A reflectionless filtering power divider based on asymmetric filtering network

Abstract

The application discloses a non-reflection filtering power divider based on an asymmetric filtering network, mainly comprising a power dividing part, a first asymmetric filtering network part and a second asymmetric filtering network part; the first asymmetric filtering network part and the second asymmetric filtering network part are rotationally symmetrical; the asymmetric filtering network has the characteristics of equal-amplitude and opposite-phase S 11 and S 22 (i.e. S 11 =-S 22 ), equal-amplitude and same-phase S 12 and S 21 (i.e. S 12 =S 21 ), etc., and can dissipate the reflected signal on the isolation resistance of the power divider. The non-reflection filtering power divider has the advantages of simple structure, no need of additional absorption circuit, wide non-reflection bandwidth, excellent frequency selection and power distribution characteristics, etc.

Description

Technical Field

[0001] This invention belongs to the field of microwave communication technology, and in particular to a non-reflection filtering power divider based on an asymmetric filtering network. Background Technology

[0002] With the rapid development of wireless communication technology in recent years, the demand for highly reliable and high-performance communication systems has led to increasing attention being paid to the design of reflection-free / absorption-type passive devices. For example, filtering circuits, indispensable in wireless systems, can absorb unwanted out-of-band radio frequency signal echoes while filtering out unwanted signals, compared to traditional reflective filters, thus preventing interference from the active stage at the front end of the system. Furthermore, power dividers are also essential passive devices in wireless systems, used as feed networks for antenna arrays, etc. Therefore, reflection-free filtering power dividers integrate port reflection-free operation, frequency selection, and power distribution functions in a single device, greatly improving system integration and reducing cascading losses, which is of great significance to the development of wireless systems. In conclusion, reflection-free filtering power dividers have significant research value.

[0003] Currently, most reflectionless filtering power dividers are based on adding an absorption branch at the input. For example, in reference 1 (Gomez-Garcia R, Munoz-Ferreras JM, Psychogiou D. RF reflectionless filtering power dividers[J]. IEEE Transactions on Circuits and Systems II-Express Briefs, 2019, 66(6): 933-937.) and reference 2 (Fan M, Song K, Yang L, Gómez-García R. Frequency reconfigurable input-reflectionless bandpass filter and filtering power divider with constant absolute bandwidth[J]. Transactions on Circuits and Systems II-Express Briefs, 2021, 68(7): 2424-2428.), the complementary duplex principle is used to achieve reflectionless characteristics by adding a band-stop circuit with resistors at the input and output ports; and reference 3 (ZhuY-H, J Cai, Y.Cao, JX Chen. Compact wideband absorptive In the filtering power divider with a reused composite T-shape network[J].IEEE Transactions on Circuits and Systems II-Express Briefs, 2023, 70(3):899-903.), an absorbing stub and a composite T-shape network are added to the input port to achieve a reflection-free input response. In reference 4 (Zhang Y, Wu Y, Yan J, Wang W. Wideband high-selectivity filtering all-frequency absorptive power divider with deepout-of-band suppression[J].IEEE Transactions on Plasma Science, 2021, 49(7):2099-2106.), three additional absorbing stubs are used to achieve reflection-free performance at the input port.Similarly, in reference 5 (Li Q, Tang H, Tang D, Deng Z, Luo X. Compact SIDGS filtering power divider with three-port 10-GHz reflectionless range[J]. IEEE Transactions on Circuits and Systems II-Express Briefs, 2022, 69(7):3129-3133.), an absorption network with a terminated common-gate topology is used to achieve reflection-free performance, but it requires additional power supply. The methods reported above that use additional absorption branches or stubs to achieve port reflection-free characteristics have two drawbacks: firstly, the added network affects the transmission response of the filter divider; secondly, it increases the additional circuit size. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by providing a reflection-free filter power divider based on an asymmetric filter network, which has the characteristics of low loss, simple design method and simple structure, and can meet the needs of current high-performance wireless communication systems.

[0005] The technical solution to achieve the purpose of this invention is: a non-reflective filter power divider based on an asymmetric filter network, the power divider including an input port power supply section, a first output port power supply section, a second output port power supply section, a power dividing section, a first asymmetric filter network section, a second asymmetric filter network section, a dielectric substrate, and a metal ground.

