CN108123196B - Broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines - Google Patents
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Abstract
The embodiment of the invention provides a broadband filtering integrated three-dimensional balun based on vertical double-sided parallel strip lines, wherein a first port feeder, a second port feeder and a third port feeder are all formed by microstrip transmission lines; on the horizontal feed board, the via hole surface is connected with a plurality of first metal via holes; the ground plane of the second layer is connected with the via hole plane through the first metal via hole; on the vertical plate, the filter has a top filtering stub; the filter and the quarter-wavelength impedance transformer are connected, are both formed by vertical double-sided parallel strip lines and are respectively and symmetrically positioned on the third layer and the fourth layer; the public ground is positioned between the third layer and the fourth layer; the top filtering branch is connected with the public ground through a second metal through hole; and the impedance gradual change structure on the fourth layer is respectively connected with the first port feeder line, the via hole surface and the filter. Therefore, the embodiment of the invention realizes the single balun for the balance-unbalance conversion from the microstrip line to the vertical double-sided parallel strip line, integrates the filtering function and improves the integration level.
Description
Technical Field
The invention relates to the technical field of radio frequency, in particular to a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines.
Background
The balun has the main function of realizing that when one input signal reaches two output ports, the two output signals output have equal amplitude and opposite phase, and vice versa. In addition, when the front-stage circuit and the rear-stage circuit of the balun are not matched, the balun can also play a role in impedance transformation. In short, the balun converts a high-frequency signal from a single-ended unbalanced input to a double-ended balanced output, and completes impedance matching. Thus, as a three-port device, balun is widely used in balanced layouts of radio frequency circuits, such as filters, power amplifiers and antenna feed networks, directly affecting the performance and quality of wireless communications. At present, balun and filter as adjacent elements of the feed front end have been indispensable constituent elements such as in radio frequency systems.
In recent years, a double-sided parallel strip line has become a research hotspot in the field of radio frequency as a balanced transmission line by virtue of the characteristic that the balanced transmission line has the phase inversion performance which is irrelevant to the frequency.
However, currently, there is still a gap in the art in the research of combining the vertical double-sided parallel strip lines with the monomer balun and making it have a filtering function.
Therefore, how to provide the combination of the vertical double-sided parallel strip line and the single balun, and making the balun with the filtering function become the technical problem to be solved.
Disclosure of Invention
The embodiment of the invention aims to provide a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines, and the balun realizes a filtering function by combining the vertical double-sided parallel strip lines with a single balun.
In order to realize the purpose, the following technical scheme is provided:
a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines comprises: the horizontal feed plate and the vertical plate are perpendicular to the horizontal feed plate; wherein:
the horizontal feed board is provided with a first port, a second port, a third port, a first port feeder line, a second port feeder line and a third port feeder line; the first port feeder, the second port feeder and the third port feeder are all formed by microstrip transmission lines, the first port feeder is connected with the first port, the second port feeder is connected with the second port, and the third port feeder is connected with the third port;
the horizontal feed plate comprises a first layer, a second layer and a plurality of first metal through holes; wherein the via surface is connected to the plurality of first metal vias, and the first layer includes a via surface; the second layer comprises a ground plane, and the ground plane is connected with the via hole plane through the first metal via hole;
the vertical plate comprises a third layer, a public ground with a cross gap, a fourth layer, an impedance gradual change structure, a second metal via hole, a filter and a quarter-wavelength impedance converter, wherein the public ground is positioned between the third layer and the fourth layer; the filter is provided with top end filtering branches bent in opposite directions; the filter and the quarter-wavelength impedance transformer are connected and both formed by vertical double-sided parallel strip lines and are symmetrically positioned on the third layer and the fourth layer respectively; the top filtering branch is connected with the public ground through the second metal through hole; the impedance gradual change structure is positioned on the fourth layer and is respectively connected with the first port feeder line, the via hole surface and the filter;
wherein the first port, the first port feed, the impedance tapering structure, the filter, the common ground, the quarter wave impedance transformer, the second port feed, the third port feed, the second port and the third port form a signal transmission path.
Optionally, the microstrip transmission line, the vertical double-sided parallel strip line, the ground plane, the via hole plane, and the common ground are all made of conductive metal.
Optionally, the conductive metal is brass.
Optionally, the plurality of first metal vias are arranged in two rows at the same pitch.
Optionally, the first port, the second port, and the third port are SMA connectors.
Optionally, the dielectric constants of the horizontal feed plate and the vertical plate are the same.
Optionally, the thickness of the horizontal feeding plate is different from that of the vertical feeding plate.
Optionally, the number of the first metal vias is 10.
Optionally, the number of the second metal via holes is 2; the first port, the first port feed line, the impedance tapering structure, the filter, the common ground, the quarter-wave impedance transformer, the second port feed line, the third port feed line, the second port, and the third port form two signal interaction transmission paths.
