A balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics

Abstract

The present invention discloses a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics, comprising: a balanced differential input port, an unbalanced output port, a balanced end non-reflection absorption matching network, two sections of quarter-wavelength filter power splitter coupling lines, two sections of quarter-wavelength anti-connected wiring, two sections of quarter-wavelength signal transmission lines, two groups of zero-point transmission branches, two sections of quarter-wavelength equal power distribution lines and a phase compensation structure. The balanced-unbalanced one-to-three filter power divider with non-reflection characteristics provided by the present invention simultaneously realizes highly selective filtering characteristics, conversion function from balanced differential signals to unbalanced single-ended signals, good common-mode suppression, three-way broadband equal power distribution, ±90-degree output signal phase difference characteristics and balanced end input non-reflection characteristics, and is very suitable for application in various types of balanced-unbalanced microwave systems and circularly polarized antennas to improve their overall performance.

Description

Technical Field

[0001] The invention relates to a filtering power divider, in particular to a balanced-unbalanced one-to-three filtering power divider with a non-reflection characteristic. Background Art

[0002] Power dividers are important components of modern wireless communication circuits and systems. They can distribute signal energy in a certain proportion and are widely used in power amplifiers, mixers, array antennas, RF transmitters and receivers. With the continuous improvement of information transmission rate, electromagnetic interference between circuits has become more and more serious. Balanced circuits have developed rapidly because of their strong immunity to environmental noise and electromagnetic interference. At present, various balanced components have been widely studied and applied, such as balanced filters, duplexers, mixers, amplifiers and power dividers. For systems with both balanced ports and unbalanced ports, it is very necessary to use balanced to unbalanced power dividers as connecting devices, and compared with balanced to balanced microwave device connections, balanced to single-ended microwave device connections have better flexibility and freedom. In RF front-end circuits, filters and power dividers are often used at the same time. For single-ended power dividers, cascade filtering structure is a simple and effective method, but it will also increase the size and mismatch loss of the circuit. Obviously, the use of traditional single-function devices leads to larger system volume and increased cost. Therefore, power dividers with filtering characteristics have been widely studied.

[0003] Normally, the signal entering the balanced end is transmitted to the unbalanced end after filtering, but the signal in the stopband is reflected back to its own balanced end, which will generate unnecessary interference to the balanced end signal and affect the overall stability of the system. In order to ensure the robust operation of the entire RF system, the non-reflective filter power divider has attracted much attention in recent years. As we all know, the reflected signal of the traditional reflective filter power divider passes through sensitive nonlinear elements such as mixers and amplifiers, which will cause the working state of adjacent active devices to deteriorate. Unlike the traditional reflective filter power divider, the non-reflective filter power divider can absorb the out-of-band interference signal reflected back to the source end, and its out-of-band reflected energy can often be absorbed by loading a terminated load at the port, so it can effectively improve the signal-to-noise ratio and stability of the adjacent active circuits in the RF front-end system.

[0004] Conventional power dividers with filtering characteristics can simultaneously realize the functions of filtering and power distribution, and can reduce the overall size of the system. However, the existing one-to-three filtering power dividers cannot be connected to balanced and unbalanced devices at the same time without a cascaded balun, and in nonlinear systems, the reflected echo signal at the balanced end and the existing signal overlap to generate many interference signals, which will also deteriorate the working state of the front-end devices in the RF system. In view of this, it is necessary to propose a balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics. Summary of the invention

[0005] Based on this, in order to solve the shortcomings of the existing technology, a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics is proposed; including: a balanced differential input port, an unbalanced output port, a balanced end non-reflection absorption matching network, two quarter-wavelength filter power splitter coupling lines, two quarter-wavelength anti-connected wiring lines, two quarter-wavelength signal transmission lines, two groups of zero-point transmission branches, two quarter-wavelength equal power distribution lines and a phase compensation structure;

[0006] The balanced differential input port 1 includes an input port 1+ and an input port 1-;

[0007] The unbalanced output ports include output port 2, output port 3 and output port 4;