[0006] The input port power supply section, the first output port power supply section, the second output port power supply section, the power divider section, the first asymmetric filter network section, and the second asymmetric filter network section are placed on the upper surface of the dielectric substrate; the metal ground is placed on the lower surface of the dielectric substrate.

[0007] The input port power supply section is located at the front end of the power divider section. The front end of the first asymmetric filter network section is connected to one side of the rear end of the power divider section. The first output port power supply section is located at the rear end of the first asymmetric filter network section. The front end of the second asymmetric filter network section is connected to the other side of the rear end of the power divider section. The second output port power supply section is located at the rear end of the second asymmetric filter network section.

[0008] Furthermore, the power distribution section includes a first transmission line, a second transmission line, a third transmission line, a fourth transmission line, a first isolation resistor, and a second isolation resistor;

[0009] The front ends of the first and third transmission lines are both connected to the input port power supply section; the rear end of the first transmission line is connected to the front end of the second transmission line; the rear end of the second transmission line is connected to the front end of the fourth transmission line; the first isolation resistor is connected between the rear ends of the first and third transmission lines; the second isolation resistor is connected between the rear ends of the second and fourth transmission lines.

[0010] Furthermore, the first transmission line and the third transmission line have the same impedance characteristics; the second transmission line and the fourth transmission line have the same characteristic impedance; and the electrical lengths of the first transmission line, the second transmission line, the third transmission line, and the fourth transmission line are all the same, at 90°.

[0011] Furthermore, the first asymmetric filter network includes a first terminal short-circuit coupled feeder, a first terminal open-circuit coupled feeder, a first open-loop resonator, a second open-loop resonator, and a third open-loop resonator; the first terminal short-circuit coupled feeder includes a first coupled feeder and a first short-circuit grounding via; one end of the first coupled feeder is connected to the rear end of the second transmission line, and the other end of the first coupled feeder is provided with the first short-circuit grounding via; one end of the first terminal open-circuit coupled feeder is connected to the first output port power supply section;

[0012] The first open-loop resonator and the second open-loop resonator are placed symmetrically with their openings facing each other between the first terminal short-circuit coupled feed line and the first terminal open-circuit coupled feed line; the third open-loop resonator is located on one side of the first open-loop resonator and the second open-loop resonator, and its opening is coaxial with the axis of symmetry of the first open-loop resonator and the second open-loop resonator, and its opening direction is away from the first open-loop resonator and the second open-loop resonator.

[0013] Furthermore, the second asymmetric filter network includes a second terminal short-circuit coupled feeder, a second terminal open-circuit coupled feeder, a fourth open-loop resonator, a fifth open-loop resonator, and a sixth open-loop resonator; the second terminal short-circuit coupled feeder includes a second coupled feeder and a second short-circuit grounding via; one end of the second coupled feeder is connected to the second output port power supply section, and the other end of the second coupled feeder is provided with the second short-circuit grounding via; one end of the second terminal open-circuit coupled feeder is connected to the rear end of the fourth transmission line;

[0014] The fourth and fifth open-loop resonators are placed symmetrically with their openings facing each other between the second terminal short-circuit coupling feed line and the second terminal open-circuit coupling feed line; the sixth open-loop resonator is located on one side of the fourth and fifth open-loop resonators, and its opening is coaxial with the axis of symmetry of the fourth and fifth open-loop resonators, and its opening direction is away from the fourth and fifth open-loop resonators.

[0015] Furthermore, the first to third open-loop resonators and the fourth to sixth open-loop resonators have the same impedance characteristics.

[0016] Furthermore, the first to third open-loop resonators and the fourth to sixth open-loop resonators are bent half-wavelength resonators, and their electrical lengths are all the same, at 180°.

[0017] Furthermore, the first asymmetric filter network portion and the second asymmetric filter network portion have the same size and are rotationally symmetrical in spatial position.

[0018] Furthermore, the power divider is a second-order Wilkinson power divider, and its center operating frequency is the same as that of the first asymmetric filter network and the second asymmetric filter network.

[0019] Furthermore, both the metal ground and the dielectric substrate are rectangular.

