Note: Descriptions are shown in the official language in which they were submitted.
CA 03097049 2020-10-14
STRIP LINE DIRECTIONAL COUPLER AND METHOD FOR ADJUSTING A
COUPLING DEGREE THEREOF
TECHNICAL FIELD
[0001] The present disclosure relates to the field of mobile
communication technology,
and more particularly, to a trip line directional coupler and a method for
adjusting a
coupling degree thereof.
BACKGROUND
[0002] Directional couplers are widely used in the fields of radio
frequency and
microwave. At present, the well-known strip line directional coupler is
composed of a pair
of strip-line lines with parallel coupling lines, a medium, and two upper and
lower ground
layers. Lines of the pair of parallel coupling lines are close to each other
to generate
coupling. The coupling degree is determined by the distance between the
coupling lines,
the relative dielectric constant of the medium, and the structure and size of
the ground layer.
In the specific implementations, forms of multi-layer printed circuit boards,
air strip lines,
and the like are usually used. However, the processing accuracy is limited,
and situations
of the coupling degree deviating from the reference range or poor indexes are
existed in
the existing strip line couplers, which reduce the performance of the device.
SUMMARY
[0003] In view of the above problem, the present disclosure provides a
strip line
directional coupler, in which openings are defined in an adjustment zone of
the ground
layer. By changing the shape, area and quantity of the openings, current
distribution of the
strip line can be changed, the coupling degree can be adjusted, which makes
the coupling
degree adjustment simple and effective.
[0004] Correspondingly, a method for adjusting a coupling degree is
provided. By
welding or etching the openings, and changing the shape and area of the
openings, the
current distribution of the strip line is changed, the coupling degree is
adjusted, and simple
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and effective coupling degree adjustment can be realized.
[0005] The present disclosure provides a strip line directional coupler,
includes: a first
ground layer, a strip line layer, and a second ground layer stacked
successively; the strip
line layer has a first line and a second line, and the first line and the
second line are provided
with coupling sections close to each other; and the first ground layer and/or
the second
ground layer is provided with an adjustment zone at a position facing or close
to the
coupling sections, and an opening for adjusting a coupling degree is defined
in the
adjustment zone.
[0006] Preferably, a plurality of the openings arranged at intervals are
defined in the
.. adjustment zone.
[0007] Further, the plurality of the openings are arranged in sequence
in an extending
direction of the coupling sections.
[0008] Preferably, the opening is a round hole, a square hole, an
annular hole, a
triangular hole, or an irregular hole.
[0009] Preferably, the first ground layer and the second ground layer are
electrically
connected to each other.
[0010] Preferably, the opening includes an annular gap and/or a strip-
shaped gap group.
The annular gap has a shape of a rectangle, and a pair of opposite edges of
the rectangle
are set as weldable zones. The strip-shaped gap group includes two strip-
shaped gaps
arranged in parallel. The ground layer between the end points of the two strip-
shaped gaps
constitutes a removable zone.
[0011] Further, a surface of each of the first ground layer and the
second ground layer
is coated with a solder mask layer, and the solder mask layer is defined in
the adjustment
zone and is provided with opening windows.
[0012] Further, the strip line directional coupler further comprises: a
first dielectric
layer and a second dielectric layer disposed between every adjacent two of the
first ground
layer, the strip line layer, and the second ground layer, and a bonding
material layer
disposed between the first dielectric layer and the second dielectric layer
for bonding the
first dielectric layer and the second dielectric layer.
[0013] Correspondingly, the present disclosure further provides a method
for adjusting
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a coupling degree based on the strip line directional coupler of any one of
the above
examples, and the method for adjusting a coupling degree includes following
steps:
[0014] testing a coupling degree of the directional coupler to obtain a
test value;
[0015] comparing the test value with a predetermined reference range of
coupling
degree; and
[0016] when the test value is not within the reference range, adjusting
the coupling
degree to make the test value within the reference range by changing at least
one of a shape,
a quantity, and an area size of the openings.
[0017] Further, when the test value is higher than the reference range,
the coupling
degree is reduced by using a first post-treatment process to cover a first
ground layer on a
corresponding opening; and when the test value is lower than the reference
range, the
coupling degree is increased by using a second post-treatment process to
remove a
corresponding first ground layer to form a new opening.
[0018] Preferably, the first post-treatment process is a welding
process, and the second
post-treatment process is an etching process.
