A planar strip-line quadripole

Abstract

This application discloses a planar sheet metal stripline multiplexer, relating to the field of communication equipment technology. The multiplexer includes an impedance matching network and four channel filters. Two channel filters are respectively positioned on either side of the impedance matching network, and the other two channel filters are inverted and positioned on either side of the top of the impedance matching network. The impedance matching network and the four channel filters correspond to five port connectors, realizing a one-input, four-output multiplexer structure. The impedance matching network includes a common stripline resonator, and each of the four channel filters includes four stripline resonators connected side-by-side. A corresponding number of tuning screws are provided to adjust the resonant frequency of the corresponding stripline resonators. The common stripline resonator is coupled to the first stripline resonator of each channel filter, achieving impedance matching between the impedance matching network and each channel filter. This multiplexer offers advantages such as planar design, high performance, ease of integration, and high reliability.

Description

Technical Field

[0001] This application relates to the field of communication equipment technology, and in particular to a planar sheet metal wire-driven four-way tool. Background Technology

[0002] A multiplexer mainly consists of an impedance matching network (common tap structure) and several (N≥2) channel filters. Its purpose is to enable simultaneous operation of multiple frequency bands, ensuring high isolation between the various channel bands to avoid signal interference and thus guarantee communication stability. Typically, a multiplexer used for frequency selection and achieving certain isolation requirements across two frequency bands (channels) is called a duplexer, which mainly consists of an impedance matching network and two channel filters. A triplexer consists of an impedance matching network and three channel filters, used to support the operation of a system with three frequency bands. A quadruplexer, as the name suggests, consists of four channel filters and an impedance matching network, capable of simultaneously supporting signals from four frequency bands. As the number of frequency bands (channels) supported by a multiplexer increases, its design complexity also increases significantly.

[0003] Currently, the most commonly used quadruplers in the industry include metal coaxial cavity quadruplers, microstrip quadruplers, and dielectric waveguide quadruplers. Metal coaxial cavity quadruplers offer advantages such as low loss, high power capacity, and high reliability, but their large size makes them unsuitable for miniaturized applications. Microstrip quadruplers feature diverse designs, are planar, and easy to integrate, but their inherent high loss limits their use. Dielectric waveguide quadruplers offer good electrical performance and are easy to surface mount, but their manufacturing process is complex, long-term reliability is generally low, and the ceramic body is prone to cracking. Therefore, to overcome the shortcomings of existing technologies, there is an urgent need for a new type of quadrupler with a structure that achieves the combined advantages of planar design, easy integration, high performance, and high reliability. Summary of the Invention

[0004] The purpose of this application is to provide a planar sheet metal wire-guided four-way tool with a novel structure and comprehensive advantages of planar design for easy integration, high performance and high reliability.

[0005] To achieve the above objectives, this application provides the following solution:

[0006] This application provides a planar sheet metal wire-connected four-way connector, including: a base plate, a planar resonator frame, and a cover plate; the base plate and the cover plate are respectively mounted on the bottom and top surfaces of the planar resonator frame via positioning pins on the planar resonator frame, and are fixed by soldering; a first channel filter, a second channel filter, a third channel filter, a fourth channel filter, and an impedance matching network are fixed in the planar resonator frame, the operating frequency bands of the first channel filter, the second channel filter, the third channel filter, and the fourth channel filter are arranged from low to high, the first channel filter and the second channel filter are respectively located on both sides of the impedance matching network, and the third channel filter and the fourth channel filter are arranged upside down on both sides of the top of the impedance matching network; five port connectors are provided on the cover plate, the inner cores of the five port connectors pass through the cover plate, and are respectively connected to the impedance matching network, the first channel filter, the second channel filter, the third channel filter, and the fourth channel filter.

