CN112133992B - Filtering power divider with high out-of-band rejection and full-band absorption functions - Google Patents

Abstract

The embodiment of the invention provides a filtering power divider with high out-of-band rejection and full-band absorption functions, relates to the technical field of electricity, and can improve the performance of a communication system. In a filtering power dividing circuit of the filtering power divider, a first port 1 is connected with one end of a first absorption branch S1 and one end of a first branch t 1; the other end of the first branch t1 is connected with one end of the first coupled line C1b and one end of the second coupled line C2 a; the other end of the first coupling line C1b is connected with one end of the second absorption branch S2; one end of the first coupled line C1a line is connected with one end of the third coupled line C3a line, and one end of the third coupled line C3b line is connected with the second port 2; the other end of the second coupling line C2a is connected with one end of the third absorption branch S3; one end of the second coupled line C2b line is connected to one end of the fourth coupled line C4b line, and one end of the fourth coupled line C4a line is connected to the third port 3.

Description

A filter power divider with high out-of-band rejection and full-band absorption

technical field

The invention relates to the field of electrical technology, in particular to a filter power divider with functions of high out-of-band suppression and full-band absorption.

Background technique

At present, with the rapid development of microwave communication technology, power divider (referred to as power divider) as one of the key components is widely used in antenna feeding networks such as wireless communication and satellite navigation systems. A common power divider is a three-port device. Signal and power are input from one port and then distributed to the other two ports. It is an important passive power distribution device.

The power divider is often connected to systems such as amplifiers and antenna arrays, and the unwanted signal (ie noise) input to the power divider is reflected through the input port into the system connected to the power divider, and is generated with nonlinear elements in these systems. Intermodulation interference. Non-linear components such as amplifiers have high sensitivity to noise, and the reflected signal will have a greater impact on the performance of the nonlinear system, which will lead to a decrease in the sensitivity and signal-to-noise ratio of the communication system, which seriously affects the performance of the communication system.

SUMMARY OF THE INVENTION

The purpose of the embodiments of the present invention is to provide a filter power divider with functions of high out-of-band suppression and full-band absorption, so as to reduce reflection noise in a communication system and improve the performance of the communication system. The specific technical solutions are as follows:

An embodiment of the present invention provides a filter power divider with high out-of-band suppression and full-band absorption functions, the filter power divider includes: a dielectric substrate and a filter power divider circuit arranged on the upper surface of the dielectric substrate; wherein ,

The filtering power division circuit includes: a first port 1, a second port 2, a third port 3, a first branch t1, a first coupling line C1, a second coupling line C2, a third coupling line C3, and a fourth coupling line Line C4, first absorbing branch S1, second absorbing branch S2 and third absorbing branch S3; each coupled line includes a line and b line, the first absorbing branch S1, the second absorbing branch S2 and the The third absorption branch S3 is used for absorbing the noise reflected into the first port 1;

The first port 1 is connected to one end of the first absorbing branch S1 and one end of the first branch t1, and the other end of the first absorbing branch S1 is grounded;

The other end of the first branch t1 is connected to one end of the first coupling line C1 b line and one end of the second coupling line C2 a line;

The other end of the first coupling line C1 b is connected to one end of the second absorption branch S2, and the other end of the second absorption branch S2 is grounded;

One end of the first coupling line C1 a is connected to one end of the third coupling line C3 a, and one end of the third coupling line C3 b is connected to the second port 2;

The other end of the second coupling line C2 a is connected to one end of the third absorbing branch S3, and the other end of the third absorbing branch S3 is grounded;

One end of the second coupling line C2 b is connected to one end of the fourth coupling line C4 b, and one end of the fourth coupling line C4 a is connected to the third port 3 .

Optionally, the first absorption branch S1 includes a first resistor R11 and a first short-circuit branch S11 connected in series, and the first short-circuit branch S11 is grounded;

The second absorption branch S2 includes a second resistor R21 and a second short-circuit branch S21 connected in series, and the second short-circuit branch S21 is grounded;

The third absorption branch S3 includes a third resistor R31 and a third short-circuit branch S31 connected in series, and the third short-circuit branch S31 is grounded.

Optionally, the filtering power division circuit further includes: a first half-wavelength open-circuit branch K1 and a second half-wavelength open-circuit branch K2;

One end of the first coupling line C1 a line is also connected to the first half-wavelength open branch node K1;

One end of the second coupling line C2 b line is also connected to the second half-wavelength open-circuit branch K2.

