Filter

Abstract

Provided in the present application is a filter, comprising a first resonator (11), which comprises a resonator housing (111) and a dielectric resonance member (112). The filter further comprises a first coupling structure (20), which is arranged in the resonator housing (111), wherein the first coupling structure (20) comprises a first coupling portion (21), which is spaced apart from a first wall (1111) in parallel, and a second coupling portion (22), which is connected between one end of the first coupling portion (21) and the first wall (1111), the first coupling structure (20) being used for coupling a TE mode and a TM mode of the first resonator (11). In the filter, the TE mode and TM mode of the first resonator (11) can be coupled by means of the first coupling structure (20) having a simplified and optimized structure, and the coupling effect is relatively good; thus, the structure and performance of the filter can be optimized, and the simulation design of the filter can be facilitated.

Description

filter

[0001] This application claims priority to Chinese Patent Application No. 202411555990.5, filed on October 31, 2024, with the State Intellectual Property Office of the People's Republic of China, entitled "Filter," the entire contents of which are incorporated herein by reference. This application also claims priority to two other Chinese Patent Applications Nos. 202411556005.2 and 202422671375.2, both filed on October 31, 2024, with the State Intellectual Property Office of the People's Republic of China, entitled "Filter and Communication Device," the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of communication technology, and in particular relates to a filter. Background Technology

[0003] In some cases, the filter includes a dielectric cavity resonator capable of coupling at least two orthogonal high-Q resonant modes, namely TE mode and TM mode, in a single cavity. That is, the dielectric cavity resonator has at least two resonant modes, TE mode and TM mode, which can be used to establish a coupling relationship with resonators such as metal coaxial resonators with better coupling effect, thereby improving the usability, applicability and practicality of the dielectric cavity resonator.

[0004] The aforementioned dielectric cavity resonator can achieve at least a second-order filtering effect, equivalent to the filtering effect of at least two single-mode resonators, or at least two microwave resonators, thereby improving the performance and space utilization of the dielectric cavity resonator. Furthermore, the dielectric cavity resonator has a small size, which is beneficial for miniaturization and lightweight design.

[0005] In this situation, how to couple the TE mode and TM mode of the dielectric cavity resonator has become a problem to be solved in the industry.

[0006] Application content

[0007] This application provides a filter designed to address the problem of coupling the TE and TM modes of a dielectric cavity resonator when the filter includes at least two resonant modes: TE and TM.

[0008] To achieve the above objectives, the technical solution adopted in the embodiments of this application is as follows:

[0009] In a first aspect, a filter is provided, including a first resonator having at least two resonant modes: a TE mode and a TM mode. The first resonator includes a resonator housing and a dielectric resonator disposed within the resonator housing, the dielectric resonator being connected to a first wall of the resonator housing. The filter further includes a first coupling structure disposed within the resonator housing, the first coupling structure including a first coupling portion spaced parallel to and parallel to the first wall, and a second coupling portion connected between one end of the first coupling portion and the first wall. The first coupling structure is used to couple the TE mode and the TM mode of the first resonator.

[0010] The beneficial effects of the filter provided in this application are as follows:

[0011] The filter provided in this application embodiment has a first coupling structure within a first resonator having at least two resonant modes: TE mode and TM mode. This first coupling structure couples the TE and TM modes of the first resonator. Specifically, the first coupling structure allows the electric field of the TE mode to be coupled to a first coupling portion parallel to and spaced from a first wall, such that the current direction of the first coupling portion is the same as the electric field direction and the current direction of the TE mode. The first coupling structure can also directly conduct the current of the TM mode from the first wall through a second coupling portion connected between one end of the first coupling portion and the first wall. Based on the connection between the second and first coupling portions and the current flow, the current of the TE mode and the current of the TM mode can flow simultaneously in the same direction or simultaneously in opposite directions on the first coupling structure, thereby enabling the TE and TM modes to couple with each other on the first coupling structure. Thus, the filter can achieve coupling of the TE and TM modes of the first resonator through a simplified and optimized first coupling structure, with better coupling effect. This optimizes the structure and performance of the filter and facilitates its simulation design. Attached Figure Description

[0012] To clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art 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.

[0013] Figure 1 is a three-dimensional schematic diagram of a filter provided in some embodiments of this application;

[0014] Figure 2 is a partial structural schematic diagram of the filter provided in Figure 1, in which both resonators are TE-TM dual-mode resonators;

[0015] Figure 3 is a top view of the filter provided in Figure 2;

[0016] Figure 4 is a structural schematic diagram of an assembly of a resonator, a first coupling structure, a second coupling structure, and a base provided in some embodiments of this application;

[0017] Figure 5 is a magnetic field distribution diagram of the TE mode of the first resonator provided in some embodiments of this application;

[0018] Figure 6 is an electric field distribution diagram of the TE mode of the first resonator provided in some embodiments of this application;

[0019] Figure 7 is a magnetic field distribution diagram of the TM mode of the first resonator provided in some embodiments of this application;

[0020] Figure 8 is an electric field distribution diagram of the TM mode of the first resonator provided in some embodiments of this application;

[0021] Figure 9 is a top view of a first resonator provided in some other embodiments of this application. Compared with Figure 3, the second coupling part of the first coupling structure is changed to be disposed at one end of the first coupling part in a clockwise direction, so that the coupling polarity between the TE mode and the TM mode of the first resonator is reversed.

[0022] Figure 10 is a schematic diagram of the filter topology provided in Figure 2, where 12-TM is the TM mode of the second resonator, 12-TE is the TE mode of the second resonator, 13-TM is the TM mode of the third resonator, 13-TE is the TE mode of the third resonator, solid lines represent inductive coupling, and dashed lines represent capacitive coupling.

[0023] Figure 11 is a top view of a filter provided in some other embodiments of this application, wherein the second coupling structure includes a fourth coupling part and a fifth coupling part that are bent and connected in sequence;

[0024] Figure 12 is a top view of a filter provided in some other embodiments of this application, wherein the second coupling structure is disposed in the first coupling window and intersects the center line connecting the second resonator and the third resonator;

[0025] Figure 13 is a top view of a filter provided in some other embodiments of this application, wherein, compared with Figure 3, the second coupling structure is mirror-flipped along the center line connecting the second resonator and the third resonator to reverse the coupling polarity between the TE mode of the second resonator and the TM or TEM mode of the third resonator.

[0026] Figure 14 is a partial structural schematic diagram of a filter provided in some other embodiments of this application, wherein the fourth resonator is a TE single-mode resonator and the fifth resonator is a TE-TM dual-mode resonator.

[0027] Figure 15 shows the frequency simulation diagrams of each resonant mode provided in Figure 14, where line a represents the TE mode of the fourth resonator, line b represents the TM mode of the fifth resonator, and line c represents the TE mode of the fifth resonator.

[0028] Figure 16 shows the coupling simulation diagrams of each resonant mode provided in Figure 14. Line a represents the coupling amount between the TE mode of the fourth resonator and the TM mode of the fifth resonator, line b represents the coupling amount between the TE mode of the fourth resonator and the TE mode of the fifth resonator, and line c represents the coupling amount between the TE mode of the fifth resonator and the TM mode of the fifth resonator.

[0029] Figure 17 is a perspective view of a medium provided in some other embodiments of this application, wherein the medium is provided with an opening;

[0030] Figure 18 is a partial structural schematic diagram of a filter provided in some other embodiments of this application, wherein the fourth resonator is a TE single-mode resonator and the fifth resonator is a TE single-mode resonator;

[0031] Figure 19 shows the frequency simulation diagrams of each resonant mode provided in Figure 18, where line a represents the TE mode of the fourth resonator and line b represents the TE mode of the fifth resonator.

[0032] Figure 20 shows the coupling simulation diagrams of each resonant mode provided in Figure 18. Line a represents the coupling amount between the TE mode of the fourth resonator and the TE mode of the fifth resonator when no dielectric element is provided, and line b represents the coupling amount between the TE mode of the fourth resonator and the TE mode of the fifth resonator when a dielectric element is provided.

[0033] Figure 21 is a top view of a filter provided in some other embodiments of this application, wherein the third coupling structure couples the TE mode of the fourth resonator with the TE mode of the fifth resonator, and the sixth and seventh coupling parts of the third coupling structure are bent toward the same side of the connection.

[0034] Figure 22 is a top view of a filter provided in some other embodiments of this application, wherein the sixth coupling part of the third coupling structure is bent toward the side of the connecting part, and the seventh coupling part is bent toward the other side of the connecting part;

[0035] Figure 23 is a top view of a filter provided in some other embodiments of this application, wherein the fourth coupling structure is a coupling rib with both ends grounded, so that the TM mode or TEM mode of the sixth resonator is inductively coupled to the TM mode or TEM mode of the seventh resonator.

[0036] In the figures, the following labels are used: 10-resonator, 11-first resonator, 111-resonator housing, 1111-first wall, 1112-resonant cavity, 112-dielectric resonator; 12- 13-Second resonator, L-Center line connecting the second and third resonators; 14-Resonator, 15-Fourth resonator, 16-Fifth resonator; 17-Sixth resonator, 18-Seventh resonator; 20-First coupling structure, 21-First coupling part, 22-Second coupling part, 23-Third coupling part; 30-Coupling window, 30a-First coupling window; 40-Second coupling structure, 41-Fourth coupling part, 42-Fifth coupling part, 50-Dielectric element, d1-Height of dielectric element, d2-Width of dielectric element, d3-Thickness of dielectric element, 51-Opening; 60-Third coupling structure, 61-Connecting part, 62-Sixth coupling part, 63-Seventh coupling part; 70-Fourth coupling structure; 80-Base, 90-Tuning structure, 100-Coupling adjustment structure. Detailed Implementation

[0037] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clear, the application will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application. Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0038] In this application, "axial" refers to the direction of extension of the central axis of the corresponding structure, "radial" refers to any direction of the corresponding structure that passes through and is perpendicular to the central axis, and "circumferential" refers to the direction of circumference of the outer circumference of the corresponding structure.

[0039] A single-mode resonator is a resonator that supports only one resonant mode within its passband. This resonant mode can be a TE (Transverse Electric) mode, a TM (Transverse Magnetic) mode, a TEM (Transverse Electric and Magnetic Field) mode, etc. For example, a metal coaxial resonator is a single-mode resonator; it only supports the TEM mode within its passband, making it a TEM single-mode resonator.

[0040] A dual-mode resonator is a resonator capable of simultaneously generating two stable oscillating signals at different frequencies. A dual-mode resonator supports two resonant modes within its passband. For example, a TE-TM dual-mode resonator supports both TE and TM modes within its passband; a HE dual-mode resonator supports both degenerate HE modes within its passband.

[0041] A multimode resonator is a resonator capable of simultaneously generating two or more stable oscillation signals at different frequencies. A multimode resonator can support multiple resonance modes within its passband. Multimode resonators can be three-mode resonators, four-mode resonators, etc. For example, the HE-TE three-mode resonator supports three resonance modes—TE mode and HE degenerate mode—within its passband; the HE-TM three-mode resonator supports three resonance modes—TM mode and HE degenerate mode—within its passband; and the HE-TE-TM four-mode resonator supports four resonance modes—TE mode, TM mode, and HE degenerate mode—within its passband.

[0042] A dielectric cavity resonator possesses at least two resonance modes: TE mode and TM mode. That is, within its passband, the dielectric cavity resonator can support at least two resonance modes: TE mode and TM mode. The dielectric cavity resonator can be a dual-mode resonator or a multi-mode resonator. When the dielectric cavity resonator is a dual-mode resonator, it is a TE-TM dual-mode resonator; when the dielectric cavity resonator is a multi-mode resonator, it possesses TE mode, TM mode, and other resonance modes.

[0043] In some cases, the filter includes the aforementioned dielectric cavity resonator, which has at least two resonance modes: TE mode and TM mode. In this situation, how to couple the TE and TM modes of the dielectric cavity resonator becomes a problem that needs to be solved in the industry.

[0044] The embodiments provided in this application will solve the above problems.

[0045] The specific implementation of this application will be described in detail below with reference to specific embodiments:

[0046] Please refer to Figures 1, 2, 3, and 4. Some embodiments of this application provide a filter, including a first resonator 11. The first resonator 11 has at least two resonant modes: TE mode and TM mode. The first resonator 11 includes a resonator housing 111 and a dielectric resonator 112 disposed within the resonator housing 111. The dielectric resonator 112 is connected to a first wall 1111 of the resonator housing 111. The filter also includes a first coupling structure 20 disposed within the resonator housing 111. The first coupling structure 20 includes a first coupling portion 21 parallel to and spaced from the first wall 1111, and a second coupling portion 22 connected between one end of the first coupling portion 21 and the first wall 1111. The first coupling structure 20 is used to couple the TE mode and TM mode of the first resonator 11.

[0047] It should be noted that the filter has at least one resonator 10, and the at least one resonator 10 is a first resonator 11. The first resonator 11 is a dielectric cavity resonator with at least two resonance modes: TE mode and TM mode. It can be understood that the first resonator 11 has at least two resonance modes: TE mode and TM mode, that is, the first resonator 11 can support at least two resonance modes, TE mode and TM mode, within its passband range.