[0020] Compared with the prior art, the significant advantages of this invention are:

[0021] (1) A reflection-free power divider was implemented by designing an asymmetric filter network combined with a Wilkinson power divider. The asymmetric filter network used has an equal amplitude and inverse phase S-wave polarity. 11 and S 22 (i.e. S) 11 =-S 22 ), equal amplitude and in phase S 12 and S 21 (i.e. S) 12 =S 21 The advantages of easy-to-design filtering response and the ability to connect two asymmetric filtering networks to the two branches of the power divider in a rotationally symmetrical manner can dissipate the reflected signal on the isolation resistor of the power divider.

[0022] (2) The non-reflective filter power divider of the present invention has a simple structure, does not require additional absorption circuit, and has advantages such as wide non-reflective bandwidth and excellent filtering characteristics.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of a reflectionless filter power divider based on an asymmetric filter network in one embodiment.

[0025] Figure 2 This is a top view of a reflection-free filter power divider in one embodiment;

[0026] Figure 3 Here is a simulation diagram of the S-parameters of a reflectionless filter power divider in one embodiment;

[0027] Figure 4 This represents the phase difference at the output port of a reflectionless filter power divider in one embodiment. Detailed Implementation

[0028] Various embodiments of a reflectionless filter power divider with asymmetric filter networks will be described more fully below. Various embodiments may be made with respect to this disclosure, and adjustments and changes may be made therein. However, it should be understood that there is no intention to limit the various embodiments of this disclosure to the specific embodiments disclosed herein, but rather this disclosure should be understood to cover all adjustments, equivalents, and / or alternatives falling within the spirit and scope of the various embodiments of this disclosure.

[0029] The expressions used in various embodiments of the reflectionless filter power divider of the asymmetric filter network (such as "first," "second," etc.) may modify various components in various embodiments, but are not limiting of the corresponding components. For example, the above expressions do not limit the order and / or importance of the components. The above expressions are only used for the purpose of distinguishing one component from others. For example, a first user device and a second user device refer to different user devices, although both are user devices. For example, a first component may be referred to as a second component without departing from the scope of various embodiments of this disclosure, and similarly, a second component may be referred to as a first component.

[0030] It should be noted that when describing the connection relationships between the power dividing section, the first asymmetric filter network section, and the second asymmetric filter network section in a reflectionless filter power divider, if describing the "connection" of one component to another, the first component can be directly connected to the second component, and a third component can be "connected" between the first and second components. Conversely, when a component is "directly connected" to another component, it can be understood that there is no third component between the first and second components.

[0031] The terminology used in the various embodiments of the reflectionless filter power divider is for the purpose of describing particular embodiments only and is not intended to limit the various embodiments of this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this disclosure pertain. Terms (such as those defined in generally used dictionaries) are to be interpreted as having the same meaning as in the context of the relevant art and are not to be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this disclosure.

[0032] In one embodiment, combined Figures 1 to 2A reflection-free filter power divider based on an asymmetric filter network is provided. The power divider includes an input port power supply section 1, a first output port power supply section 2, a second output port power supply section 3, a power dividing section, a first asymmetric filter network section, a second asymmetric filter network section, a dielectric substrate 7, and a metal ground 8.

[0033] The input port power supply section 1, the first output port power supply section 2, the second output port power supply section 3, the power divider section, the first asymmetric filter network section, and the second asymmetric filter network section are placed on the upper surface of the dielectric substrate 7; the metal ground 8 is placed on the lower surface of the dielectric substrate 7.

[0034] The input port power supply section 1 is located at the front end of the power divider section. The front end of the first asymmetric filter network section is connected to one side of the rear end of the power divider section. The first output port power supply section 2 is located at the rear end of the first asymmetric filter network section. The front end of the second asymmetric filter network section is connected to the other side of the rear end of the power divider section. The second output port power supply section 3 is located at the rear end of the second asymmetric filter network section.

[0035] Preferably, the first output port power supply section 2 and the second output port power supply section 3 are symmetrical about the axis of the input port power supply section 1, the power distribution section is symmetrical about the axis of the input port power supply section 1, and the first asymmetric filter network section and the second asymmetric filter network section are symmetrical about the axis of the input port power supply section 1.

