Filter and multiplexer, combiner and intermodulation instrument comprising same

Abstract

The invention provides a filter and a multiplexer, a combiner and an intermodulation instrument comprising the filter, the filter comprises a left lower resonator, a left upper resonator, a right upper resonator and a right lower resonator which are arranged in sequence to form a box-type topological structure, the left lower resonator and the right upper resonator are arranged diagonally, and the left upper resonator and the right upper resonator are arranged diagonally. The box type topological structure is input by the left lower resonator and output by the right upper resonator, the left upper resonator and the right lower resonator are arranged diagonally, and the left upper resonator and the right lower resonator are arranged in an isolated mode. According to the box-type topological structure filter, by optimizing the arrangement and coupling mode of the internal resonators, the problems of islands and beveled edges in a traditional structure are eliminated, the intermodulation performance stability of the filter is remarkably improved, meanwhile, the structure of a multiplexer is simplified, the system complexity and cost are reduced, and the application range of the box-type topological structure filter is widened. And an effective solution is provided for miniaturization and high-performance design of the multi-band intermodulation instrument.

Description

Technical Field

[0001] The present invention relates to the field of microwave communication technology, and particularly relates to a filter, a multiplexer, a combiner and an intermodulation meter including the filter. Background Art

[0002] In the application of a multi-band intermodulation meter, as a core component, the intermodulation performance of the multiplexer plays a crucial role in the performance of the entire device. The main function of the multiplexer is to achieve the combination of multi-system signals and the effective separation of transmitted signals and intermodulation signals. Among them, the performance of the filter directly determines the intermodulation performance of the multiplexer. Since the working environment of the intermodulation meter has extremely high requirements for signal purity and frequency selectivity, the intermodulation performance of the multiplexer is much more strictly required than other general usage scenarios. However, traditional multiplexer designs face many challenges in meeting these requirements.

[0003] Traditional filters usually adopt CT or CQ topological structures, and their physical structures are triangles or parallelograms with a diagonal line. Although this structure can achieve the function of multi-system combination to a certain extent, there are obvious deficiencies in intermodulation performance. Due to its structural characteristics, islets and hypotenuses are likely to appear in the design and manufacturing process of traditional multiplexers, which not only increases the difficulty of screw arrangement but also causes uneven stress on the cover plate. This uneven stress structural design makes the multiplexer prone to stress concentration during operation, thereby affecting the stability of its intermodulation performance. In addition, this structural design of traditional multiplexers also limits their potential for miniaturization and is difficult to meet the strict requirements of modern intermodulation meters for device volume and weight.

[0004] In traditional technologies, in order to achieve low intermodulation performance, it is usually necessary to additionally connect a filter with high filtering characteristics based on the multiplexer. Although this two-stage combination scheme can improve the intermodulation performance to a certain extent, it also brings many problems. First, the additional filter increases the volume and weight of the device, making the overall structure of the intermodulation meter bulky and not conducive to the miniaturization design of the device. Second, the complex structure of the two-stage combination scheme increases the cost and manufacturing difficulty of the system, and also reduces the reliability and stability of the system. In addition, there are also many technical problems in the connection method between the traditional filter and the multiplexer in practical applications, such as signal loss and reflection at the connection, etc., which will have a negative impact on the overall performance of the intermodulation meter.

[0005] In summary, in the traditional technology, the CT or CQ topological structures of the multiplexer and the two-stage combination scheme relying on additional filters can, to a certain extent, meet the basic requirements of the multi-band intermodulation instrument for intermodulation performance. However, there are many deficiencies in terms of miniaturization, cost control, and system stability. The existence of these problems limits the application and development of the intermodulation instrument in modern communication systems, and there is an urgent need for a new multiplexer structure that can effectively solve the above problems. Summary of the Invention

[0006] In view of the shortcomings of the existing methods, the present invention provides a multiplexer to solve the technical problems of the existing technology, such as complex structure, difficult assembly, poor intermodulation performance, and large volume.

[0007] An embodiment of the present invention provides a filter, which includes a lower left resonator, an upper left resonator, an upper right resonator, and a lower right resonator arranged in sequence in a box-shaped topological structure. The lower left resonator and the upper right resonator are arranged diagonally, and the box-shaped topological structure is input from the lower left resonator and output from the upper right resonator. The upper left resonator and the lower right resonator are arranged diagonally and are isolated from each other.