Optionally, the filtering power dividing circuit further includes: an isolation resistor R3;

The other end of the first coupling line C1 b is also connected to one end of the isolation resistor R3;

The other end of the second coupling line C2 a line is also connected to the other end of the isolation resistor R3.

Optionally, the even-mode impedance of the first coupling line C1 and the second coupling line C2 are the same, and the odd-mode impedance is the same;

The third coupling line C3 and the fourth coupling line C4 have the same even-mode impedance and the same odd-mode impedance.

Optionally, the electrical lengths of the first coupling line C1, the second coupling line C2, the third coupling line C3 and the fourth coupling line C4 are the same.

Optionally, the characteristic impedances of the first half-wavelength open-circuit branch K1 and the second half-wavelength open-circuit branch K2 are the same.

Optionally, the second short-circuit branch S21 of the second absorption branch S2 and the third short-circuit branch S31 of the third absorption branch S3 have the same characteristic impedance.

Optionally, the characteristic impedances of the first short-circuit branch S11 of the first absorption branch S1, the second short-circuit branch S21 of the second absorption branch S2 and the first branch t1 are different.

Optionally, the filter power divider further includes: a metal layer covering the lower surface of the dielectric substrate, and the metal layer is grounded;

The first absorbing branch S1, the second absorbing branch S2 and the third absorbing branch S3 further include through holes connecting the metal layers.

The filter power divider with high out-of-band suppression and full-band absorption functions provided by the embodiment of the present invention has three absorbing branches that can absorb the noise reflected into the first port, that is, the three absorbing branches can absorb the signal reflected from the input port, Reduce the interference of reflected signals to the communication system, improve the sensitivity and signal-to-noise ratio of the communication system, and improve the performance of the communication system.

Of course, it is not necessary for any product or method of the present invention to achieve all of the advantages described above at the same time.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other embodiments can also be obtained according to these drawings without creative efforts.

1 is a circuit schematic diagram of a filter power divider provided by an embodiment of the present invention;

2a is a schematic diagram of the circuit structure of a filter power divider provided by an embodiment of the present invention when the center operating frequency is 1.75 GHz;

2b is a schematic diagram of a partial circuit structure of a connection between a first port of a filter power divider and a first absorption branch according to an embodiment of the present invention;

2c is a schematic diagram of a partial circuit structure at the connection of an isolation resistor, a second absorption branch, and a third absorption branch of a filter power divider according to an embodiment of the present invention;

3 is a schematic diagram of the simulation results of the reflection coefficient of any output port and the transmission coefficient of the filter power divider when the input port of the filter power divider provided by the embodiment of the present invention is excited at a center operating frequency of 1.75 GHz;

4 is a schematic diagram of a simulation result of the matching coefficient of any output port and the isolation coefficient between two output ports when the input port of a filter power divider according to an embodiment of the present invention is excited at a center operating frequency of 1.75 GHz .

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to reduce the reflected noise in the communication system and improve the performance of the communication system, an embodiment of the present invention provides a filtering power divider with high out-of-band suppression and full-band absorption functions. As shown in FIG. 1 , the filtering power divider The device includes: a dielectric substrate and a filtering power division circuit arranged on the upper surface of the dielectric substrate; wherein,

The filtering power division circuit includes: a first port 1, a second port 2, a third port 3, a first branch t1, a first coupling line C1, a second coupling line C2, a third coupling line C3, and a fourth coupling line C4 , the first absorbing branch S1, the second absorbing branch S2 and the third absorbing branch S3; each coupling line includes a line and b line, the first absorbing branch S1, the second absorbing branch S2 and the third absorbing branch S3 are used for absorbing Noise reflected into the first port 1.

The first port 1 is connected to one end of the first absorbing branch S1 and one end of the first branch t1 , and the other end of the first absorbing branch S1 is grounded. It can be seen that the first absorption branch S1 is connected in parallel with the first port 1, and the first absorption branch S1 is connected in parallel with the first branch t1.

The other end of the first branch t1 is connected to one end of the first coupling line C1 b line and one end of the second coupling line C2 a line.

The other end of the first coupling line C1 b is connected to one end of the second absorbing branch S2, and the other end of the second absorbing branch S2 is grounded. It can be seen that the second absorbing branch S2 is connected in parallel with the first coupling line C1 b.