[0048] The resonator housing 111 has a resonant cavity 1112 inside. The resonant cavity 1112 can be, but is not limited to, a rectangular resonant cavity, a square resonant cavity, a polygonal cylindrical resonant cavity, a cylindrical resonant cavity, etc. The resonant cavity 1112 can accommodate a dielectric resonator 112. Optionally, the dielectric resonator 112 can be centrally arranged within the resonant cavity 1112. The resonator housing 111 can provide shielding to prevent signal leakage.

[0049] One of the walls of the resonator housing 111 is the first wall 1111. In practical applications, the first wall 1111 of the resonator housing 111 can be the wall located on the lower side, or it can be any wall located on the upper side, left side, right side, front side, or rear side. In addition, the shape, size, material, etc. of the resonator housing 111 can be flexibly set as needed.

[0050] The dielectric resonator 112 is a resonator 14 made of dielectric material. The dielectric resonator 112 can be a ceramic dielectric resonator or a dielectric resonator made of other materials. One end of the dielectric resonator 112 along its axial direction is connected to the first wall 1111. The dielectric resonator 112 can be directly connected and fixed to the first wall 1111 by, but not limited to, welding, bonding, riveting, pressing, plugging, screw fastening, threaded connection, snap-fitting, etc., or it can be indirectly connected and fixed to the first wall 1111 by other structures connected to it (such as the base 80, ceramic base, coupling rib, etc.). The dielectric resonator 112 can be, but not limited to, columnar, block-shaped, rod-shaped, etc. The cross-sectional shape of the dielectric resonator 112 perpendicular to its axial direction can be, but not limited to, circular, rectangular, square, polygonal, petal-shaped, cross-shaped, etc. The cross-sectional shape of the dielectric resonator 112 parallel to its axial direction can also be, but not limited to, circular, rectangular, square, polygonal, petal-shaped, cross-shaped, etc. A central hole may or may not be provided at the central axis of the dielectric resonator 112.

[0051] As shown in Figure 1, in some embodiments, the filter may be configured with a tuning structure 90 to adjust the resonant frequency of the first resonator 11 via the tuning structure 90.

[0052] It should also be noted that, in order to couple the TE mode and TM mode of the first resonator 11, this embodiment provides at least one first coupling structure 20 within the resonant cavity 1112 of the resonator housing 111. The first coupling structure 20 is a metal component, or it is a non-metallic component with a metal layer on its surface. The first coupling structure 20 is located close to the first wall 1111, and its specific location is not limited for the time being.

[0053] The first coupling structure 20 includes a first coupling portion 21 and a second coupling portion 22. The first coupling portion 21 is arranged parallel to and spaced apart from the first wall 1111, that is, the first coupling portion 21 is located in a plane parallel to the first wall 1111 and is suspended relative to the first wall 1111 (i.e., the side of the first coupling portion 21 facing the first wall 1111 is spaced apart from the first wall 1111). When the first coupling portion 21 is parallel to and spaced apart from the first wall 1111, the first coupling portion 21 can extend in a straight line, bend, or curve (e.g., extend in an arc shape). The shape of the first coupling portion 21 can be plate-shaped, column-shaped, sheet-shaped, strip-shaped, etc. The cross-sectional shape of the first coupling portion 21 perpendicular to its extension direction can be rectangular, square, circular, triangular, trapezoidal, polygonal, irregular, or other shapes. As shown in Figures 5 and 6, since the electric field of the TE mode is distributed in a horizontal (i.e., parallel to the orientation of the first wall 1111) ring shape and the magnetic field is distributed in a vertical (i.e., perpendicular to the orientation of the first wall 1111) ring shape, the electric field of the TE mode can be coupled to the first coupling part 21 which is parallel and spaced apart from the first wall 1111 (it can also be understood that the first coupling part 21 cuts the magnetic field of the TE mode and generates current), so that the current direction of the first coupling part 21 is the same as the electric field direction and the current direction of the TE mode.

[0054] One end of the second coupling part 22 is integrally or separately connected to one end of the first coupling part 21, and the other end of the second coupling part 22 is integrally or separately connected to the first wall 1111. The second coupling part 22 can be extended in a straight line, bend, or curve. As shown in Figures 7 and 8, since the magnetic field of the TM mode is distributed in a horizontal ring and the electric field is distributed in a vertical ring, the electric field of the TM mode diverges away from the first wall 1111, and the current of the TM mode diverges towards the side closer to the first wall 1111. The current of the TM mode is stronger in the region close to the first wall 1111. Therefore, the second coupling part 22 connected to the first wall 1111 can directly obtain the current of the TM mode from the first wall 1111, thereby making the current on the second coupling part 22 stronger.

[0055] Based on this, and based on the connection between the second coupling part 22 and the first coupling part 21, the current of the TE mode on the first coupling part 21 can be conducted to the second coupling part 22, so that the current of the TE mode and the current of the TM mode can flow in the same direction on the second coupling part 22, so that the TE mode and the TM mode can be positively coupled on the second coupling part 22, or the current of the TE mode and the current of the TM mode can flow in opposite directions on the second coupling part 22, so that the TE mode and the TM mode can be negatively coupled on the second coupling part 22. Thus, the coupling of the TE mode and the TM mode of the first resonator 11 can be realized based on the first coupling structure 20.

[0056] Based on reverse thinking, it can also be understood as follows: based on the connection between the second coupling part 22 and the first coupling part 21, the current of the TM mode on the second coupling part 22 can be conducted to the first coupling part 21, so that the current of the TE mode and the current of the TM mode can flow in the same direction on the first coupling part 21, so that the TE mode and the TM mode can be positively coupled on the first coupling part 21, or the current of the TE mode and the current of the TM mode can flow in opposite directions on the first coupling part 21, so that the TE mode and the TM mode can be negatively coupled on the first coupling part 21. Thus, the coupling of the TE mode and the TM mode of the first resonator 11 can be realized based on the first coupling structure 20.

[0057] Therefore, the current in the TE mode and the current in the TM mode can flow simultaneously in the same direction or simultaneously in opposite directions on the first coupling structure 20, thereby enabling the TE mode and the TM mode to couple with each other on the first coupling structure 20.

[0058] In summary, the filter provided in this application embodiment has a first coupling structure 20 disposed within a first resonator 11 having at least two resonant modes, TE mode and TM mode, so that the TE mode and TM mode of the first resonator 11 are coupled through the first coupling structure 20. Specifically, the first coupling structure 20 can couple the electric field of the TE mode to the first coupling part 21, which is parallel and spaced apart from the first wall 1111, so that the current direction of the first coupling part 21 is the same as the electric field direction and the current direction of the TE mode; the first coupling structure 20 can also directly conduct the current of the TM mode from the first wall 1111 through a second coupling part 22 connected between one end of the first coupling part 21 and the first wall 1111; based on the connection between the second coupling part 22 and the first coupling part 21, and based on the current flow, the current of the TE mode and the current of the TM mode can flow in the same direction or in opposite directions simultaneously on the first coupling structure 20, so that the TE mode and the TM mode can be coupled to each other on the first coupling structure 20. Thus, the filter can achieve coupling of the TE mode and TM mode of the first resonator 11 through the simplified and optimized first coupling structure 20, and the coupling effect is better. This can optimize the structure and performance of the filter and facilitate the simulation design of the filter.

[0059] Furthermore, since the second coupling part 22 serves to conduct current, it does not need to bear the role of coupling the TM electric field or cutting the TM mode magnetic field. Therefore, the shape and size of the second coupling part 22 do not need to be specifically designed. The shape and size of the second coupling part 22 have a high degree of design freedom and fewer design restrictions. In the filter design process, the second coupling part 22 can be designed flexibly and freely according to the internal situation of the filter and the actual processing situation of the filter, which reduces the design difficulty and processing difficulty of the second coupling part 22 and reduces the processing and manufacturing cost of the filter.

[0060] Please refer to Figures 2, 3, and 4. In some embodiments of this application, the first coupling structure 20 is disposed between the dielectric resonator 112 and the first wall 1111; along the axial direction of the dielectric resonator 112, at least a portion of the projection of the first coupling portion 21 and at least a portion of the projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112.

[0061] It should be noted that the first coupling structure 20 is located close to the first wall 1111, specifically between the dielectric resonator 112 and the first wall 1111.

[0062] As shown in Figure 3, in some embodiments, along the axial direction of the dielectric resonator 112, the entire projection of the first coupling portion 21 and the entire projection of the second coupling portion 22 both fall within the projection of the dielectric resonator 112.

[0063] In other embodiments, along the axial direction of the dielectric resonator 112, the entire projection of the first coupling portion 21 and a portion of the projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112; or, a portion of the projection of the first coupling portion 21 and the entire projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112; or, a portion of the projection of the first coupling portion 21 and a portion of the projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112.

[0064] Since the field strength within the projection of the dielectric resonator 112 is relatively strong, by adopting the above scheme, at least a portion of the projection of the first coupling part 21 can fall within the projection of the dielectric resonator 112, so that the first coupling part 21 can couple to a stronger TE mode electric field through the portion falling within the projection of the dielectric resonator 112, thereby generating a stronger TE mode current; at least a portion of the projection of the second coupling part 22 can fall within the projection of the dielectric resonator 112, so that the second coupling part 22 can directly conduct to obtain a stronger TM mode current from the first wall 1111 through the portion falling within the projection of the dielectric resonator 112. Based on this, the coupling effect of the first coupling part 21 on the TE mode electric field can be enhanced, the intensity of the TE mode current generated by the first coupling part 21 can be enhanced, and the intensity of the TM mode current conducted on the second coupling part 22 can be enhanced. This can optimize the coupling effect of the TE mode and TM mode of the first resonator 11 on the first coupling structure 20, optimize the performance of the filter, and basically avoid the failure of the TE mode and TM mode to couple due to the inability of the first coupling part 21 and / or the second coupling part 22 to have sufficient current.

[0065] Please refer to Figures 3 and 9. In some embodiments of this application, the first coupling structure 20 changes the coupling polarity between the TE mode and the TM mode of the first resonator 11 by placing the second coupling part 22 at one end of the first coupling part 21 in a counterclockwise direction or placing the second coupling part 22 at one end of the first coupling part 21 in a clockwise direction.

[0066] It should be noted that "counterclockwise" and "clockwise" are relative concepts, and can be determined (but not limited to) from the perspective of looking down at the first wall 1111.

[0067] In the first coupling structure 20 shown in Figure 3, the second coupling part 22 is located at one end of the first coupling part 21 in a counterclockwise direction, that is, the second coupling part 22 and the first coupling part 21 are arranged sequentially in a clockwise direction. In this case, assuming that the current direction of the TE mode on the first coupling part 21 is clockwise, then based on the fact that "the second coupling part 22 and the first coupling part 21 are arranged sequentially in a clockwise direction", the current direction of the TE mode on the second coupling part 22 will correspond to "the direction away from the first wall 1111" (that is, the current of the TE mode will flow from bottom to top on the second coupling part 22).

[0068] Compared to the first coupling structure 20 shown in Figure 3, the second coupling part 22 of the first coupling structure 20 shown in Figure 9 is modified to be located at one end of the first coupling part 21 in a clockwise direction, that is, the second coupling part 22 and the first coupling part 21 are arranged in a counterclockwise direction. In this case, assuming that the current direction of the TE mode on the first coupling part 21 is still clockwise, based on the fact that "the second coupling part 22 and the first coupling part 21 are arranged in a counterclockwise direction", the current direction of the TE mode on the second coupling part 22 will change to "the direction closer to the first wall 1111" (that is, the current of the TE mode will flow from top to bottom on the second coupling part 22).

[0069] That is, by changing the second coupling part 22 from one end of the first coupling part 21 in the counterclockwise direction to one end of the first coupling part 21 in the clockwise direction, or changing the second coupling part 22 from one end of the first coupling part 21 in the clockwise direction to one end of the first coupling part 21 in the counterclockwise direction, the current direction of the TE mode on the second coupling part 22 can be reversed. Based on this, while keeping the current direction of the TM mode on the second coupling part 22 unchanged, the coupling polarity between the TE mode and the TM mode of the first resonator 11 can be reversed.

[0070] Based on reverse thinking: In the first coupling structure 20 shown in Figure 3, the second coupling part 22 is located at one end of the first coupling part 21 in a counterclockwise direction, that is, the second coupling part 22 and the first coupling part 21 are arranged sequentially in a clockwise direction. In this case, assuming that the current direction of the TM mode on the second coupling part 22 is from bottom to top, then based on the fact that "the second coupling part 22 and the first coupling part 21 are arranged sequentially in a clockwise direction", the current direction of the TM mode on the first coupling part 21 will be correspondingly clockwise.

[0071] Compared to the first coupling structure 20 shown in Figure 3, the second coupling part 22 of the first coupling structure 20 shown in Figure 9 is modified to be located at one end of the first coupling part 21 in a clockwise direction, that is, the second coupling part 22 and the first coupling part 21 are arranged in a counterclockwise direction. In this case, assuming that the current direction of the TM mode on the second coupling part 22 is still from bottom to top, then based on the fact that "the second coupling part 22 and the first coupling part 21 are arranged in a counterclockwise direction", the current direction of the TM mode will change to a counterclockwise direction on the first coupling part 21.