[0008] Preferably, any one group of the lower left resonator and the upper left resonator, the upper left resonator and the upper right resonator, the upper right resonator and the lower right resonator, and the lower right resonator and the lower left resonator is capacitively coupled, and the remaining three groups are inductively coupled;

[0009] Alternatively, any three groups of the lower left resonator and the upper left resonator, the upper left resonator and the upper right resonator, the upper right resonator and the lower right resonator, and the lower right resonator and the lower left resonator are capacitively coupled, and the remaining one group is inductively coupled.

[0010] Preferably, it further includes a middle upper resonator arranged between the upper left resonator and the upper right resonator and a middle lower resonator arranged between the lower left resonator and the lower right resonator. The lower left, upper left, middle upper, lower right resonators are arranged in a rectangular distribution and are sequentially coupled. The middle upper, middle lower, lower right, upper right resonators are also arranged in a rectangular distribution and are sequentially coupled. The resonators arranged diagonally among these six resonators are isolated from each other.

[0011] Preferably, the middle upper resonator and the middle lower resonator are capacitively coupled, and the remaining resonators connected to each other are inductively coupled;

[0012] Alternatively, the middle upper resonator and the middle lower resonator are inductively coupled, and there are two places of capacitive coupling among the remaining resonators connected to each other.

[0013] Preferably, it includes partition walls. The inductive coupling connection between the resonators is realized through openings in the partition walls, and the capacitive coupling connection is realized by arranging fly rods on the partition walls.

[0014] Preferably, the partition walls have straight walls or walls with arc transitions, and are integrally in a T shape and / or a cross shape.

[0015] Preferably, the filter includes a cavity, and the resonators constituting the box-shaped topology are arranged in a rectangular row in the cavity.

[0016] Meanwhile, a multiplexer including at least one of the above filters is provided. A combiner including at least one of the above filters is provided. An intermodulation meter including the above multiplexer is provided.

[0017] A multiplexer further provided by the present invention includes: a cavity, a first filtering unit and a second filtering unit arranged in the cavity, and the first filtering unit and the second filtering unit are cascaded; and is characterized in that: both the first filtering unit and the second filtering unit arrange their multiple resonators in the cavity according to a box-shaped topology.

[0018] Preferably, the first filtering unit or the second filtering unit includes a lower left resonator, an upper left resonator, an upper right resonator and a lower right resonator arranged in sequence in a box-shaped topology. The lower left resonator and the upper right resonator are diagonally arranged, and the box-shaped topology is input from the lower left resonator and output from the upper right resonator. The upper left resonator and the lower right resonator are diagonally arranged and are isolated from each other.

[0019] Preferably, the first filtering unit includes a plurality of first resonators distributed in a rectangular row cavity and a first partition wall arranged between the plurality of first resonators. The first partition wall has a vertical partition wall separating two of the first resonators at the rectangular bottom edge and a horizontal partition wall separating two of the first resonators at the rectangular top edge, and the vertical partition wall and the horizontal partition wall are vertically connected.

[0020] Preferably, the second filtering unit includes a plurality of second resonators distributed in a rectangular row cavity and a second partition wall arranged between the plurality of second resonators. The second resonator has a horizontal partition wall and a vertical partition wall separating three of the second resonators at the rectangular bottom edge from three of the second resonators at the rectangular top edge, and the vertical partition wall and the horizontal partition wall are cross-arranged.

[0021] Preferably, the vertical partition walls separate two adjacent second resonators among the three second resonators located at the top side of the rectangle, and separate two adjacent second resonators among the three second resonators located at the bottom side of the rectangle; the plurality of vertical partition walls and the horizontal partition walls are arranged in a crisscross manner.

[0022] Preferably, a first flybar spanning the vertical partition wall is provided between two first resonators of the first filtering unit located at the bottom side of the rectangle.

[0023] Preferably, a second flybar spanning the horizontal partition wall is provided between a second resonator located at the bottom side of the rectangle and a corresponding second resonator located at the top side of the rectangle of the second filtering unit.

[0024] Preferably, the cavity includes a bottom wall and side walls formed at the periphery of the bottom wall; the first filtering unit and the second filtering unit are disposed on the bottom wall.