One end of the first coupling line C1 a is connected to one end of the third coupling line C3 a, and one end of the third coupling line C3 b is connected to the second port 2 .

The other end of the second coupling line C2 a is connected to one end of the third absorbing branch S3, and the other end of the third absorbing branch S3 is grounded. It can be seen that the third absorbing branch S3 is connected in parallel with the second coupling line C2 a line.

One end of the second coupling line C2 b is connected to one end of the fourth coupling line C4 b, and one end of the fourth coupling line C4 a is connected to the third port 3 .

The filter power divider with high out-of-band suppression and full-band absorption functions provided by the embodiment of the present invention has three absorbing branches that can absorb the noise reflected into the first port, that is, the three absorbing branches can absorb the signal reflected from the input port, Reduce the interference of reflected signals to the communication system, improve the sensitivity and signal-to-noise ratio of the communication system, and improve the performance of the communication system.

In this embodiment of the present invention, the first port 1 may be an input port, and the second port 2 and the third port 3 may be output ports. Optionally, both the input port and the output port may be subminiature version A (SubMiniature version A, SMA) connectors. Among them, SMA is a coaxial RF connector, which can be used as the smallest connector interface of a coaxial cable with a helical coupling structure.

In the embodiment of the present invention, the filtering power dividing circuit further includes: an isolation resistor R3.

The other end of the first coupling line C1 b is also connected to one end of the isolation resistor R3; the other end of the second coupling line C2 a is also connected to the other end of the isolation resistor R3.

In the embodiment of the present invention, an isolation resistor R3 is connected in series between the first coupling line C1 and the second coupling line C2. The isolation resistor R3 can effectively isolate the signals output by the two output ports, that is, isolate the second port 2 and the third port 3 The output signal has good passband isolation performance.

Referring to Figure 1, each absorbing branch may include a resistor in series and a quarter-wave shorting branch, where the resistor absorbs the signal and power in a heat-dissipating manner, the shorting branch is grounded, and the shorting branch is equivalent to the filter power divider operating frequency It is an open circuit, so that the absorbing branch can absorb the reflected signal without affecting the normal operation of the filtering power divider.

Specifically, the first absorption branch S1 includes a first resistor R11 and a first short-circuit branch S11 connected in series, and the first short-circuit branch S11 is grounded.

The second absorption branch S2 includes a second resistor R21 and a second short circuit branch S21 connected in series, and the second short circuit branch S21 is grounded.

The third absorbing branch S3 includes a third resistor R31 and a third short-circuit branch S31 connected in series, and the third short-circuit branch S31 is grounded.

Since two absorption branches are connected in parallel at the first port 1 of the filter power divider and the end of the isolation resistor R3 in the embodiment of the present invention, and the absorption branches are formed by connecting a resistor and a short-circuited quarter-wavelength branch in series, among the three absorption branches The resistor can absorb the input power and signal in the out-of-band area input to the first port, realize the full-band absorption function, and avoid the reflection of useless signals into the equipment connected to the filter power divider, which will interfere with the performance of the communication system. Moreover, by adjusting the value of the resistance in the absorbing branch, the effect of changing the absorption degree of the absorbing reflected signal can be achieved.

Referring to FIG. 1 , the filtering power division circuit in the embodiment of the present invention may further include: a first half-wavelength open-circuit branch K1 and a second half-wavelength open-circuit branch K2.

One end of the first coupling line C1 a line is also connected to the first half-wavelength open-circuit branch K1. It can be seen that the first half-wavelength open branch K1 is connected in parallel with the first coupling line C1 a, and the first half-wavelength open branch K1 is connected in parallel with the third coupling line C3 a.

One end of the b-line of the second coupling line C2 is also connected to the second half-wavelength open-circuit branch K2. It can be seen that the second half-wavelength open branch K2 is connected in parallel with the second coupling line C2 b, and the second half-wavelength open branch K2 is connected in parallel with the fourth coupling line C4 b.

In the embodiment of the present invention, the half-wavelength open-circuit branch is introduced, which improves the suppression of out-of-band unwanted signals, so that there are multiple transmission zeros out of the band and multiple transmission poles in the band, which enhances the out-of-band suppression and has good pass-through. Out-of-band isolation performance, and has a wide filter frequency range. By adjusting the impedance of the half-wavelength open-circuit branch, the effect of independently adjusting the passband bandwidth of the filter power divider can be achieved, and the bandwidth can be expanded and the filter selectivity can be improved.

