U.S. patent application number 14/204631 was filed with the patent office on 2014-07-10 for printed circuit board including electromagnetic bandgap structure.
This patent application is currently assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD.. The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Won Woo CHO, Myung Gun CHONG, Hyung Ho KIM, Jung Soo KIM, Dek Gin YANG.
Application Number | 20140191907 14/204631 |
Document ID | / |
Family ID | 43380113 |
Filed Date | 2014-07-10 |
United States Patent
Application |
20140191907 |
Kind Code |
A1 |
CHO; Won Woo ; et
al. |
July 10, 2014 |
PRINTED CIRCUIT BOARD INCLUDING ELECTROMAGNETIC BANDGAP
STRUCTURE
Abstract
Embodiments of the present invention provide a printed circuit
board, which includes an electromagnetic bandgap structure disposed
around an antenna, so as to prevent noise from being transmitted to
the antenna. The printed circuit board includes an antenna, a
circuit chip, a plurality of metal layers and a plurality of
dielectric layers, a pair of transmission lines for transmitting a
signal to the antenna, and an electromagnetic bandgap structure
disposed between the antenna and the circuit chip and for
preventing an electromagnetic wave from being transmitted from the
circuit chip to the antenna.
Inventors: |
CHO; Won Woo; (Gyunggi-do,
KR) ; YANG; Dek Gin; (Gyunggi-do, KR) ; CHONG;
Myung Gun; (Gyunggi-do, KR) ; KIM; Jung Soo;
(Gyunggi-do, KR) ; KIM; Hyung Ho; (Gyunggi-do,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Gyunggi-do |
|
KR |
|
|
Assignee: |
SAMSUNG ELECTRO-MECHANICS CO.,
LTD.
Gyunggi-do
KR
|
Family ID: |
43380113 |
Appl. No.: |
14/204631 |
Filed: |
March 11, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12650482 |
Dec 30, 2009 |
8711055 |
|
|
14204631 |
|
|
|
|
Current U.S.
Class: |
343/700MS |
Current CPC
Class: |
H01Q 1/38 20130101; H01L
2224/16227 20130101; H01Q 1/2283 20130101; H01Q 15/008 20130101;
H01L 2223/6677 20130101; H01L 2924/15313 20130101 |
Class at
Publication: |
343/700MS |
International
Class: |
H01Q 1/38 20060101
H01Q001/38 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 24, 2009 |
KR |
10-2009-0056534 |
Nov 3, 2009 |
KR |
10-2009-0105670 |
Claims
1. A printed circuit board, comprising: an antenna; a circuit chip;
a plurality of metal layers and a plurality of dielectric layers; a
pair of transmission lines configured to transmit a signal to the
antenna; and an electromagnetic bandgap structure disposed between
the antenna and the circuit chip in the printed circuit board and
configured to prevent an electromagnetic wave from being
transmitted from the circuit chip to the antenna, wherein the
electromagnetic bandgap structure comprises a dielectric layer; a
plurality of conductive plates; and a stitching via configured to
electrically connect the conductive plates to each other, and
wherein the stitching via passes through the dielectric layer, and
a part of the stitching via is placed in a planar surface that is
different from a planar surface in which the conductive plates are
placed.
2. The printed circuit board as set forth in claim 1, wherein the
stitching via comprises: a first via passing through the dielectric
layer and having an end part being connected to any one of two
adjacent conductive plates, and a second via passing through the
dielectric layer and having an end part being connected to the
other of two adjacent conductive plates; and a connection pattern
having one end part being connected to the other end part of the
first via and the other end part being connected to the other end
part of the second via.
2. The printed circuit board as set forth in claim 2, further
comprising: a conductive layer, wherein the dielectric layer is
placed between the conductive plates and the conductive layer.
4. The printed circuit board as set forth in claim 3, wherein the
conductive layer comprises a-clearance hole, and the connection
pattern is accommodated in the clearance hole.
5. The printed circuit board as set forth in claim 1, wherein the
conductive plates have a polygonal, circular or elliptical
shape.
6. The printed circuit board as set forth in claim 1, wherein the
conductive plates have the same size
7. The printed circuit board as set forth in claim 1, wherein the
conductive plates are distinguished into a plurality of groups
having different conductive plate sizes.
8. The printed circuit board as set forth in claim 1, wherein the
conductive plates are placed on the same planar surface.
Description
CROSS REFERENCE TO RELATED APPLICATION:
[0001] This application claims the benefit of and priority to U.S.
patent application Ser. No. 12/650,482, entitled "Printed Circuit
Board Including Electromagnetic Bandgap Structure," filed. Dec. 30,
2009, which claims the benefit of and priority under 35 U.S.C.
.sctn.119 to Korean Patent Application No. KR 10-2009-0056534,
entitled, "Printed Circuit Substrate Using the Electromagnetic
:Bandgap," filed on Jun. 24, 2009, and Korean Patent Application
No. KR 2009-0105670, entitled, "Printed Circuit Substrate Using the
Electromagnetic Bandgap," filed on Nov. 3, 2009, which are all
hereby incorporated by reference in their entirety into this
application.
BACKGROUND:
[0002] 1. Field of the Invention
[0003] The present invention relates to a quartz vibrator and a
printed circuit board (PCB), and more particularly, to a PCB which
includes an electromagnetic bandgap structure that is disposed
around an antenna so as to prevent noise from being transmitted to
the antenna.
[0004] 2. Description of the Related Art
[0005] Recently, as a radio communication device is required to
have a large number of different functions, the number of
components mounted on the device has increased and the size and
thickness of the device have been remarkably reduced, and thus the
density of a PCB which is an important component of the device is
on a continuously increasing trend.