[0025] Preferably, a plurality of the first filtering units cascaded with each other are provided on the bottom wall.

[0026] Preferably, a plurality of the second filtering units cascaded with each other are provided on the bottom wall.

[0027] Preferably, the first filtering unit and the second filtering unit are cascaded with each other.

[0028] Preferably, a plurality of shunt ports are provided at one end of the side wall, and a combined port is provided at the other end of the side wall. One ends of the plurality of cascaded first filtering units are respectively communicatively connected to corresponding shunt ports, and the other ends are communicatively connected to the combined port; or, one ends of the plurality of cascaded second filtering units are respectively communicatively connected to corresponding shunt ports, and the other ends are communicatively connected to the combined port; or, one ends of multiple groups of cascaded first and second filtering units are respectively communicatively connected to corresponding shunt ports, and the other ends are communicatively connected to the combined port.

[0029] The beneficial technical effects brought by the technical solution provided by the embodiment of the present invention include:

[0030] First of all, by adopting a box-type topology structure, the filter of the present application realizes the sequential arrangement of the lower left resonator, the upper left resonator, the upper right resonator and the lower right resonator, and the lower left resonator and the upper right resonator are arranged diagonally, and the upper left resonator and the lower right resonator are arranged in isolation. This structural design fundamentally eliminates the island and bevel problems existing in the traditional CT or CQ topology structure, making the internal structure of the filter more regular and compact. This regular structure not only simplifies the arrangement of screws, but also makes the force on the cover plate more uniform, thus effectively avoiding the stress concentration phenomenon and significantly improving the stability of the intermodulation performance of the filter.

[0031] Secondly, when this filter with a box-shaped topology is applied to a multiplexer, it can directly integrate high filtering characteristics and low intermodulation characteristics. Due to the structural optimization of the filter itself, there is no need to rely on an additional filter with high filtering characteristics to be combined with the multiplexer, thus omitting the complex connection structure in the traditional two-stage combination scheme. This improvement not only reduces the volume and weight of the system, but also reduces the performance degradation problems caused by signal loss and reflection at the connection points, significantly improving the overall performance of the multiplexer and also making it possible for the miniaturized design of the multiplexer.

[0032] In addition, when this optimized multiplexer is applied to a multi-band intermodulation meter, the technical advantages it brings are more significant. Since the intermodulation meter has extremely high requirements for signal purity and frequency selectivity, the multiplexer of the present application can directly meet these strict requirements without the assistance of an additional filter. This not only simplifies the overall structure of the intermodulation meter, reduces the complexity and cost of the equipment, but also improves the reliability and stability of the system. At the same time, due to the reduction in the volume and weight of the multiplexer, the overall design of the intermodulation meter is more flexible, and it can better meet the dual requirements of modern communication systems for equipment miniaturization and high performance.

[0033] Additional aspects and advantages of the present invention will be given in part in the following description, and these will become apparent from the following description or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings, in which:

[0035] Figure 1 is a planar structure diagram of the multiplexer provided by an embodiment of the present invention, showing a first filtering unit and a second filtering unit, both of which are arranged in a cavity and are cascaded with each other;

[0036] Figures 2a to 2h are various types of single transmission zero box-shaped topologies of the first filtering unit of the multiplexer provided by an embodiment of the present invention; and

[0037] Figures 3a to 3b are various types of double transmission zero box-shaped topologies of the second filtering unit of the multiplexer provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] The present invention will be described in detail below. Examples of embodiments of the present invention are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. In addition, if a detailed description of the known art is not necessary for showing the features of the present invention, it will be omitted. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention.

[0039] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless specifically defined as here.

[0040] Those skilled in the art of the present technology can understand that, unless specifically stated, the singular forms "a", "an", "the" and "said" used herein may also include the plural forms. It should be further understood that the term "comprising" used in the specification of the present invention means the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or their groups. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to other elements, or there may also be intermediate elements. In addition, the "connection" or "coupling" used here may include wireless connection or wireless coupling. The phrase "and / or" used here includes all or any unit and all combinations of one or more related listed items.