[0036] Furthermore, in one embodiment, the power distribution section includes a first transmission line 411, a second transmission line 412, a third transmission line 421, a fourth transmission line 422, a first isolation resistor 43, and a second isolation resistor 44.

[0037] The front ends of the first transmission line 411 and the third transmission line 421 are both connected to the input port power supply section 1; the rear end of the first transmission line 411 is connected to the front end of the second transmission line 412; the rear end of the second transmission line 421 is connected to the front end of the fourth transmission line 422; the first isolation resistor 43 is connected between the rear ends of the first transmission line 411 and the third transmission line 421; the second isolation resistor 44 is connected between the rear ends of the second transmission line 412 and the fourth transmission line 422. The rear ends of the second transmission line 412 and the fourth transmission line 422 respectively serve as one side and the other side of the rear end of the power distribution section.

[0038] Preferably, the first transmission line 411 and the third transmission line 421 have the same impedance characteristics; the second transmission line 412 and the fourth transmission line 422 have the same characteristic impedance; and the electrical lengths of the first transmission line 411, the second transmission line 412, the third transmission line 421, and the fourth transmission line 422 are all the same, at 90°.

[0039] Preferably, the first transmission line 411 and the second transmission line 412, the third transmission line 421 and the fourth transmission line 422 are symmetrical about the input port power supply section 1.

[0040] Preferably, the first transmission line 411 and the second transmission line 412 are bent into an S-shaped structure, and the third transmission line 421 and the fourth transmission line 422 are bent into an S-shaped structure.

[0041] It can be seen that in the aforementioned reflectionless filter power divider, the power divider section 4 is a second-order Wilkinson power divider and has the same center operating frequency as the first asymmetric filter network section and the second asymmetric filter network section.

[0042] Further, in one embodiment, the first asymmetric filter network portion includes a first terminal short-circuit coupling feed line 51, a first terminal open-circuit coupling feed line 52, a first open-loop resonator 531, a second open-loop resonator 532, and a third open-loop resonator 533; the first terminal short-circuit coupling feed line 51 includes a first coupling feed line 511 and a first short-circuit grounding via 512; one end of the first coupling feed line 511 is connected to the rear end of the second transmission line 412, and the other end of the first coupling feed line 511 is provided with the first short-circuit grounding via 512; one end of the first terminal open-circuit coupling feed line 52 is connected to the first output port power supply portion 2;

[0043] The first open-loop resonator 531 and the second open-loop resonator 532 are placed symmetrically with their openings facing each other between the first terminal short-circuit coupled feed line 51 and the first terminal open-circuit coupled feed line 52; the third open-loop resonator 533 is located on one side of the first open-loop resonator 531 and the second open-loop resonator 532 (e.g., Figure 2 As shown, located on the upper side), its opening is coaxial with the axis of symmetry of the first open-loop resonator 531 and the second open-loop resonator 532, and the opening direction is away from the first open-loop resonator 531 and the second open-loop resonator 532 (e.g., Figure 2 As shown, the opening faces upwards.

[0044] Preferably, the first to third open-loop resonators 531-533 have the same impedance characteristics; the first to third open-loop resonators 531-533 are bent half-wavelength resonators and all have the same electrical length of 180°; the short-circuit grounding via 512 is placed at the end of the coupling feed line 511.

[0045] It can be seen that in the aforementioned reflectionless filter power divider, the first to third open-loop resonators 531-533 in the first asymmetric filter network part 5 use cross-coupling to generate out-of-band zeros.

[0046] Further, in one embodiment, the second asymmetric filter network includes a second terminal short-circuit coupling feed line 61, a second terminal open-circuit coupling feed line 62, a fourth open-loop resonator 631, a fifth open-loop resonator 632, and a sixth open-loop resonator 633; ​​the second terminal short-circuit coupling feed line 61 includes a second coupling feed line 611 and a second short-circuit grounding via 612; one end of the second coupling feed line 611 is connected to the second output port power supply section 3, and the other end of the second coupling feed line 611 is provided with the second short-circuit grounding via 612; one end of the second terminal open-circuit coupling feed line 62 is connected to the rear end of the fourth transmission line 422;

[0047] The fourth open-loop resonator 631 and the fifth open-loop resonator 632 are placed symmetrically with their openings facing each other between the second terminal short-circuit coupling feed line 61 and the second terminal open-circuit coupling feed line 62; the sixth open-loop resonator 633 is located on one side of the fourth open-loop resonator 631 and the fifth open-loop resonator 632 (e.g., Figure 2 As shown, located on the lower side), its opening is coaxial with the axis of symmetry of the fourth open-ring resonator 631 and the fifth open-ring resonator 632, and the direction of the opening is away from the fourth open-ring resonator 631 and the fifth open-ring resonator 632 (as shown). Figure 2 As shown, the opening faces downwards.