[0072] That is, by changing the second coupling part 22 from one end of the first coupling part 21 in the counterclockwise direction to one end of the first coupling part 21 in the clockwise direction, or changing the second coupling part 22 from one end of the first coupling part 21 in the clockwise direction to one end of the first coupling part 21 in the counterclockwise direction, the current direction of the TM mode on the first coupling part 21 can be reversed. Based on this, while the current direction of the TE mode on the first coupling part 21 remains unchanged, the coupling polarity between the TE mode and the TM mode of the first resonator 11 can be reversed.

[0073] It can be understood that if the current direction of the TE mode and the current direction of the TM mode are the same on the second coupling part 22, then the current direction of the TE mode and the current direction of the TM mode are also the same on the first coupling part 21; if the current direction of the TE mode and the current direction of the TM mode are opposite on the second coupling part 22, then the current direction of the TE mode and the current direction of the TM mode are also opposite on the first coupling part 21.

[0074] In this context, the polarity reversal of coupling is the reversal of positive and negative coupling, and the reversal between the coupling properties of inductive and capacitive coupling, not the reversal between the coupling relationships of inductive and capacitive coupling; the coupling relationship may remain unchanged. If the current direction of the TE mode and the current direction of the TM mode are the same on the first coupling structure 20, then the TE mode and the TM mode can form positive coupling on the first coupling structure 20. Conversely, if the current direction of the TE mode and the current direction of the TM mode are opposite on the first coupling structure 20, then the TE mode and the TM mode can form negative coupling on the first coupling structure 20.

[0075] By adopting the above scheme, the first coupling structure 20 can reverse the current direction of the TE mode on the second coupling part 22 and the current direction of the TM mode on the first coupling part 21 by changing the second coupling part 22 from one end of the first coupling part 21 in the counterclockwise direction to one end of the first coupling part 21 in the clockwise direction, or from one end of the first coupling part 21 in the clockwise direction to one end of the first coupling part 21 in the counterclockwise direction. Since the current direction of the TM mode on the second coupling part 22 and the current direction of the TE mode on the first coupling part 21 remain unchanged, the current direction of the TE mode on the second coupling part 22 and the current direction of the TM mode can be switched between the same direction and opposite direction, and the current direction of the TE mode on the first coupling part 21 can be switched between the same direction and opposite direction. In turn, the current direction of the TE mode on the first coupling structure 20 and the current direction of the TM mode can be switched between the same direction and opposite direction, and the coupling polarity between the TE mode and the TM mode of the first resonator 11 can be reversed. Therefore, the coupling polarity between the TE mode and TM mode of the first resonator 11 can be easily changed as needed, the performance of the filter can be optimized, and the simulation design of the filter can be facilitated.

[0076] Please refer to Figures 2, 3, and 4. In some embodiments of this application, the first coupling portion 21 extends circumferentially along the dielectric resonator 112. It should be noted that the first coupling portion 21 extends in an arc shape along the circumferential direction of the dielectric resonator 112.

[0077] Since the electric field of the TE mode is distributed in a horizontal ring shape, by adopting the above-described scheme, the coupling amount between the first coupling part 21 and the TE mode can be increased by extending the first coupling part 21 in an arc shape along the circumference of the dielectric resonator 112. This allows the first coupling part 21 to have a larger coupling amount with the same electric field distribution as the TE mode, thereby generating more and stronger TE mode current. Therefore, the extension path and layout of the first coupling part 21 can be optimized, enhancing the coupling effect of the first coupling part 21 on the TE mode. This optimizes the coupling effect of the TE mode and TM mode of the first resonator 11 on the first coupling structure 20, improving the filter performance and essentially preventing the TE mode and TM mode from failing to couple due to insufficient current in the first coupling part 21.

[0078] This embodiment is particularly suitable for use in conjunction with the embodiment in which "the first coupling structure 20 is disposed between the dielectric resonator 112 and the first wall 1111; along the axial direction of the dielectric resonator 112, at least a portion of the projection of the first coupling portion 21 and at least a portion of the projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112". This arrangement allows for better coupling of the TE mode by the first coupling portion 21, significantly optimizing the coupling effect of the TE and TM modes of the first resonator 11 on the first coupling structure 20, and essentially avoiding the inability of the TE and TM modes to couple due to insufficient current in the first coupling portion 21.

[0079] Of course, in other embodiments, when the first coupling portion 21 is parallel and spaced apart from the first wall 1111, the first coupling portion 21 may be extended in a straight line, or it may be extended in a bent direction, or it may be extended in a curve.

[0080] Please refer to Figures 2, 3, and 4. In some embodiments of this application, the second coupling portion 22 extends along the axial direction of the dielectric resonator 112. It should be noted that the second coupling portion 22 extends in a straight strip shape along the axial direction of the dielectric resonator 112.

[0081] By adopting the above-described scheme, and by extending the second coupling part 22 along the axial direction of the dielectric resonator 112, the structural design and extension path of the second coupling part 22 can be effectively simplified and optimized, facilitating its processing, forming, and connection. Based on this, the processing convenience, structural strength, and assembly convenience of the second coupling part 22 and the first coupling structure 20 can be improved. Furthermore, it helps to reduce the space occupied by the second coupling part 22 and the first coupling structure 20 within the first resonator 11, facilitating the layout of other structures and components within the first resonator 11, and promoting the miniaturization of the first resonator 11 and the filter.

[0082] Of course, in other embodiments, when the second coupling part 22 is connected between one end of the first coupling part 21 and the first wall 1111, the second coupling part 22 can be extended in a straight line, or it can be extended in a bent direction, or it can be extended in a curve.

[0083] Please refer to Figures 2, 3, and 4. In some embodiments of this application, the area of ​​the side of the first coupling portion 21 facing the dielectric resonator 112 is greater than or equal to the area of ​​the side of the first coupling portion 21 facing the first wall 1111. That is, compared to the area of ​​the side of the first coupling portion 21 facing the first wall 1111, the area of ​​the side of the first coupling portion 21 facing the dielectric resonator 112 is equal to or larger.

[0084] By adopting the above scheme, and by ensuring that the area of ​​the side of the first coupling part 21 facing the dielectric resonator 112 is not less than the area of ​​the side of the first coupling part 21 facing the first wall 1111, the area of ​​the side of the first coupling part 21 facing the dielectric resonator 112 can be larger (or even the largest) among all the sides of the first coupling part 21. Based on this, the coupling amount between the first coupling part 21 and the TE mode can be increased, allowing the first coupling part 21 to have a larger coupling area with the TE mode electric field through its side facing the dielectric resonator 112, thereby generating more and stronger TE mode current. Thus, the structural design of the first coupling part 21 can be optimized, the coupling effect of the first coupling part 21 on the TE mode can be enhanced, thereby optimizing the coupling effect of the TE mode and TM mode of the first resonator 11 on the first coupling structure 20, optimizing the performance of the filter, and basically avoiding the inability of the TE mode and TM mode to couple due to insufficient current strength on the first coupling part 21.

[0085] Please refer to Figures 2, 3, and 4. In some embodiments of this application, the first coupling structure 20 includes a third coupling portion 23 connected to the end of the first coupling portion 21 away from the second coupling portion 22. The end of the third coupling portion 23 away from the first coupling portion 21 extends beyond the outer peripheral surface of the dielectric resonator 112 and is connected to the resonator housing 111.

[0086] It should be noted that if the first coupling structure 20 is based solely on the first coupling portion 21 and the second coupling portion 22, a floating arm will be formed. The floating arm will generate resonances with frequencies outside the passband but close to the passband range, which may affect the out-of-band suppression performance. To address this, a third coupling portion 23 can be added to the end of the first coupling portion 21 that is away from the second coupling portion 22.

[0087] One end of the third coupling portion 23 is integrally or separately connected to the end of the first coupling portion 21 away from the second coupling portion 22, and the other end of the third coupling portion 23 extends beyond the outer peripheral surface of the dielectric resonator 112 and is grounded to the resonator housing 111. The third coupling portion 23 and the resonator housing 111 can be integrally connected or separately connected. The third coupling portion 23 is not limited to being connected to the top wall, side wall, first wall 1111, etc. of the resonator housing 111 to achieve a grounded connection to the resonator housing 111. The third coupling portion 23 can play a balancing role to prevent the first coupling portion 21 and the second coupling portion 22 from forming a floating arm and to suppress the resonance of the first coupling portion 21 and the second coupling portion 22.

[0088] The end of the third coupling part 23 that is away from the first coupling part 21 needs to extend beyond the outer peripheral surface of the dielectric resonator 112 before being grounded. It cannot directly extend from the end of the first coupling part 21 away from the second coupling part 22 toward the first wall 1111 and be grounded.

[0089] If the third coupling part 23 extends directly from the end of the first coupling part 21 away from the second coupling part 22 towards the first wall 1111 and is grounded, the structure and function of the third coupling part 23 will be similar to those of the second coupling part 22. This will allow the third coupling part 23 to also conduct TM mode current, and the direction of the TM mode current on the third coupling part 23 will be the same as the direction of the TM mode current on the second coupling part 22. Consequently, the TM mode current on the third coupling part 23 and the TM mode current on the second coupling part 22 will cancel each other out when conducted to the first coupling part 21. It can be understood that when the TM mode current intensities conducted by the second coupling part 22 and the third coupling part 23 are the same, they will completely cancel each other out. When the TM mode current intensities conducted by the second coupling part 22 and the third coupling part 23 are different, the TM mode current on the first coupling structure 20 will not completely cancel out, but it will be weakened. Therefore, if the third coupling part 23 extends directly from the end of the first coupling part 21 away from the second coupling part 22 to the first wall 1111 and is grounded, the first coupling structure 20 will not have TM mode current or will only have a small amount of TM mode current. This will result in the first coupling structure 20 being unable to couple TE mode and TM mode, or even if the first coupling structure 20 can couple TE mode and TM mode, the coupling effect will be poor, thus causing the coupling effect of the first coupling structure 20 on TE mode and TM mode to deteriorate or even fail.

[0090] Therefore, the end of the third coupling part 23 away from the first coupling part 21 needs to extend beyond the outer peripheral surface of the dielectric resonator 112 before being grounded. Since the electric field strength in the projection of the dielectric resonator 112 along its axial direction is relatively strong, the current of the TM mode is relatively concentrated in the projection of the dielectric resonator 112 along its axial direction. Therefore, by making the end of the third coupling part 23 away from the first coupling part 21 extend beyond the outer peripheral surface of the dielectric resonator 112 before being grounded, the current intensity and current amount of the TM mode conducted by it can be minimized, or even avoided as much as possible. Moreover, the further the end of the third coupling part 23 away from the first coupling part 21 is from the dielectric resonator 112, the less TM mode current is conducted by the third coupling part 23, or even no TM mode current is conducted. This makes the influence of the third coupling part 23 on the second coupling part 22 smaller, and makes the effect of the first coupling structure 20 better.

[0091] The third coupling part 23 can extend in any direction, and it can extend in a straight line, bend, or curve.

[0092] By adopting the above scheme, in the first resonator 11, the first coupling structure 20 can be further improved by adding a third coupling part 23 at the end of the first coupling part 21 away from the second coupling part 22, and making the end of the third coupling part 23 away from the first coupling part 21 extend beyond the outer peripheral surface of the dielectric resonator 112 before being grounded. This allows the third coupling part 23 to play a balancing role, thereby preventing the first coupling part 21 and the second coupling part 22 from forming a floating arm. This suppresses the resonance generated by the first coupling part 21 and the second coupling part 22, which occurs at a frequency outside the passband but near the passband. Based on this, the structure and effectiveness of the first coupling structure 20 can be optimized, the influence of the first coupling structure 20 on the resonance of the dielectric resonator 112 can be reduced, and the out-of-band suppression performance of the first resonator 11 and the filter can be optimized.

[0093] This embodiment is particularly suitable for use in conjunction with the embodiment in which "the first coupling structure 20 is disposed between the dielectric resonator 112 and the first wall 1111; along the axial direction of the dielectric resonator 112, at least a portion of the projection of the first coupling portion 21 and at least a portion of the projection of the second coupling portion 22 fall within the projection of the dielectric resonator 112". This arrangement enhances the coupling effect of the first coupling portion 21 on the TE mode electric field, strengthens the intensity of the TE mode current generated by the first coupling portion 21, strengthens the intensity of the TM mode current conducted on the second coupling portion 22, and minimizes (or even avoids) the intensity and amount of the TM mode current conducted by the third coupling portion 23. It also suppresses the resonance generated by the first coupling portion 21 and the second coupling portion 22 at frequencies outside but near the passband, thereby making the first coupling structure 20 more effective and superior.

[0094] Of course, in other embodiments, the first coupling structure 20 may only include the first coupling portion 21 and the second coupling portion 22, without the third coupling portion 23. The end of the first coupling portion 21 away from the second coupling portion 22 is suspended and not grounded (if the end of the first coupling portion 21 away from the second coupling portion 22 is grounded through a structure similar to the second coupling portion 22, this structure will cancel the coupling effect of the second coupling portion 22 on the TM mode). In this case, the suspended arm formed by the first coupling structure 20 will generate resonance with a frequency near the passband range but still outside the passband range. This situation is suitable for the first resonator 11 and filter with low requirements for out-of-band suppression performance.