[0006] When the density of the PCB is increased in this way, the
distances separating the mounted components become reduced, and
accordingly, signal interference occurs therebetween. A signal
generated from a component has an influence in the form of noise on
another adjacent component.
[0007] In particular, depending on an increase in the density of
the PCB, a chip component which has been mounted around the antenna
may he located nearby the antenna, so that a signal generated from
the chip component affects the antenna, undesirably deteriorating
performance of the antenna.
[0008] Generally, communication is achieved in such a manner that
the antenna receives power from the feed line of a main PCB to thus
radiate radio frequency to the outside.
[0009] In the case where the antenna is a FIFA or loop type
antenna, the antenna simultaneously uses the ground and feed
terminals of the main PCB. In this way, when the antenna
simultaneously uses the ground and feed terminals of the main PCB,
noise generated from the RF circuit or digital circuit of the main
PCB propagates to the inside or outside of the PCB and thus affects
a radio frequency output, consequently deteriorating performance of
the antenna in the frequency band affected by noise,
[0010] Because noise has a direct or indirect influence on antenna
performance along the feed or ground line of the antenna, even when
the antenna is differently designed, there is a limitation on an
improvement in its performance.
[0011] Although such noise may be blocked using a passive element
or an L/C filer, in the case where the propagation pathway of noise
cannot be exactly determined, design lead time may be increased,
undesirably resulting in high cost.
[0012] Specifically, in the case where the propagation pathway of
noise is unclear, many designs for blocking noise should be
reexamined, and thus the lead time is increased, undesirably
causing a problem of increasing the cost.
[0013] Furthermore, when the pathway of noise varies depending on
changes in antenna design or a new noise source may be created,
antenna performance may deteriorate as a result.
SUMMARY:
[0014] Embodiments of the present invention have been made keeping
in mind the problems encountered in the related art and the present
invention intends to provide a PCB including an electromagnetic
bandgap structure in order to prevent performance of an antenna
from being deteriorated due to noise inside the PCB,
[0015] According to an embodiment of the present invention, there
is provided a PCB including an antenna, a circuit chip, a plurality
of metal layers and a plurality of dielectric layers, a pair of
transmission lines for transmitting a signal to the antenna, and an
electromagnetic bandgap structure disposed between the antenna and
the circuit chip in the PCB and for preventing an electromagnetic
wave from being transmitted from the circuit chip to the
antenna.
[0016] In accordance with an embodiment of the present invention,
the circuit chip is an analog circuit chip for transmitting the
signal to the antenna, and the electromagnetic wave transmitted
from the circuit chip to the antenna is an electromagnetic wave
caused by an operating frequency and harmonic components of the
circuit chip.
[0017] In accordance with an embodiment of the present invention,
mention, the circuit chip is digital circuit chip, and the
electromagnetic wave transmitted from the circuit chip to the
antenna is an electromagnetic wave caused by an operating frequency
and harmonic components of the circuit chip.
[0018] In accordance with an embodiment of the present invention,
one of the pair of transmission lines is formed in a first metal
layer of the plurality of metal layers so as to transmit the signal
to the antenna, and the electromagnetic bandgap structure includes
a plurality of metal plates spaced apart from the one of the pair
of transmission lines in a direction of the antenna, and a
plurality of vias for connecting the one of the pair of
transmission lines and the metal plates to each other, in which
sets of the metal plates and the vias are periodically arranged at
a predetermined interval.
[0019] In accordance with an embodiment of the present invention,
the other of the pair of transmission lines is formed in a second
metal layer of the plurality of metal layers which is spaced apart
from the first metal layer in a direction of the antenna, and the
metal plates are formed in the second metal layer.
[0020] In accordance with an embodiment of the present invention,
the one of the pair of transmission lines is a ground plate, and
the other of the pair of transmission lines is a feed line.
[0021] In accordance with an embodiment of the present invention,
the other of the pair of transmission lines is formed in a second
metal layer of the plurality of metal layers which is spaced apart
from the first metal layer in a direction of the antenna, and the
metal plates are formed between the first metal layer and the
second metal layer.
[0022] In accordance with an embodiment of the present invention,
the one of the pair of transmission lines is a ground plate, and
the other of the pair of transmission lines is a feed line.
[0023] In accordance with an embodiment of the present invention,
the other of the pair of transmission lines is formed around the
one of the pair of transmission lines on the first metal layer.
[0024] In accordance with an embodiment of the present invention,
the one of the pair of transmission lines is a feed line, and the
other of the pair of transmission lines is a ground plate.
[0025] In accordance with an embodiment of the present invention,
the PCB further includes an organic titanium coating layer formed
on an outer surface of each of the metal plates.
[0026] In accordance with an embodiment of the present invention, a
pad for electrically connecting the antenna and the transmission
line to each other is provided at a surface of the antenna, and the
plurality of metal plates of the electromagnetic bandgap structure
are periodically arranged so as to enclose the pad.
[0027] Various objects, advantages and features of the present
invention will become apparent from the following description of
embodiments with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS:
[0028] These and other features, aspects, and advantages of the
present invention are better understood with regard to the
following Detailed Description, appended Claims, and accompanying
Figures. It is to be noted, however, that the Figures illustrate
only various embodiments of the present invention and are therefore
not to be considered limiting of the invention's scope as it may
include other effective embodiments as well.
[0029] FIG. 1 is a cross-sectional view showing a PCB including an
electromagnetic bandgap structure, in accordance with an embodiment
of the invention.
[0030] FIG. 2 is a perspective view showing the electromagnetic
bandgap structure of FIG. 1, in accordance with an embodiment of
the invention.