[0019] Compared with the prior art, in the strip line directional
coupler of the present
disclosure, the first grounding layer facing the coupling sections is dug out
processed to
provide an adjustment zone with an opening having at least one shape; the
coupling degree
is adjusted by changing the shape, area, and quantity of the openings, thus
the method for
adjusting the coupling degree adjustment is simple and effective.
[0020] Preferably, the opening is classified into annular gaps and strip-
shaped gap
groups alternately arranged along the extension direction of the coupling
sections; the
transformation between the two types of openings is achieved by welding, which
also
makes the method for adjusting the coupling degree simple and effective.
[0021] Preferably, the annular gap is configured to have a shape of
rectangle, and a
pair of opposite edges of the rectangle are respectively set as weldable
zones. The strip-
shaped gap group includes two strip-shaped gaps arranged in parallel, and each
of the
connecting lines between the end points of the two strip-shaped gaps
constitutes a
removable zone respectively. The weldable zone and the removable zone have
regular
shapes, which is convenient for welding or removing the metal layer to adjust
the coupling
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degree, and has a beautiful appearance before and after the adjustment.
[0022] The surfaces of the first ground layer and the second ground
layer each are
further coated with a solder mask layer, and opening windows are defined in
the removable
zone and the weldable zone, which not only can effectively protect the metal
layer in the
non-adjustment zone from being damaged, but also can make the operation
position of the
cutting and welding process more accurate and easy to control.
[0023] For the adjustment zone on the ground layer of the strip line
directional coupler
of the present disclosure, a method for adjusting the coupling degree is
provided. The
method for adjusting the coupling degree is simple and effective by using two
simple
.. processes (welding and etching) to adjust the coupling degree, and the pass
rate of the
coupling degree index is increased. The method for adjusting the coupling
degree can meet
the more stringent coupling degree index under the same processing accuracy,
and is
especially suitable for application scenarios that use a plurality of couplers
at the same
time and require high consistency of the coupling degree.
[0024] These and other aspects of the present disclosure will be more
apparent and
easily understood in the descriptions of the embodiments below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to illustrate the technical solutions of the embodiments
of the present
disclosure more clearly, the accompanying drawings used in the description of
the
embodiments are briefly described below. Obviously, the accompanying drawings
described below are only some embodiments of the present disclosure, and a
person skilled
in the art can obtain other drawings according to these accompanying drawings
without
creative effort.
[0026] FIG. 1 is an exploded view of a strip line directional coupler
according to an
embodiment of the present disclosure.
[0027] FIG. 2 is a cross-sectional view of a strip line directional
coupler according to
an embodiment of the present disclosure.
[0028] FIG. 3 is a schematic structure diagram of a first ground layer
of a strip line
directional coupler according to an embodiment of the present disclosure.
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[0029] FIG. 4 is a schematic structure diagram of a first ground layer
after the annular
gaps are transformed into strip-shaped gaps according to an embodiment of the
present
disclosure.
[0030] FIG. 5 is a schematic structure diagram of a first ground layer
after the strip-
.. shaped gaps are transformed into annular gaps according to an embodiment of
the present
disclosure.
DETAILED DESCRIPTION
[0031] In order to enable those skilled in the art to better understand
the solutions of
the present disclosure, the technical solutions in the embodiments of the
present disclosure
are clearly and completely described below with references to drawings in the
embodiments of the present disclosure. Obviously, the embodiments described
are only a
part of the embodiments of the present disclosure, and not all of the
embodiments. All
other embodiments obtained by a person skilled in the art based on the
embodiments in the
present disclosure without creative efforts are within the protection scope of
the present
disclosure.
[0032] Referring to FIG. 1, a strip line directional coupler 100 is
provided according
to the present disclosure, which includes a first ground layer 1, a first
dielectric layer 2, a
strip line layer 3, a bonding material layer 4, a second dielectric layer 5,
and a second
ground layer 6 stacked successively.
[0033] In combination with FIG. 2, the first dielectric layer 2 and the
second dielectric
layer 5 are stacked with each other and are bonded to each other through the
bonding
material, so as to form a multilayer circuit board.
[0034] The strip line layer 3 is disposed on a side of the first
dielectric layer 2 close to
the second dielectric layer 5. The strip line layer 3 includes a first line 31
and a second line
32 that are coupled to each other. The two lines are provided with coupling
sections 30
extending parallel to each other, so that when a signal is input from one line
and output at
its through end, part of the signal can be simultaneously coupled to the other
line and
output by the other line.