[0008] The balanced-end non-reflection absorption matching network includes a first balanced-end non-reflection absorption matching network and a second balanced-end non-reflection absorption matching network; wherein the first balanced-end non-reflection absorption matching network is connected to the connection between the B port of the first filter power split-circuit coupling line and the input port 1+; and the second balanced-end non-reflection absorption matching network is connected to the connection between the B port of the second filter power split-circuit coupling line and the input port 1-;

[0009] The two sections of quarter-wavelength filter power split coupling lines include a first filter power split coupling line and a second filter power split coupling line; wherein the B port of the first filter power split coupling line is connected to the input port 1+; the D port of the first filter power split coupling line is connected to the connection between the first anti-connecting wiring and the first signal transmission line; the A port and the C port of the first filter power split coupling line are both open; the B port of the second filter power split coupling line is connected to the input port 1-; the D port of the second filter power split coupling line is connected to the connection between the second anti-connecting wiring and the second signal transmission line; the A port and the C port of the second filter power split coupling line are both open;

[0010] The two quarter-wavelength anti-connected wirings include a first anti-connected wiring and a second anti-connected wiring; wherein one end of the first anti-connected wiring is connected to the connection between the D port of the first filter power split-circuit coupling line and the first signal transmission line, and the other end is connected to the second anti-connected wiring; one end of the second anti-connected wiring is connected to the connection between the D port of the second filter power split-circuit coupling line and the second signal transmission line, and the other end is connected to the first anti-connected wiring;

[0011] The two quarter-wavelength signal transmission lines include a first signal transmission line and a second signal transmission line; wherein one end of the first signal transmission line is connected to the connection between the D port of the first filter power split-circuit coupling line and the first anti-connecting wiring, and the other end is connected to the output port two; one end of the second signal transmission line is connected to the connection between the D port of the second filter power split-circuit coupling line and the second anti-connecting wiring, and the other end is connected to the output port four;

[0012] The two groups of zero-point transmission branches include a first zero-point transmission branch and a second zero-point transmission branch; wherein the first zero-point transmission branch is connected to the connection between the first signal transmission line and the output port 2; and the second zero-point transmission branch is connected to the connection between the second signal transmission line and the output port 4;

[0013] The two quarter-wavelength equal power distribution lines include a first equal power distribution line and a second equal power distribution line; wherein one end of the first equal power distribution line is connected to the output port two phases, and the other end is connected to the output port three phases; one end of the second equal power distribution line is connected to the output port three phases, and the other end is connected to the phase compensation structure;

[0014] One end of the phase compensation structure is connected to the second equal power distribution line, and the other end is connected to the output port four;

[0015] The first balanced-end reflectionless absorption matching network and the second balanced-end reflectionless absorption matching network have the same structure; the first balanced-end reflectionless absorption matching network includes a reflectionless absorption branch line, a reflectionless absorption open line, a reflectionless absorption resistor, a reflectionless absorption transmission line and a reflectionless grounding resistor; one end of the reflectionless absorption branch line is connected to the connection between the B port of the first filter power open circuit coupling line and the input port 1+, and the other end is connected to the reflectionless absorption open line; one end of the reflectionless absorption open line is open, and the other end is connected to the reflectionless absorption branch line; one end of the reflectionless absorption resistor is grounded, and the other end is connected to the reflectionless absorption branch line; one end of the reflectionless absorption transmission line is connected to the connection between the reflectionless absorption branch line and the reflectionless absorption resistor, and the other end is connected to the reflectionless grounding resistor; one end of the reflectionless grounding resistor is grounded, and the other end is connected to the reflectionless absorption transmission line;

[0016] The first zero-point transmission branch and the second zero-point transmission branch have the same structure; the first zero-point transmission branch includes a high-impedance zero-point transmission line and a low-impedance zero-point transmission line; one end of the high-impedance zero-point transmission line is connected to the connection between the first signal transmission line and the output port two, and the other end is connected to the low-impedance zero-point transmission line; one end of the low-impedance zero-point transmission line is open, and the other end is connected to the high-impedance zero-point transmission line.

[0017] The non-reflection characteristic of the balanced-end differential signal is adjusted by adjusting the first balanced-end non-reflection absorption matching network and the second balanced-end non-reflection absorption matching network.