[0031] FIG. 3 is a cross-sectional view showing a unit of the
electromagnetic bandgap structure of FIG. 1, in accordance with an
embodiment of the invention.
[0032] FIG. 4 is a cross-sectional view showing a unit array of the
electromagnetic bandgap structure of FIG. 1, in accordance with an
embodiment of the invention.
[0033] FIG. 5 is a top plan view showing the unit array of the
electromagnetic bandgap structure of FIG. 1, in accordance with an
embodiment of the invention,
[0034] FIG. 6 is a perspective view showing an electromagnetic
bandgap structure, in accordance with an embodiment of the
invention.
[0035] FIG. 7 is a cross-sectional view showing a unit of the
electromagnetic bandgap structure of FIG. 6, in accordance with an
embodiment of the invention,
[0036] FIG. 8 is a cross-sectional view showing a unit array of the
electromagnetic bandgap structure of FIG. 6, in accordance with an
embodiment of the invention.
[0037] FIG. 9 is a top plan view showing the unit array of the
electromagnetic bandgap structure of FIG. 6, in accordance with an
embodiment of the invention.
[0038] FIG. 10 is a perspective view showing an electromagnetic
bandgap structure according to a further embodiment of the present
invention, in accordance with an embodiment of the invention.
[0039] FIG. 11 is a cross-sectional view showing a unit of the
electromagnetic bandgap structure of FIG. 10, in accordance with an
embodiment of the invention.
[0040] FIG. 12 is a cross-sectional view showing a unit array of
the electromagnetic bandgap structure of FIG. 10, in accordance
with an embodiment of the invention.
[0041] FIG. 13 is a top plan view showing the unit array of the
electromagnetic bandgap structure of FIG. 10, in accordance with an
embodiment of the invention.
[0042] FIG. 14 is a 3-D perspective view showing an electromagnetic
bandgap structure, in accordance with an embodiment of the
invention.
[0043] FIG. 15 is a sectional view showing the electromagnetic
bandgap structure of FIG. 14, in accordance with an embodiment of
the invention.
[0044] FIG. 16 is a plan view showing, a configuration of the
electromagnetic bandgap structure of FIG. 14, in accordance with an
embodiment of the invention.
[0045] FIG. 17 shows an equivalent circuit of the electromagnetic
bandgap structure of FIG. 14, in accordance with an embodiment of
the invention.
[0046] FIG. 18 is a 3-D perspective view showing an electromagnetic
bandgap structure, accordance with an embodiment of the
invention.
[0047] FIG. 19 is a 3-D perspective view showing an electromagnetic
bandgap structure, in accordance with an embodiment of the
invention,
[0048] FIG. 20 is a 3-D perspective view showing an electromagnetic
bandgap structure, in accordance with an embodiment of the
invention.
DETAILED DESCRIPTION:
[0049] The present invention will now be described more fully
hereinafter with reference to the accompanying drawings, which
illustrate embodiments of the present invention. This invention
may, however, be embodied in many different forms and should not be
construed as limited to the illustrated embodiments set forth
herein. Rather, these embodiments are provided so that this
disclosure will be thorough and complete, and will fully convey the
scope of the present invention to those skilled in the art. Like
numbers refer to like elements throughout. Prime notation, if used
indicates similar elements in alternative embodiments.
[0050] FIG. 1 is a cross-sectional view showing a PCB including an
electromagnetic bandgap structure, in accordance with an embodiment
of the invention.
[0051] With reference to FIG. 1, a PCB 100 using an electromagnetic
bandgap structure 150 according to the embodiment of the present
invention includes metal layers 110-1, 110-2, 110-3, 110-4, 110-5,
110-6 (hereinafter, collectively referred to as "110"), dielectric
layers 120-1, 120-2, 120-3, 120-4, 120-5 (hereinafter, collectively
referred to as "120") disposed between the metal layers 110, a
circuit chip 130 mounted on the first upper metal layer 110-1, an
antenna 140 mounted on the first upper metal layer 110-1 and spaced
apart from the circuit chip 130, an electromagnetic bandgap
structure 150 disposed between the circuit chip 130 and the antenna
140 and between the first upper metal layer 110-1 and the second
upper metal layer 110-2 (or between the first upper metal layer
110-1 and the third upper metal layer 110-3), and solder resists
160-1, 160-2 respectively formed in the first upper metal layer
110-1 and the lowermost metal layer 110-6.
[0052] Supposing that the metal layer 110-3 is a ground layer and
the metal layer 110-4 is a power layer, current flows through a via
170 connected between the ground layer 110-3 and the power layer
110-4, and the PCB 100 performs a predetermined operation or
function.
[0053] In accordance with at least one embodiment, the metal layer
110-1 includes a pad 110a for electrically connecting the antenna
140 and the metal layer to each other.
[0054] In accordance with at least one embodiment, the pad 110a
formed in the metal layer 110-1 is a feed pad or a ground pad. In
the case where the metal layer 110-1 includes a feed line as a
transmission line, the feed line contained in the metal layer 110-1
is connected to the antenna 140 through a feed pad.
[0055] In the case where the metal layer 110-1 includes the feed
line as above, the metal layer 110-2 or 110-3 includes a ground
line (or a ground plate) as a transmission line. In this case, the
ground line is electrically connected to the antenna 140 through a
via (not shown) and the ground pad.
[0056] In addition, the metal layer 110-1 or the metal layer 110-2
or 110-3 includes both the ground line and the feed line as
transmission lines.
[0057] In accordance with at least one embodiment, when the antenna
140 simultaneously uses the feed line and the ground line, which
are a pair of transmission lines in the same PCB 100, an
electromagnetic wave 180 caused by an operating frequency and
harmonic components of the circuit chip 130 is transmitted to
between the ground line and the feed line of the antenna 140,
undesirably causing a mixed signal problem.
