of the via is connected to a via land located in the hole, and the metal line connects the via land to the first metal layer. The method of claim 8, The hole is a printed circuit board, characterized in that for receiving the via and the metal wire. The method of claim 8, The mushroom structure is a printed circuit board, characterized in that there is a plurality between the first metal layer and the second metal layer. The method of claim 8, The metal line is a printed circuit board, characterized in that the straight line connecting the other end of the via and the first metal layer. The method of claim 8, The metal line has a spiral structure surrounding the other end of the via. The method of claim 8, Printed circuit board, it characterized in that it is possible to prevent the electromagnetic wave transmission in the shielding target frequency band by using an inductance connected in series between the metal plate and the first metal layer corresponding to the via.

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