[0041] The multiplexer provided by the present invention aims to solve the above technical problems of the prior art. Generally speaking, based on the amplitude-phase superposition principle for determining the transmission zero position of a filter, this application summarizes the general rule that if the phases of an even number of coupling coefficients are simultaneously flipped by 180°, the transmission characteristics of the filter remain unchanged. For the first time in the design of a low-intermodulation multiplexer, a filter with a "box-shaped topology structure" is introduced. By utilizing the box-shaped characteristics of its physical structure, the islands and bevels in the multiplexer are eliminated, a horizontal and vertical multi-row cavity structure is achieved, the difficulty of arranging screws is greatly simplified, the force on the cover plate of the multiplexer is made more uniform, and thus the intermodulation performance of the multiplexer is greatly improved. In order to enrich the product design of the "box-shaped topology structure", this application will give the general forms of coupling polarity transformation in the single-transmission-zero and double-transmission-zero box-shaped structures through the following multiple embodiments.

[0042] The technical solution of the present invention and how the technical solution of the present invention solves the above technical problems will be described in detail below with specific embodiments.

[0043] An embodiment of the present invention provides a multiplexer 100, which integrates a filter provided in another embodiment of the present application. The structural schematic diagram of this product is as follows Figures 1 to 3b shown, including: a cavity 10 and a first filtering unit 20 and a second filtering unit 30 disposed in the cavity 10, and the first filtering unit 20 and the second filtering unit 30 are cascaded.

[0044] The cavity 10 provides a receiving space for the internal components of the multiplexer 100. Specifically, the cavity 10 includes a bottom wall 12 and a side wall 14 formed on the periphery of the bottom wall 12. The first filtering unit 20 and the second filtering unit 30 are disposed on the bottom wall 12.

[0045] Each filtering unit is a part of the filter adopted by the multiplexer of the present application. In one embodiment, a plurality of, for example, four first resonators 22 distributed in a rectangular shape and a first partition wall 24 disposed between the plurality of first resonators 22 may be provided on the bottom wall 12; a plurality of second filtering units 30 cascaded with each other may also be provided; even in other embodiments, a plurality of first filtering units 20 and a plurality of second filtering units 30 may be provided, and these filtering units are cascaded with each other to form a filtering module of the multiplexer 100.

[0046] In the present application, since a plurality of cascaded filtering units form a filtering module, and a plurality of filtering modules can access communication signals of different frequency bands (such as through a plurality of dividing ports 142 at one end of the side wall 14), and then these filtering modules are combined into one signal through, for example, a combining port 144 at the other end of the side wall 14, so as a whole, it is equivalent to a multiplexer with good filtering characteristics and low intermodulation characteristics. In contrast, the multiplexer in the prior art uses a filter and a multiplexer separately, with two different devices to respectively implement signal filtering and splitting / combining. In the present application, the two functions are combined into one, thus greatly simplifying the structure of the multiplexer. When the multiplexer of the present application is used in an intermodulation meter, the volume and weight of the intermodulation meter can be greatly reduced.

[0047] In one embodiment, the first filtering unit 20 includes a plurality of, for example, four first resonators 22 distributed in a rectangular shape and a first partition wall 24 disposed between the plurality of first resonators 22. The first partition wall 24 has a vertical partition wall 244 separating two of the first resonators 22 located at the bottom side of the rectangle and a horizontal partition wall 246 separating two of the first resonators 22 located at the top side of the rectangle. The vertical partition wall 244 and the horizontal partition wall 246 are connected to form a T-shaped structure.

[0048] In the present application, since the first partition wall 24 that separates multiple first resonators 22 includes a vertical partition 244 and a horizontal partition 246 that are orthogonally arranged, a T-shaped structure is formed between the two. Therefore, the first partition wall 24 has a horizontal and vertical structure, thus avoiding the formation of bevel edges or island structures on the first partition wall 24. As a result, threaded holes can be more evenly formed on the first partition wall 24 so that a cover plate (not shown in the figure) can be locked to the first partition wall 24 by screws. This greatly simplifies the arrangement difficulty of the screws on the first partition wall 24, makes the force on the cover plate more uniform, and thus greatly improves the intermodulation performance of the product.