[0058] The mixed signal problem means disturbing an accurate
operation of the antenna 140 because the electromagnetic wave from
the circuit chip 130 has a frequency within the operating frequency
band of the antenna 140.
[0059] For example, when the antenna 140 transmits or receives a
predetermined frequency signal, the electromagnetic wave 180
including the predetermined frequency signal is transmitted from
the circuit chip 130, making it difficult to accurately transmit or
receive the signal.
[0060] In order to solve such a mixed signal problem, in accordance
with various embodiments of the present invention, the
electromagnetic bandgap structure 150 is mounted between the
circuit chip 130 and the antenna 140 and also between the metal
layer 110-1 having the feed line and the metal layer 110-2 or 110-3
having the ground line, thus blocking the transmission of the mixed
signal to the antenna 140 from the circuit chip 130.
[0061] In accordance with at least one embodiment, the circuit chip
130 is an RE analog circuit chip directly connected to the antenna
140 through the feed line or a digital circuit chip indirectly
connected to the antenna 40 through the RF analog circuit chip.
[0062] In the case of the digital circuit chip, it is not directly
connected to the antenna 140 as in the RF analog circuit chip, and
thus may reduce an effect of noise on the antenna 140.
[0063] However, the digital circuit chip deals with signals 0 and
1, and the influence of frequency is not negligible because the
frequency falls within a high frequency band.
[0064] For this reason, in order to block noise between the antenna
140 and the digital circuit chip, the bandgap structure may be
mounted therebetween.
[0065] Specifically, in accordance with an embodiment, the bandgap
structure is provided between the antenna 140 and the analog
circuit chip and/or between the antenna 140 and the digital circuit
chip.
[0066] FIG. 2 is a perspective view showing the electromagnetic
bandgap structure of FIG. 1, FIG. 3 is a cross-sectional view
showing a unit of the electromagnetic bandgap structure of FIG. 1,
FIG. 4 is a cross-sectional view showing a unit array of the
electromagnetic bandgap structure of FIG. 1, and FIG. 5 is a top
plan view showing the unit array of the electromagnetic bandgap
structure of FIG. 1, in accordance with an embodiment of the
invention.
[0067] With reference to FIGS. 2 to 5, the electromagnetic bandgap
structure according to an embodiment of the present invention
includes metal plates 150-1 formed in the first upper metal layer
110-1 and vias 150-2 formed in the upper dielectric layer 120-1,
and is formed on the ground plate (or ground line) 110-2a, which is
the transmission line formed in the second upper metal layer
110-2.
[0068] In accordance with at least one embodiment, the ground plate
110-2a is formed on the dielectric layer 120-2 and thus provides a
ground for the transmitted or received signal of the antenna
140.
[0069] The metal plates 150-1 are spaced apart from the upper
surface of the ground plate 110-2a. The metal plates 150-1 are
provided in the form of a rectangular parallelepiped or a thin
film, and are formed away from the ground plate 110-2a.
[0070] In accordance with at least one embodiment, the metal plates
150-1 are disposed to face the ground plate 110-2a, thus making it
possible to form capacitance between the metal plates 150-1 and the
ground plate 110-2a.
[0071] In accordance with at least one embodiment, the metal plates
150-1 are formed of the same metal as that of the ground plate
110-2a, thus enabling signal transmission.
[0072] The vias 150-2 connect the ground plate 110-2a and the metal
plates 150-1 to each other. Specifically, the vias 150-2 extend
perpendicularly from the ground plate 110-2a, so that one end of
each via is connected to the center of the metal plates 150-1.
[0073] In accordance with at least one embodiment, the vias 150-2
are formed of the same metal as that of the ground plate 110-2a. In
this case, the vias 150-2 enable the signal or structural
connection between the ground plate 110-2a and the metal plates
150-1.
[0074] In the electromagnetic bandgap structure, according to
certain embodiments, the metal plates 150-1 and the vias 150-2
constitute respective units, and these units are periodically
arranged at predetermined intervals. As shown in the top plan view
of FIG. 5, the units are periodically arranged so as to enclose the
feed pad 110a' and the ground pad 110a'' formed in the first upper
metal layer 110-1, thus blocking the transmission of an
electromagnetic wave from the circuit chip 130. Herein, a periodic
array indicates that the units are repeatedly arranged at
predetermined intervals. Thus, the distances between the units need
not be uniform.
[0075] Furthermore, the dimension (e.g. interval, area or
thickness) of the units vary and are appropriately adjusted.
[0076] Although the formation of the electromagnetic bandgap
structure between the first upper metal layer 110-1 and the second
upper metal layer 110-2 is illustrated, the present invention is
not limited thereto. Alternatively, the electromagnetic bandgap
structure is formed between the other metal layer and the
dielectric layer.
[0077] FIG. 6 is a perspective view showing an electromagnetic
bandgap structure, FIG. 7 is a cross-sectional view showing a unit
of the electromagnetic bandgap structure of FIG. 6, FIG. 8 is a
cross-sectional view showing a unit array of the electromagnetic
bandgap structure of FIG. 6, and FIG. 9 is a top plan view showing
the unit array of the electromagnetic bandgap structure of FIG. 6,
in accordance with an embodiment of the invention. In this
embodiment, a feed line and a ground line are present in the same
plane.
[0078] With reference to FIGS. 6 to 9, the electromagnetic bandgap
structure according to another embodiment of the present invention
includes metal plates 150-1' formed in a first upper metal layer
110-1 and vias 150-2' formed in an upper dielectric layer 120-1,
and is formed on a feed line 210 which is a transmission line. The
feed line 210 is formed on a dielectric layer 120-2 and transmits a
signal. The signal passing through the feed line 210 becomes an
electromagnetic wave having high frequency.