In an embodiment of the present invention, the even-mode impedances of the first coupling line C1 and the second coupling line C2 are the same, and the odd-mode impedances are the same. As shown in FIG. 1 , the even-mode impedance of the first coupling line C1 and the second coupling line C2 is Z _e1 , and the odd-mode impedance is Z _o1 .

The even mode impedances of the third coupling line C3 and the fourth coupling line C4 are the same, and the odd mode impedances are the same. As shown in FIG. 1 , the even-mode impedance of the third coupling line C3 and the fourth coupling line C4 is Z _e2 , and the odd-mode impedance is Z _o2 .

Correspondingly, the line width, interval and line length of the first coupling line C1 and the second coupling line C2 are the same; the line width, interval and line length of the third coupling line C3 and the fourth coupling line C4 are the same. The line width refers to the line width of each line in the coupled line, the interval refers to the interval between the a line and the b line in the coupled line, and the line length refers to the line length of each line in the coupled line.

In one embodiment of the present invention, the electrical lengths of the first coupling line C1, the second coupling line C2, the third coupling line C3 and the fourth coupling line C4 are the same. Optionally, the electrical length θ of the first coupling line C1 , the second coupling line C2 , the third coupling line C3 and the fourth coupling line C4 is 90°.

In an embodiment of the present invention, the characteristic impedances of the first half-wavelength open-circuit branch K1 and the second half-wavelength open-circuit branch K2 are the same. The characteristic impedance of the first half-wavelength open stub K1 and the second half-wavelength open stub K2 is Z _s2 , and the electrical length of the first half-wavelength open stub K1 and the second half-wavelength open stub K2 is 180°.

In an embodiment of the present invention, the second short-circuit branch S21 of the second absorption branch S2 and the third short-circuit branch S31 of the third absorption branch S3 have the same characteristic impedance. The characteristic impedance of the second short-circuit branch S21 and the third short-circuit branch S31 is Z _s3 , and the electrical length is 90°. Correspondingly, the line width and length of the second short-circuit branch S21 and the third short-circuit branch S31 are the same.

In an embodiment of the present invention, the characteristic impedance Z _s1 of the first short-circuit branch S11 , the characteristic impedance Z _s3 of the second short-circuit branch S21 , and the characteristic impedance Z _t1 of the first branch t1 are different.

Correspondingly, the line widths and lengths of the first short-circuit branch S11 , the second short-circuit branch S21 and the first short-circuit branch t1 are all different.

Optionally, the electrical lengths of the first short-circuit branch S11, the second short-circuit branch S21, the third short-circuit branch S31 and the first branch t1 are 90°.

It can be seen that the circuit structure of the filter power divider provided by the embodiment of the present invention is a structure that is symmetrical up and down, and has the characteristics of simple structure and easy processing.

The embodiment of the present invention can be implemented by the design method of a single-layer printed circuit board, that is, a filter power division circuit can be printed on the upper surface of the dielectric substrate, and a grounded metal layer can be covered on the lower surface. Optionally, the model of the dielectric substrate can be TaconicCER-10, the dielectric constant is 10, the thickness is 1.6mm, and the dielectric loss is 0.0035.

The first absorbing branch S1, the second absorbing branch S2 and the third absorbing branch S3 further include through holes connecting the metal layers, so that one end of the three absorbing branches is grounded.

The filter power divider provided by the embodiment of the present invention has a small size and a wide passband bandwidth, which conforms to the miniaturization trend of communication systems and the demand for bandwidth. Moreover, the overall filter power divider is a simple plane structure, which is easy to implement. Because the structure realizes multi-function multiplexing, it can effectively improve the performance of the radio frequency system, reduce the impact of reflected noise on the system, and reduce the microwave system. complexity and significantly improve system performance.

In order to facilitate presentation and adaptation to current communication frequency band requirements, an embodiment of the present invention exemplarily provides an embodiment with a center frequency of 1.75 gigahertz (GigaHertz, GHz). In this embodiment, the selected model of the dielectric substrate is TaconicCER-10, the dielectric constant is 10, the thickness is 1.6 millimeters (millimeter, mm), and the dielectric loss is 0.0035. The filter power divider circuit is arranged on the upper surface of the dielectric substrate, and the grounded metal is covered on the lower surface as the ground.