[0035] The first ground layer 1 and the second ground layer 6 are both
copper coating
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layers. They are disposed on the first dielectric layer 2 and the second
dielectric layer 5,
respectively, and are located on sides of the two dielectric layers away from
each other,
respectively. Preferably, the projections of the first grounding layer 1 and
the second
grounding layer 6 onto the strip line layer 3 each cover the strip line layer
3, and the first
.. grounding layer 1 and the second grounding layer 6 are configured to play
adjusting and
shielding roles to the signal of the strip line layer 3. Preferably, the first
ground layer 1 and
the second ground layer 6 are electrically connected to each other.
[0036] An adjustment zone 10 for adjusting the coupling degree of the
strip line
directional coupler is provided at a position of the first ground layer 1
facing or close to
the coupling sections 30. A plurality of openings are defined in the
adjustment zone 10 by
etching the metal layer of the first ground layer 1 (processing of digging the
copper).
Preferably, a plurality of the openings arranged at intervals are defined in
the adjustment
zone 10, and the plurality of openings are arranged in sequence in the
extending direction
of the coupling sections 30.
[0037] In other embodiments, an adjustment zone for adjusting the coupling
degree of
the strip line directional coupler may be further provided at a position of
the second ground
layer 6 facing or close to the coupling sections 30. A plurality of openings
are defined in
the adjustment zone 10 by etching the metal layer of the second ground layer 6
(processing
of digging the copper).
[0038] Preferably, the opening is classified into an annular gap 11 and a
strip gap 12.
The annular gap 11 is provided with two weldable zones 110. The quantity of
the strip-
shaped gaps 12 is an even number, two adjacent strip-shaped gaps 12 form a
strip-shaped
gap group, and each of the strip-shaped gaps groups is provided with two
removable zones
120.
[0039] Referring to FIG. 3, in this embodiment, the annular gap 11 is
configured into
a shape of a rectangle, and the two weldable zones 110 are two opposite edges
of the
rectangle, respectively. The strip-shaped gap group has a shape of two strip-
shaped gaps
12 arranged in parallel, and the two removable zones 120 are the lines
connecting the end
points of the two strip-shaped gaps 12.
[0040] In other embodiments, there may be a plurality of annular gaps 11
and a
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plurality of strip-shaped gap groups, and they are arranged alternately in the
extending
direction of the coupling sections 30, respectively.
[0041] As an embodiment, a solder mask layer (not shown) is further
coated on a
surface of each of the first ground layer 1 and the second ground layer 6, and
the solder
mask layer is a liquid photoimagable solder mask (green oil) . The solder mask
layer
locates at the adjustment zone 10 and is provided with opening windows (not
shown).
Preferably, the opening windows are defined at the removable zone 120 and the
weldable
zone 110, which can make the operation position of the cutting and welding
process more
accurate.
[0042] Correspondingly, the present disclosure provides a method for
adjusting a
coupling degree based on the strip line directional coupler 100, which
includes the
following steps:
[0043] testing a coupling degree of the directional coupler to obtain a
test value;
[0044] comparing the test value with a predetermined reference range of
coupling
degree; and
[0045] when the test value is not within the reference range, adjusting
the coupling
degree to make the test value within the reference range by changing at least
one of shapes,
quantity, and area sizes of the openings.
[0046] Specifically, when the test value is higher than the reference
range, the coupling
degree is reduced by covering a first ground layer on a corresponding opening
through a
first post-treatment process; when the test value is lower than the reference
range, the
coupling degree is increased by removing a corresponding first ground layer
through a
second post-treatment process to form a new opening.
[0047] Preferably, the first post-treatment process is a welding
process, and the second
post-treatment process is an etching process.
[0048] Referring to FIG. 3 to FIG. 5, preferably, when the gap is
classified into an
annular gap 11 and a strip-shaped gap group, the method includes: if the test
value is higher
than the reference range, transforming the annular gap 11 into a strip-shaped
gap 12' to
reduce the coupling degree; if the test value is lower than the reference
range, transforming
the strip-shaped gap group into an annular gap 11' to increase the coupling
degree.