[0095] Please refer to Figures 3 and 9. In some embodiments of this application, in the same first resonator 11, there are multiple first coupling structures 20. The second coupling part 22 of each first coupling structure 20 is disposed at one end of the first coupling part 21 in the counterclockwise direction (as shown in Figure 3), or the second coupling part 22 of each first coupling structure 20 is disposed at one end of the first coupling part 21 in the clockwise direction (as shown in Figure 9).

[0096] It should be noted that the filter can be provided with multiple first coupling structures 20 as needed within the first resonator 11. In the same first resonator 11, the specific construction (which may include only the first coupling part 21 and the second coupling part 22, or may include the first coupling part 21, the second coupling part 22 and the third coupling part 23), size, shape, etc. of the multiple first coupling structures 20 can be the same or different.

[0097] In each of the first coupling structures 20 located within the same first resonator 11, the second coupling portion 22 of each first coupling structure 20 is uniformly located at one end of its first coupling portion 21 in a counterclockwise direction (as shown in Figure 3), or the second coupling portion 22 of each first coupling structure 20 is uniformly located at one end of its first coupling portion 21 in a clockwise direction (as shown in Figure 9). Based on this, in the same first resonator 11, the current direction of the TM mode of each first coupling structure 20 is the same, and the current direction of the TE mode of each first coupling structure 20 is the same. This allows each first coupling structure 20 to couple the TE mode and TM mode of the first resonator 11 to each other with the same coupling polarity (i.e., each first coupling structure 20 couples the TE mode and TM mode positively, or each first coupling structure 20 couples the TE mode and TM mode negatively). This allows the effects of each first coupling structure 20 (i.e., the effect of "coupling the TE mode and TM mode of the first resonator 11") to be superimposed rather than canceled out.

[0098] It should be noted that in each of the first coupling structures 20 within the same first resonator 11, the TE mode current direction on the first coupling part 21 of each first coupling structure 20 is the same, and the TM mode current direction on the second coupling part 22 of each first coupling structure 20 is the same. If the second coupling part 22 of one of the first coupling structures 20 is located at one end of its first coupling part 21 in a counterclockwise direction, and the second coupling part 22 of the other first coupling structure 20 is located at one end of its first coupling part 21 in a clockwise direction, then the TM mode current direction on the first coupling part 21 of the two first coupling structures 20 will be opposite, and the TE mode current direction on the second coupling part 22 of the two first coupling structures 20 will be opposite. This will cause the coupling polarity of the two first coupling structures 20 to be opposite, which will cause the two first coupling structures 20 to cancel each other out. As a result, the TE mode and TM mode of the first resonator 11 cannot be coupled or the coupling effect is poor, and the structure of the filter becomes redundant and complex. Of course, theoretically, within the same first resonator 11, as long as the effect of at least one of the multiple first coupling structures 20 is not canceled, the TE mode and TM mode of the first resonator 11 can be coupled through the first coupling structure 20 whose effect is not canceled, but the structure is relatively redundant.

[0099] It should also be noted that the specific positions of each first coupling structure 20 in the same first resonator 11 can be flexibly arranged. For example, multiple first coupling structures 20 can be uniformly distributed on one side of the dielectric resonator 112, or distributed on both sides of the dielectric resonator 112, or arranged in equal-angle circles around the central axis of the dielectric resonator 112, or arranged in unequal-angle circles around the central axis of the dielectric resonator 112, and so on.

[0100] For example, as shown in Figure 3, in some embodiments, two first coupling structures 20 are provided in the same first resonator 11 as needed, and the two first coupling structures 20 are distributed on opposite sides of the dielectric resonator 112. This arrangement not only enhances the coupling of the TE and TM modes of the first resonator 11 via the two first coupling structures 20, but also optimizes the number and location of the first coupling structures 20, freeing up space for other coupling structures. This facilitates planning, design, and coupling construction, and improves the performance and design flexibility of the filter.

[0101] By adopting the above scheme, the filter can be configured with multiple first coupling structures 20 as needed within the first resonator 11. The second coupling portion 22 of each first coupling structure 20 is uniformly located at one end of its first coupling portion 21 in a counter-clockwise direction, or uniformly located at one end of its first coupling portion 21 in a clockwise direction. This ensures that the multiple first coupling structures 20 can couple the TE and TM modes of the first resonator 11, and that the effects of the multiple first coupling structures 20 are superimposed without canceling each other out. Therefore, the coupling of the TE and TM modes of the first resonator 11 can be enhanced through the multiple first coupling structures 20, optimizing the coupling strength and effect, thereby improving the filter's performance.

[0102] Of course, in other embodiments, the filter may be provided with a first coupling structure 20 as needed within the first resonator 11.

[0103] Please refer to Figures 3 and 9. In some embodiments of this application, each first coupling structure 20 is replicated by rotating around the central axis of the dielectric resonator 112.

[0104] It should be noted that the meaning of rotational replication is: in the same first resonator 11, each first coupling structure 20 can rotate around the central axis of the dielectric resonator 112 and coincide with other first coupling structures 20, that is, each first coupling structure 20 is a copy obtained by rotating other first coupling structures 20 around the central axis of the dielectric resonator 112 by a certain angle.

[0105] By adopting the above scheme, when multiple first coupling structures 20 are provided as needed within the first resonator 11, the specific structure, size, and shape of each first coupling structure 20 within the first resonator 11 can be set identically. Based on this, the structural design of each first coupling structure 20 within the same first resonator 11 can be standardized and unified, thereby improving the molding convenience of each first coupling structure 20.

[0106] Please refer to Figures 2 and 3. In some embodiments of this application, the filter includes at least two resonators 10, and a coupling window 30 connecting the interior of each other is provided between two adjacent resonators 10.

[0107] It should be noted that the filter includes at least two resonators 10, and each resonator 10 is coupled as needed. The structure, type, and size of each resonator 10 can be the same or different. The type of resonator 10 can be a single-mode resonator, such as a TE single-mode resonator, a TM single-mode resonator, a TEM single-mode resonator (e.g., a metal coaxial resonator), etc.; the type of resonator 10 can also be a dual-mode resonator or a multi-mode resonator, such as a TE-TM dual-mode resonator, a TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, etc.

[0108] It can be understood that among the resonators 10 of the filter, at least one resonator 10 is the first resonator 11.

[0109] In the case where the resonator 10 is a dielectric cavity resonator having at least two resonance modes, TE mode and TM mode, the dielectric cavity resonator may be the first resonator 11 provided in any of the above embodiments of this application, or it may not be the first resonator 11 provided in any of the above embodiments of this application. When the dielectric cavity resonator is the first resonator 11 provided in any of the above embodiments of this application, the dielectric cavity resonator may, as needed, have the first coupling structure 20 mentioned above, so that its TE mode and TM mode are coupled via the first coupling structure 20; the dielectric cavity resonator may also not have the first coupling structure 20 mentioned above, so that its TE mode and TM mode are not coupled, or its TE mode and TM mode may be coupled via other coupling structures.

[0110] It should also be noted that a coupling window 30 is provided between two adjacent resonators 10 to connect their internal spaces. Two adjacent resonators 10 can establish a coupling relationship based on the coupling window 30. In particular, resonant modes of two adjacent resonators 10 with similar electromagnetic field distributions can be coupled to each other through the coupling window 30. For example, TE mode and TE mode can be coupled to each other through the coupling window 30, TM mode and TM mode can be coupled to each other through the coupling window 30, TM mode and TEM mode can be coupled to each other through the coupling window 30 (because the electromagnetic field distribution of TEM mode is similar to that of TM mode), TEM mode and TEM mode can be coupled to each other through the coupling window 30, and so on.

[0111] Specifically, when the coupling window 30 has a certain size (i.e., a relatively large size), the coupling between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10 is better and more stable through the coupling window 30. Conversely, when the coupling window 30 is small, the coupling between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10 is weaker, and may even be essentially suppressed. Based on this, the size of the coupling window 30 can be designed as needed to ensure that the coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10 reaches the required specifications.

[0112] By adopting the above scheme, coupling windows 30 connecting the interiors of adjacent resonators 10 can be set as needed between them. This allows resonant modes with similar electromagnetic field distributions of adjacent resonators 10 to couple with each other through the coupling windows 30. This facilitates the establishment of coupling relationships between adjacent resonators 10, the transfer of energy between them, and the transmission of energy along desired paths within each resonator 10. It also facilitates filter simulation design and optimizes filter performance. Furthermore, due to the simple structure of the coupling window 30, establishing coupling relationships through it simplifies and optimizes the coupling structure design between adjacent resonators 10, simplifies the filter structure, and promotes filter miniaturization, simplification, and weight reduction.

[0113] In particular, as shown in Figures 2, 3, and 10, when two adjacent resonators 10 are both first resonators 11, and the TE mode and TM mode of the first resonator 11 are coupled, by coupling the TE mode to each other through the coupling window 30, and by coupling the TM mode to each other through the coupling window 30, a main signal transmission path and a cross-coupling path can be formed between the two TM modes and the two TE modes. These two transmission paths will have a 180-degree phase difference in the filter passband, thus forming a transmission zero in the filter passband. This allows the filter to form a multi-zero scheme by combining the formed transmission zero with other zeros, effectively enhancing the out-of-band suppression and filtering effect of the filter, thereby enabling the filter to meet the high selectivity requirements.

[0114] Please refer to Figures 2, 3, and 10. In some embodiments of this application, at least one pair of adjacent resonators 10 are a second resonator 12 and a third resonator 13. The second resonator 12 has a TE mode resonance mode, and the third resonator 13 has a TM mode resonance mode or a TEM mode resonance mode. The coupling window 30 between the second resonator 12 and the third resonator 13 is a first coupling window 30a. The filter includes a second coupling structure 40 with both ends grounded. At least a portion of the second coupling structure 40 is disposed in the first coupling window 30a. The second coupling structure 40 couples the TE mode of the second resonator 12 with the TM mode or TEM mode of the third resonator 13.

[0115] It should be noted that at least one set of two adjacent resonators 10 uses a combination of the second resonator 12 and the third resonator 13. The second resonator 12 has a TE mode, meaning that the second resonator 12 can support at least the TE mode within its passband. For example, the second resonator 12 can be a TE single-mode resonator, a TE-TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The third resonator 13 has a TM mode or a TEM mode, meaning that the third resonator 13 can support at least the TM mode or the TEM mode within its passband. The third resonator 13 can be a TM single-mode resonator, a TM dual-mode resonator, a TEM single-mode resonator, a TE-TM dual-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The coupling window 30 between the second resonator 12 and the third resonator 13 is the first coupling window 30a.

[0116] The TE mode of the second resonator 12 and the TM or TEM mode of the third resonator 13 can be coupled via the second coupling structure 40. The second coupling structure 40 is a metal component, or a non-metallic component with a metal layer on its surface. Both ends of the second coupling structure 40 are grounded, making the coupling formed through the second coupling structure 40 inductive. The ends of the second coupling structure 40 can be directly connected to the housing component of the resonator 10, or indirectly connected to the housing component of the resonator 10 via other metal components (such as the base 80), thereby achieving grounding.

[0117] At least a portion of the second coupling structure 40 is disposed within the first coupling window 30a, so that the second coupling structure 40 can couple the TE mode of the second resonator 12 with the TM mode or TEM mode of the third resonator 13. The specific construction, extension path, shape, size, etc. of the second coupling structure 40 are not limited for the time being.

[0118] By adopting the above scheme, the TE mode of the second resonator 12 and the TM or TEM mode of the third resonator 13 can be coupled through the second coupling structure 40, thereby achieving coupling between the TE mode of the second resonator 12 and the TM or TEM mode of the third resonator 13. This facilitates the construction of desired coupling relationships between adjacent second resonators 12 and third resonators 13 via the second coupling structure 40; it even allows cross-coupling between the TE mode of the second resonator 12 and the TM or TEM mode of the third resonator 13 via the second coupling structure 40, enabling the generation of transmission zeros or balanced transmission zeros in the passband as needed. This facilitates filter simulation design and performance optimization.

[0119] As shown in Figures 2, 3, and 10, in one example, both the second resonator 12 and the third resonator 13 are first resonators 11. The TE and TM modes of the second resonator 12 are coupled, as are the TE and TM modes of the third resonator 13. The TM modes of the second resonator 12 and the third resonator 13 are mutually coupled, and the TE modes of the second resonator 12 and the third resonator 13 are mutually coupled. The TE mode of the second resonator 12 and the TM mode of the third resonator 13 are cross-coupled through the second coupling structure 40. Based on this, there is one main signal transmission path and two cross-coupled paths between the second resonator 12 and the third resonator 13. Thus, a CQ (Cascaded Quadruplet) structure can be formed between adjacent second resonators 12 and third resonators 13, enabling the design of a coupling structure at the CQ zero point. This allows for optimization of the filter's structure and performance, especially its out-of-band rejection performance.

[0120] Of course, in other embodiments, the second coupling structure 40 may be omitted.

[0121] Please refer to Figures 2 and 3. In some embodiments of this application, the second coupling structure 40 is disposed within the third resonator 13. The second coupling structure 40 intersects the circumferential direction of the resonator 14 of the third resonator 13 to couple the TM mode or TEM mode of the third resonator 13. One end of the second coupling structure 40 extends to the first coupling window 30a and intersects the radial direction of the resonator 14 of the second resonator 12 to couple the TE mode of the second resonator 12.