[0007] The impedance matching network includes a common stripline resonator. The first, second, third, and fourth channel filters each include four stripline resonators connected side-by-side. Several tuning screws are provided on the cover plate corresponding to the positions of each stripline resonator. The tuning screws are used to adjust the resonant frequency of the corresponding stripline resonator. The common stripline resonator is coupled to the first stripline resonator of the first channel filter, the first stripline resonator of the second channel filter, the first stripline resonator of the third channel filter, and the first stripline resonator of the fourth channel filter, respectively, to achieve impedance matching between the impedance matching network and the first, second, third, and fourth channel filters.

[0008] Optionally, the frequency-varying coupling between the first and second stripline resonators of the first channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the first channel filter, respectively generate a transmission zero outside the high end of the passband of the first channel filter.

[0009] Frequency-varying coupling between the first stripline resonator of the second channel filter and the second stripline resonator of the second channel filter produces a transmission zero outside the high end of the passband of the second channel filter. Frequency-varying coupling between the third stripline resonator of the second channel filter and the fourth stripline resonator of the second channel filter produces a transmission zero outside the low end of the passband of the second channel filter.

[0010] Frequency-varying coupling between the first and second stripline resonators of the third channel filter produces a transmission zero outside the lower end of the passband of the third channel filter, and frequency-varying coupling between the third and fourth stripline resonators of the third channel filter produces a transmission zero outside the upper end of the passband of the third channel filter.

[0011] The frequency-varying coupling between the first and second stripline resonators of the fourth channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the fourth channel filter, respectively generate a transmission zero outside the low-end band of the passband of the fourth channel filter.

[0012] Optionally, each line resonator of the first channel filter and each line resonator of the third channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each line resonator of the first channel filter is offset from the corresponding line resonator in the third channel filter by a distance of half the width of the line resonator.

[0013] Each stripline resonator of the second channel filter and each stripline resonator of the fourth channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each stripline resonator of the second channel filter is offset from the corresponding stripline resonator in the fourth channel filter by a distance of half the width of the stripline resonator.

[0014] The first channel filter is positioned to the left of the common stripline resonator, and the top left corner of the first stripline resonator of the third channel filter is positioned opposite to the top left corner of the common stripline resonator; the second channel filter is positioned to the right of the common stripline resonator, and the top right corner of the first stripline resonator of the fourth channel filter is positioned opposite to the top right corner of the common stripline resonator.

[0015] Optionally, both the stripline resonator and the common stripline resonator are stripline stepped impedance resonators; the electric field of the stripline stepped impedance resonator is concentrated in the upper half of the stripline stepped impedance resonator, and the magnetic field of the stripline stepped impedance resonator is concentrated in the lower half of the stripline stepped impedance resonator; the top of the first stripline resonator of the third channel filter is electrically coupled to the top left of the common stripline resonator, and the top of the first stripline resonator of the fourth channel filter is electrically coupled to the top right of the common stripline resonator.

[0016] Optionally, the first stripline resonator of the first channel filter is magnetically coupled to a common stripline resonator, and the first stripline resonator of the second channel filter is magnetically coupled to a common stripline resonator.

[0017] Optionally, the first stripline resonator of the first channel filter is magnetically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is electrically coupled to the common stripline resonator.

[0018] Optionally, the first stripline resonator of the first channel filter is electrically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is magnetically coupled to the common stripline resonator.

[0019] Optionally, the first stripline resonator of the first channel filter is electrically coupled to a common stripline resonator, and the first stripline resonator of the second channel filter is electrically coupled to a common stripline resonator.

[0020] Optionally, the magnetic coupling is achieved by connecting the lower halves of the two stripline resonators through a reinforcing rib, and the distance between the reinforcing rib and the side wall of the planar resonator frame connected to the bottom of the two stripline resonators is proportional to the magnetic coupling strength between the two stripline resonators.

[0021] Optionally, the electrical coupling is such that the upper halves of the two stripline resonators are unobstructed and isolated, and the distance between the upper halves of the two stripline resonators is inversely proportional to the degree of electrical coupling between the two stripline resonators.