FIG. 2a is a schematic diagram of the circuit structure of a filter power divider provided by an embodiment of the present invention when the center operating frequency is 1.75 GHz, and FIG. 2b is a partial circuit structure of the connection between the first port of the filter power divider and the first absorption branch Schematic diagram, FIG. 2c is a schematic diagram of the partial circuit structure of the connection between the isolation resistance of the filter power divider and the second and third absorption branches.

In this embodiment, the characteristic impedances of the first, second and third ports are all 50 ohms (Ω). As shown in Figs. 2a-2c, the width Wp of the three ports is 2 mm, and the length lp of the three ports is 16.4 mm. The line width W _e1 of the first coupling line C1 and the second coupling line C2 is 0.1 mm, the slit width (interval) S _e1 is 0.1 mm, and the line length l _e1 is 18.9 mm. The line width _{We2 of the third coupling line C3 and the fourth coupling line C4 is 0.2 mm, the slit width S e2 is} 0.3 mm, and the line length l _e2 is 18.1 mm. The width W _s2 of the first half-wavelength open stubs K1 and the second half-wavelength open stubs K2 is 3.8 mm, and the length _ls2 is 34.3 mm. The width W _t of the first branch t1 is 1.3 mm, and the length l _t1 is 15 mm. The resistance value of the isolation resistor R3 is R ₃ =270Ω.

In Figures 2a-2c, the two parallel absorbing branches connected to the first port 1 are equivalent to the first branch S1. The resistance value of the first resistor R11 in the first absorbing branch S1 is R ₁ =145Ω, the line width W _s1 is 0.8 mm, and the length l _s1 is 15.2 mm. The line of the first absorbing branch S1 is grounded through the grounding hole. The second absorbing branch S2 and the third absorbing branch S3 have a resistance value R ₂ =135Ω, a line width W _s3 of 1.1 mm, a length _ls 3 of 15.4 mm, and are grounded through a grounding hole.

3 is a schematic diagram of the simulation results of the reflection coefficient S ₁₁ of any output port and the transmission coefficient S ₂₁ of the filter power divider when the input port of the filter power divider is excited at the center operating frequency of 1.75 GHz in the embodiment of the present invention. The input port is the first port, and the output ports are the second port and the third port. The reflection coefficient S ₁₁ of any one output port can also be referred to as the return loss of the filter. The transmission coefficient S ₂₁ may also be referred to as insertion loss. The curve with squares is S ₁₁ , and the curve with circles is S ₂₁ .

When the input port is excited, when the center operating frequency is 1.75GHz, the insertion loss S21 of the filter power divider at _1.75GHz is -3.86 decibels (decibel, dB), and the filter power divider can achieve full-frequency The absorption of the reflected signal at the input port, the return loss _S11 in the passband is less than -10dB in the range of 1.21GHz to 2.30GHz. In particular, if the absorption of the filter power divider is defined as the return loss S ₁₁ is less than -10dB, outside the passband range, the filter power divider can achieve the absorption of out-of-band reflected signals, then the filter power divider can Effective absorption of reflected signals over the full frequency range is achieved. At the same time, the filter power divider can achieve effective deep suppression of out-of-band transmission signals, and the suppression depth is 22dB.

4 is the simulation result of the matching coefficient S ₂₂ of any output port and the isolation coefficient S ₂₃ between the two output ports when the input port of the filter power divider is excited at the center operating frequency of 1.75 GHz in the embodiment of the present invention Schematic. The input port is the first port, and the output ports are the second port and the third port. The curve with a triangle is S ₂₂ , and the curve with a pentagram is S ₂₃ .

The isolation coefficient S ₂₃ in the passband is greater than _14.3dB , and the isolation coefficient S23 outside the passband is greater than 15dB, indicating that the two output ports of the filter power divider have good isolation performance. The matching coefficient S ₂₂ of any output port is less than -10dB in the range of 1.10GHz to 2.30GHz, and there are two poles at the cut-off frequency of the passband, indicating that the two output ports of the filter power divider have good matching performance. .

