TW201924515A - Circuit board and electromagnetic band gap structure thereof - Google Patents

Abstract

A circuit board includes a dielectric layer, an electrically conductive layer disposed on a surface of the dielectric layer, and an electromagnetic band gap (EBG) structure disposed in the dielectric layer. The electromagnetic band gap structure includes a via and a signal suppression board. Two opposite ends of the via are connected to the electrically conductive layer and the signal suppression board, respectively. The signal suppression board has at least one hollow pattern.

Description

Circuit board and electromagnetic band gap structure thereof

The present invention relates to an electromagnetic bandgap structure (EBG) and a circuit board, particularly an electromagnetic bandgap structure capable of suppressing a dual band signal and a circuit board having the electromagnetic bandgap structure.

At present, the internal functions of products such as circuit boards tend to be complicated, and signals of multiple frequency bands are transmitted inside, so that the cross-talk between the power supply and the signal (Crosstalk) becomes more frequent and unavoidable. In general, in order to maintain the integrity of the signal, there is an additional configuration of the microstrip line for impedance control to protect the integrity of the signal. In addition, the power supply layer of the board cannot be avoided because it does not require additional protection due to its own function and has a rated current limit. When the power layer passes through the signal line, the signal in the signal line is brought into the power layer by coupling, and then radiated into the air through a large area of the power layer, which will cause self-interference and affect wireless (Wireless) Receiving performance.

The existing method is to cover the power layer with a large area of Shielding, conductive cloth or aluminum foil to prevent self-interference, but the disadvantage is that the additional auxiliary materials increase the steps required for the production line assembly product, thus increasing cost.

In view of the above problems, the present invention discloses a circuit board and an electromagnetic bandgap structure thereof, which helps to block signal transmission at a specific frequency to prevent self-interference.

The circuit board disclosed in the present invention comprises a dielectric layer, a conductor layer and an electromagnetic energy gap structure. The conductor layer is disposed on a surface of the dielectric layer, and the electromagnetic energy gap structure is disposed in the dielectric layer. The electromagnetic energy gap structure comprises a via and a signal suppression plate. The opposite ends of the via are respectively connected to the conductor layer and the signal suppression board, and the signal suppression board has at least one hollow pattern.

The electromagnetic band gap structure disclosed in the present invention comprises a via hole and a signal suppressing plate. The signal suppression plate is connected to the via hole, and the signal suppression plate has a two-empty pattern which is point-symmetric centered on the via hole. The two hollow patterns each have a first L-shaped channel and a second L-shaped channel. The first L-shaped channel has a first extension and a second extension. The second L-shaped channel has a third extension and a fourth extension. The first extension and the third extension are respectively located on opposite sides of the via hole, and the second extension section and the fourth extension section are respectively located on opposite sides of the via hole. The second extension is connected to the third extension, and the first extension is spaced apart from the fourth extension by one end away from the second extension.

The electromagnetic bandgap structure disclosed in the present invention comprises a via hole and a signal suppressing plate. The signal suppression board is connected to the via hole, and the signal suppression board has two first hollow patterns and two second hollow patterns. The first hollow pattern is point-symmetric centered on the via hole, and the second second hollow pattern is also point-symmetric centered on the via hole. The first first hollow pattern and the second second hollow pattern are staggered around the via. The first first hollow patterns each have a first L-shaped channel and a spiral channel, and the two first L-shaped channels are respectively located on opposite sides of the via. The second hollow patterns each have a second L-shaped channel and a comb channel, and the second L-shaped channels are respectively located on opposite sides of the via.

According to the electromagnetic band gap structure and the circuit board disclosed in the present invention, an electromagnetic band gap structure having a hollow pattern is disposed in the dielectric layer of the circuit board to be electrically connected to the conductor layer, and the hollow pattern has a specific geometric shape to block the specific double The signal of the frequency band continues to be transmitted, thereby reducing the self-interference phenomenon and reducing the effect of noise diffusion and radiation.

The above description of the disclosure and the following description of the embodiments of the present invention are intended to illustrate and explain the spirit and principles of the invention, and to provide further explanation of the scope of the invention.