[0022] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0023] This application provides a planar sheet metal four-way connector with wires. In this four-way connector, the base plate and the cover plate are fixed to the bottom and top surfaces of the planar resonator frame by soldering, respectively. An impedance matching network and four-channel filters are fixed in the planar resonator frame. The operating frequency bands of the four-channel filters are arranged from low to high. The first and second channel filters are respectively located on both sides of the impedance matching network, and the third and fourth channel filters are arranged upside down on both sides of the top of the impedance matching network. The impedance matching network and the four-channel filters correspond to five port connectors, realizing one input and four outputs. The structure of the four-channel filter includes a common stripline resonator, and each channel filter comprises four parallel stripline resonators with corresponding tuning screws for adjusting their resonant frequencies. The common stripline resonator is coupled to the first stripline resonator of each channel filter, achieving impedance matching between the impedance matching network and each channel filter. The planar sheet metal stripline quad converter described in this application has a unique and compact structure, allowing for flexible introduction of frequency-varying coupling structures between the resonators of the four-channel filters to meet the electrical performance design requirements. This design facilitates the implementation of multiple transmission zeros, thereby achieving high out-of-band rejection and high inter-channel isolation. Compared to currently available quad converters, the planar sheet metal stripline quad converter of this application exhibits advantages such as planar design, high performance, ease of integration, and high reliability. Furthermore, due to its compact structure, simple production and assembly, and easy debugging, it has broad application potential in the field of wireless communication, where electrical performance and miniaturization requirements are extremely high. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the external structure of a planar sheet metal wire-guided four-tool provided in one embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the internal structure of a planar sheet metal wire-guided four-tool provided in one embodiment of this application.

[0027] Figure 3 This is a schematic diagram of the frequency response curve of a planar sheet metal wire-driven four-way actuator provided in one embodiment of this application.

[0028] Figure 4 This is a partially enlarged schematic diagram of an impedance matching network for a planar sheet metal wire-connected quadcopter, provided as an embodiment of this application.

[0029] Figure 5 A schematic diagram of the group delay curve of an impedance matching network for a planar sheet metal wire quadrature provided in an embodiment of this application.

[0030] Figure 6 This is a schematic diagram of the top surface of a planar sheet metal wire-lined four-tool, provided for another embodiment of this application.

[0031] Figure 7 This is a schematic diagram of the bottom surface of a planar sheet metal wire-lined four-tool, provided for another embodiment of this application.

[0032] Figure 8 This is a schematic diagram of the internal structure of a planar sheet metal wire-guided four-way tool provided in another embodiment of this application.

[0033] Figure 9 This is a schematic diagram of the internal structure of a planar sheet metal wire-driven four-tool provided in another embodiment of this application.

[0034] Figure 10 This is a schematic diagram of the internal structure of a planar sheet metal wire-driven four-tool provided in another embodiment of this application.

[0035] Figure label:

[0036] 100: Common stripline resonator; 201: First stripline resonator of the first channel filter; 202: Second stripline resonator of the first channel filter; 203: Third stripline resonator of the first channel filter; 204: Fourth stripline resonator of the first channel filter; 301: First stripline resonator of the second channel filter; 302: Second stripline resonator of the second channel filter; 303: Third stripline resonator of the second channel filter; 304: Fourth stripline resonator of the second channel filter; 401: Third stripline resonator of the second channel filter; 402: The first stripline resonator of the third channel filter; 403: The third stripline resonator of the third channel filter; 404: The fourth stripline resonator of the third channel filter; 501: The first stripline resonator of the fourth channel filter; 502: The second stripline resonator of the fourth channel filter; 503: The third stripline resonator of the fourth channel filter; 504: The fourth stripline resonator of the fourth channel filter; Port1: Input port; Port2~Port5: Output ports. Detailed Implementation