The embodiment of the invention provides a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines, which comprises the following steps: the horizontal feed plate and the vertical plate are perpendicular to the horizontal feed plate; the horizontal feed board is provided with a first port, a second port, a third port, a first port feeder line, a second port feeder line and a third port feeder line; the first port feeder, the second port feeder and the third port feeder are all formed by microstrip transmission lines, the first port feeder is connected with the first port, the second port feeder is connected with the second port, and the third port feeder is connected with the third port; the horizontal feed plate comprises a first layer, a second layer and a plurality of first metal through holes; the first layer comprises a through hole surface, and the through hole surface is connected with the first metal through holes; the second layer comprises a ground plane, and the ground plane is connected with the via hole plane through a first metal via hole; the vertical plate comprises a third layer, a public ground with a cross gap, a fourth layer, an impedance gradual change structure, a second metal via hole, a filter and a quarter-wavelength impedance converter, wherein the public ground is positioned between the third layer and the fourth layer; the filter is provided with top filtering branches bent in opposite directions; the filter and the quarter-wavelength impedance transformer are connected, are both formed by vertical double-sided parallel strip lines and are respectively and symmetrically positioned on the third layer and the fourth layer; the top filtering branch is connected with the public ground through a second metal through hole; the impedance gradual change structure is respectively connected with the first port feeder line, the via hole surface and the filter; the impedance gradual change structure is positioned on the fourth layer; the first port, the first port feeder, the impedance gradual change structure, the filter, the public ground, the quarter-wavelength impedance transformer, the second port feeder, the third port feeder, the second port and the third port form a signal transmission path.
Compared with the prior art, the embodiment of the invention adopts the technical scheme that the microstrip line is utilized to form the first port feeder line, the second port feeder line and the third port feeder line, and the first port feeder line, the second port feeder line and the third port feeder line are respectively connected with the first port, the second port and the third port; then, a filter and a quarter-wavelength impedance converter are formed by utilizing the vertical double-sided parallel strip lines; the filter and the quarter-wavelength impedance converter are respectively and symmetrically arranged on the third layer and the fourth layer and are respectively connected with the impedance gradual change structure, the first port feeder line, the second port feeder line and the third port feeder line, so that a signal transmission path from the first port to the second port and the third port through the first port feeder line, the impedance gradual change structure, the filter, the public ground, the quarter-wavelength impedance converter, the second port feeder line and the third port feeder line is formed; therefore, the balun and the filter are integrated together, and the impedance matching between the vertical board and the horizontal feed board is realized through the quarter-wavelength impedance converter; therefore, the embodiment of the invention realizes the single balun for the balance-unbalance conversion from the microstrip line to the vertical double-sided parallel strip line, also integrates the filtering function, eliminates parasitic coupling, reduces loss, has smaller size than the whole balun and filter which are separately designed, and improves the integration level.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
Of course, not all of the advantages described above need to be achieved at the same time in the practice of any one product or method of the invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a vertical double-sided parallel strip line-based broadband filtering integrated stereo balun according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a vertical double-sided parallel strip line-based broadband filtering integrated stereo balun according to an embodiment of the present invention;
FIG. 3a is a schematic diagram of an electric field distribution and an equivalent of a first virtual port according to an embodiment of the present invention;
FIG. 3b is a schematic diagram of an electric field distribution and an equivalent of a second virtual port according to an embodiment of the present invention;
FIG. 4 is a schematic structural view of a vertical plate according to an embodiment of the present invention;
FIG. 5a is a schematic diagram of a conventional double-sided parallel strip line disposed in a high power metal shielding can;
fig. 5b is a schematic diagram of a balun disposed in a high power metal shielding box according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of an equivalent circuit of the balun shown in FIG. 2 according to an embodiment of the present invention;
FIG. 7a is a schematic circuit diagram of an equivalent circuit of the balun shown in FIG. 2 under excitation of the odd mode, which is obtained by using the odd-even mode method according to the embodiment of the present invention;
FIG. 7b is a schematic circuit diagram of an equivalent circuit of the balun shown in FIG. 2 under the excitation of the even mode, which is obtained by the odd-even mode method according to the embodiment of the present invention;
fig. 8a is a schematic diagram of the structure size of a vertical double-sided parallel strip line-based broadband filtering integrated stereo balun according to the embodiment of the invention;
fig. 8b is a schematic diagram of the structural dimensions of a vertical double-sided parallel stripline-based broadband filtering integrated stereo balun vertical plate according to an embodiment of the present invention;
fig. 9 is a simulation curve diagram of a vertical double-sided parallel strip line-based broadband filtering integrated stereo balun according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In the face of the change of information and network technologies, electronic information systems such as smart wireless mobile communication and multi-system radar are developing towards multi-frequency multi-modeling, dynamic cognition, miniaturization, low power consumption and the like. Thus, more stringent performance requirements are placed on the units in the radio frequency system. For example, because the conventional microwave device has a single function, the application requirement of multi-frequency multi-channel parallel makes the front end of the radio frequency system have a tendency of increasing the number of devices by times, and further causes the defects of large volume, complex structure, high power consumption, low energy efficiency and the like of the whole electronic information system.