The detailed features and advantages of the present invention are set forth in the Detailed Description of the Detailed Description of the <RTIgt; </ RTI> <RTIgt; </ RTI> </ RTI> </ RTI> <RTIgt; The objects and advantages associated with the present invention can be readily understood by those skilled in the art. The following examples are intended to describe the present invention in further detail, but are not intended to limit the scope of the invention.

Please refer to FIG. 1 to FIG. 3 at the same time. 1 is a perspective view of a circuit board in accordance with a first embodiment of the present invention. 2 is a cross-sectional view of the circuit board of FIG. 1. 3 is a bottom view of the signal suppression plate of the electromagnetic bandgap structure in the circuit board of FIG. 1. In the present embodiment, the circuit board 1 includes a dielectric layer 10, a conductor layer 20, a ground layer 30, and an electromagnetic bandgap structure 40.

The dielectric layer 10 can be, for example, an electric wood board, a fiberglass board, or a plastic board having opposing two surfaces 110. The conductor layer 20 is disposed on one of the surfaces 110 of the dielectric layer 10. The conductor layer 20 is, for example but not limited to, a metal layer comprising a plurality of microstrips for signal routing to control impedance. The ground layer 30 is disposed on the other surface 110 of the dielectric layer 10 such that the conductor layer 20 and the ground layer 30 are respectively located on opposite sides of the dielectric layer 10.

The electrical tape gap structure 40 is disposed in the dielectric layer 10 between the microstrip line of the conductor layer 20 and the ground layer 30. The electrical tape gap structure 40 includes a plurality of vias 410 and a plurality of signal suppression plates 420 corresponding to the number of vias 410. However, the number of vias 410 and signal suppression plates 420 is not intended to limit the present invention. The opposite ends of the via hole 410 are electrically connected to the conductor layer 20 and the signal suppression plate 420, respectively. In the present embodiment, the via hole 410 is a through hole on which the metal film is plated on the inner sidewall, but the invention is not limited thereto. In other embodiments, the via 410 is a solid metal pillar embedded in the dielectric layer 10.

The signal suppression plate 420 is, for example but not limited to, a metal plate having two first hollow patterns 421 and two second hollow patterns 422. Each of the first hollow pattern 421 and the second hollow pattern 422 runs through the signal suppression plate 420. In the present embodiment, since each of the signal suppression plates 420 has the same structural size, one of the signal suppression plates 420 will be described in detail below.

As shown in FIG. 3, the first hollow pattern 421 and the second hollow pattern 422 of the signal suppression plate 420 are staggered around the via 410. In detail, the hollow pattern surrounds the via hole 410 in accordance with the arrangement order of the first hollow pattern 421 , the second hollow pattern 422 , the first hollow pattern 421 and the second hollow pattern 422 . The two first hollow patterns 421 are distributed point-symmetrically about the central axis 411 of the via 410. Similarly, the second second hollow patterns 422 are also distributed point-symmetrically about the central axis 411 of the via 410.

The two first hollow patterns 421 each have a first L-shaped channel 4211 and a spiral channel 4212, and the two first L-shaped channels 4211 are respectively located on opposite sides of the via 410. The spiral channel 4212 is connected to the first L-shaped channel 4211. In the present embodiment, the spiral channel 4212 is connected to the long side of the first L-shaped channel 4211, but the invention is not limited thereto. In other embodiments, the spiral channel 4212 is coupled to the short side of the first L-shaped channel 4211. In addition, the two first hollow patterns 421 of the embodiment are all closed loops, that is, the first hollow pattern 421 is not connected to the periphery 423 of the signal suppression plate 420 via any gap.