[0049] In another embodiment, similarly, the second filtering unit 30 includes a plurality of, for example, six second resonators 32 arranged in a rectangular distribution and a second partition wall 34 disposed between the plurality of second resonators 32. The second resonators 32 have a horizontal partition 344 and a vertical partition 346 that vertically separate the three second resonators 32 located at the bottom of the rectangle from the three second resonators 32 located at the top of the rectangle. The vertical partition 346 intersects with the horizontal partition 344. Here, the vertical partition 346 not only separates two adjacent second resonators 32 among the three second resonators 32 located at the top of the rectangle, but also separates two adjacent second resonators 32 among the three second resonators 32 located at the bottom of the rectangle. For example, in this embodiment, the second partition wall 34 has two vertical partitions 346 that intersect with the horizontal partition 344, and each vertical partition 346 intersects through the horizontal partition 344 to respectively separate two adjacent second resonators 32 at the top and bottom of the rectangle from each other. Here, a cross-shaped structure is formed between the plurality of vertical partitions 346 and the horizontal partition 344.

[0050] Similarly, no island or bevel edge structures appear on the second partition wall 34 with such a cross-shaped structure. Therefore, to a certain extent, the second partition wall 34 has a horizontal and vertical structure, thus avoiding the formation of bevel edges or island structures on the second partition wall 34. In this way, threaded holes can be more evenly formed on the second partition wall 34 so that the cover plate can be locked to the second partition wall 34 by screws. This also greatly simplifies the arrangement difficulty of the screws on the second partition wall 34, makes the force on the cover plate more uniform, and thus greatly improves the intermodulation performance of the multiplexer.

[0051] In a further embodiment, the partition wall is designed to have a flat wall surface or an arc transition is provided at the corner to further ensure that there are no islands and bevel edges in the cavity space where the resonator is located, strengthening the embodiment of the inventive concept of the present application.

[0052] It should be noted that: Communication signals of multiple different frequency bands can be fed into the multiplexer 100 through, for example, multiple demultiplexing ports 142 located at one end of the sidewall 14. The multiple filtering units are cascaded with each other, and one ends of the multiple filtering units are respectively communicatively connected to the corresponding demultiplexing ports 142, while the other ends of the multiple filtering units are connected to each other and communicatively connected to the multiplexing port 144 located at the other end of the sidewall 14, thereby enabling multiple paths of signals to enter the corresponding filtering modules respectively, and being multiplexed and output after filtering, ultimately realizing the multiplexing function of the signals.

[0053] Here, communication signals of multiple different frequency bands can have the following forms. For example, the technical form of the current RRU has also gradually evolved from single-mode frequency bands such as 700M, 800M, 900M, 1.8G, 2.1G, 2.6G, etc. to dual-mode forms such as 1.8 + 2.1G or 700 + 900M or 800 + 900M, and triple-mode forms such as (700M + 800M + 900M) and (1.8G + 2.1G + 2.6G). Among them, the mainstream FDD RRU of macro base stations is configured as 4TR, and the antennas have also developed into 4-port or multi-port broadband antennas accordingly. One antenna needs to test the passive intermodulation indexes of multiple ports and multiple frequency bands. For 5G Massive MIMO, it has also evolved from single-mode to multi-mode (such as 1.8G + 2.1G + 2.6G triple-mode), and the antennas have even developed into three-frequency 32-port or even three-frequency 64-port.

[0054] According to an embodiment of the present application, a first flying bar 28 spanning the vertical partition wall 244 is provided between two first resonators 22 of the first filtering unit 20 located at the rectangular bottom side. In the design of microwave devices in the communication field, a flying bar is a mechanical tuning element used to adjust the performance of a multiplexer (Multiplexer), usually in the form of a metal bar or probe. In the present application, the first flying bar is located between two first resonators 22 of the multiplexer, and the first flying bar realizes precise control of the electromagnetic coupling strength and frequency response through adjustment of the physical position.

[0055] The functions realized by the flying bar mainly include:

[0056] Coupling strength adjustment: By changing the depth or horizontal position of the flying bar inserted into the resonant cavity, the electromagnetic coupling amount between adjacent resonators is adjusted. The coupling strength directly affects the passband bandwidth and out-of-band rejection performance of the multiplexer. For example: Weak coupling: Narrow passband, high out-of-band rejection, suitable for narrowband filtering requirements. Strong coupling: Wide passband, but reduced out-of-band rejection, suitable for broadband applications.