At present, although extensive research is carried out in the field on the integration of the filtering function of the radio frequency device, the research on combining the vertical double-sided parallel strip line and the monomer balun and enabling the vertical double-sided parallel strip line and the monomer balun to have the filtering function is still blank. How to provide and combine together vertical two-sided parallel stripline and monomer balun to make it have concurrently the balun of filtering function to be used for the technical problem who awaits solving. Therefore, the embodiment of the invention provides a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines.
Fig. 1 is a schematic structural diagram of a broadband filtering integrated stereo balun based on vertical double-sided parallel strip lines according to an embodiment of the present invention. The balun comprises: the feed board comprises a horizontal feed board 1 and a vertical board 2 vertical to the horizontal feed board 1; the horizontal feed board 1 is provided with a first port 11, a second port 12, a third port 13, a first port feeder 14, a second port feeder 15 and a third port feeder 16; the first port feeder 14, the second port feeder 15 and the third port feeder 16 are all formed by microstrip transmission lines, the first port feeder 14 is connected with the first port 11, the second port feeder 15 is connected with the second port 12, and the third port feeder 16 is connected with the third port 13;
the horizontal feed plate 1 comprises a first layer 17, a second layer 18 and a plurality of first metal vias 1711; wherein the first layer 17 comprises a via surface 171, the via surface 171 being connected to a plurality of first metal vias 1711; the second layer 18 includes a ground plane 181, the ground plane 181 is connected to the via plane 171 through a first metal via 1711;
the vertical plate 2 comprises a third layer 21, a public ground 22 with a cross gap, a fourth layer 23, a filter 24, a quarter-wave impedance transformer 25, a second metal via 26 and an impedance gradual change structure 27, wherein the public ground 22 is positioned between the third layer 21 and the fourth layer 23; the filter 24 has top filtering branches 241 bent in opposite directions; the filter 24 and the quarter-wave impedance transformer 25 are connected and both formed by vertical double-sided parallel strip lines, and are symmetrically positioned on the third layer 21 and the fourth layer 23 respectively; the top filtering branch 241 is connected with the public ground 22 through a second metal through hole 26; the impedance gradual change structure 27 is positioned on the fourth layer 23 and is respectively connected with the first port feeder 14, the via hole surface 171 and the filter 24;
wherein the first port 11, the first port feeder 14, the impedance tapering structure 27, the filter 24, the common ground 22, the quarter-wave impedance transformer 25, the second port feeder 15, the third port feeder 16, the second port 12 and the third port 13 form a signal transmission path.
In the embodiment of the invention, the filter 24 and the quarter-wave impedance transformer 25 are symmetrically arranged on the third layer 21 and the fourth layer 23 of the vertical plate 2, so that impedance matching is realized, and the filter is integrated on the balun, so that the balun integrated with the filter has the functions of signal balance-unbalance conversion and frequency selection. Compared with the integral size of two discrete components of the independent balun and the filter, the size is reduced, the integration level of a radio frequency system applying the balun and the filter can be improved, parasitic coupling and loss can be effectively reduced, and the stability of electronic information engineering is improved. In addition, the vertical plate 2 and the horizontal feed plate 1 are arranged vertically in the embodiment, and the three-dimensional balun constructed by double-sided parallel strip lines in a vertical mode is realized, so that the integrity of the horizontal ground can be ensured, and the installation process of the metal shielding box is simplified.
In the embodiment shown in fig. 1, the integrity of the ground plane 181 on the second layer 18 of the horizontal feeding board 1 can be ensured by arranging the horizontal feeding board 1 perpendicular to the vertical board 2.
In some embodiments, the microstrip transmission line, the vertical double-sided parallel strip line, the ground plane 181, the via plane 171, and the common ground plane 22 are all conductive metals. In particular, the conductive metal is brass.
In practical application, the vertical plate 2 adopts vertical double-sided parallel strip lines except the impedance gradual change structure 27.
The vertical double-sided parallel strip line has the anti-phase characteristic independent of frequency, so that the balun provided by the embodiment of the invention has good broadband performance.
In practical application, the microstrip transmission line can be realized on the horizontal feed board 1 by copper cladding; the vertical double-sided parallel strip lines constituting the filter 24 and the quarter-wave impedance transformer 25 may be implemented by copper-clad on the third layer 21 and the fourth layer 23 of the vertical plate 2, respectively; similarly, the common ground plane 22, the ground plane 181, and the via plane 171 may be implemented by copper plating.