[0122] It should be noted that each resonator 10 has a resonant element 14 (the resonant element 14 of the first resonator 11 is the dielectric resonant element 112). Depending on the needs of the resonator 10, the resonant element 14 can be a metal resonant element, a ceramic dielectric resonant element, or a dielectric resonant element of other materials; the resonant element 14 can be a hollow resonant element or a solid resonant element; the resonant element 14 can have a resonant disk or not; the resonant disk can have a flange or not; the resonant element can be a coaxial cylindrical resonant element, a coaxial cylindrical resonant element, or a sheet metal plate resonant element; the cross-sectional shape of the resonant element 14 perpendicular to its axial direction can be, but is not limited to, circular, rectangular, square, polygonal, petal-shaped, cross-shaped, etc., and the cross-sectional shape of the resonant element 14 parallel to its axial direction can also be, but is not limited to, circular, rectangular, square, polygonal, petal-shaped, cross-shaped, etc.

[0123] It should also be noted that the second coupling structure 40 is located within the third resonator 13. Since the magnetic field of the TM mode is distributed in a horizontal ring and the electric field is distributed in a vertical ring (the electromagnetic field distribution of the TEM mode is similar to that of the TM mode), the second coupling structure 40 intersects the circumferential direction of the resonator 14 of the third resonator 13. This allows the second coupling structure 40 as a whole to cut the magnetic field of the TM mode (or TEM mode) of the third resonator 13, thereby coupling the TM mode (or TEM mode) of the third resonator 13. Furthermore, this results in a stronger coupling strength between the second coupling structure 40 and the TM mode (or TEM mode) of the third resonator 13.

[0124] One end of the second coupling structure 40 (the resonator 14 away from the third resonator 13) extends to the first coupling window 30a to facilitate coupling with the second resonator 12. Since the electric field of the TE mode is distributed in a horizontal ring and the magnetic field is distributed in a vertical ring, the end of the second coupling structure 40 extending to the first coupling window 30a intersects the radial direction of the resonator 14 of the second resonator 12 (in particular, the second coupling structure 40 cannot be extended along the center line L connecting the second resonator 12 and the third resonator 13). This allows the end of the second coupling structure 40 to cut the magnetic field of the TE mode of the second resonator 12 and couple the TE mode of the second resonator 12.

[0125] Since the second coupling structure 40 couples both the TM mode (or TEM mode) of the third resonator 13 and the TE mode of the second resonator 12, the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 can be mutually coupled on the second coupling structure 40.

[0126] The second coupling structure 40 can be extended in a straight line, in a bent direction, or in a curve.

[0127] By adopting the above scheme, the second coupling structure 40 as a whole can cut the magnetic field of the TM mode (or TEM mode) of the third resonator 13, thus enabling the second coupling structure 40 to couple the TM mode (or TEM mode) of the third resonator 13 with a strong coupling strength. Furthermore, the end of the second coupling structure 40 extending to the first coupling window 30a can cut the magnetic field of the TE mode of the second resonator 12, thus enabling the second coupling structure 40 to couple the TE mode of the second resonator 12. Based on this, the second coupling structure 40 can achieve a simplified and optimized structural design, allowing the TE mode of the second resonator 12 to couple with the TM mode (or TEM mode) of the third resonator 13, with a better coupling effect. Moreover, compared to other schemes, the main space occupied by the second coupling structure 40 is within the third resonator 13, and it does not occupy much space in the first coupling window 30a. This facilitates the optimization of the size of the first coupling window 30a and also allows for the placement of other coupling structures (such as the third coupling structure 60 or the fourth coupling structure 70 mentioned later) or the dielectric component 50 in the first coupling window 30a. This facilitates the design of the coupling structure between adjacent second resonators 12 and third resonators 13, facilitates the simulation design of filters, and optimizes the performance of filters.

[0128] Furthermore, since the second coupling structure 40 intersects the circumferential direction of the resonator 14 of the third resonator 13, the second coupling structure 40 can basically not occupy the circumferential space of the third resonator 13. When the third resonator 13 is the first resonator 11 and the third resonator 13 is provided with the first coupling structure 20, it can provide sufficient space for the first coupling structure 20 of the third resonator 13 (i.e., the first resonator 11). Since one end of the second coupling structure 40 (the resonator 14 away from the third resonator 13) extends to the first coupling window 30a, the second coupling structure 40 can basically not occupy the internal space of the second resonator 12. When the second resonator 12 is the first resonator 11 and the second resonator 12 is provided with the first coupling structure 20, it can provide sufficient space for the first coupling structure 20 of the second resonator 12 (i.e., the first resonator 11).

[0129] Based on the previous embodiment, please refer to Figures 2, 3 and 4. In some embodiments of this application, the end of the second coupling structure 40 near the resonator 14 of the third resonator 13 is connected to the base 80 of the third resonator 13.

[0130] It should be noted that the end of the second coupling structure 40 near the resonator 14 of the third resonator 13 (i.e., the end of the second coupling structure 40 away from the first coupling window 30a) can extend towards and approach the central axis of the resonator 14 of the third resonator 13, and connect to the base 80 of the third resonator 13. The base 80 of the third resonator 13 is used to position and mount the resonator 14, raise the position of the resonator 14, and stabilize the mounting position and state of the resonator 14. As shown in Figure 4, in some embodiments, the base 80 is arranged in a ring shape and is confined around the outer periphery of the connection end of the resonator 14.

[0131] As shown in Figure 4, in some embodiments, the end of the second coupling structure 40 is integrally connected to the base 80 of the third resonator 13. This configuration allows for convenient, quick, and reliable processing and connection of the second coupling structure 40, improving its processing convenience, structural strength, assembly convenience, and assembly efficiency, and simplifying the assembly process of the second coupling structure 40.

[0132] In other embodiments, the end portion of the second coupling structure 40 is separately connected to the base 80 of the third resonator 13. The separate connection method may be, but is not limited to, welding, bonding, riveting, pressing, plugging, screw fastening, threaded connection, snap-fitting, etc.

[0133] By adopting the above scheme, by connecting one end of the second coupling structure 40 close to the resonator 14 of the third resonator 13 to the base 80 of the third resonator 13, this end of the second coupling structure 40 can extend and approach the central axis of the resonator 14 of the third resonator 13. Based on this, the cutting amount of the magnetic field of the TM mode (or TEM mode) of the third resonator 13 by the second coupling structure 40 can be increased, and the coupling strength and coupling effect between the second coupling structure 40 and the TM mode (or TEM mode) of the third resonator 13 can be enhanced. This can optimize the coupling effect between the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 on the second coupling structure 40, and optimize the performance of the filter.

[0134] Furthermore, it facilitates the connection and fixation of the second coupling structure 40, and facilitates the stabilization of the installation position and state of the second coupling structure 40 relative to the base 80 of the third resonator 13 and the resonator 14. Based on this, it is beneficial for the rapid fixation and assembly of the second coupling structure 40, and for the second coupling structure 40 to stably and reliably perform the function of "coupling the TE mode of the second resonator 12 with the TM mode (or TEM mode) of the third resonator 13".

[0135] Of course, in other embodiments, the second coupling structure 40 can be connected and fixed to other components. For example, the second coupling structure 40 can be connected and fixed to the edge of the first coupling window 30a, or the second coupling structure 40 can be connected and fixed to the housing component of the third resonator 13, and so on. When the resonant element 14 of the third resonator 13 is a metal resonant element, the second coupling structure 40 can also be connected and fixed to the resonant element 14 of the third resonator 13.

[0136] Referring to Figure 11, in some embodiments of this application, the second coupling structure 40 includes a fourth coupling portion 41 and a fifth coupling portion 42 that are bent and connected in sequence; the fourth coupling portion 41 is disposed in the first coupling window 30a, or extends from the first coupling window 30a into the second resonator 12, and the fourth coupling portion 41 intersects the radial direction of the resonator element 14 of the second resonator 12 to couple the TE mode of the second resonator 12; the fifth coupling portion 42 is disposed in the third resonator 13 and intersects the circumferential direction of the resonator element 14 of the third resonator 13 to couple the TM mode or TEM mode of the third resonator 13.

[0137] It should be noted that the fifth coupling part 42 is located within the third resonator 13 and intersects the circumference of the resonator element 14 of the third resonator 13. Since the magnetic field of the TM mode is distributed in a horizontal ring and the electric field in a vertical ring, and since the electromagnetic field distribution of the TEM mode is similar to that of the TM mode, the fifth coupling part 42 can cut the magnetic field of the TM mode (or TEM mode) of the third resonator 13, thus coupling the TM mode (or TEM mode) of the third resonator 13. Furthermore, as the amount of cutting of the magnetic field of the TM mode (or TEM mode) of the third resonator 13 by the fifth coupling part 42 increases, the coupling strength between the fifth coupling part 42 and the TM mode (or TEM mode) of the third resonator 13 gradually increases. Therefore, the specific position, extension path, and extension direction of the fifth coupling part 42 can be designed according to the required coupling strength between the fifth coupling part 42 and the TM mode (or TEM mode) of the third resonator 13. The fifth coupling part 42 can be extended in a straight line, bent, or curved. The fifth coupling portion 42 may coincide with the center line L connecting the second resonator 12 and the third resonator 13, or it may not coincide with the center line L connecting the second resonator 12 and the third resonator 13. In some embodiments, the fifth coupling portion 42 may be arranged to extend radially along the resonator element 14 of the third resonator 13 and close to the central axis of the resonator element 14 of the third resonator 13. This arrangement can increase the amount of cutting off the magnetic field of the TM mode (or TEM mode) of the third resonator 13 by the fifth coupling portion 42, and can enhance the coupling strength between the fifth coupling portion 42 and the TM mode (or TEM mode) of the third resonator 13.

[0138] One end of the fourth coupling part 41 is integrally or separately connected to one end of the fifth coupling part 42 (the resonant element 14 away from the third resonator 13). The fourth coupling part 41 is bent relative to the fifth coupling part 42, that is, the fourth coupling part 41 and the fifth coupling part 42 are arranged at an angle. The angle between the fourth coupling part 41 and the fifth coupling part 42 can be set as needed, and the specific angle is not limited.

[0139] The fourth coupling part 41 is integrally disposed within the first coupling window 30a; or, the fourth coupling part 41 passes through the first coupling window 30a and extends into the second resonator 12. The fourth coupling part 41 intersects the radial direction of the resonant element 14 of the second resonator 12. Since the electric field of the TE mode is distributed in a horizontal ring and the magnetic field is distributed in a vertical ring, the fourth coupling part 41 can cut the magnetic field of the TE mode of the second resonator 12 and couple the TE mode of the second resonator 12. Furthermore, as the amount of cutting of the magnetic field of the TE mode of the second resonator 12 by the fourth coupling part 41 increases, the coupling strength between the fourth coupling part 41 and the TE mode of the second resonator 12 gradually increases. Therefore, the specific position, extension path, and extension direction of the fourth coupling part 41 can be designed according to the required coupling strength between the fourth coupling part 41 and the TE mode of the second resonator 12. The fourth coupling part 41 can be extended in a straight line, extended in a bent direction, or extended in a curve. In some embodiments, the fourth coupling portion 41 is perpendicular to the radial direction of the resonator 14 of the second resonator 12. This arrangement increases the amount of cutting off the TE mode magnetic field of the second resonator 12 by the fourth coupling portion 41, thereby enhancing the coupling strength between the fourth coupling portion 41 and the TE mode of the second resonator 12. In some embodiments, the fourth coupling portion 41 extends circumferentially along the second resonator 12. This arrangement also increases the amount of cutting off the TE mode magnetic field of the second resonator 12 by the fourth coupling portion 41, thereby enhancing the coupling strength between the fourth coupling portion 41 and the TE mode of the second resonator 12.

[0140] Since the fifth coupling part 42 couples the TM mode (or TEM mode) of the third resonator 13, and since the fourth coupling part 41 couples the TE mode of the second resonator 12, and based on the sequential connection of the fourth coupling part 41 and the fifth coupling part 42, the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 can be mutually coupled on the second coupling structure 40.

[0141] By adopting the above scheme, the second coupling structure 40 can cut the magnetic field of the TE mode of the second resonator 12 through the fourth coupling part 41 and couple the TE mode of the second resonator 12. It can also cut the magnetic field of the TM mode (or TEM mode) of the third resonator 13 through the fifth coupling part 42, which is bent and connected to the fourth coupling part 41, and couple the TM mode (or TEM mode) of the third resonator 13. Based on this, and based on the sequential connection relationship of the fourth coupling part 41 and the fifth coupling part 42, the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 can be mutually coupled on the second coupling structure 40. Thus, the second coupling structure 40 can achieve coupling between the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 with a modular and simplified structural design. Furthermore, compared to other solutions, it is easier to design the coupling strength of the "fourth coupling part 41 and the TE mode of the second resonator 12" and the "coupling strength of the fifth coupling part 42 and the TM mode (or TEM mode) of the third resonator 13" separately, thereby optimizing the coupling effect achieved by the second coupling structure 40 and optimizing the performance of the filter.