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[0049] Referring to FIGS. 3 and 4, where FIG. 4 is a schematic diagram
of the first
ground layer l' and the adjustment zone 10' after the annular gap 11 is
transformed into a
strip-shaped gap 12'. The specific adjustment method may be: welding the metal
layer in
the weldable zone 110 to short-circuit the metal layer in the weldable zone
110. Preferably,
the welding method may include: applying molten solder in the welding zone 110
through
an electric soldering iron, short-circuiting the two edges of the annular gap
11 with the
metal layer of the adjustment zone 10' through the solder, and further
transforming the
annular gap 11 into a strip-shaped gap 12'. By changing the shape of the gap,
the local
current distribution is changed, and the coupling degree is thus changed.
[0050] Referring to FIGS. 3 and 5, where FIG. 5 is a schematic diagram of
the first
ground layer 1" and the adjustment zone 10" after the strip-shaped gap group
is
transformed into an annular gap 11'. The specific adjustment method may be:
etching or
cutting the metal layer in the removable zone 120 to disconnect the metal
layer in the
removable zone 120. Preferably, the cutting method may include: digging out
the metal
layer in the removable zone 120 through a knife, so that the metal layer
connecting the end
points of the two strip-shaped gaps 12 in the strip-shaped gap group is
disconnected, and
the strip-shaped gap group is further transformed into an annular gap 11'. By
changing the
shape of the gap, the local current distribution is changed, and therefore the
coupling
degree is changed.
[0051] It should be noted that, the ranges and positions of the weldable
zone 110 and
the removable zone 120 as shown in figure according to the embodiment are
preferred
implementations conducive to operation. However, the illustrated figures are
not intended
to limit the precise ranges of the two. That is, their ranges can be
appropriately enlarged or
reduced based on the frame selections, and their positions can also be
appropriately moved
based on the frame selections.
[0052] The etching process may include, but is not limited to, processes
such as
physical engraving, cutting, laser engraving, chemical etching,
electrochemical etching, or
the like.
[0053] In other embodiments, the opening may also be a round hole, a
square hole, an
annular hole, a triangular hole, a special-shaped hole, an "H" shaped hole, a
square hole
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with a cross shape inside, or other shaped holes, or any combination thereof.
An opening
is within the scope of the present application as long as it is defined in the
adjustment zone
of the ground layer and the current distribution of the strip line can be
changed by operating
the opening to change its shape and area.
[0054] Compared with the prior art, the strip line directional coupler and
the method
for adjusting the coupling degree thereof according to the present disclosure
have the
following advantages:
[0055] (1) The first ground layer facing the coupling sections is
processed by digging
out to provide an adjustment zone with openings having various shapes such
that the
coupling degree is adjusted by changing the shape and area of the opening,
which makes
the adjusting of the coupling degree simple and effective.
[0056] (2) The opening is classified into annular gaps and strip-shaped
gap groups
alternately arranged in the extension direction of the coupling sections in
which the
transformation between the two types of gaps can be made by welding and
etching, which
also makes the adjusting of the coupling degree simple and effective.
[0057] (3) The annular gap has a shape of a rectangle, and a pair of
opposite edges of
the rectangle are respectively set as weldable zones. The strip-shaped gap
group includes
two strip-shaped gaps arranged in parallel, and each of the connecting lines
between the
end points of the two strip-shaped gaps forms a removable zone respectively.
The weldable
zone and the removable zone have regular shapes, which is convenient for
welding or
removing the metal layer to adjust the coupling degree, and has an aesthetic
appearance
before and after the adjustment.
[0058] (4) The surfaces of the first ground layer and the second ground
layer each are
further coated with a solder mask layer, and opening windows are defined in
the removable
.. zone and the weldable zone, which not only can effectively protect the
metal layer in the
non-adjustment zone from being damaged, but also can make the operation
position of the
cutting and welding process more accurate and easy to control.
[0059] (5) For the adjustment zone on the ground layer of the strip line
directional
coupler of the present disclosure, a method for adjusting the coupling degree
is provided.
.. Two simple processes (welding and etching) are used to adjust the coupling
degree. The
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method for adjusting of the coupling degree is simple and effective, and the
pass rate of
the coupling degree index is increased, which can meet the more strict
coupling degree
index under the same processing accuracy, and is especially suitable for
application
scenarios that use a plurality of couplers at the same time and that require
high consistency
of the coupling degree.
[0060] Some embodiments provided by the present disclosure are described
in detail
above, for those of ordinary skill in the art, according to the concept of the
embodiments
of the present disclosure, there will be changes in the specific
implementation and the
application range. In summary, the content of this description should not be
construed as a
limitation on the present disclosure.
Date Recue/Date Received 2020-10-14