[0037] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] This application provides a planar sheet metal wire-guided four-way tool, such as... Figure 1 As shown, it includes: a base plate, a planar resonator frame, and a cover plate; the base plate and cover plate are respectively mounted on the bottom and top surfaces of the planar resonator frame via positioning pins on the planar resonator frame, and fixed by soldering; as one embodiment, the cover plate and base plate are first pre-assembled with the frame via positioning pins, and then the cover plate and base plate are fixed to the upper and lower surfaces of the frame by soldering. Further, as... Figure 2 As shown, a first-channel filter, a second-channel filter, a third-channel filter, a fourth-channel filter, and an impedance matching network are fixed within the planar resonator frame. The operating frequency bands of the first-channel filter, second-channel filter, third-channel filter, and fourth-channel filter are arranged from low to high. The first-channel filter and second-channel filter are respectively positioned on both sides of the impedance matching network, while the third-channel filter and fourth-channel filter are positioned upside down on both sides of the top of the impedance matching network. The four channel filters are integrated with the planar resonator frame and can be directly machined, wire-cut, or stamped. The processing technology is mature and low-cost. Five port connectors are provided on the cover plate. The inner core of each of the five port connectors passes through the cover plate and connects to the impedance matching network, the first-channel filter, the second-channel filter, the third-channel filter, and the fourth-channel filter, respectively. This planar sheet metal wire-connected four-channel filter has few parts, a simple assembly process, and is easy to debug.

[0040] As one implementation method, the cover plate, frame, and base plate of the planar sheet metal wire-connected quadcopter can be made of metal materials such as copper, aluminum, iron, and stainless steel and then electroplated with silver. The cover plate, planar resonator frame, and base plate can also be made of plastic materials such as PEEK, POM, PPO, and PET dielectric materials and then electroplated with silver. In this way, the weight of the product can be reduced by more than 30%, achieving lightweighting.

[0041] like Figure 2As shown, the impedance matching network includes a common stripline resonator 100. The first, second, third, and fourth channel filters each include four stripline resonators connected side-by-side. All channel filters are arranged in a linear configuration. A frequency-varying coupling structure is introduced between the resonators to generate transmission zeros, improving the out-of-band rejection characteristics of the channel filters and enhancing the isolation of each channel filter component. Figure 2 As shown, 201-204 are the four resonators of the first channel filter, 301-304 are the four resonators of the second channel filter, 401-404 are the four resonators of the third channel filter, and 501-504 are the four resonators of the fourth channel filter. Several tuning screws are provided on the cover plate corresponding to the positions of each line resonator. The tuning screws are used to adjust the resonant frequency of the corresponding line resonator. This planar sheet metal line multiplexer is a one-input four-output multiplexer. The input port Port1 is set on the line resonator 100, and the four output ports Port2, Port3, Port4 and Port5 are set on the line resonators 204, 304, 404 and 504 respectively. The input and output ports are all 50-ohm matched. The common stripline resonator is coupled to the first stripline resonator of the first channel filter, the first stripline resonator of the second channel filter, the first stripline resonator of the third channel filter, and the first stripline resonator of the fourth channel filter, respectively, to achieve impedance matching between the impedance matching network and the first channel filter, the second channel filter, the third channel filter, and the fourth channel filter.

[0042] When designing the product, the coupling polarity between the common stripline resonator 100 and the first stripline resonators 201, 301, 401 and 501 of each channel filter can be flexibly set as needed. The common stripline resonator 100 and the first stripline resonator of each channel filter can be magnetically coupled or electrically coupled.

[0043] As an optional implementation, the frequency-varying coupling between the first and second stripline resonators of the first channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the first channel filter, respectively generate a transmission zero outside the high-end band of the passband of the first channel filter.

[0044] Frequency-varying coupling between the first stripline resonator of the second channel filter and the second stripline resonator of the second channel filter produces a transmission zero outside the high end of the passband of the second channel filter. Frequency-varying coupling between the third stripline resonator of the second channel filter and the fourth stripline resonator of the second channel filter produces a transmission zero outside the low end of the passband of the second channel filter.

[0045] Frequency-varying coupling between the first and second stripline resonators of the third channel filter produces a transmission zero outside the lower end of the passband of the third channel filter, and frequency-varying coupling between the third and fourth stripline resonators of the third channel filter produces a transmission zero outside the upper end of the passband of the third channel filter.