[0142] Furthermore, since the fifth coupling part 42 intersects the circumferential direction of the resonator 14 of the third resonator 13, the fifth coupling part 42 can basically not occupy the circumferential space of the third resonator 13. When the third resonator 13 is the first resonator 11 and the third resonator 13 is provided with a first coupling structure 20, it can provide sufficient space for the first coupling structure 20 of the third resonator 13 (i.e., the first resonator 11). Since the fourth coupling part 41 is disposed entirely in the first coupling window 30a or penetrates into the second resonator 12, the fourth coupling part 41 can basically not occupy the internal space of the second resonator 12. When the second resonator 12 is the first resonator 11 and the second resonator 12 is provided with a first coupling structure 20, it can provide sufficient space for the first coupling structure 20 of the second resonator 12 (i.e., the first resonator 11).

[0143] Please refer to Figure 12. In some embodiments of this application, the second coupling structure 40 is disposed in the first coupling window 30a and intersects the center line L connecting the second resonator 12 and the third resonator 13; along the axial direction of the resonator 14 of the third resonator 13, the second coupling structure 40 is disposed on the same side as the connection end of the resonator 14 of the third resonator 13.

[0144] It should be noted that, since the electric field of the TE mode is distributed in a horizontal ring and the magnetic field is distributed in a vertical ring, by placing the second coupling structure 40 in the first coupling window 30a and making the second coupling structure 40 intersect (for example, perpendicular to) the center line L connecting the second resonator 12 and the third resonator 13, the second coupling structure 40 can cut the magnetic field of the TE mode of the second resonator 12 to couple the TE mode of the second resonator 12.

[0145] The connection end of the resonator 14 of the third resonator 13 refers to the end of the resonator 14 of the third resonator 13 that is connected and fixed to the housing of the third resonator 13. Along the axial direction of the resonator 14 of the third resonator 13 (that is, the direction corresponding to the axial direction of the resonator 14 of the third resonator 13, which is also the height direction of the first coupling window 30a), the second coupling structure 40 is disposed on the same side as the connection end of the resonator 14 of the third resonator 13. That is, the second coupling structure 40 is disposed close to the housing wall to which the connection end of the resonator 14 of the third resonator 13 is connected and fixed. For example, if the connection end of the resonator 14 of the third resonator 13 is connected and fixed to the bottom wall of the filter housing, then the second coupling structure 40 is disposed close to the bottom wall of the filter housing; or, for example, if the connection end of the resonator 14 of the third resonator 13 is connected and fixed to the top wall of the filter housing, then the second coupling structure 40 is disposed close to the top wall of the filter housing.

[0146] Because the current of the TM mode (or TEM mode) of the third resonator 13 diverges towards the housing wall connected to the "connection end of the resonator 14 of the third resonator 13," meaning the current of the TM mode (or TEM mode) is concentrated near the housing wall connected to the "connection end of the resonator 14 of the third resonator 13," by setting the second coupling structure 40 on the same side as the connection end of the resonator 14 of the third resonator 13, the second coupling structure 40 can directly conduct the current of the TM mode (or TEM mode) from the housing wall connected to the "connection end of the resonator 14 of the third resonator 13," thereby achieving coupling of the TM mode (or TEM mode) of the third resonator 13. In this case, the amount of magnetic field cut-off between the second coupling structure 40 and the TM mode (or TEM mode) is less.

[0147] Since the second coupling structure 40 couples both the TM mode (or TEM mode) of the third resonator 13 and the TE mode of the second resonator 12, the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 can be coupled to each other on the second coupling structure 40.

[0148] The second coupling structure 40 can be extended in a straight line, in a bent direction, or in a curve.

[0149] By adopting the above scheme, the second coupling structure 40 can conduct current of the TM mode (or TEM mode) from the housing wall connected to the "connection end of the resonator 14 of the third resonator 13" in the first coupling window 30a, thereby achieving coupling of the TM mode (or TEM mode) of the third resonator 13. The second coupling structure 40 can also cut the magnetic field of the TE mode of the second resonator 12 in the first coupling window 30a, thus enabling the second coupling structure 40 to couple the TE mode of the second resonator 12. Based on this, the second coupling structure 40 can achieve a simplified and optimized structural design to couple the TE mode of the second resonator 12 with the TM mode (or TEM mode) of the third resonator 13. Furthermore, compared to other solutions, the second coupling structure 40 occupies primarily within the first coupling window 30a, essentially not occupying the internal space of the resonator 10, thus facilitating the structural design of the resonator 10 itself. When the third resonator 13 is the first resonator 11 and the third resonator 13 is correspondingly provided with the first coupling structure 20, sufficient space can be provided for the first coupling structure 20 of the third resonator 13 (i.e., the first resonator 11). Similarly, when the second resonator 12 is the first resonator 11 and the second resonator 12 is correspondingly provided with the first coupling structure 20, sufficient space can be provided for the first coupling structure 20 of the second resonator 12 (i.e., the first resonator 11). Therefore, the coupling structure design of adjacent second resonators 12 and third resonators 13 is facilitated, as is the simulation design of the filter, and the performance of the filter can be optimized. Since the second coupling structure 40 has a small cutting amount with the TM mode (or TEM mode) magnetic field, this embodiment is mainly applicable to situations requiring a small coupling amount.

[0150] Of course, in other embodiments, the second coupling structure 40 may adopt other structural designs.

[0151] Please refer to Figures 3 and 13. In some embodiments of this application, the second coupling structure 40 is mirror-flipped along the center line L connecting the second resonator 12 and the third resonator 13, so that the coupling polarity between the TE mode of the second resonator 12 and the TM mode or TEM mode of the third resonator 13 is reversed.

[0152] It should be noted that, compared with the second coupling structure 40 shown in Figure 3, the second coupling structure 40 shown in Figure 13 reverses its orientation by mirroring along the center line L connecting the second resonator 12 and the third resonator 13. This reverses the direction of the current generated by the second coupling structure 40 cutting the magnetic field, thereby reversing the coupling polarity achieved by the second coupling structure 40. That is, the coupling polarity between the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13 is reversed. Note that this polarity reversal is a reversal of positive and negative coupling, not a reversal of inductive and capacitive coupling; the coupling relationship may remain unchanged.

[0153] By adopting the above scheme, the second coupling structure 40 can be mirror-flipped along the center line L connecting the second resonator 12 and the third resonator 13, thereby reversing the direction of the current generated by the second coupling structure 40 cutting the magnetic field. This reverses the coupling polarity between the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13. This facilitates the on-demand change of the coupling polarity between the TE mode of the second resonator 12 and the TM mode (or TEM mode) of the third resonator 13, facilitates the design of coupling structures between adjacent second resonators 12 and third resonators 13, facilitates filter simulation design, and optimizes filter performance.

[0154] Please refer to Figures 2 and 3. In some embodiments of this application, the filter includes a medium 50 disposed in the coupling window 30.

[0155] It should be noted that at least one coupling window 30 is provided with a dielectric element 50. The dielectric element 50 can be made of a dielectric material with a high dielectric constant, and the material of the dielectric element 50 can be, but is not limited to, ceramic. The dielectric element 50 can be a regular structure (e.g., columnar structure, block structure, conical structure, etc.) or an irregular structure.

[0156] Since the dielectric element 50 mainly changes the propagation medium of electromagnetic waves in the coupling window 30, the dielectric element 50 can affect the coupling effect and coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10. The dielectric element 50 can affect the coupling effect and coupling strength between TE modes and TE modes, and can also affect the coupling effect and coupling strength between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode).

[0157] The dielectric element 50 primarily enhances capacitive coupling, which is equivalent to weakening inductive coupling. If two adjacent resonators 10 have resonant modes with similar electromagnetic field distributions capacitively coupled through the coupling window 30, the coupling strength of this capacitive coupling can be enhanced by placing the dielectric element 50 in the coupling window 30. For example, TE modes can capacitively couple with each other through the coupling window 30, and the capacitive coupling strength between TE modes can be enhanced through the dielectric element 50.

[0158] If two adjacent resonators 10 have resonant modes with similar electromagnetic field distributions that are inductively coupled through the coupling window 30, then by placing a dielectric element 50 in the coupling window 30, the capacitive coupling can be enhanced through the dielectric element 50, which is equivalent to weakening the inductive coupling. Specifically, if the enhancement effect of the dielectric element 50 on the capacitive coupling is weaker than the strength of the inductive coupling formed by the two resonant modes through the coupling window 30, then the two resonant modes are still inductively coupled through the coupling window 30 and the dielectric element 50, with the dielectric element 50 mainly weakening the strength of the inductive coupling between the two resonant modes. If the enhancement effect of the dielectric element 50 on the capacitive coupling is equal to the strength of the inductive coupling formed by the two resonant modes through the coupling window 30, then the capacitive coupling enhanced by the dielectric element 50 is equivalent to canceling the inductive coupling formed by the two resonant modes through the coupling window 30, making the two resonant modes essentially uncoupled through the coupling window 30 and the dielectric element 50. If the enhancement effect of the dielectric 50 on capacitive coupling is stronger than the strength of the inductive coupling formed by the two resonant modes through the coupling window 30, then the inductive coupling formed by the two resonant modes through the coupling window 30 is completely canceled out, and the inductive coupling between the two resonant modes is reversed to capacitive coupling through the dielectric 50. For example, TM mode and TM mode (or TM mode and TEM mode; or TEM mode and TEM mode) were originally inductively coupled to each other through the coupling window 30. On this basis, the capacitive coupling can be enhanced through the dielectric 50. Depending on the enhancement effect of the dielectric 50 on capacitive coupling, TM mode and TM mode (or TM mode and TEM mode; or TEM mode and TEM mode) may still be inductively coupled but the inductive coupling strength is weakened, or they may be basically uncoupled, or they may be reversed from inductive coupling to capacitive coupling.

[0159] If there is both TE-mode coupling and TM-mode coupling (or TM-mode and TEM-mode; or TEM-mode and TEM-mode) between two adjacent resonators 10, then the dielectric 50 can both enhance the coupling strength of the capacitive coupling between TE-mode and TE-mode and weaken the coupling strength of the inductive coupling between TM-mode and TM-mode (or TM-mode and TEM-mode; or TEM-mode and TEM-mode). When the enhancement effect of the dielectric 50 on capacitive coupling is weaker than or equal to the strength of the inductive coupling formed between TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode) through coupling window 30, the dielectric 50 can enhance the coupling between TE mode and TE mode and weaken the coupling between TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode). In particular, if the size of coupling window 30 is small, the dielectric 50 can cooperate with coupling window 30 to suppress inductive coupling, so that the coupling between TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode) is weaker or even basically non-coupled. When the enhancement effect of the dielectric 50 on capacitive coupling is stronger than the strength of the inductive coupling formed between TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode) through coupling window 30, the dielectric 50 can enhance the coupling between TE mode and TE mode and reverse the inductive coupling between TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode) to capacitive coupling.

[0160] It should be noted that resonant modes with dissimilar electromagnetic field distributions between two adjacent resonators 10 will not be coupled through the coupling window 30 and the dielectric 50. For example, the TE mode and the TM mode will not be coupled through the coupling window 30 and the dielectric 50, and the TE mode and the TEM mode will not be coupled through the coupling window 30 and the dielectric 50. Resonant modes with dissimilar electromagnetic field distributions need to be coupled through other coupling structures (such as the second coupling structure 40, etc.).

[0161] For example, as shown in Figures 14, 15, and 16, in a specific embodiment of the filter, the fourth resonator 15 is a TE single-mode resonator, and the fifth resonator 16 is a TE-TM dual-mode resonator. According to Figure 15, the center frequencies of the three resonant modes—the TE mode of the fourth resonator 15, the TM mode of the fifth resonator 16, and the TE mode of the fifth resonator 16—are approximately around 2.6 GHz. According to Figure 16, when a dielectric element 50 is provided in the coupling window 30 between the fourth resonator 15 and the fifth resonator 16, the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be capacitively coupled to each other. The coupling amount between the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 (around the 2.6 GHz resonant frequency) is approximately 48 GHz. The coupling amount between the TE mode of the fourth resonator 15 and the TM mode of the fifth resonator 16 (around the 2.6 GHz resonant frequency) is approximately 0 GHz, which is equivalent to no coupling and requires other coupling structures for coupling. The coupling amount between the TE mode of the fifth resonator 16 and the TM mode of the fifth resonator 16 (around the 2.6 GHz resonant frequency) is approximately 0 GHz, which is equivalent to no coupling and requires other coupling structures for coupling. Therefore, the dielectric element 50 can affect the coupling effect, coupling strength, and coupling polarity between resonant modes of two adjacent resonators 10 with similar electromagnetic field distributions. For example, it can affect the coupling between TE modes, TM modes, TM and TEM modes, and TEM modes. The dielectric element 50 cannot affect the coupling between resonant modes of two adjacent resonators 10 with dissimilar electromagnetic field distributions. For example, it cannot affect the coupling between TE and TM modes, or between TE and TEM modes. The dielectric element 50 cannot affect the coupling between multiple resonant modes of a dual-mode resonator or multi-mode resonator itself. For example, it cannot affect the coupling between the TE and TM modes of a TE-TM dual-mode resonator itself.

[0162] It should also be noted that the enhancement effect of the dielectric component 50 on capacitive coupling can be adjusted based on parameters such as the size and dielectric constant of the dielectric component 50, thereby affecting the coupling effect and coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10. That is, the size, dielectric constant, and other parameters of the dielectric component 50 can be set as needed.