In some embodiments, the plurality of first metal vias 1711 are arranged in two rows with the same pitch.
In some alternative embodiments, the number of the first metal vias 1711 is 10.
In this embodiment, the first metal via 1711 may be implemented by coating copper on the surface of the via. Among them, brass may be used. The first metal via 1711 connects the via face 171 on the first layer 17 to the ground plane 181 on the second layer 18 through metal (e.g., brass) on the inner wall.
In some embodiments, the first port 11, the second port 12, and the third port 13 are SMA connectors. The first port 11, the second port 12 and the third port 13 are used for connecting with external equipment. In practical application, the first port 11, the second port 12 and the third port 13 are reasonably distributed on the horizontal feeding board 1 as three feeding ports of the balun provided by the embodiment of the invention; the first port is used as an input port, and the other two ports are used as output ports.
In some embodiments, the dielectric constant of the horizontal feeding plate 1 and the vertical plate 2 is the same, for example, 3.48.
In some embodiments, the thickness of the horizontal feeding plate 1 and the vertical plate 2 are different. Specifically, the horizontal feeding plate 1 may be 0.762 millimeter, and the vertical plate 2 may have a thickness of 1.016 millimeter.
The plate material of the horizontal feeding board 1 and the vertical board 2 in the above embodiments may be Rogers (Rogers) 4350B type plate material, etc.
In the embodiment shown in fig. 1, the filter 24 and the quarter-wave impedance transformer 25 being symmetrically located on the third layer 21 and the fourth layer 23, respectively, means that the filter 24 and the quarter-wave impedance transformer 25 are integrally provided on the third layer 21 and the fourth layer 23, respectively, of the vertical plate 2, correspondingly, and are identical in shape and size on the third layer 21 and the fourth layer 23, respectively.
In some embodiments, the number of second metal vias 26 is 2; the first port 11, the first port feeder 14, the impedance tapering structure 27, the filter 24, the common ground 22, the quarter-wave impedance transformer 25, the second port feeder 15, the third port feeder 16, the second port 12 and the third port 13 form two signal interaction transmission paths.
In this embodiment, the common ground 22 with the cross gap is located between the third layer 21 and the fourth layer 23 of the vertical plate 2, and the top filter branch 241 on the filter 24 is grounded through the two second metal via holes 26, so that two signal interaction transmission paths are formed on the vertical plate 2.
Here, for convenience of describing the embodiment of the present invention, as shown in fig. 2, the following definitions are made:
first virtual port 28A: the junction of the impedance grading structure 27 and the first port feed line 14, the first virtual port being also connected to the via surface 171;
second virtual port 28B: the junction of the quarter wave impedance transformers 25 of the third and fourth layers 21, 23 of the vertical plate 2 with the second and third port feeds 15, 16 respectively.
Due to the large difference in conduction band widths on the third layer 21 and the fourth layer 23 on the first virtual port; therefore, the present embodiment provides the resistance gradation structure 27 on the fourth layer 23 of the vertical plate 2. Fig. 1 and 2 show that the resistance graduating structure 27 is located on the vertical plate 2 near the first port 11, but the present invention is not limited thereto, and for example, the resistance graduating structure 27 may be provided on both sides of the vertical plate 2.
Through the above description of the embodiments of the present invention, the balun provided in the embodiments of the present invention is compared with the prior art to illustrate the technical effects achieved by the embodiments of the present invention.
The filter and balun, as the feed front end adjacent element, are indispensable elements such as those in radio frequency systems. The conventional method is to design both the filter and balun independently and then make the connection. Thus, it is not favorable for miniaturization and integration of the radio frequency system. Also, this conventional approach can cause parasitic coupling and loss due to the connection between the two separate components.
However, in the embodiment of the present invention, the filter 24 is disposed on the vertical plate 2, and the balun and the filter 24 are integrated, so that a single balun with a filtering function is used to replace two separate components, which are conventionally and independently used, of the balun and the filter, and the size of the balun and the filter is reduced compared with the size of a radio frequency system using the balun and the filter, which can improve the integration level of the radio frequency system using the balun and the filter, effectively reduce parasitic coupling and loss, and improve the stability of electronic information engineering.
The balun provided by the present invention is described in detail with reference to fig. 2, 3a, 3b and 4.
In this embodiment, an example will be described in which the first port 11 is an input port, the second port 12 is a first output port, the third port 13 is a second output port, the first port feeder 14 is an input port feeder, the second port feeder 15 is a first output port feeder, and the third port feeder 16 is a second output port feeder.