The second hollow patterns 422 each have a second L-shaped channel 4221 and a comb channel 4222, and the two second L-shaped channels 4221 are respectively located on opposite sides of the via 410. An L-shaped channel 4211 and a second L-shaped channel 4221 collectively surround the via 410. The comb channel 4222 is coupled to the second L-shaped channel 4221, and the comb channel 4222 has a spiral section 4222a and a branch section 4222b surrounded by the spiral section 4222a. In the present embodiment, the comb channel 4222 is connected to the long side of the second L-shaped channel 4221, but the invention is not limited thereto. In other embodiments, the comb channel 4222 is coupled to the short side of the second L-shaped channel 421. In addition, the two second hollow patterns 422 of the embodiment are all non-closed loops, that is, the second hollow pattern 422 is connected to the periphery 423 of the signal suppression board 420 via a notch 424.

By the electromagnetic bandgap structure 40 disposed in the dielectric layer 10, the S21 parameter (feed loss, S(2, 1)) of the specific frequency signal can be reduced to block the transmission of the specific frequency signal in the conductor layer 20. Sex. Further, the electromagnetic bandgap structure 40 can adjust the parasitic inductance and the parasitic capacitance such that the overall bandwidth of the frequency to be blocked increases and the resonant frequency is changed. The parasitic inductance can be increased by changing the position of the via 410 and forming a hollow pattern of a particular geometric shape on the signal suppression plate 420. In addition, the parasitic capacitance can be adjusted by the size of the signal suppression board 420 and the hollow pattern. A hollow pattern with a point symmetry distribution around the via 410 can generate a signal resonance point adjacent to the hollow pattern, thereby achieving blocking of the dual band signal. Thereby, the electromagnetic bandgap structure 40 helps to prevent noise radiation or spread along the power layer, thereby reducing self-interference.

4 is a diagram showing the relationship between the S21 parameter and the signal frequency in the first embodiment of the present invention. When the electromagnetic bandgap structure 40 of FIG. 3 is disposed in the dielectric layer 10, the blocking effect of the dual-band signal can be achieved, so that the frequency band of the microstrip line of the conductor layer 20 is between 2.26 GHz (GHz) and 2.60 GHz. The S21 parameter is less than -30 dB (decibel), while the S21 parameter of the signal in other bands is maintained at approximately -5 dB. This means that signals with a frequency band between 2.26 GHz and 2.60 GHz are blocked by the electromagnetic bandgap structure 40 and cannot continue to be transmitted within the microstrip line, while most of the other band signals can be transmitted completely within the microstrip line.

The signal suppression plate of the electromagnetic bandgap structure of the present invention is not limited to the hollow pattern disclosed in the first embodiment. Figure 5 is a perspective view of a circuit board in accordance with a second embodiment of the present invention. 6 is a bottom view of the signal suppression plate of the electromagnetic bandgap structure in the circuit board of FIG. 5. In the present embodiment, the circuit board 1 ′′ includes a dielectric layer 10 , a conductor layer 20 , a ground layer 30 , and an electromagnetic band gap structure 40 ′′ disposed in the dielectric layer 10 . The structures of the dielectric layer 10, the conductor layer 20, and the ground layer 30 are similar to those of the circuit board 1 of the first embodiment, and therefore will not be repeatedly described below.

The electrical tape gap structure 40" includes a plurality of vias 410 and a plurality of signal suppression plates 420", but the number of vias 410 and signal suppression plates 420" is not intended to limit the invention. The opposite ends of the vias 410 are respectively electrically Connected to the conductor layer 20 and the signal suppression plate 420.

Each of the signal suppression plates 420" has two hollow patterns 421", and each of the hollow patterns 421" runs through the signal suppression plate 420". In the present embodiment, since each of the signal suppression plates 420" has the same structural size, one of the signal suppression plates 420" will be described in detail below.