[0018] The filtering characteristic of the output port three is improved by adjusting the first filtering power open-circuit coupling line and the second filtering power open-circuit coupling line.

[0019] The high impedance zero point transmission line and the low impedance zero point transmission line have different characteristic impedance values. The transmission zero point positions of output port two, output port three and output port four are adjusted by adjusting the characteristic impedance values ​​of the high impedance zero point transmission line and the low impedance zero point transmission line.

[0020] In order to realize the conversion function from balanced differential signal to unbalanced single-ended signal, multi-channel bandpass filtering power distribution and non-reflection characteristics under differential signal excitation, the present invention provides a balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics. The power divider realizes the interconnection of balanced and unbalanced devices without using a balun. In addition, it also realizes three-way equal-power broadband output characteristics, ±90-degree output signal phase difference characteristics, highly selective bandpass filtering characteristics, good common-mode suppression and balanced end input non-reflection characteristics, which is very suitable for application in various balanced-unbalanced microwave systems and circularly polarized antennas to improve their overall performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a structural schematic diagram of a balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics of the present invention;

[0023] Figure 2 It is a mixed S parameter curve diagram of a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics under differential signal excitation of the present invention;

[0024] Figure 3It is a mixed S parameter curve diagram of a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics under common mode signal excitation of the present invention;

[0025] Figure 4 The output signal phase difference curve diagram of a balanced-unbalanced one-to-three filtering power divider with a non-reflection characteristic of the present invention. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The present invention discloses a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics, comprising: a balanced differential input port 1, an unbalanced output port, a balanced end non-reflection absorption matching network, two sections of quarter-wavelength filter power splitter coupling lines, two sections of quarter-wavelength anti-connected wiring lines, two sections of quarter-wavelength signal transmission lines, two groups of zero-point transmission branches, two sections of quarter-wavelength equal power distribution lines and a phase compensation structure 18;

[0028] The balanced differential input port 1 includes an input port 1+1 and an input port 1-2;

[0029] The unbalanced output ports include output port two 3, output port three 4 and output port four 5;

[0030] The balanced-end non-reflection absorption matching network includes a first balanced-end non-reflection absorption matching network 6 and a second balanced-end non-reflection absorption matching network 7; wherein the first balanced-end non-reflection absorption matching network 6 is connected to the connection between the B port 1b of the first filter power split-circuit coupling line 8 and the input port 1+1; the second balanced-end non-reflection absorption matching network 7 is connected to the connection between the B port 2b of the second filter power split-circuit coupling line 9 and the input port 1-2;

[0031] The two sections of quarter-wavelength filter power split coupling lines include a first filter power split coupling line 8 and a second filter power split coupling line 9; wherein the B port 1b of the first filter power split coupling line 8 is connected to the input port 1+1; the D port 1d of the first filter power split coupling line 8 is connected to the connection between the first anti-connecting wiring 10 and the first signal transmission line 12; the A port 1a and the C port 1c of the first filter power split coupling line 8 are both open circuits; the B port 2b of the second filter power split coupling line 9 is connected to the input port 1-2; the D port 2d of the second filter power split coupling line 9 is connected to the connection between the second anti-connecting wiring 11 and the second signal transmission line 13; the A port 2a and the C port 2c of the second filter power split coupling line 9 are both open circuits;

[0032] The two quarter-wavelength anti-connected wirings include a first anti-connected wiring 10 and a second anti-connected wiring 11; wherein one end of the first anti-connected wiring 10 is connected to the connection between the D port 1d of the first filter power split-circuit coupling line 8 and the first signal transmission line 12, and the other end is connected to the second anti-connected wiring 11; one end of the second anti-connected wiring 11 is connected to the connection between the D port 2d of the second filter power split-circuit coupling line 9 and the second signal transmission line 13, and the other end is connected to the first anti-connected wiring 10;

[0033] The two quarter-wavelength signal transmission lines include a first signal transmission line 12 and a second signal transmission line 13; wherein one end of the first signal transmission line 12 is connected to the connection between the D port 1d of the first filter power split coupling line 8 and the first anti-connecting wiring 10, and the other end is connected to the output port two 3; one end of the second signal transmission line 13 is connected to the connection between the D port 2d of the second filter power split coupling line 9 and the second anti-connecting wiring 11, and the other end is connected to the output port four 5;