[0046] The frequency-varying coupling between the first and second stripline resonators of the fourth-channel filter, and between the third and fourth stripline resonators, respectively generate a transmission zero outside the low-end band of the fourth-channel filter's passband. The frequency response curve of this planar sheet metal stripline quadrature is shown below. Figure 3 As shown; S11 represents the reflection coefficient at port 1; S21 represents the transmission coefficient from port 2 to port 1; S31 represents the transmission coefficient from port 3 to port 1; S41 represents the transmission coefficient from port 4 to port 1; S51 represents the transmission coefficient from port 5 to port 1.

[0047] As an exemplary implementation, such as Figure 2 As shown, each stripline resonator of the first channel filter and each stripline resonator of the third channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each stripline resonator of the first channel filter is offset from the corresponding stripline resonator in the third channel filter by a distance of half the width of the stripline resonator.

[0048] Each stripline resonator of the second channel filter and each stripline resonator of the fourth channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each stripline resonator of the second channel filter is offset from the corresponding stripline resonator in the fourth channel filter by a distance of half the width of the stripline resonator.

[0049] The first channel filter is positioned to the left of the common stripline resonator, and the top left corner of the first stripline resonator of the third channel filter is positioned opposite to the top left corner of the common stripline resonator; the second channel filter is positioned to the right of the common stripline resonator, and the top right corner of the first stripline resonator of the fourth channel filter is positioned opposite to the top right corner of the common stripline resonator.

[0050] As an exemplary implementation, both the stripline resonator and the common stripline resonator are stripline stepped impedance resonators; the electric field of the stripline stepped impedance resonator is concentrated in the upper half, and the magnetic field is concentrated in the lower half. The top of the first stripline resonator of the third channel filter is electrically coupled to the left top of the common stripline resonator, and the top of the first stripline resonator of the fourth channel filter is electrically coupled to the right top of the common stripline resonator. The electrical coupling is such that the upper halves of the two stripline resonators are unobstructed and isolated, as shown below. Figure 4 As shown, the distance (d1 or d2) between the upper halves of the two stripline resonators is inversely proportional to the degree of electrical coupling between the two stripline resonators; that is, the smaller d1 or d2 is, the greater the corresponding electrical coupling.

[0051] The first stripline resonator of the first channel filter is magnetically coupled to a common stripline resonator, and the first stripline resonator of the second channel filter is also magnetically coupled to a common stripline resonator. The magnetic coupling is achieved by connecting the lower halves of the two stripline resonators via reinforcing ribs, such as... Figure 4 As shown, the distance (h1 or h2) between the reinforcing rib and the side wall of the planar resonator frame connected to the bottom of the two strip resonators is proportional to the magnetic coupling strength between the two strip resonators. That is, the larger h1 or h2 is, the stronger the corresponding magnetic coupling.

[0052] The impedance matching network design of this planar sheet metal strip resonator 100 is ingenious and flexible, and can easily achieve impedance matching and coupling control between the strip resonator 100 and the four-channel filter. Its corresponding group delay curve is shown below. Figure 5 As shown, Figure 5 The four protrusions represent the coupling strength between the common stripline resonator 100 and the four channel filters. Each protrusion corresponds to the time delay peak at the center frequency of each channel filter. The stronger the coupling, the lower the time delay peak. GD(1,1) represents the group delay at input port 1. The weaker the coupling, the weaker the time delay peak. Adjusting h1, h2, d1, and d2 can control the strength of the corresponding coupling structure, that is, control the height of the corresponding time delay peak.

[0053] In another exemplary embodiment of this application, the input / output ports of the planar sheet metal wire quadrupole can use either traditional port connectors or probe-to-patch connections. In this case, the probes of the input / output ports are on the base plate, which facilitates integration and installation with other planar circuits in the system. The product thickness can be further reduced, achieving miniaturization and planarization. Figures 6-7 As shown.