[0079] In accordance with an embodiment of the invention, the metal
plates 150-1' are spaced apart from the upper surface of the feed
line 210. The metal plates 150-1' are provided in the form of a
rectangular parallelepiped or a thin film, and are formed away from
the feed line 210 and the ground plate 110-2a formed in the second
upper metal layer 110-2.
[0080] The metal plates 150-1' are disposed so that partial
surfaces thereof face the ground plate 110-2a, thus making it
possible to form capacitance between the metal plates 150-1' and
the ground plate 110-2a.
[0081] In accordance with an embodiment of the invention, the metal
plates 150-1' are formed of the same metal as that of the feed line
210, thus enabling signal transmission.
[0082] The vias 150-2' connect the feed line 210 and the metal
plates 150-1' to each other. Specifically, the vias 150-2' extend
perpendicularly from the feed line 210 so that one end of each via
is connected to the center of the metal plates 150-1'.
[0083] In accordance with an embodiment of the invention, the vias
150-2' are also formed of the same metal as that of the feed line
210. In this case, the vias 150-2' enable the signal or structural
connection between the feed line 210 and the metal plates
150-1'.
[0084] In the electromagnetic bandgap structure, the metal plates
150-1' and the vias 150-2' constitute respective units, and these
units are periodically arranged at predetermined intervals. As
shown in the top plan view of FIG. 9, the units are periodically
arranged so as to enclose the feed pad 110a' and the ground pad
110a'' formed in the first upper metal layer 110-1, thus blocking,
the transmission of an electromagnetic wave from the circuit chip
130. Herein, a periodic array indicates that the units are
repeatedly arranged at predetermined intervals. Thus, the distances
between the units need not be uniform.
[0085] Furthermore, the dimension (e.g., interval, area or
thickness) of the units vary, and are appropriately adjusted.
[0086] Although the formation of the electromagnetic bandgap
structure between the first upper metal layer 110-1 and the second
upper metal layer 110-2 is illustrated, the present invention is
not limited thereto. Alternatively, the electromagnetic bandgap
structure may be formed between the other metal layer and the
dielectric layer.
[0087] FIG. 10 is a perspective view showing an electromagnetic
bandgap structure, FIG. 11 is a cross-sectional view showing a unit
of the electromagnetic bandgap structure of FIG. 10, 12 is a
cross-sectional view showing a unit array of the electromagnetic
bandgap structure of FIG. 10, and FIG. 13 is a top plan view
showing the unit array of the electromagnetic bandgap structure of
FIG. 10, in accordance with an embodiment of the invention. In this
embodiment, in the case where a metal layer 110-1 includes a feed
line and a metal layer 110-3 includes a ground line (or a ground
plate), the electromagnetic bandgap structure is disposed between
the metal layers 110-1, 110-3.
[0088] With reference to FIGS. 10 to 13, the electromagnetic
bandgap structure according to a further embodiment of the present
invention includes metal plates 150-1'' formed in a metal layer
110-2, organic titanium coating layers 311, 312, and vias 150-2'',
and is formed on a ground Plate 110-3a which is a transmission line
formed in the metal layer 110-3.
[0089] In accordance with an embodiment of the invention, the
ground plate 110-3a and the metal plates 150-1'' are electrically
connected to each other using the vias 150-2'', and the metal
plates 150-1'' and the vias 150-2'' form respective mushroom type
structures,
[0090] The first upper metal layer 110-1 includes a feed line
110-1a, and the circuit chip 130 transmits data to the antenna 140
through the feed line 110-1a.
[0091] In accordance with an embodiment of the invention, the
mushroom type structures consisting of the metal plates 150-1'' and
the vias 150-2'' are formed between the ground plate 110-3a and the
feed line 110-1a, giving a bandgap structure for blocking a signal
included in a predetermined frequency band.
[0092] Dielectric layers 120-1, 120-2 are respectively interposed
between the metal plates 150-1'' and the feed line 110-1a and
between the metal plates 150-1'' and the ground plate 110-3a.
[0093] In accordance with an embodiment of the invention, the upper
dielectric layer 120-1 and the lower dielectric layer 120-2 are
formed of the same dielectric material, or of dielectric materials
having different dielectric constants. For example, in order to
further lower the bandgap frequency, the upper dielectric layer
120-1 are formed of a dielectric material having a higher
dielectric constant than that of the dielectric material of the
lower dielectric layer 120-2.
[0094] In accordance with an embodiment of the invention, the
thickness of each of the lower dielectric layer 120-2 and the upper
dielectric layer 120-1 are appropriately adjusted, so as to obtain
the bandgap frequency approximate to an intended bandgap frequency.
Specifically, the thickness of the upper dielectric layer 120-1 are
reduced and the thickness of the lower dielectric layer 120-2 are
increased to that extent, and thereby, even when using the
electromagnetic bandgap structure having the same size, the bandgap
frequency is controlled to be closer to an intended frequency band.
The bandgap frequency means the frequency of an electromagnetic
wave that is suppressed from being transmitted from one side of the
electromagnetic bandgap structure to the other site thereof.
[0095] The mushroom type structures are repeatedly formed as shown
in FIGS. 12 and 13. Specifically, the metal plates are repeatedly
disposed, and the vias are formed to equal in number the number of
metal plates and are connected thereto in respective units.
[0096] Although the metal plates are illustrated in the form of a
square shape in FIGS. 10 to 13, they may have other shapes
including polygonal such as triangular or hexagonal, circular, or
oval shapes.