[0034] The two groups of zero-point transmission branches include a first zero-point transmission branch 14 and a second zero-point transmission branch 15; wherein the first zero-point transmission branch 14 is connected to the connection between the first signal transmission line 12 and the output port 23; the second zero-point transmission branch 15 is connected to the connection between the second signal transmission line 13 and the output port 45;

[0035] The two quarter-wavelength equal power distribution lines include a first equal power distribution line 16 and a second equal power distribution line 17; wherein one end of the first equal power distribution line 16 is connected to the output port 2 3, and the other end is connected to the output port 3 4; one end of the second equal power distribution line 17 is connected to the output port 3 4, and the other end is connected to the phase compensation structure 18;

[0036] One end of the phase compensation structure 18 is connected to the second equal power distribution line 17, and the other end is connected to the output port 24 5;

[0037] The first balanced-end non-reflection absorption matching network 6 and the second balanced-end non-reflection absorption matching network 7 have the same structure; the first balanced-end non-reflection absorption matching network 6 includes a non-reflection absorption branch line 61, a non-reflection absorption open line 62, a non-reflection absorption resistor 63, a non-reflection absorption transmission line 64 and a non-reflection grounding resistor 65; one end of the non-reflection absorption branch line 61 is connected to the connection between the B port 1b of the first filter power open circuit coupling line 8 and the input port 1+1, and the other end is connected to the non-reflection absorption open line 62; one end of the non-reflection absorption open line 62 is open, and the other end is connected to the non-reflection absorption branch line 61; one end of the non-reflection absorption resistor 63 is grounded, and the other end is connected to the non-reflection absorption branch line 61; one end of the non-reflection absorption transmission line 64 is connected to the connection between the non-reflection absorption branch line 61 and the non-reflection absorption resistor 63, and the other end is connected to the non-reflection grounding resistor 65; one end of the non-reflection grounding resistor 65 is grounded, and the other end is connected to the non-reflection absorption transmission line 64;

[0038] The first zero-point transmission branch 14 and the second zero-point transmission branch 15 have the same structure; the first zero-point transmission branch 14 includes a high-impedance zero-point transmission line 141 and a low-impedance zero-point transmission line 142; one end of the high-impedance zero-point transmission line 141 is connected to the connection between the first signal transmission line 12 and the output port 23, and the other end is connected to the low-impedance zero-point transmission line 142; one end of the low-impedance zero-point transmission line 142 is open, and the other end is connected to the high-impedance zero-point transmission line 141.

[0039] The non-reflection characteristic of the balanced-end differential signal is adjusted by adjusting the first balanced-end non-reflection absorption matching network 6 and the second balanced-end non-reflection absorption matching network 7 .

[0040] The filtering characteristics of the output port three 4 are improved by adjusting the first filtering power open-circuit coupling line 8 and the second filtering power open-circuit coupling line 9.

[0041] The high impedance zero point transmission line 141 and the low impedance zero point transmission line 142 have different characteristic impedance values. The transmission zero point positions of output port two 3, output port three 4 and output port four 5 are adjusted by adjusting the characteristic impedance values ​​of the high impedance zero point transmission line 141 and the low impedance zero point transmission line 142.

[0042] In order to further illustrate the balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics provided by the present invention, a specific example implemented based on the technical solution of the present invention is described in detail below, but the protection scope of the present invention is not limited to the following embodiments, and the methods used in the following embodiments are all conventional methods unless otherwise specified.