The size of the filtering power dividing circuit provided by the embodiment of the present invention can be designed to be 69 mm×52 mm, and has the characteristics of miniaturization and easy integration. It is explained that the filter power divider with deep out-of-band suppression and full-frequency absorption provided by the embodiment of the present invention can be widely used in various microwave systems, conforms to the trend of miniaturization of systems and devices, and can reduce interference to communication systems , the application prospect is wide.

It should be noted that, in this document, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any relationship between these entities or operations. any such actual relationship or sequence exists. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article or apparatus that includes the element.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims (9)

1. A filter power divider with high out-of-band rejection and full-band absorption, comprising: the filter power divider comprises a dielectric substrate and a filter power dividing circuit arranged on the upper surface of the dielectric substrate; wherein,

the filtering power dividing circuit comprises: a first port (1), a second port (2), a third port (3), a first stub (t1), a first coupled line (C1), a second coupled line (C2), a third coupled line (C3), a fourth coupled line (C4), a first absorption stub (S1), a second absorption stub (S2), and a third absorption stub (S3); each coupled line comprises an a-line and a b-line, the first (S1), second (S2) and third (S3) absorbing stub being for absorbing noise reflected into the first port (1); the first absorption branch (S1) comprises a first resistor (R11) and a first short-circuit branch (S11) which are connected in series, and the first short-circuit branch (S11) is grounded; the second absorption branch (S2) comprises a second resistor (R21) and a second short-circuit branch (S21) which are connected in series, and the second short-circuit branch (S21) is grounded; the third absorption branch (S3) comprises a third resistor (R31) and a third short-circuit branch (S31) connected in series, the third short-circuit branch (S31) is grounded;

the first port (1) is connected with one end of a first absorption branch (S1) and one end of the first branch (t1), and the other end of the first absorption branch (S1) is grounded;

the other end of the first branch (t1) is connected with one end of the first coupled line (C1) b line and one end of the second coupled line (C2) a line;

the other end of the first coupling line (C1) b line is connected with one end of the second absorption branch (S2), and the other end of the second absorption branch (S2) is grounded;

one end of the first coupled line (C1) a line is connected with one end of the third coupled line (C3) a line, and one end of the third coupled line (C3) b line is connected with the second port (2);

the other end of the second coupling line (C2) a line is connected with one end of the third absorption branch (S3), and the other end of the third absorption branch (S3) is grounded;

one end of the second coupled line (C2) b line is connected with one end of the fourth coupled line (C4) b line, and one end of the fourth coupled line (C4) a line is connected with the third port (3).

2. The filtered power divider of claim 1, wherein the filtered power dividing circuit further comprises: a first half-wavelength open stub (K1) and a second half-wavelength open stub (K2);

one end of the first coupling line (C1) a is also connected with the first half-wavelength open-circuit stub (K1);

one end of the second coupling line (C2) b is also connected with the second half-wavelength open-circuit branch (K2).

3. The filtered power divider of claim 1, wherein the filtered power dividing circuit further comprises: an isolation resistor (R3);

the other end of the first coupling line (C1) b line is also connected with one end of the isolation resistor (R3);

the other end of the second coupling line (C2) a is also connected with the other end of the isolation resistor (R3).

4. The filtering power divider of claim 1, wherein the even mode impedance and the odd mode impedance of the first coupled line (C1) and the second coupled line (C2) are the same;

the even mode impedance of the third coupled line (C3) and the fourth coupled line (C4) are the same, and the odd mode impedance is the same.

5. The filtered power divider of claim 4, characterized in that the electrical lengths of the first coupled line (C1), the second coupled line (C2), the third coupled line (C3) and the fourth coupled line (C4) are the same.

6. The filtering power divider of claim 2, characterized in that the characteristic impedances of the first half-wavelength open stub (K1) and the second half-wavelength open stub (K2) are the same.

7. The filtering power divider of claim 6, wherein the characteristic impedances of the second short-circuit branch (S21) of the second absorption branch (S2) and the third short-circuit branch (S31) of the third absorption branch (S3) are the same.

8. The filtering power divider of claim 7, wherein the characteristic impedances of the first short-circuit branch (S11) of the first absorption branch (S1), the second short-circuit branch (S21) of the second absorption branch (S2) and the first branch (t1) are different.

9. The filtered power divider of claim 1, further comprising: the metal layer covers the lower surface of the dielectric substrate and is grounded;

the first absorption branch (S1), the second absorption branch (S2), and the third absorption branch (S3) further include a through hole connecting the metal layers.

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