As shown in fig. 2, the vertical double-sided parallel strip line-based broadband filtering integrated stereo balun includes: a horizontal feeding board 1 and a vertical board 2. Wherein:
the horizontal feeding board 1 is a two-layer printed circuit board including a first layer (also referred to as a top layer in this embodiment) 17 and a second layer (also referred to as a bottom layer in this embodiment) 18; the horizontal feed plate 1 is provided with an input port, a first output port, a second output port, an input port feeder, a first output port feeder, a second output port feeder and 10 first metal via holes 1711; the input port is connected with the input port feeder line, the first output port is connected with the first output port feeder line, the second output port is connected with the second output port feeder line, and the impedance of the input port, the impedance of the first output port and the impedance of the second output port are 50 ohms; the input port feeder line, the first output port feeder line and the second output port feeder line are realized in the form of three microstrip lines; the 10 first metal via holes 1711 are arranged in the horizontal feed plate 1, and the 10 first metal via holes 1711 are arranged in two rows at the same pitch; the first layer 17 of the horizontal feed plate 1 is provided with a via surface 171; the second layer 18 of the horizontal feeding board 1 is provided with a ground plane 181;
the vertical board 2 is a three-layer printed circuit board including: a third layer 21, a common ground 22 with a cross slit, a fourth layer 23, and two second metal vias 26 penetrating the third layer 21, the common ground 22, and the fourth layer 23; wherein, the third layer 21 and the fourth layer 23 are symmetrically provided with a filter 24 and a quarter-wave impedance transformer 25 both formed by vertical double-sided parallel strip lines; wherein, the filter 24 has a pair of top filter branches 241 bending oppositely; the common ground 22 connects the pair of top filter branches 241 bent in opposite directions to the ground through the second metal via 26, so as to form two interactive transmission paths on the vertical plate 2;
the impedance transition structure 27 is disposed on the side of the vertical board 2 close to the input port, and is connected to the input port feeder, the via surface 171, and the filter 24, so as to realize the conversion from the microstrip line to the vertical double-sided parallel strip line.
Here, for the convenience of describing the embodiments of the present invention, the following definitions are made:
the impedance of half of the vertical double-sided parallel strip line is defined as Z1～Z5(ii) a Therefore, the impedance of the vertical double-sided parallel strip line is defined as 2Z1～2Z5；
Odd mode excitation means that excitation signals of the first virtual port 28A and the second virtual port 28B are in equal amplitude and opposite phase; the even mode excitation means that excitation signals of the first virtual port 28A and the second virtual port 28B are in equal amplitude and in phase; zino、ZineRespectively representing equivalent input impedance under excitation of odd-even modes; when Z isinoAnd ZineWhen the frequency tends to infinity, the resonant frequency of the filter can be obtained.
As shown in fig. 2, a first virtual port 28A and a second virtual port 28B are shown.
FIG. 3a schematically shows an electric field distribution and an equivalent schematic of the first virtual port 28A; fig. 3B schematically shows an electric field distribution and an equivalent schematic diagram of the second virtual port 28B. Wherein epsilonrRepresents a dielectric constant; 2h2Represents the thickness of the vertical plate 2, for example, 1.016 mm; zsRepresenting an input impedance; 2ZLRepresenting the output impedance; θ represents the electrical length of the transmission line.
In this embodiment, since the widths of the conduction bands of the first virtual port 28A on the third layer 21 and the fourth layer 23 on the vertical plate 2 are different greatly, the first virtual port 28A can be equivalently distributed on the vertical plate 2 in a segment with a thickness of 2h2Input impedance of ZsA microstrip line of (2). Since the signals output by the first and second output ports of the balun are in equal amplitude and opposite phase, the second virtual port 28B can be regarded as a series connection of the first and second output ports, i.e. equivalently, the signals are distributed on the vertical plate 2 with a thickness of 2h2Output impedance of 2ZLDouble-sided parallel strip lines.
Based on the positions of the first and second virtual ports (28A,28B) shown in fig. 2, the center position of the first virtual port 28A is aligned with one end of the input port feed line, and the center position of the second virtual port 28B is aligned with one end of the first output port feed line and one end of the second output port feed line, so that the signals can pass through with maximum energy; the other end of the input port feeder, the other end of the first output port feeder and the other end of the second output port feeder are used for connecting external equipment.