[0057] Resonant frequency fine-tuning: The metal characteristics of the flying bar will disturb the electromagnetic field distribution in the resonant cavity, thereby slightly changing the resonant frequency. It is used to compensate for frequency drift caused by manufacturing tolerances or environmental temperature and humidity changes, and ensure the frequency accuracy of each channel of the multiplexer.

[0058] Suppression of mode interference: In a multiplexer, different resonant modes (such as TE / TM modes) may cause interference. The flybar can suppress the excitation of higher-order modes and optimize the mode purity.

[0059] Similarly, a second flybar 38 spanning the horizontal partition 344 is provided between a second resonator 32 at the bottom edge of the rectangle and the corresponding second resonator 32 at the top edge of the rectangle in the second filtering unit 30. Similarly, in the present application, the second flybar is located between two second resonators 32 of the multiplexer, and the second flybar realizes precise control of the electromagnetic coupling strength and frequency response through adjustment of the physical position.

[0060] In an embodiment of the present application, several forms of equivalent transformation of coupling polarity in a single transmission zero box-type topology are provided at the same time, such as Figures 2a to 2h Shown are various different types of single transmission zero box-type topologies of the first filtering unit 20. By arranging a single capacitor between two adjacent first resonators 22 at different positions, or by arranging multiple capacitors, such as 3 capacitors, between two adjacent first resonators 22 at different positions, various different single transmission zero box-type topologies are formed. In the figure, the numbers in the circles only represent the first resonators 22 at different positions.

[0061] Figures 3a to 3b Shows various different types of double transmission zero box-type topologies of the second filtering unit of the multiplexer provided in the embodiment of the present invention. As shown in the figure, by arranging a single or two capacitors between two adjacent second resonators 32 at different positions, various different double transmission zero box-type topologies are formed. These different types of single transmission zero box-type topologies or double transmission zero box-type topologies can greatly simplify the product design. In the figure, the numbers in the circles only represent the second resonators 32 at different positions.

[0062] The above embodiments of the present invention can also be described in the following manner:

[0063] In the first filtering unit 20, the 4 first resonators 22 distributed in a rectangular shape can be named respectively according to their positions in the rectangular topology: the lower left resonator 1, the upper left resonator 2, the upper right resonator 3, and the lower right resonator 4.

[0064] The resonators located at the four corner positions of the box-type topology form a filter of the present application. The lower left resonator 1 and the upper right resonator 3 are diagonally arranged, and the box-type topology is input from the lower left resonator 1 and output from the upper right resonator 3. The upper left resonator 2 and the lower right resonator 4 are diagonally arranged, and the upper left resonator 2 and the lower right resonator 4 as well as the lower left resonator 1 and the upper right resonator 3 are respectively isolated.

[0065] In one embodiment, the resonators may be connected in the following manner:

[0066] The lower left resonator 1 is connected to the upper left resonator 2, the upper left resonator 2 is connected to the upper right resonator 3, the upper right resonator 3 is connected to the lower left resonator 1, and the lower right resonator 4 is connected to the lower left resonator 1.

[0067] Regarding the coupling manner between the resonators, the following settings can be made:

[0068] Combined with Figures 2a - 2d , any one of the groups of the lower left resonator 1 and the upper left resonator 2, the upper left resonator 2 and the upper right resonator 3, the upper right resonator 3 and the lower right resonator 4, and the lower right resonator 4 and the lower left resonator 1 is capacitively coupled, and the remaining three groups are inductively coupled.

[0069] Combined with Figures 2e - 2h , in another embodiment, referring to the first filtering unit 20, several forms of equivalent transformation of coupling polarities in the single transmission zero box-shaped topology are given. The coupling manner between the resonators in the filter can be set as: any three of the groups of the lower left resonator 1 and the upper left resonator 2, the upper left resonator 2 and the upper right resonator 3, the upper right resonator 3 and the lower right resonator 4, and the lower right resonator 4 and the lower left resonator 1 are capacitively coupled, and the remaining one group is inductively coupled.