[0054] In addition to the coupling methods described above, other coupling methods can also be used between the four-channel filter and the impedance matching network. Another exemplary embodiment of this application is as follows: Figure 8 As shown, the first stripline resonator of the first channel filter is magnetically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is electrically coupled to the common stripline resonator. In the impedance matching network, the coupling between the common stripline resonator 100 and the first stripline resonator 201 of the first channel filter is magnetic; the coupling between the common stripline resonator 100 and the first stripline resonator 301 of the second channel filter is electrical.

[0055] In another exemplary embodiment of this application, such as Figure 9 As shown, the first stripline resonator of the first channel filter is electrically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is magnetically coupled to the common stripline resonator. The coupling between the common stripline resonator 100 and the first stripline resonator 201 of the first channel filter in the impedance matching network is electrical coupling; the coupling between the common stripline resonator 100 and the first stripline resonator 301 of the second channel filter is magnetic coupling.

[0056] In another exemplary embodiment of this application, such as Figure 10 As shown, the first stripline resonator of the first channel filter is electrically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is also electrically coupled to the common stripline resonator. The coupling between the common stripline resonator 100 and the first stripline resonator 201 of the first channel filter in the impedance matching network is electrical coupling; the coupling between the common stripline resonator 100 and the first stripline resonator 301 of the second channel filter is also electrical coupling.

[0057] The planar sheet metal stripline quadrupole proposed in this application mainly includes a novel impedance matching network and four channel filters composed of stripline resonators. This planar sheet metal quadrupole has a planar structure and is thin and lightweight. Each channel filter is arranged linearly, and frequency-varying coupling structures can be easily introduced into the resonators of each channel filter to generate transmission zeros, improving the out-of-band rejection of the channel filters and the isolation between the channel filters. The coupling between the common stripline resonator and the first resonator of each channel filter can be either electrical or magnetic coupling. The structure is novel and compact, and the coupling implementation is flexible and diverse, with the coupling polarity and strength also easily controlled. Furthermore, the materials used in this quadrupler are simple, the processing technology is mature, the assembly process is minimal, and the production consistency is good. Its power capacity is comparable to that of a small metal coaxial cavity quadrupler, the single cavity Q value is high, the insertion loss is low (greater than that of a dielectric waveguide resonator, and slightly less than that of a metal coaxial resonator), and its harmonic suppression characteristics are good. This type of planar sheet metal quadrupler with wires has a simple material structure and is easy to assemble. Its resonator frame is fixed together with the cover plate and the base plate by soldering, resulting in high reliability and good intermodulation characteristics. It has broad application potential in the field of wireless communication where electrical performance and miniaturization requirements are extremely high.

[0058] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A planar sheet metal wire-guided four-tool, characterized in that, include: The system comprises a base plate, a planar resonator frame, and a cover plate. The base plate and the cover plate are respectively mounted on the bottom and top surfaces of the planar resonator frame via positioning pins on the frame, and are fixed by soldering. The planar resonator frame houses a first-channel filter, a second-channel filter, a third-channel filter, a fourth-channel filter, and an impedance matching network. The operating frequency bands of the first-channel filter, second-channel filter, third-channel filter, and fourth-channel filter are arranged from low to high. The first-channel filter and second-channel filter are respectively positioned on opposite sides of the impedance matching network, while the third-channel filter and fourth-channel filter are positioned upside down on opposite sides of the top of the impedance matching network. The cover plate has five port connectors, the inner cores of which pass through the cover plate and connect to the impedance matching network, the first-channel filter, the second-channel filter, the third-channel filter, and the fourth-channel filter, respectively. The impedance matching network includes a common stripline resonator. Each of the first, second, third, and fourth channel filters includes four stripline resonators connected side-by-side. Several tuning screws are positioned on the cover plate corresponding to each stripline resonator, and these screws are used to adjust the resonant frequency of the corresponding stripline resonator. The common stripline resonator is coupled to the first stripline resonator of the first, second, third, and fourth channel filters, respectively, to achieve impedance matching between the impedance matching network and the first, second, third, and fourth channel filters.