In addition, since the first virtual port 28A is connected to the input port feeder on the one hand and also connected to the via surface 171 on the other hand; therefore, the sizes of the feeder line and the via hole surface of the input port are considered, and the discontinuity of signal transmission is reduced; therefore, the present embodiment provides the impedance gradual structure 27 on the side of the vertical plate 2 close to the input port, specifically, on the side of the fourth layer 23 of the vertical plate 2 where the first dummy port 28A is connected to the via face. Thus, discontinuity of signal transmission is reduced by the impedance transition structure 27, and good impedance matching from the first virtual port 28A to the second virtual port 28B is further achieved. The material of the impedance gradual change structure 27 is formed by copper cladding. Therefore, the embodiment of the invention forms the input port feeder, the first output port feeder and the second output port feeder by using the microstrip line, and connects the input port feeder, the first output port feeder and the second output port feeder with the input port, the first output port and the second output port respectively; then, the filter 24 and the quarter-wave impedance transformer 25 are formed by using the vertical double-sided parallel strip lines; and the impedance gradual change structure 27 is connected to the input port feeder, the via surface 171, and the filter 24, respectively, so that a balance-unbalance conversion from the microstrip line to the vertical double-sided parallel strip line is realized.
Fig. 4 exemplarily shows a structural view of the above-described vertical plate. The impedance gradual change structure 27 is distributed on the left side of the vertical board 2, and the conversion from the microstrip line to the vertical double-sided parallel strip line is realized by connecting the input port feeder line of the horizontal feed board 1, the via hole surface 171 and the filter 24. The filter 24 can be implemented as follows: 2013, Novelminaturization method for wireless filter design with enhanced upperstop and IEEE trans.
In the present embodiment, based on a signal interference technology (transient signal-interference concepts), the common ground 22 with a cross gap is disposed between the third layer 21 and the fourth layer 23, and the pair of top filtering branches 241 bent in opposite directions is grounded through, for example, two second metal vias 26, so that the balun provided in the present embodiment has a more stable balanced conversion function, further expands the filtering bandwidth, and has a steep depth stopband attenuation performance.
In summary, in the present embodiment, the horizontal feeding board 1 and the vertical board 2 are vertically disposed, so that the integrity of the ground plane 181 on the second layer 18 of the horizontal feeding board 1 is ensured; meanwhile, except for the impedance gradual change structure 27 on the vertical plate 2, the filter 24 and the quarter-wave impedance converter 25 both adopt vertical double-sided parallel strip lines, so that the broadband performance of the balun provided by the embodiment of the invention is realized by utilizing the anti-phase characteristic that the vertical double-sided parallel strip lines are irrelevant to the frequency; moreover, the public ground 22 with the cross gap is arranged between the third layer 21 and the fourth layer 23, so that two transmission paths for transmitting signals in an interactive manner are formed on the vertical plate 2, the balance conversion function of the balun provided by the embodiment of the invention can be stable, the filtering bandwidth is expanded, the stopband attenuation performance of a steep depth is realized, and the miniaturized broadband filtering integrated single stereo balun based on the vertical double-sided parallel strip lines is realized.
The technical effect achieved by the embodiment of the present invention will be described in detail with reference to fig. 5a and 5 b.
In order to visually show the technical effects of the embodiment of the invention, the embodiment of the invention and the traditional double-sided parallel strip line are placed in a high-power metal shielding box for comparison.
The distance between the bottom layer strip line of the traditional double-sided parallel strip line and the bottom of the high-power metal shielding box is assumed to be S1(ii) a The distance between the strip line of the balun and the side wall of the high-power metal shielding box is S2。
FIG. 5a schematically illustrates a conventional double-sided parallel strip line disposed in a high power metal shield can; fig. 5b schematically shows a schematic diagram of the balun disposed in the high-power metal shielding box according to the embodiment of the present invention.
As shown in fig. 5a, in order to avoid a ground loop generated due to direct contact between the bottom layer strip line of the conventional double-sided parallel strip line and the bottom of the high-power metal shielding box, the conventional double-sided parallel strip line needs to be suspended from the high-power metal shielding box. It can be seen that the conventional method not only increases the manufacturing difficulty, but also increases the manufacturing difficulty due to the distance S1The presence of (a) can produce a parasitic response between the underlying strip line and the bottom of the high power metal shield can. However, as shown in fig. 5b, the embodiment of the present invention lays out the double-sided parallel strip lines on the vertical board 2 perpendicular to the horizontal feeding board 1, thereby ensuring the integrity of the ground plane 181 on the horizontal feeding board 1. In practical engineering, when S2>At 10h (h is the thickness of the dielectric plate), the side wall of the high-power metal shielding box has negligible influence on the vertical double-sided parallel strip line. Therefore, the balun provided by the embodiment of the invention can be directly contacted with the bottom of the high-power metal shielding box. Thereby, not only parasitic resonance is eliminated, but also the mounting process of the high power metal shield case is simplified.