As shown in FIG. 6, the two hollow patterns 421" are distributed point-symmetrically about the central axis 411 of the via 410. Each of the hollow patterns 421" has a first L-shaped channel 4211" surrounding the via 410 and A second L-shaped channel 4212". The first L-shaped channel 4211" has a first extension 4211a" and a second extension 4211b", and the width of the first extension 4211a" is greater than the width of the second extension 4211b". The channel 4212" has a third extension 4212a", a fourth extension 4212b" and a projection 4212c", and the width of the third extension 4212a" is greater than the width of the fourth extension 4212b". The first extension 4211a" and the third extension 4212a" are respectively located on opposite sides of the via 410, and the thinner second extension 4211b" and the fourth extension 4212b" are respectively located on the opposite side of the via 410. The second extension 4211b" of the first L-shaped channel 4211" is coupled to the third extension 4212a" of the second L-shaped channel 4212", and the first extension 4211a" is remote from the second extension 4211b" One end is spaced from the fourth extension 4212b" to form a crossing area A. The first L-shaped channel 4211" of one of the hollow patterns 421" passes through the crossing area A and is surrounded by another hollow pattern 421". The protruding section 4212c" of the second L-shaped channel 4212" is connected to the fourth extension 4212b One end away from the third extension 4212a, and the projection 4212c" extends from the fourth extension 4212b" away from the via 410.

In addition, the shape of the perimeter 423" of each of the signal suppression plates 420" of the present embodiment is a parallelogram, and the two hollow patterns 421" of each of the signal suppression plates 420" are closed loops. Further, in this embodiment, the hollow pattern 421" is not connected to the periphery 423" of the signal suppression plate 420" via any gap, and the angle between any two adjacent sides of the perimeter 423" is not 90 degrees, that is, the periphery The 423" shape is not square or rectangular.

By configuring the electromagnetic bandgap structure 40", the S21 parameter of the specific frequency signal can be lowered to block the transmission integrity of the specific frequency signal in the conductor layer 20. Figure 7 is a S21 parameter versus signal frequency in the second embodiment of the present invention. The relationship between the dual-band signals can be achieved when the electromagnetic bandgap structure 40" of FIG. 6 is disposed in the dielectric layer 10, so that the frequency of the conductor layer 20 is between 2.26 GHz (GHz) and 2.59 GHz. The S21 parameter is less than -30 dB (decibel), while the S21 parameter of the signal in the other bands is maintained at approximately -5 dB. This means that signals with a frequency band between 2.26 GHz and 2.59 GHz are blocked by the electromagnetic bandgap structure 40" and cannot continue to be transmitted in the conductor layer 20, while most of the other frequency band signals can be transmitted completely within the conductor layer 20.

In summary, in the circuit board and the electromagnetic band gap structure disclosed in the present invention, an electromagnetic band gap structure having a hollow pattern is disposed in the dielectric layer of the circuit board to be electrically connected to the conductor layer, and the hollow pattern has a specific geometry. The styling prevents the transmission of specific dual-band signals, thereby reducing self-interference and reducing the effects of noise diffusion and radiation.

Although the present invention has been disclosed above in the foregoing embodiments, these embodiments are not intended to limit the invention. It is within the scope of the invention to be modified and modified without departing from the spirit and scope of the invention. Please refer to the attached patent application for the scope of protection defined by the present invention.

1, 1" ‧ ‧ circuit board

10‧‧‧Dielectric layer

110‧‧‧ surface

20‧‧‧Conductor layer

30‧‧‧ Grounding layer

40, 40" ‧ ‧ electromagnetic band gap structure

410‧‧‧through hole

411‧‧‧ center axis

420, 420"‧‧‧ signal suppression board

421‧‧‧ first openwork pattern

4211‧‧‧First L-shaped channel

4212‧‧‧Spiral channel

422‧‧‧Second hollow pattern

4221‧‧‧Second L-shaped channel

4222‧‧‧Comb channel

4222a‧‧‧Spiral section

Section 4222b‧‧‧

423, 423" ‧ ‧ surrounding

424‧‧‧ gap

421"‧‧‧ hollow pattern

4211”‧‧‧First L-shaped channel

4212”‧‧‧Second L-shaped channel

4211a”‧‧‧First extension

4211b”‧‧‧Second extension

4212a”‧‧‧ third extension

4212b”‧‧‧4th extension

4212c”‧‧‧High section

A‧‧‧ crossing area

1 is a perspective view of a circuit board in accordance with a first embodiment of the present invention. 2 is a cross-sectional view of the circuit board of FIG. 1. 3 is a bottom view of the signal suppression plate of the electromagnetic bandgap structure in the circuit board of FIG. 1. 4 is a diagram showing the relationship between the S21 parameter and the signal frequency in the first embodiment of the present invention. Figure 5 is a perspective view of a circuit board in accordance with a second embodiment of the present invention. 6 is a bottom view of the signal suppression plate of the electromagnetic bandgap structure in the circuit board of FIG. 5. Figure 7 is a diagram showing the relationship between the S21 parameter and the signal frequency in the second embodiment of the present invention.