[0097] When the mushroom type structures are repeatedly formed in
this way, it is possible to block a signal having a frequency band
corresponding to an operating frequency band of the circuit chip
among an electromagnetic wave proceeding from the circuit chip to
the antenna.
[0098] In accordance with an embodiment of the invention, the
organic titanium coating layers 311, 31.2 are disposed between the
metal plates 150-1'' and the dielectric layer 120-1 and between the
ground plate 110-3a and the dielectric layer 120-2, in order to
enhance the adhesivity therebetween in a compression process. The
organic titanium coating layers 311, 312 are formed on the surfaces
of the metal plates 150-1'' and the ground plate 110-3a, and the
dielectric layer 120-2 is interposed between the metal plates
150-1'' and the ground plate 110-3 after which compression is
performed under conditions of high temperature and high pressure,
thereby forming a highly reliable electromagnetic bandgap
structure.
[0099] In the electromagnetic bandgap structure, the metal plates
150-1'' and the vias 150-2'' constitute respective units, and these
units are periodically arranged at predetermined intervals. As
shown in the top, plan view of FIG. 13, the units are periodically
arranged, so as to enclose the feed pad 110a' and the ground pad
110a'' formed in the first upper metal layer 110-1, thus blocking
the transmission of the electromagnetic wave from the circuit chip
130. Herein, a periodic array indicates that the units are
repeatedly formed at predetermined intervals. Thus, the distances
between the units need not be uniform.
[0100] In accordance with an embodiment of the invention, the
formation of the electromagnetic bandgap structure between the
first upper metal layer 110-1 and the third upper metal layer 110-3
is illustrated, but the present invention is not limited thereto.
Alternatively, the electromagnetic bandgap structure may be formed
between the other metal layer and the dielectric layer.
[0101] FIG. 14 is a 3-D perspective view showing an electromagnetic
bandgap structure, FIG. 15 is a sectional view showing the
electromagnetic bandgap structure of FIG. 14, and FIG. 16 is a plan
view showing a configuration of the electromagnetic bandgap
structure of FIG. 14, in accordance with another embodiment of the
present invention. Particularly. FIG. 15 show a section viewed
along the AA line of FIG. 14.
[0102] As shown in FIG. 14 through FIG. 16, the electromagnetic
bandgap structure in accordance with another embodiment of the
present invention includes a plurality of metal plates 210a, 210b
and 210c, a metal layer 220 placed on a planar surface that is
different from a planar surface in which the metal plates 210a,
210b, and 210c are placed and a stitching via 230 electrically
connecting two adjacent metal plates among the metal plates.
[0103] In other words, the electromagnetic bandgap structure 200
shown in FIG. 14 through FIG. 16 includes a two-layered planar
structure having a First layer in which the metal layer 220 is
placed and a second layer in which the plurality of metal plates
210a, 210b and 210c are placed. A dielectric layer is interposed
between the metal layer 220 and the plurality of metal plates 210a,
210b and 210c.
[0104] FIG. 14 through FIG. 16 show elements constituting the
electromagnetic bandgap structure (i.e., a part constituting the
2-layered electromagnetic bandgap including the stitching via) for
the convenience of illustration (also, in the case of FIG. 18
through FIG. 20). Accordingly, the first layer in which the metal
layer 220 shown in FIG. 14 through FIG. 16 is placed and the second
layer in which the plurality of metal plates 210a, 210b and 210c
shown in FIG. 14 through FIG. 16 are placed is any two layers of a
multi-layered printed circuit board.
[0105] In other words, it shall be obvious that there is at least
one additional metal layer below the metal layer 220, above the
metal plates 210a, 210b and 210c and/or between the metal layer 220
and the metal plates 210a, 210b and 210c.
[0106] For example, the electromagnetic bandgap structure 200 shown
in FIG. 14 through FIG. 16 is placed between any two metal layers
functioning as a power layer and a ground layer, respectively, in a
multi-layered printed circuit board, in order to block a conductive
noise (the same can be applied to electromagnetic bandgap
structures shown in FIG. 18 to FIG. 20 in accordance with an
embodiment of the invention).
[0107] Since the conductive noise problem is not limited to the
space between the power layer and the ground layer, the
electromagnetic bandgap structure shown in FIG. 14 through FIG. 20
is placed between any two ground layers or power layers placed on
different layers from each other in a multi-layered printed circuit
board.
[0108] In accordance with an embodiment of the present invention,
metal plates 210a, 210b and 210c are spaced from each other at a
predetermined distance on the same planar surface. Here, the metal
layer 220 and the metal plates 210a, 210b and 210c are a material
(e.g., copper (Cu)) to which power is supplied and a signal is
transmitted.
[0109] In accordance with an embodiment of the present invention,
stitching via 230 electrically connects two adjacent metal plates
(e.g. the metal plates 210b and 210c in FIG. 14). However, the two
metal plates 210b and 210c are connected not on the same layer in
which the metal plates 210b and 210c are placed but through another
layer (e.g. the metal layer 220) that is different from the layer
in which the metal plates 210b and 210c are placed.
[0110] The stitching via 230 is formed to include a first via 232,
a connection pattern 234 and a second via 236. The first via 232
includes one end part, connected to the first metal plate 210b, and
the other end part, connected to one end part of the connection
pattern 234. The second via 236 includes one end part, connected to
the second metal plate 210c, and the other end part, connected to
the other end part of the connection pattern 234. A via land for
being connected to the first via 232 and/or the second via 236 is
formed on either end part of the connection pattern 234.
[0111] It shall be evident here that, in order to allow the metal
plates to be electrically connected to each other, it is necessary
that a plating layer be formed on an inner wall only of the first
via 232 and the second via 236 of the stitching via 230 or the
inside of the stitching via 230 be filled with a conductive
material (e.g., conductive paste), and the connection pattern 234
be a conductive material, such as a metal.