[0163] In this design, the height d1 of the dielectric element 50 is its dimension along the height direction of the coupling window 30, which corresponds to the axial direction of the resonator 14 and is perpendicular to the through direction of the coupling window 30. The width d2 of the dielectric element 50 is its dimension along the width direction of the coupling window 30, which is perpendicular to both the through direction and the height direction of the coupling window 30. The height d1 and width d2 of the dielectric element 50 primarily affect the coupling strength between TE modes, while having little effect on the coupling strength between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode). Generally, the higher the height d1 and the wider the width d2 of the dielectric element 50, the stronger the coupling strength between TE modes.

[0164] Wherein, the thickness d3 of the dielectric element 50 is the dimension of the dielectric element 50 in the direction through which the coupling window 30 passes, and is also the dimension on the line connecting the centers of two adjacent resonators 10. The thickness d3 of the dielectric element 50 mainly affects the coupling strength between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode), while having little effect on the coupling strength between TE modes. As the thickness d3 of the dielectric element 50 increases, it is equivalent to gradually strengthening the capacitive coupling between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode). Depending on the enhancement effect of the dielectric element 50 on capacitive coupling, the TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode) may still be inductively coupled but the inductive coupling strength is weakened, they may be basically uncoupled, or they may reverse from inductive coupling to capacitive coupling.

[0165] By adopting the above scheme, not only can the size of the coupling window 30 be adjusted, but also the dielectric element 50 used to enhance capacitive coupling can be set in the coupling window 30 as needed. This allows for convenient and reliable precise adjustment of the coupling effect and coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10. This facilitates adjusting the coupling between multiple sets of resonant modes of two adjacent resonators 10 to the required strength, or reversing it to the desired coupling relationship (i.e., capacitive or inductive coupling). Therefore, it is convenient to construct coupling relationships between two adjacent resonators 10 as needed via the coupling window 30 and the dielectric element 50, achieving the required coupling strength, coupling relationship, and coupling polarity. Furthermore, the dielectric element 50 can achieve superior coupling adjustment effects with a relatively small size. This simplifies and optimizes the coupling structure design between two adjacent resonators 10, facilitates filter simulation design, optimizes filter performance, and expands the coupling bandwidth range.

[0166] Furthermore, compared to existing technologies that use flying rods to establish coupling relationships, the dielectric component 50 is a non-metallic component, which will not form a floating arm and will not generate additional resonances with frequencies near the passband range. Therefore, the performance of the filter can be optimized and improved, especially the filtering performance and out-of-band rejection performance of the filter.

[0167] Furthermore, in existing technologies, the fly rod needs to be installed on the coupling window via an insulating bracket. The fly rod and the insulating bracket require assembly, as does the insulating bracket and the coupling window, making the assembly process cumbersome. In addition, due to these two assembly steps, it is difficult to maintain a stable installation position and state of the fly rod at the coupling window. However, the dielectric component 50 provided in this embodiment can be directly installed onto the coupling window 30, simplifying installation, reducing assembly steps, and improving filter assembly efficiency. Moreover, since the dielectric component 50 is directly installed onto the coupling window 30, its installation accuracy, positional accuracy, installation stability, and positional stability within the coupling window 30 are improved, ensuring stable filter performance.

[0168] Furthermore, compared to existing technologies that use flying rods to construct coupling relationships, the dielectric element 50 is not limited to affecting only the coupling effect and coupling strength of one set of resonant modes. The dielectric element 50 can affect the coupling effect and coupling strength between TE modes, as well as between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode). Therefore, the dielectric element 50 has better applicability and a wider range of applications. The dielectric element 50 is particularly suitable for situations where "there is both TE mode coupling and TM mode coupling (or, TM mode and TEM mode; or, TEM mode and TEM mode) between two adjacent resonators 10". In this case, the dielectric element 50 can simultaneously affect the coupling effect and coupling strength between TE modes and between TM modes, and can simultaneously control the "TE mode coupling" and "TM mode coupling" between two adjacent resonators 10.

[0169] Furthermore, compared to existing technologies that use flying rods to establish coupling relationships, the dielectric element 50 can achieve superior coupling adjustment effects with a smaller size. Therefore, while improving filter performance, the space required by the dielectric element 50 can be reduced, which is beneficial to the miniaturization and weight reduction of the filter.

[0170] Of course, in other embodiments, the medium element 50 may be omitted from the coupling window 30.

[0171] Referring to Figure 2, in some embodiments of this application, the dielectric element 50 is a columnar structure. For example, the dielectric element 50 may be a polygonal prism structure or a cylindrical structure.

[0172] By adopting the above scheme and making the dielectric component 50 a columnar structure, on the one hand, the structure and shape of the dielectric component 50 can be made more regular and modular. Based on this, it is convenient to process the columnar dielectric component 50 by methods such as machining, injection molding, dry pressing, and sintering, which can improve the processing convenience, processing accuracy, and processing efficiency of the dielectric component 50. It can also make the formed dielectric component 50 have better structural stability and strength, and facilitate the connection, fixation, and assembly of the dielectric component 50. On the other hand, it is convenient to accurately control the dimensions (e.g., height, width, and thickness) of the columnar dielectric component 50. Based on this, it is convenient to accurately adjust the coupling effect and coupling strength between TE modes, and to accurately adjust the coupling effect, coupling strength, and coupling polarity between TM modes (or, TM mode and TEM mode; or, TEM mode and TEM mode). This facilitates the coupling design between two adjacent resonators 10, facilitates the simulation design of the filter, and optimizes the performance of the filter.

[0173] Of course, in other embodiments, the medium 50 can be a regular structure of other forms (e.g., a conical structure, a frustum structure, etc.) or an irregular structure.

[0174] Please refer to Figure 2. In some embodiments of this application, the medium 50 is a cuboid structure (including a cube structure).

[0175] Compared to other columnar structures, making the dielectric element 50 a cuboid structure allows for more standardized and defined dimensions and shape. This facilitates precise determination and control of the height d1, width d2, and thickness d3 of the dielectric element 50 using the length, width, and height of the cuboid. This allows for precise adjustment of the coupling effect and strength between TE modes, and between TM modes (or TM and TEM modes; or TEM and TEM modes). Consequently, it facilitates precise coupling design between adjacent resonators 10, enables filter simulation design, and optimizes filter performance.

[0176] Please refer to Figure 17. In some embodiments of this application, the dielectric element 50 has a cylindrical structure. Since the cylindrical shape is more regular, it is more conducive to the processing, shaping, and assembly of the dielectric element 50.

[0177] Of course, in other embodiments, the medium 50 may be other columnar structures, such as triangular prism structures, etc.

[0178] Referring to Figure 2, in some embodiments of this application, the medium 50 is a solid structure. That is, the interior of the medium 50 has no voids or gaps (e.g., holes, grooves).

[0179] Compared to a hollow structure of the same volume, making the dielectric component 50 a solid structure allows for a greater amount of dielectric material to serve as the propagation medium for electromagnetic waves. This eliminates internal voids or gaps (since voids or gaps use air as the propagation medium for electromagnetic waves). Consequently, the dielectric component 50 can more effectively influence the coupling effect and coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10. This optimizes the utility of the dielectric component 50, facilitating coupling design and energy propagation between adjacent resonators 10, simplifying filter simulation design, and optimizing filter performance. Furthermore, the processing and manufacturing of a solid dielectric component 50 is relatively simple, eliminating the need for drilling, grooving, and demolding. Therefore, it improves the ease of processing, accuracy, and efficiency of the dielectric component 50, resulting in a more stable and stronger structure.

[0180] Of course, in other embodiments, the medium element 50 can be a hollow structure, that is, the medium element 50 can be provided with holes, gaps, hole structures, groove structures, etc.

[0181] Please refer to Figures 1, 2, and 14. In some embodiments of this application, the filter includes a coupling adjustment structure 100 disposed on one side of the dielectric 50 along its own height direction.

[0182] It should be noted that the filter may be provided with a coupling adjustment structure 100 on one side of the dielectric 50 along the height direction of the dielectric 50 as needed. That is, the coupling adjustment structure 100 is also provided in the coupling window 30 and is provided corresponding to the dielectric 50 along the height direction of the dielectric 50.

[0183] The coupling adjustment structure 100 can be directly threaded into the threaded hole of the corresponding wall of the filter housing; alternatively, a mounting part (not shown in the figure) can be embedded in the corresponding wall of the filter housing, and the coupling adjustment structure 100 can be threaded into the threaded hole of the mounting part. Based on this, the coupling adjustment structure 100 can be screwed in or out relative to the corresponding wall of the filter housing to adjust the length of the portion of the coupling adjustment structure 100 extending into the filter housing, thereby adjusting the coupling strength between two adjacent resonators 10.

[0184] By adopting the above scheme, when two adjacent resonators 10 with similar electromagnetic field distributions are coupled through the coupling window 30 and the dielectric 50, by setting the coupling adjustment structure 100 on one side of the dielectric 50 along its own height direction, the length of the part of the coupling adjustment structure 100 extending into the filter can be easily and quickly adjusted by rotating it in or out. This allows for fine adjustment of the coupling strength between the two adjacent resonators 10 with similar electromagnetic field distributions, making the adjustment convenient, fast, and accurate.

[0185] Of course, in other embodiments, the coupling adjustment structure 100 can be replaced with other types of coupling adjustment structures. Alternatively, if it is not necessary to adjust the coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10, the coupling adjustment structure 100 and other types of coupling adjustment structures can be omitted.

[0186] Please refer to Figures 1 and 17. In some embodiments of this application, when a coupling adjustment structure 100 is provided on one side of the medium 50 along its own height direction, an opening 51 is provided on the side of the medium 50 facing the coupling adjustment structure 100. The opening 51 is correspondingly provided with the coupling adjustment structure 100, and the opening 51 allows the coupling adjustment structure 100 to pass through it.

[0187] It should be noted that when the dielectric element 50 has a coupling adjustment structure 100 on one side along its height direction, an opening 51 can be provided on the side of the dielectric element 50 facing the coupling adjustment structure 100. The opening 51 can be a blind hole or a through hole. The opening 51 can be a circular hole, a rectangular hole, etc. The opening 51 corresponds to the coupling adjustment structure 100 along the axial direction of the coupling adjustment structure 100, the extension direction of the opening 51 corresponds to the extension direction of the coupling adjustment structure 100, and the cross-sectional dimension of the opening 51 is greater than or equal to the cross-sectional dimension of the coupling adjustment structure 100. When the length of the portion of the coupling adjustment structure 100 extending into the filter is relatively long, the coupling adjustment structure 100 is allowed to extend into the opening 51.

[0188] By adopting the above scheme, when the length of the part of the coupling adjustment structure 100 extending into the filter is relatively long, the coupling adjustment structure 100 can be allowed to extend into the opening 51 of the dielectric 50. Based on this, the adjustment range of the coupling adjustment structure 100 can be expanded accordingly, and the adjustable range of the coupling strength between the resonant modes with similar electromagnetic field distributions of two adjacent resonators 10 can be expanded accordingly, thereby improving the performance index of the filter.

[0189] Of course, in other embodiments, if the coupling adjustment structure 100 is provided on one side of the medium 50 along its own height direction, the opening 51 may not be provided on the side of the medium 50 facing the coupling adjustment structure 100. For example, the medium 50 may be a solid structure.

[0190] Referring to Figure 2, in some embodiments of this application, the dielectric element 50 is formed independently. That is, the dielectric element 50 is first formed independently and then assembled into the coupling window 30.

[0191] By adopting the above scheme and making the dielectric component 50 independently molded, on the one hand, it is convenient to independently mold the dielectric component 50 through methods such as machining, injection molding, dry pressing, and sintering. It is also convenient to select different materials for independently molding the dielectric component 50, which can improve the processing convenience, processing accuracy, processing efficiency, material selectivity, and design flexibility of the dielectric component 50. It also facilitates the connection, fixation, and assembly of the dielectric component 50. On the other hand, it is convenient to accurately control the size of the dielectric component 50 during the independent molding of the dielectric component 50, so that the dielectric component 50 can accurately affect the coupling effect, coupling strength, and coupling polarity between two adjacent resonators 10, thereby optimizing the performance of the filter.

[0192] Referring to Figure 2, in some embodiments of this application, the dielectric constant of the dielectric element 50 is 30 to 40. Optionally, the material of the dielectric element 50 may be, but is not limited to, ceramic.

[0193] By adopting the above scheme, and by making the dielectric constant of dielectric element 50 30 to 40, dielectric element 50 can have a high dielectric constant. Based on this, the capacitance effect of dielectric element 50 can be significantly enhanced, enabling dielectric element 50 to provide a strong capacitive coupling enhancement effect between adjacent resonators 10. This allows dielectric element 50 to more significantly affect the coupling effect and coupling strength between resonant modes with similar electromagnetic field distributions of two adjacent resonators 10, thus optimizing the utility of dielectric element 50. This facilitates the coupling design and energy propagation between two adjacent resonators 10, facilitates the simulation design of filters, and optimizes the performance of filters.