The mirror image theory shows that when opposite-phase voltages are applied to the upper end and the lower end of the double-sided parallel strip line, the voltage in the middle of the medium plate in the middle is 0. Therefore, in the balun shown in fig. 2, when the common ground 22 with the cross slit is provided to the middle of the two-sided parallel strip lines, the electric field distribution of the second virtual port 28B does not change. Based on this, the double-sided parallel strip line of the second virtual port 28B can be regarded as two microstrip lines arranged back to back on the same dielectric board, and the electrical length of each microstrip line is kept unchanged, but the thickness and the impedance value of the dielectric board are halved, which are h respectively2And ZL。
Fig. 6 schematically shows an equivalent circuit diagram of the balun shown in fig. 2; fig. 7a is a schematic circuit diagram of an equivalent circuit of the balun shown in fig. 2 obtained by using an odd-even mode method under excitation of an odd mode;
fig. 7b exemplarily shows a circuit diagram of an equivalent circuit of the balun shown in fig. 2 under the excitation of the even mode, which is obtained by using the odd-even mode method.Wherein, two sections of double-sided parallel strip lines (2Z)1Theta/2) and open-circuit branches (2Z) connected in between2θ) constitutes one main transmission path 29B; a pair of double-sided parallel strip lines (2Z)3Theta) and short-circuit minor matters (2Z)4And θ) are cascaded to form one auxiliary transmission path 29A. The two transmission paths (29B,29A) interact with each other, and based on a mutual signal interference technique, a phase difference between signals on the two transmission paths generates a wider stop band, which jointly transmits the signals from the first virtual port 28A to the second virtual port 28B, thereby improving balun filtering, balance conversion and stop band attenuation performance. In addition, a quarter-wave double-sided parallel strip line (2Z) is also passed5θ) (i.e., the quarter-wave impedance transformer 25), impedance matching of the equivalent output impedance of the main transmission path 29B and the auxiliary transmission path 29A with the second virtual port 28B is achieved.
Fig. 8a and 8b are schematic diagrams illustrating exemplary dimensions of structures of a balun provided by an embodiment of the present invention.
The present embodiment assumes an input impedance (i.e., Z)s) And output impedance (i.e. Z)L) 50 ohms (Ω); the electrical length (θ) is 90 °; the other circuit impedances are (unit: Ω): z1＝70，Z2＝16.5，Z3＝16，Z4＝49，Z535.36. The following physical dimensions of balun (in mm) were obtained using an electromagnetic simulation application (High Frequency Structure Simulator) at an operating Frequency of 6 GHz: l is0＝10.0，W0＝1.7，L1＝4.3，W1＝0.7，L2＝5.1，W2＝7.1，L3＝7.0，W3＝5.3，L4＝7.5，W4＝1.2，L5＝2.0，W5＝1.9，W6＝1.0，L7＝10.0，W7＝2.5，W88.9. Wherein L is0...L5、L7Represents a length; w0...W8Indicating the width.
Fig. 9 is a schematic diagram illustrating a simulation curve of the balun provided in the embodiment shown in fig. 2.
Wherein, | S11I tableShowing the matching performance of the input ports; i S21L represents the transmission performance of the first output port; i S31∠, represents the transmission performance of the second output port ∠, S21-∠S31Representing the phase difference between the first output port and the second output port.
As can be seen from FIG. 9, when | S11|<At-15 dB, the operating band is 1.46 GHz-3.48 GHz, and within this bandwidth, | S21I and I S31all the time, | is kept in the range of-3.1 +/-1 dB, and is within the range of 2.88 GHz-3.84 GHz, and the angle S is21-∠S31Fluctuates in the range of-180 ° ± 10 °, and the resulting error is caused by the signal superposition of the main transmission path 29B and the auxiliary transmission path 29A or the inductance effect by the metal via. In addition, | S in the upper stop band with width of 5.13GHz (4.08 GHz-9.21 GHz) | S21|、|S31All less than-20 dB. Where dB represents decibel.
As can be known from the simulation result shown in fig. 9, the balun provided by the embodiment of the present invention has at least the following beneficial effects: the input matching is good, the insertion loss is small, the phase difference is stable, the filter band width is wide, and the stop band attenuation is steep and deep.