[0048] Preferably, the second asymmetric filter network portion has the same size as the first asymmetric filter network portion and is rotationally symmetrical in space.

[0049] Preferably, the fourth to sixth open-loop resonators 631-633 have the same impedance characteristics; the fourth to sixth open-loop resonators 631-633 are bent half-wavelength resonators and all have the same electrical length of 180°; the short-circuit grounding via 612 is placed at the end of the coupling feed line 611.

[0050] The present invention will now be described in detail.

[0051] Figure 3 The diagram shows the S-parameters of the power divider as a function of frequency. It can be observed that the center frequency of the power divider is 2GHz, the passband 3dB bandwidth ranges from 1.945GHz to 2.045GHz, the relative bandwidth is 5%, the zero point is located at 2.1GHz, and the -10dB non-reflection bandwidth ranges from 1GHz to 2.95GHz.

[0052] It should be noted that the power divider is not limited to operating in the above frequency bands and bandwidths. As needed, the power divider can be made to operate in other frequency bands by adjusting the length and distance of the first to third open-loop resonators 531-533 and the fourth to sixth open-loop resonators 631-633.

[0053] Figure 4 The figure shows the phase difference between the output ports of the reflectionless filter power divider. It can be seen that the two output ports of the filter power divider maintain the same phase within the passband.

[0054] In summary, the reflection-free power divider based on an asymmetric filter network of this invention achieves excellent reflection-free performance, frequency selectivity, and power distribution characteristics across a wide frequency band with a simple structure, which is beneficial for improving the stability and integration of wireless communication systems. Furthermore, this invention is lightweight, easy to manufacture, and inexpensive.

[0055] It should be understood that when the reflectionless filter power divider of the present invention refers to one element or layer being "connected" or "coupled" to another element or layer "on" or "on" another element or layer, it may be directly connected or coupled to said other element or layer, or there may be intermediate elements or layers. Conversely, when one element is referred to as being "directly connected" or "directly coupled" to another element or layer "on" or "on" another element or layer, there are no intermediate elements or layers. Similar numbers in all figures indicate similar elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0056] Spatially relative terms such as “below,” “under,” “lower,” “above,” “above,” etc., may be used here to describe the relationship between one element or feature and another, as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation other than those shown in the figure. For example, if the device in the figure were flipped over, the element described as “below” or “under” other elements or features would be facing “above” other elements or features. Thus, the exemplary term “below” can include both above and below orientations. Other orientations (rotation 90 degrees or other orientations) may be adopted, and the spatially relative terms used herein will be interpreted accordingly.