[0112] In accordance with an embodiment of the present invention,
the two adjacent metal plates 210b and 210e are connected in series
through the stitching via 230. In particular, the two adjacent
metal plates 210b and 210c are electrically connected in series in
the order of the first metal plate 210b.fwdarw.the stitching via
230 (the first via 232.fwdarw.the connection pattern 234.fwdarw.the
second via 236).fwdarw.the second metal plate 210b.
[0113] The first metal plate 210b is connected to the other metal
plate 210a through the stitching via 230. The second metal plate
210c is also connected to another metal plate (not shown) through
the stitching via 230. As a result, all metal plates, placed on the
second layer, are connected in series through the stitching via
230.
[0114] In accordance with an embodiment of the present invention,
the metal layer 220 is formed with a clearance hole 225
accommodating the connection pattern 234. The clearance hole 225
also accommodates the via land for easy connection with the first
via. 232 and/or the second via 236 as well as the connection
pattern 234. The clearance hole 225 allows the stitching via 230
and the metal layer 220 to be electrically disconnected from each
other.
[0115] Connecting the metal plates 210a, 210b and 210c through the
stitching via 230 makes it unnecessary to form a pattern for
connecting the metal plates 210a, 210b and 210c on the second
layer. This makes the metal plates 210a, 210b and 210c smaller and
the gap between the metal plates 210a, 210b and 210c narrower,
increasing the capacitance in the gaps between the metal plates
210a, 210b and 210c.
[0116] FIG. 17 shows an equivalent circuit of an electromagnetic
bandgap structure having the above structure, in accordance with an
embodiment of the invention.
[0117] Comparing the equivalent circuit of FIG. 15 with the
electromagnetic bandgap structure of FIG. 14, an inductance
component L1 corresponds to the fist. via 232, and an inductance
component L2 corresponds to the second via 236. An inductance
component L3 corresponds to the connection pattern 234. C1 is a
capacitance component by the metal plates 210a and 210b and another
dielectric layer and another metal layer to be placed above the
metal plates 210a and 210b. C2 and C3 are capacitance components by
the metal layer 220 placed on the same planar surface as that of
the connection pattern 234 and another dielectric layer and another
metal layer are placed below the planar surface of the connection
pattern 234.
[0118] The electromagnetic bandgap structure shown in FIG. 14
through FIG. 16 functions as a band stop filter, which blocks a
signal of a certain frequency band according to the above
equivalent circuit. In other words, as seen in the equivalent
circuit of FIG. 15, a signal x of a low frequency band (refer to
FIG. 17) and a signal y of a high frequency band (refer to FIG. 17)
pass through the electromagnetic bandgap structure, and signals z1,
z2 and z3 of a certain frequency band (refer to FIG. 17) ranging
between the low frequency band and the high frequency band are
blocked by the electromagnetic bandgap structure.
[0119] In accordance with an embodiment of the present invention,
the metal plates 210a, 210b and 210c are placed on a planar surface
in which another metal layer that is different from the metal layer
220 is placed. The metal plate 210a placed at a far left side,
therefore, are connected to the other metal layer that is different
from the metal layer 220 through a stitching via., in accordance
with the present invention.
[0120] If the metal layer 220 is a power layer, the different metal
layer is a ground layer, and if the metal layer 220 is a ground
layer, the different metal layer is a power layer.
[0121] Alternatively, a signal is transferred in a predetermined
direction by allowing the metal layer 220 to be the ground layer
and the other metal layer to be a signal layer, and the noise of a
certain frequency of the signal is reduced by allowing the
mentioned metal plates 210a, 210b and 210c and the stitching via
230 to be arranged on some areas of a signal transfer path of the
signal layer.
[0122] As shown in FIG. 14 through FIG. 16, the metal plates 210a,
210b and 210c are arranged in one row, and two stitching vias are
connected to each of the metal plates 210a, 210b and 210c. However,
in accordance with another embodiment of the present invention, a
metal plate is arranged in a matrix of m*n, m and n being natural
numbers, and its adjacent metal plates are connected by using the
stitching via. In this case, each metal plate functions as a path
connecting its adjacent other metal plates and be connected to at
least two stitching vias.
[0123] In other words, the connection form shown in FIG. 14 through
FIG. 16 is merely an example, and as long as all metal plates form
a closed loop by being electrically connected to each other, any
method of connecting the metal plates through the stitching via is
used.
[0124] Hereinafter, some electromagnetic bandgap structures in
accordance with another embodiments of the present invention will
be described in turn with reference to FIG. 18 through FIG. 20. Any
matter already described in FIG. 14 through FIG. 16 will be not be
redundantly described, and the electromagnetic bandgap structures
will be briefly described based on the features of each embodiment
of the present invention. This is because the same technological
principle as described in FIG. 14 through FIG. 16 is applied to the
electromagnetic bandgap structures of FIG. 18 through FIG. 20 in
accordance with another embodiments of the present invention,
except for some differences.
[0125] Accordingly, in FIG. 18 through FIG. 20, each corresponding
element is assigned the identical reference numeral as in FIG. 14
through FIG. 16, for easy comparison.
[0126] As shown in FIG. 18, the electromagnetic bandgap structure
in accordance with another embodiment of the present invention
includes a plurality of metal plates 210a, 210b and 210c and a
stitching via 230 electrically connecting two adjacent metal plates
of the metal plates 210a, 210b and 210c to each other. In other
words, the electromagnetic bandgap structure of FIG. 18 does not
have a metal layer corresponding to the metal layer 220 shown in
FIG. 14 through FIG. 15.