[0043] Specific example: This example lists a balanced-unbalanced one-to-three filter power divider with non-reflection characteristics. Figure 2 As shown, the balanced-unbalanced one-to-three filter power divider with non-reflection characteristics described in the present invention has a differential mode to single-ended transmission coefficient of |S within the working frequency band of 0.75GHz to 1.25GHz. sd21 |、|S sd31 |、|S sd41 | is -4.98±0.3dB, achieving broadband equal power distribution of differential signals; |S sd31 Four transmission zeros are introduced at 0.43 GHz, 0.5 GHz, 1.53 GHz, and 1.67 GHz, respectively. sd21 | and |S sd41 |Two transmission zeros are introduced at 0.42GHz and 1.69GHz respectively, and the differential mode to two-port, three-port and four-port|S sd21 |、|S sd31 |、|S sd41 | is less than -20dB outside the working frequency band, which improves the frequency selectivity and out-of-band suppression capability of the filter power divider; the balanced port reflection coefficient |S under the excitation of the differential mode signal at the center frequency of 1GHz dd11 | is -32.7dB, achieving good impedance matching characteristics at the balanced end; the balanced end differential mode reflection coefficient |S dd11 |In the frequency range of 0GHz to 2.5GHz, it is less than -11.25dB, achieving the input reflection-free characteristic of the balanced end. Figure 3 As shown, the balanced-unbalanced one-to-three filter power divider with non-reflection characteristics described in the present invention has a transmission coefficient of |S from the common mode to the two ports and the four ports under the common mode signal excitation. sc21 | and |S sc41 |-38.9dB at the center frequency 1GHz, common mode to three-port transmission coefficient |S sc31 |Better than -50dB at the center frequency of 1GHz, |S sc21 |、|S sc31 |、|S sc41 |In the frequency range of 0GHz to 2.5GHz, it is less than -10dB, achieving broadband common mode suppression. Figure 4 As shown, the phase difference between the output signals of port 2 and port 3 of the balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics described in the present invention is 90 degrees, and the phase difference between the output signals of port 3 and port 4 is -90 degrees.

[0044] In summary, the balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics provided by the present invention simultaneously realizes highly selective filtering characteristics, conversion function of balanced differential signals to unbalanced single-ended signals, good common-mode suppression, three-way broadband equal power distribution, ±90 degree output signal phase difference characteristics and balanced end input non-reflection characteristics, and is very suitable for application in various balanced-unbalanced microwave systems and circularly polarized antennas to improve their overall performance.