2. The planar sheet metal wire-guided four-tool according to claim 1, characterized in that, The frequency-varying coupling between the first and second stripline resonators of the first channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the first channel filter, respectively generate a transmission zero outside the high-end band of the passband of the first channel filter. The frequency-varying coupling between the first and second stripline resonators of the second channel filter generates a transmission zero outside the high end of the passband of the second channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the second channel filter generates a transmission zero outside the low end of the passband of the second channel filter. The frequency-varying coupling between the first and second stripline resonators of the third channel filter generates a transmission zero outside the low end of the passband of the third channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the third channel filter generates a transmission zero outside the high end of the passband of the third channel filter. The frequency-varying coupling between the first and second stripline resonators of the fourth channel filter, and the frequency-varying coupling between the third and fourth stripline resonators of the fourth channel filter, respectively generate a transmission zero outside the low-end band of the passband of the fourth channel filter.

3. The planar sheet metal wire-guided four-tool according to claim 1, characterized in that, Each line resonator of the first channel filter and each line resonator of the third channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each line resonator of the first channel filter is offset from the corresponding line resonator in the third channel filter by a distance of half the width of the line resonator. Each line resonator of the second channel filter and each line resonator of the fourth channel filter are fixed on the side wall of the planar resonator frame according to the top-to-top position relationship, and each line resonator of the second channel filter is offset from the corresponding line resonator in the fourth channel filter by a distance of half the width of the line resonator. The first channel filter is located to the left of the common stripline resonator, and the top left corner of the first stripline resonator of the third channel filter is opposite to the top left corner of the common stripline resonator; the second channel filter is located to the right of the common stripline resonator, and the top right corner of the first stripline resonator of the fourth channel filter is opposite to the top right corner of the common stripline resonator.

4. The planar sheet metal wire-guided four-tool according to claim 3, characterized in that, Both the stripline resonator and the common stripline resonator are stripline stepped impedance resonators; the electric field of the stripline stepped impedance resonator is concentrated in the upper half of the stripline stepped impedance resonator, and the magnetic field of the stripline stepped impedance resonator is concentrated in the lower half of the stripline stepped impedance resonator. The top of the first stripline resonator of the third channel filter is electrically coupled to the left top of the common stripline resonator, and the top of the first stripline resonator of the fourth channel filter is electrically coupled to the right top of the common stripline resonator.

5. The planar sheet metal wire-guided four-tool according to claim 4, characterized in that, The first stripline resonator of the first channel filter is magnetically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is magnetically coupled to the common stripline resonator.

6. The planar sheet metal wire-guided four-tool according to claim 4, characterized in that, The first stripline resonator of the first channel filter is magnetically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is electrically coupled to the common stripline resonator.

7. The planar sheet metal wire-guided four-tool according to claim 4, characterized in that, The first stripline resonator of the first channel filter is electrically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is magnetically coupled to the common stripline resonator.

8. The planar sheet metal wire-guided four-tool according to claim 4, characterized in that, The first stripline resonator of the first channel filter is electrically coupled to the common stripline resonator, and the first stripline resonator of the second channel filter is electrically coupled to the common stripline resonator.

9. The planar sheet metal wire-operated four-tool according to any one of claims 5-7, characterized in that, The magnetic coupling is achieved by connecting the lower halves of the two stripline resonators through a reinforcing rib. The distance between the reinforcing rib and the side wall of the planar resonator frame connected to the bottom of the two stripline resonators is proportional to the magnetic coupling strength between the two stripline resonators.

10. The planar sheet metal wire-operated four-tool according to any one of claims 4-8, characterized in that, The electrical coupling is such that the upper halves of the two stripline resonators are unobstructed and isolated, and the distance between the upper halves of the two stripline resonators is inversely proportional to the degree of electrical coupling between the two stripline resonators.

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