[0127] As such, it is not always necessary that the electromagnetic
bandgap structure having a stitching via in accordance with another
embodiment of the present invention include a metal layer below an
area in which the stitching via and metal plates are placed. This
is because it is not necessary that the connection pattern 234 of
the stitching via 230 be formed on an area in which the metal layer
is placed.
[0128] In other words, if there is a metal layer on the same planar
surface to correspond to an area in which the connection pattern
234 will be placed, the connection pattern 234 is manufactured in
the form of being accommodated into the clearance hole 225 formed
in the metal layer 220 on the same planar surface, as shown in FIG.
14 through FIG. 16. However, no additional metal layer is placed in
the area in which the connection pattern 234 will be placed, as
shown in FIG. 18. Of course, there may be a dielectric layer below
the metal plates in FIG. 1.8.
[0129] As shown in FIG. 19, the electromagnetic bandgap structure
in accordance with another embodiment of the present invention has
a stacked structure,the position of the upper layer and the lower
layer inversed from that of FIG. 14 through FIG. 16.
[0130] In other words, while the electromagnetic bandgap structure
shown in FIG. 14 through FIG. 16 has the metal layer 220 forming a
lower layer, the metal plates 210a, 210b and 210c forming an upper
layer and the dielectric layer interposed between the lower layer
and the upper layer, the electromagnetic bandgap structure shown in
FIG. 19 inversely have the metal layer 220 forming the upper layer,
the metal plates 210a, 210b and 210c forming the lower layer and
the dielectric layer interposed between the lower layer and the
upper layer. Of course, it can be expected that the electromagnetic
bandgap structure shown in FIG. 19 has the identical or similar
noise blocking effect to that of FIG. 14 through FIG. 16.
[0131] As shown in FIG. 20, the electromagnetic bandgap structure
in accordance with another embodiment of the present invention has
the same structure of the electromagnetic bandgap structure shown
in FIG. 19 without the metal layer 220. This reason, already
described above with reference to FIG. 18, will be omitted.
[0132] The electromagnetic bandgap structure in accordance with the
present invention can have various types of stacked structures.
Although all of the foresaid drawings show that all metal plates
are stacked in the same planar surface, it is not always necessary
that all metal plates are stacked in the same planar surface.
[0133] In case at least one of the metal plates is stacked in a
planar surface that is different from the planar surface in which
the other metal plates are stacked, the electromagnetic bandgap
structure will have two or more layers. However, this increased
number of layers may have no disadvantageous effect on the design
when the electromagnetic bandgap structure of the present invention
is applied to a multi-layered printed circuit board.
[0134] The aforementioned drawings also show that each stitching
via electrically connects two adjacent metal plates to each other.
However, it may be unnecessary that two plates connected by the
stitching via are adjacent to each other.
[0135] Even though one metal plate is shown to be connected to
another metal plate through one stitching via, it is obviously
unnecessary that the electromagnetic bandgap structure has any
limitation to the number of the stitching vias connecting any two
metal plates.
[0136] For the convenience of illustration and understanding of the
invention, in FIG. 14 through FIG. 20, only three metal plates are
shown, and one metal plate is electrically connected to another
adjacent metal plate and yet another adjacent metal plate through
/one stitching via each (i.e. two adjacent cells around one cell
are connected).
[0137] In addition, the organic titanium coating layer formed on
outer surfaces of the metal plates may be further included.
[0138] As described hereinbefore, embodiments of the present
invention provide a PCB including an electromagnetic bandgap
structure. According to embodiments of the present invention, the
electromagnetic bandgap structure is disposed between the circuit
chip and the antenna, thus efficiently reducing unnecessary signal
interference,
[0139] Also, according to embodiments of the present invention,
there is no need for additional change in antenna design in order
to block noise, thus shortening the lead time.
[0140] Also, according to embodiments of the present invention, as
the lead time is shortened, additional costs do not occur.
[0141] Embodiments of the present invention may suitably comprise,
consist or consist essentially of the elements disclosed and may be
practiced in the absence of an element not disclosed. For example,
it can be recognized by those skilled in the art that certain steps
can be combined into a single step.
[0142] The terms and words used in the present specification and
claims should not be interpreted as being limited to typical
meanings or dictionary definitions, but should be interpreted as
having meanings and concepts relevant to the technical scope of the
present invention based on the role according to which an inventor
can appropriately define the concept of the term to describe the
best method he or she knows for carrying out the invention.
[0143] As used herein, terms such as "first," "second," "one side,"
"the other side" and the like are arbitrarily assigned and are
merely intended to differentiate between two or more components of
an apparatus. It is to be understood that the words "first,"
"second," "one side," and "the other side" serve no other purpose
and are not part of the name or description of the component, nor
do they necessarily define a relative location or position of the
component. Furthermore, it is to be understood that the mere use of
the term "first" and "second" does not require that there be any
"third" component., although that possibility is contemplated under
the scope of the embodiments of the present invention.
[0144] The singular forms "a," "an," and "the" include plural
referents, unless the context clearly dictates otherwise.
[0145] As used herein and in the appended claims, the words
"comprise," "has," and "include" and all grammatical variations
thereof are each intended to have an open, non-limiting meaning
that does not exclude additional elements or steps.
[0146] Ranges may be expressed herein as from about one particular
value, and/or to about another particular value. When such a range
is expressed, it is to be understood that another embodiment is
from the one particular value and/or to the other particular value,
along with all combinations within said range.
[0147] Although the present invention has been described in detail,
it should be understood that various changes, substitutions, and
alterations can be made hereupon without departing from the
principle and scope of the present invention. Accordingly, the
scope of the present invention should be determined by the
following claims and their appropriate legal equivalents.
* * * * *