[0057] The terms "first," "second," "third," "fourth," etc., used in the specification, claims, and accompanying drawings of this invention, are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0058] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A reflection-free power divider based on an asymmetric filter network, characterized in that, The power divider includes an input port power supply section (1), a first output port power supply section (2), a second output port power supply section (3), a power dividing section, a first asymmetric filter network section, a second asymmetric filter network section, a dielectric substrate (7), and a metal ground (8). The input port power supply section (1), the first output port power supply section (2), the second output port power supply section (3), the power divider section, the first asymmetric filter network section and the second asymmetric filter network section are placed on the upper surface of the dielectric substrate (7); the metal ground (8) is placed on the lower surface of the dielectric substrate (7); The input port power supply section (1) is located at the front end of the power divider section. The front end of the first asymmetric filter network section is connected to one side of the rear end of the power divider section. The first output port power supply section (2) is located at the rear end of the first asymmetric filter network section. The front end of the second asymmetric filter network section is connected to the other side of the rear end of the power divider section. The second output port power supply section (3) is located at the rear end of the second asymmetric filter network section. The power distribution section includes a first transmission line (411), a second transmission line (412), a third transmission line (421), a fourth transmission line (422), a first isolation resistor (43), and a second isolation resistor (44). The front ends of the first transmission line (411) and the third transmission line (421) are both connected to the input port power supply section (1); the rear end of the first transmission line (411) is connected to the front end of the second transmission line (412); the rear end of the third transmission line (421) is connected to the front end of the fourth transmission line (422); the first isolation resistor (43) is connected between the rear ends of the first transmission line (411) and the third transmission line (421); the second isolation resistor (44) is connected between the rear ends of the second transmission line (412) and the fourth transmission line (422). The first asymmetric filter network includes a first terminal short-circuit coupling feed (51), a first terminal open-circuit coupling feed (52), a first open-loop resonator (531), a second open-loop resonator (532), and a third open-loop resonator (533); the first terminal short-circuit coupling feed (51) includes a first coupling feed (511) and a first short-circuit grounding via (512); one end of the first coupling feed (511) is connected to the rear end of the second transmission line (412), and the other end of the first coupling feed (511) is provided with the first short-circuit grounding via (512); one end of the first terminal open-circuit coupling feed (52) is connected to the first output port power supply section (2); The first open-loop resonator (531) and the second open-loop resonator (532) are placed symmetrically between the first terminal short-circuit coupling feed line (51) and the first terminal open-circuit coupling feed line (52) with their openings facing each other; the third open-loop resonator (533) is located on one side of the first open-loop resonator (531) and the second open-loop resonator (532), and its opening is coaxial with the axis of symmetry of the first open-loop resonator (531) and the second open-loop resonator (532), and the opening direction is away from the first open-loop resonator (531) and the second open-loop resonator (532). The second asymmetric filter network includes a second terminal short-circuit coupling feed (61), a second terminal open-circuit coupling feed (62), a fourth open-loop resonator (631), a fifth open-loop resonator (632), and a sixth open-loop resonator (633); the second terminal short-circuit coupling feed (61) includes a second coupling feed (611) and a second short-circuit grounding via (612); one end of the second coupling feed (611) is connected to the second output port power supply section (3), and the other end of the second coupling feed (611) is provided with the second short-circuit grounding via (612); one end of the second terminal open-circuit coupling feed (62) is connected to the rear end of the fourth transmission line (422); The fourth open-loop resonator (631) and the fifth open-loop resonator (632) are placed symmetrically with their openings facing each other between the second terminal short-circuit coupling feed line (61) and the second terminal open-circuit coupling feed line (62); the sixth open-loop resonator (633) is located on one side of the fourth open-loop resonator (631) and the fifth open-loop resonator (632), and its opening is coaxial with the axis of symmetry of the fourth open-loop resonator (631) and the fifth open-loop resonator (632), and the opening direction is away from the fourth open-loop resonator (631) and the fifth open-loop resonator (632). The first asymmetric filter network portion and the second asymmetric filter network portion have the same size and are rotationally symmetrical in spatial position.

2. The reflection-free filter power divider based on an asymmetric filter network according to claim 1, characterized in that, The first transmission line (411) and the third transmission line (421) have the same impedance characteristics; the second transmission line (412) and the fourth transmission line (422) have the same characteristic impedance; the electrical lengths of the first transmission line (411), the second transmission line (412), the third transmission line (421) and the fourth transmission line (422) are all the same, which is 90°.

3. The reflection-free filter power divider based on an asymmetric filter network according to claim 1, characterized in that, The first to third open-loop resonators (531-533) and the fourth to sixth open-loop resonators (631-633) have the same impedance characteristics.

4. The reflection-free filter power divider based on an asymmetric filter network according to claim 3, characterized in that, The first to third open-loop resonators (531-533) and the fourth to sixth open-loop resonators (631-633) are bent half-wavelength resonators, and their electrical lengths are all the same, at 180°.

5. The reflection-free filter power divider based on an asymmetric filter network according to claim 1, characterized in that, The power divider section is a second-order Wilkinson power divider, and its center operating frequency is the same as that of the first asymmetric filter network section and the second asymmetric filter network section.

6. The reflection-free filter power divider based on an asymmetric filter network according to claim 1, characterized in that, Both the metal ground (8) and the dielectric substrate (7) are rectangular.

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