Claims (10)

A circuit board comprising: a dielectric layer; a conductor layer disposed on a surface of the dielectric layer; and an electromagnetic energy gap structure disposed in the dielectric layer, the electromagnetic energy gap structure including a via hole and a signal suppression board, the opposite ends of the via are respectively connected to the conductor layer and the signal suppression board, and the signal suppression board has at least one hollow pattern. The circuit board of claim 1, wherein each of the at least one hollow pattern of the signal suppression plate has a first L-shaped channel and a second L-shaped channel surrounding the via hole, The first L-shaped channel has a first wide extension and a first thin extension, and the second L-shaped channel has a second wide extension and a second extension. A wide extension and the second extension are respectively located on opposite sides of the through hole, and the first extension and the second extension are respectively located on opposite sides of the via, the first extension The segment is connected to the second wide extension, and the first wide extension is spaced apart from the second thin extension by one end of the first thin extension. The circuit board of claim 2, wherein the second L-shaped channel further has a protruding section, the protruding section being connected to the second thin extending section away from one end of the second wide extending section and The second thin extension extends away from the via. The circuit board of claim 1 or 2, wherein the number of the at least one hollow pattern is two, and the two hollow patterns are point-symmetric centered on the via. The circuit board of claim 1, wherein the signal suppression plate has a peripheral shape of a parallelogram, and the at least one hollow pattern is a closed loop. The circuit board of claim 1, wherein the at least one hollow pattern of the signal suppression plate comprises two first hollow patterns, the two first hollow patterns being point-symmetric centered on the via hole, the second Each of the hollow patterns has a first L-shaped channel and a spiral channel, and the two first L-shaped channels are respectively located on opposite sides of the via. The circuit board of claim 6, wherein the at least one hollow pattern further comprises two second hollow patterns, the second hollow patterns being point-symmetric centered on the via, the second hollow patterns being respectively Having a second L-shaped channel and a comb-shaped channel, the two second L-shaped channels are respectively located on opposite sides of the via hole, and the two first hollow patterns and the second second hollow pattern Staggered around the via. The circuit board of claim 7, wherein the two first hollow patterns are closed loops, and the two second hollow patterns are unclosed loops. An electromagnetic energy gap structure comprising: a via hole; and a signal suppression plate connected to the via hole, wherein the signal suppression plate has a two-empty pattern which is point-symmetric around the via hole; wherein the two hollow patterns Each has a first L-shaped channel and a second L-shaped channel, the first L-shaped channel has a first extension and a second extension, and the second L-shaped channel has a connection a third extension segment and a fourth extension segment, the first extension segment and the third extension are respectively located on opposite sides of the via hole, and the second extension segment and the fourth extension segment are respectively located in the via hole The second extension is connected to the third extension on opposite sides, and the first extension is spaced apart from the fourth extension by one end of the second extension. An electromagnetic energy gap structure includes: a via hole; and a signal suppression plate connected to the via hole, and the signal suppression plate has two first hollow patterns and two second hollow patterns, wherein the two first hollow patterns are The via hole is center-symmetric, the second hollow pattern is point-symmetric centered on the via hole, and the two first hollow patterns and the two second hollow patterns are staggered around the via hole; wherein the two The first hollow patterns each have a first L-shaped channel and a spiral channel. The two first L-shaped channels are respectively located on opposite sides of the via, and the two second hollow patterns are respectively connected. a second L-shaped channel and a comb channel, and the two second L-shaped channels are respectively located on opposite sides of the via.