[0070] Combined with Figures 3a - 3b , in one embodiment, referring to the second filtering unit 30, the filter further includes a middle upper resonator 5 disposed between the upper left resonator 2 and the upper right resonator 3 and a middle lower resonator 6 disposed between the lower left resonator 1 and the lower right resonator 4. The lower left, upper left, middle upper, and lower right resonators (1, 2, 5, 6) are arranged in a rectangular distribution and are sequentially coupled. The middle upper, middle lower, lower right, and upper right resonators 3 are also arranged in a rectangular distribution and are sequentially coupled. The resonators arranged diagonally among these six resonators (5, 6, 4, 3) are isolated from each other. This double transmission zero box-shaped topology is input from the lower left resonator 1 and output from the upper right resonator 3.

[0071] Combined with the attached Figure 3a , in one embodiment, the middle upper resonator 5 and the middle lower resonator 6 are inductively coupled, and there are two capacitive couplings among the remaining resonators connected to each other.

[0072] In addition, combined with the attached Figure 3b, in one embodiment, the upper-middle resonator 5 and the lower-middle resonator 6 are capacitively coupled, and the rest of the resonators connected to each other are inductively coupled. In this way, while implementing a dual-transmission-zero box-shaped topology, the minimum number of flying bars can be achieved.

[0073] Preferably, the filter further includes the above-mentioned partition wall. The inductive coupling between the resonators is realized through the openings on the partition wall, and the capacitive coupling is realized by arranging flying bars on the partition wall. For example, the partition wall can be in a T shape and / or a cross shape. Preferably, the filter further includes a cavity, and the resonator is arranged in the cavity.

[0074] The present invention also simultaneously provides a multiplexer, including a plurality of the above-mentioned filters. A combiner including a plurality of the above-mentioned filters is also provided. An intermodulation meter including the above-mentioned multiplexer is also provided.

[0075] The above are only partial embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A filter, characterized in that: The invention comprises a lower left resonator, an upper left resonator, an upper right resonator and a lower right resonator which are arranged in sequence in a box-type topology structure, wherein the lower left resonator and the upper right resonator are arranged diagonally, and the box-type topology structure is input by the lower left resonator and output by the upper right resonator, the upper left resonator and the lower right resonator are arranged diagonally, and the upper left resonator and the lower right resonator are isolated from each other.

2. The filter according to claim 1, characterized in that Any one of the lower left resonator and the upper left resonator, the upper left resonator and the upper right resonator, the upper right resonator and the lower right resonator, and the lower right resonator and the lower left resonator is capacitively coupled, and the other three groups are inductively coupled; Alternatively, any three groups of the lower left resonator and the upper left resonator, the upper left resonator and the upper right resonator, the upper right resonator and the lower right resonator, and the lower right resonator and the lower left resonator are capacitively coupled, and the remaining group is inductively coupled.

3. The filter according to claim 1, characterized in that It also includes an upper-middle resonator arranged between the upper-left resonator and the upper-right resonator and a lower-middle resonator arranged between the lower-left resonator and the lower-right resonator. The lower-left, upper-left, upper-middle, and lower-right resonators are distributed in a rectangular shape and are coupled in sequence. The upper-middle, lower-middle, lower-right, and upper-right resonators are also distributed in a rectangular shape and are coupled in sequence. The diagonally arranged resonators among the six resonators are isolated from each other.

4. The filter according to claim 3, characterized in that The upper middle resonator is connected to the lower middle resonator in a capacitive coupling manner, and the other resonators connected to each other are connected in an inductive coupling manner. Alternatively, the upper middle resonator is connected to the lower middle resonator in an inductive coupling manner, and two of the remaining resonators connected to each other are capacitive coupling connections.

5. The filter according to claim 2 or 4, characterized in that: The invention comprises a partition wall, wherein the inductive coupling connection between the resonators is realized by opening a window on the partition wall, and the capacitive coupling connection is realized by arranging a flying rod on the partition wall.

6. The filter according to claim 5, characterized in that The partition wall has a straight wall or a wall surface with an arc transition, and is in a T-shape and / or a cross shape as a whole.

7. The filter according to claim 1, characterized in that It comprises a cavity, and the resonators constituting the box-type topological structure are arranged in a rectangular row in the cavity.

8. A multiplexer, characterized in that: Comprising a plurality of filters as claimed in any one of claims 1 to 7.

9. A combiner, characterized in that: Comprising a plurality of filters as claimed in any one of claims 1 to 7.

10. An intermodulation instrument, characterized in that: Comprising the multiplexer as claimed in claim 8.

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