In summary, compared with the conventional method that two separate baluns and filters are connected when the baluns and the filters are applied, the prior art has the defects of parasitic coupling and loss caused by the connection of the baluns and the filters; in the embodiment of the invention, the balun and the filter 24 are integrated, the impedance matching between the vertical plate and the horizontal feed plate is realized through the quarter-wavelength impedance converter, the impedance matching between the first virtual port 28A and the second virtual port 28B is ensured, the single balun for the balance-unbalance conversion from the microstrip line to the vertical double-sided parallel strip line is realized, the filtering function is also fused, the parasitic coupling is eliminated, the loss is reduced, the size of the embodiment of the invention is smaller than that of the whole balun and the filter which are separately designed, and the integration level is improved.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiments in the present specification are described in a related manner, each embodiment focuses on differences from other embodiments, and the same and similar parts in the embodiments are referred to each other. Reference is made to the description of the method embodiments.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (8)
1. The utility model provides a three-dimensional balun of broadband filtering integration based on vertical two-sided parallel stripline which characterized in that includes: the horizontal feed plate and the vertical plate are perpendicular to the horizontal feed plate; wherein:
the horizontal feed board is provided with a first port, a second port, a third port, a first port feeder line, a second port feeder line and a third port feeder line; the first port feeder, the second port feeder and the third port feeder are all formed by microstrip transmission lines, the first port feeder is connected with the first port, the second port feeder is connected with the second port, and the third port feeder is connected with the third port;
the horizontal feed plate comprises a first layer, a second layer and a plurality of first metal through holes; wherein the first layer comprises a via surface, the via surface being connected to the plurality of first metal vias; the second layer comprises a ground plane, and the ground plane is connected with the via hole plane through the first metal via hole;
the vertical plate comprises a third layer, a public ground with a cross gap, a fourth layer, an impedance gradual change structure, a second metal via hole, a filter and a quarter-wavelength impedance converter, wherein the public ground is positioned between the third layer and the fourth layer; the filter is provided with top end filtering branches bent in opposite directions; the filter and the quarter-wavelength impedance transformer are connected and both formed by vertical double-sided parallel strip lines and are symmetrically positioned on the third layer and the fourth layer respectively; the top filtering branch is connected with the public ground through the second metal through hole; the impedance gradual change structure is positioned on the fourth layer and is respectively connected with the first port feeder line, the via hole surface and the filter;
the number of the second metal through holes is 2; the first port, the first port feed line, the impedance tapering structure, the filter, the common ground, the quarter-wave impedance transformer, the second port feed line, the third port feed line, the second port, and the third port form two signal interaction transmission paths.
2. The balun of claim 1, wherein the microstrip transmission line, the vertical double-sided parallel strip line, the ground plane, the via plane, and the common ground plane are all conductive metals.
3. Balun according to claim 2, characterized in that the electrically conductive metal is brass.
4. The balun according to claim 2 or 3, wherein the plurality of first metal vias are arranged in two columns at the same pitch.
5. The balun of claim 2, wherein the first port, the second port and the third port are SMA connectors.
6. The balun of claim 5, wherein the dielectric constants of the horizontal feed plate and the vertical plate are the same.
7. The balun of claim 1, wherein the horizontal feed plate and the vertical feed plate have different thicknesses.
8. The balun of claim 4, wherein the number of the plurality of first metal vias is 10.
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| CN109088137B (en) * | 2018-08-31 | 2022-03-01 | 易力声科技(深圳)有限公司 | Lumped circuit balance converter applied to double-sided parallel lines |
| CN109301406B (en) * | 2018-09-14 | 2020-02-18 | 北京邮电大学 | Bandwidth-adjustable miniaturized filtering integrated three-dimensional balun |
| CN110247145B (en) * | 2019-06-26 | 2020-10-30 | 北京邮电大学 | Bandwidth-adjustable broadband filtering balun with in-band good matching and isolation |
| CN110676554B (en) * | 2019-08-02 | 2021-04-30 | 杭州法动科技有限公司 | Low-profile ultra-wideband indoor communication plane structure antenna |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105789802A (en) * | 2014-12-15 | 2016-07-20 | 南京理工大学 | Ultra-wideband Balun based on new interconnection structure |
| CN206564312U (en) * | 2017-03-24 | 2017-10-17 | 电子科技大学 | A kind of double frequency applied to WLAN filters power splitter |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9634639B2 (en) * | 2015-09-10 | 2017-04-25 | Harris Corporation | Tunable electronic circuit which converts balanced signals to unbalanced signals |
| CN106921014B (en) * | 2017-03-02 | 2019-01-18 | 南京理工大学 | A kind of highly selective balun filter |
-
2017
- 2017-12-25 CN CN201711420770.1A patent/CN108123196B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105789802A (en) * | 2014-12-15 | 2016-07-20 | 南京理工大学 | Ultra-wideband Balun based on new interconnection structure |
| CN206564312U (en) * | 2017-03-24 | 2017-10-17 | 电子科技大学 | A kind of double frequency applied to WLAN filters power splitter |
Non-Patent Citations (3)
| Title |
|---|
| Three-dimensional high-isolated dual-band balun using double-sided parallel-strip line with inserted conductor plane;Lidan Yao et al;《ELECTRONICS LETTERS》;20170813;第53卷(第17期);第1211-1213页 * |
| UWB balun with complete ground based on vertically mounted planar structure;Yongle Wu et al;《ELECTRONICS LETTERS》;20160303;第52卷(第5期);摘要、第443页右栏-第446页右栏及图5-9 * |
| 基于宽带滤波巴伦的端射滤波天线;周彦，丁博;《海军航空工程学院学报》;20160720;第31卷(第4期);第405-406页 * |
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