[0045] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A balanced-unbalanced one-to-three filter power divider with non-reflection characteristics, characterized in that: include: A balanced differential input port, an unbalanced output port, a balanced end non-reflective absorption matching network, two quarter-wavelength filter power split-circuit coupling lines, two quarter-wavelength anti-connected wiring lines, two quarter-wavelength signal transmission lines, two sets of zero-point transmission branches, two quarter-wavelength equal power distribution lines and a phase compensation structure (18); The balanced differential input port 1 includes an input port 1+(1) and an input port 1-(2); The unbalanced output ports include output port two (3), output port three (4) and output port four (5); The balanced-end non-reflection absorption matching network comprises a first balanced-end non-reflection absorption matching network (6) and a second balanced-end non-reflection absorption matching network (7); wherein the first balanced-end non-reflection absorption matching network (6) is connected to the connection between the B port (1b) of the first filter power split-circuit coupling line (8) and the input port 1+(1); and the second balanced-end non-reflection absorption matching network (7) is connected to the connection between the B port (2b) of the second filter power split-circuit coupling line (9) and the input port 1-(2); The two sections of quarter-wavelength filter power split-circuit coupling lines comprise a first filter power split-circuit coupling line (8) and a second filter power split-circuit coupling line (9); The B port (1b) of the first filter power split coupling line (8) is connected to the input port 1+ (1); the D port (1d) of the first filter power split coupling line (8) is connected to the connection point between the first anti-connecting line (10) and the first signal transmission line (12); The A port (1a) and the C port (1c) of the first filter power open circuit coupling line (8) are both open circuited; the B port (2b) of the second filter power open circuit coupling line (9) is connected to the input port 1-(2); the D port (2d) of the second filter power open circuit coupling line (9) is connected to the connection point between the second anti-connecting line (11) and the second signal transmission line (13); The A port (2a) and the C port (2c) of the open-circuit coupling line (9) of the second filtering function are both open-circuited; The two quarter-wavelength anti-connected wirings include a first anti-connected wiring (10) and a second anti-connected wiring (11); wherein one end of the first anti-connected wiring (10) is connected to the connection between the D port (1d) of the first filter power split-circuit coupling line (8) and the first signal transmission line (12), and the other end is connected to the second anti-connected wiring (11); one end of the second anti-connected wiring (11) is connected to the connection between the D port (2d) of the second filter power split-circuit coupling line (9) and the second signal transmission line (13), and the other end is connected to the first anti-connected wiring (10); The two quarter-wavelength signal transmission lines include a first signal transmission line (12) and a second signal transmission line (13); wherein one end of the first signal transmission line (12) is connected to the connection point between the D port (1d) of the first filter power split coupling line (8) and the first anti-connecting wiring (10), and the other end is connected to the output port two (3); one end of the second signal transmission line (13) is connected to the connection point between the D port (2d) of the second filter power split coupling line (9) and the second anti-connecting wiring (11), and the other end is connected to the output port four (5); The two groups of zero-point transmission branches include a first zero-point transmission branch (14) and a second zero-point transmission branch (15); wherein the first zero-point transmission branch (14) is connected to the connection between the first signal transmission line (12) and the second output port (3); and the second zero-point transmission branch (15) is connected to the connection between the second signal transmission line (13) and the fourth output port (5); The two quarter-wavelength equal power distribution lines include a first equal power distribution line (16) and a second equal power distribution line (17); wherein one end of the first equal power distribution line (16) is connected to the second output port (3), and the other end is connected to the third output port (4); and one end of the second equal power distribution line (17) is connected to the third output port (4), and the other end is connected to the phase compensation structure (18); One end of the phase compensation structure (18) is connected to the second equal power distribution line (17), and the other end is connected to the output port four (5); The first balanced-end non-reflection absorption matching network (6) and the second balanced-end non-reflection absorption matching network (7) have the same structure; the first balanced-end non-reflection absorption matching network (6) comprises a non-reflection absorption branch line (61), a non-reflection absorption open line (62), a non-reflection absorption resistor (63), a non-reflection absorption transmission line (64) and a non-reflection grounding resistor (65); one end of the non-reflection absorption branch line (61) is connected to the connection between the B port (1b) of the first filter power open circuit coupling line (8) and the input port 1+(1), and the other end is connected to the non-reflection absorption open circuit coupling line (8). The non-reflection absorption line (62) is connected to a non-reflection absorption line (62); one end of the non-reflection absorption open line (62) is open-circuited, and the other end is connected to the non-reflection absorption branch line (61); one end of the non-reflection absorption resistor (63) is grounded, and the other end is connected to the non-reflection absorption branch line (61); one end of the non-reflection absorption transmission line (64) is connected to the connection between the non-reflection absorption branch line (61) and the non-reflection absorption resistor (63), and the other end is connected to the non-reflection grounding resistor (65); one end of the non-reflection grounding resistor (65) is grounded, and the other end is connected to the non-reflection absorption transmission line (64); The first zero-point transmission branch (14) and the second zero-point transmission branch (15) have the same structure; the first zero-point transmission branch (14) comprises a high-impedance zero-point transmission line (141) and a low-impedance zero-point transmission line (142); one end of the high-impedance zero-point transmission line (141) is connected to the connection between the first signal transmission line (12) and the second output port (3), and the other end is connected to the low-impedance zero-point transmission line (142); one end of the low-impedance zero-point transmission line (142) is open-circuited, and the other end is connected to the high-impedance zero-point transmission line (141).

2. A balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics according to claim 1, characterized in that: The non-reflection characteristic of the balanced end differential signal is adjusted by adjusting the first balanced end non-reflection absorption matching network (6) and the second balanced end non-reflection absorption matching network (7).

3. The balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics according to claim 1, characterized in that: The filtering characteristics of the output port three (4) are improved by adjusting the first filtering power split-circuit coupling line (8) and the second filtering power split-circuit coupling line (9).

4. The balanced-unbalanced one-to-three filtering power divider with non-reflection characteristics according to claim 1, characterized in that: The high impedance zero point transmission line (141) and the low impedance zero point transmission line (142) have different characteristic impedance values, and the transmission zero point positions of the output port two (3), the output port three (4) and the output port four (5) are adjusted by adjusting the characteristic impedance values ​​of the high impedance zero point transmission line (141) and the low impedance zero point transmission line (142).

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