[0194] Of course, in other embodiments, the dielectric element 50 may be made of a dielectric material, and the dielectric constant of the dielectric element 50 is not limited to the range of 30 to 40.

[0195] Please refer to Figures 2, 14, and 18. In some embodiments of this application, at least one set of two adjacent resonators 10 are a fourth resonator 15 and a fifth resonator 16. The fourth resonator 15 has a TE mode resonance mode, and the fifth resonator 16 has a TE mode resonance mode. The TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 are capacitively coupled through a coupling window 30 and a dielectric 50.

[0196] It should be noted that at least one set of two adjacent resonators 10 uses a combination of a fourth resonator 15 and a fifth resonator 16. The fourth resonator 15 has a TE mode, meaning that the fourth resonator 15 can support at least the TE mode within its passband. For example, the fourth resonator 15 can be a TE single-mode resonator, a TE-TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The fifth resonator 16 has a TE mode, meaning that the fifth resonator 16 can support at least the TE mode within its passband. For example, the fifth resonator 16 can be a TE single-mode resonator, a TE-TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc.

[0197] When the coupling window 30 has a certain size (i.e., the size of the coupling window 30 is relatively large), the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be capacitively coupled to each other through the coupling window 30, and the dielectric element 50 in the coupling window 30 can enhance the capacitive coupling strength between the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16.

[0198] When the coupling window 30 is small, the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 are mainly capacitively coupled based on the dielectric 50. The main function of the coupling window 30 is to accommodate the dielectric 50.

[0199] The capacitive coupling strength between the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be adjusted mainly by adjusting the height d1, width d2, and dielectric constant of the dielectric component 50.

[0200] By adopting the above scheme, the TE mode of the fourth resonator 15 and the fifth resonator 16 can be capacitively coupled through the coupling window 30 and the dielectric element 50 disposed in the coupling window 30, and the coupling effect is better. Based on this, two adjacent resonators 10 with TE mode resonance can be adapted to use the coupling window 30 and the dielectric element 50 to construct the required capacitive coupling relationship as needed and achieve the required coupling strength, thereby improving the design flexibility of the filter, facilitating the simulation design of the filter, and optimizing the performance of the filter.

[0201] For example, as shown in Figures 18, 19, and 20, in one specific embodiment of the filter, the fourth resonator 15 is a TE single-mode resonator, and the fifth resonator 16 is a TE single-mode resonator. According to Figure 19, the resonant frequency of the fourth resonator 15 is approximately 2.4 GHz, and the resonant frequency of the fifth resonator 16 is approximately 2.4 GHz. According to Figure 20, when the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 are capacitively coupled only through the coupling window 30 (i.e., without the dielectric 50), the coupling amount between the TE modes of the fourth resonator 15 and the fifth resonator 16 (around the 2.4 GHz resonant frequency) is approximately 37 GHz; while when the TE modes of the fourth resonator 15 and the fifth resonator 16 are capacitively coupled through both the coupling window 30 and the dielectric 50 (i.e., with the dielectric 50), the coupling amount between the TE modes of the fourth resonator 15 and the fifth resonator 16 (around the 2.4 GHz resonant frequency) is approximately 46 GHz, and the coupling effect is significantly better than that without the dielectric 50.

[0202] Referring to Figure 2, in some embodiments of this application, at least one pair of adjacent resonators 10 are a sixth resonator 17 and a seventh resonator 18. The sixth resonator 17 has a TM mode or a TEM mode, and the seventh resonator 18 has a TM mode or a TEM mode. The TM mode or TEM mode of the sixth resonator 17 is inductively coupled to the TM mode or TEM mode of the seventh resonator 18 through a coupling window 30, and the coupling strength between them is adjusted by a dielectric 50; or, the TM mode or TEM mode of the sixth resonator 17 is capacitively coupled to the TM mode or TEM mode of the seventh resonator 18 through a dielectric 50.

[0203] It should be noted that at least one set of two adjacent resonators 10 uses a combination of the sixth resonator 17 and the seventh resonator 18. The sixth resonator 17 has a TM mode or a TEM mode, that is, the sixth resonator 17 can support at least the TM mode or the TEM mode within its passband. The sixth resonator 17 can be a TM single-mode resonator, a TEM single-mode resonator, a TM dual-mode resonator, a TE-TM dual-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The seventh resonator 18 has a TM mode or a TEM mode, that is, the seventh resonator 18 can support at least the TM mode or the TEM mode within its passband. The seventh resonator 18 can be a TM single-mode resonator, a TEM single-mode resonator, a TM dual-mode resonator, a TE-TM dual-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc.

[0204] The TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18 can be inductively coupled to each other through the coupling window 30. On this basis, the dielectric element 50 in the coupling window 30 can enhance the capacitance between the sixth resonator 17 and the seventh resonator 18, which is equivalent to weakening the inductive coupling strength between the TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18.

[0205] Based on this, when the enhancement effect of the dielectric 50 on capacitive coupling is weaker than the strength of the inductive coupling formed by the TM mode and the TM mode (or, the TM mode and the TEM mode; or, the TEM mode and the TEM mode) through the coupling window 30, the TM mode or TEM mode of the sixth resonator 17 and the TM mode or TEM mode of the seventh resonator 18 achieve inductive coupling through the coupling window 30 and the dielectric 50. The effect of the dielectric 50 is to weaken the inductive coupling strength (i.e., adjust the inductive coupling strength).

[0206] When the enhancement effect of the dielectric 50 on capacitive coupling is stronger than the strength of the inductive coupling formed by the TM mode and the TM mode (or, the TM mode and the TEM mode; or, the TEM mode and the TEM mode) through the coupling window 30, the TM mode or TEM mode of the sixth resonator 17 and the TM mode or TEM mode of the seventh resonator 18 achieve capacitive coupling through the coupling window 30 and the dielectric 50. The function of the dielectric 50 is to cancel the "inductive coupling formed through the coupling window 30" and reverse the coupling relationship from inductive coupling to capacitive coupling.

[0207] When the enhancement effect of dielectric 50 on capacitive coupling is equal to the strength of inductive coupling formed by TM mode and TM mode (or, TM mode and TEM mode; or, TEM mode and TEM mode) through coupling window 30, the coupling between the TM mode or TEM mode of the sixth resonator 17 and the TM mode or TEM mode of the seventh resonator 18 through coupling window 30 and dielectric 50 is weak, basically non-coupled. The effect of dielectric 50 is to effectively cancel out the "inductive coupling formed through coupling window 30".

[0208] The coupling relationship, coupling strength, and coupling polarity between the TM mode or TEM mode of the sixth resonator 17 and the TM mode or TEM mode of the seventh resonator 18 can be adjusted mainly by adjusting the thickness d3 and the dielectric constant of the dielectric component 50.

[0209] By adopting the above scheme, the adjacent sixth resonator 17 and seventh resonator 18 can be inductively or capacitively coupled to each other through the coupling window 30 and the dielectric element 50 disposed in the coupling window 30, and the coupling effect is better. Based on this, two adjacent resonators 10 with TM mode or TEM mode respectively can be adapted to use the coupling window 30 and the dielectric element 50 to construct the required coupling relationship (which can be inductive coupling relationship, capacitive coupling relationship, or no coupling relationship) as needed, and achieve the required coupling strength, thereby improving the design flexibility of the filter, facilitating the simulation design of the filter, and optimizing the performance of the filter.

[0210] Please refer to Figures 21 and 22. In some embodiments of this application, at least one pair of adjacent resonators 10 are a fourth resonator 15 and a fifth resonator 16. The fourth resonator 15 has a TE mode resonance mode, and the fifth resonator 16 has a TE mode resonance mode. The filter includes a third coupling structure 60, which is disposed in the coupling window 30 between the fourth resonator 15 and the fifth resonator 16, and couples the TE mode of the fourth resonator 15 with the TE mode of the fifth resonator 16.

[0211] It should be noted that at least one set of two adjacent resonators 10 uses a combination of a fourth resonator 15 and a fifth resonator 16. The fourth resonator 15 has a TE mode, meaning that the fourth resonator 15 can support at least the TE mode within its passband. For example, the fourth resonator 15 can be a TE single-mode resonator, a TE-TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The fifth resonator 16 has a TE mode, meaning that the fifth resonator 16 can support at least the TE mode within its passband. For example, the fifth resonator 16 can be a TE single-mode resonator, a TE-TM dual-mode resonator, a HE-TE tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc.

[0212] The TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be coupled via a third coupling structure 60. At least a portion of the third coupling structure 60 is disposed in the coupling window 30 between the fourth resonator 15 and the fifth resonator 16.

[0213] The third coupling structure 60 can be a metal component, a non-metallic component with a metal layer on its surface, or a non-metallic component. The specific construction, extension path, shape, and size of the third coupling structure 60 are not currently limited. The third coupling structure 60 can be insulated and installed in the coupling window 30 between the fourth resonator 15 and the fifth resonator 16 via an insulating component, or it can be insulated and installed on the housing of the fourth resonator 15 and / or the housing of the fifth resonator 16 via an insulating component.

[0214] It should be noted that the third coupling structure 60 enables coupling between TE modes, but due to the different electromagnetic field distributions of the TE and TM modes, the third coupling structure 60 may or may not enable coupling between TM modes (or TM mode and TEM mode; or TEM mode and TEM mode). Whether or not the third coupling structure 60 can achieve coupling between TM modes (or TM mode and TEM mode; or TEM mode and TEM mode) can be determined according to the specific design requirements of the filter, and the specific structure of the third coupling structure 60 can be designed as needed.

[0215] By adopting the above scheme, the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be coupled through the third coupling structure 60, thereby achieving coupling between the TE modes of the fourth resonator 15 and the fifth resonator 16. This facilitates the construction of the required coupling relationship between the adjacent fourth resonator 15 and fifth resonator 16 via the third coupling structure 60, achieving the desired coupling strength and relationship. This simplifies filter simulation design and facilitates the optimization of filter performance.

[0216] Of course, in other embodiments, the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 can be coupled directly through the larger coupling window 30, or through the coupling window 30 and the dielectric 50, thus omitting the third coupling structure 60.

[0217] Referring to Figures 21 and 22, in some embodiments of this application, the third coupling structure 60 includes a connecting portion 61, a sixth coupling portion 62 bent and connected to one end of the connecting portion 61, and a seventh coupling portion 63 bent and connected to the other end of the connecting portion 61. The sixth coupling portion 62 and the seventh coupling portion 63 are bent toward the same side of the connecting portion 61 (as shown in Figure 21); or, the sixth coupling portion 62 is bent toward one side of the connecting portion 61 and the seventh coupling portion 63 is bent toward the other side of the connecting portion 61 (as shown in Figure 22).

[0218] It should be noted that the connecting portion 61 passes through the coupling window 30 between the fourth resonator 15 and the fifth resonator 16. The connecting portion 61 can connect between the sixth coupling portion 62 and the seventh coupling portion 63 to support them. The extending direction of the connecting portion 61 can be parallel to or not parallel to the through direction of the coupling window 30. The connecting portion 61 can extend in a straight line, bend, or curve.

[0219] The sixth coupling portion 62 is bent and connected to one end of the connecting portion 61. The sixth coupling portion 62 and the connecting portion 61 can be integrally connected or separately connected. The sixth coupling portion 62 is used to couple the TE mode of the fourth resonator 15. Specifically, the sixth coupling portion 62 may intersect the radial direction of the resonator element 14 of the fourth resonator 15 to cut the magnetic field of the TE mode of the fourth resonator 15, thereby coupling the TE mode of the fourth resonator 15. As shown in Figures 21 and 22, in some embodiments, the sixth coupling portion 62 may extend in an arc shape along the circumference of the resonator element 14 of the fourth resonator 15 to couple the TE mode of the fourth resonator 15 and achieve a better coupling effect.

[0220] The seventh coupling portion 63 is bent and connected to the end of the connecting portion 61 away from the sixth coupling portion 62. The seventh coupling portion 63 and the connecting portion 61 can be integrally connected or separately connected. The seventh coupling portion 63 is used to couple the TE mode of the fifth resonator 16. Specifically, the seventh coupling portion 63 may intersect the radial direction of the resonator element 14 of the fifth resonator 16 to cut the magnetic field of the TE mode of the fifth resonator 16, thereby coupling the TE mode of the fifth resonator 16. As shown in Figures 21 and 22, in some embodiments, the seventh coupling portion 63 may extend in an arc shape along the circumference of the resonator element 14 of the fifth resonator 16 to couple the TE mode of the fifth resonator 16 and achieve a better coupling effect.

[0221] By adopting the above scheme, the third coupling structure 60 can be connected between the sixth coupling section 62 and the seventh coupling section 63 via the connecting part 61 to support the sixth coupling section 62 and the seventh coupling section 63. The TE mode of the fourth resonator 15 can also be coupled via the sixth coupling section 62, and the TE mode of the fifth resonator 16 can be coupled via the seventh coupling section 63, so that the TE modes of the fourth resonator 15 and the fifth resonator 16 can be coupled on the third coupling structure 60. Thus, the filter can achieve coupling of the TE modes of the fourth resonator 15 and the fifth resonator 16 through the simplified and optimized third coupling structure 60, with better coupling effect, thereby optimizing the structure and performance of the filter and facilitating filter simulation design.

[0222] It should also be noted that in the third coupling structure 60 shown in FIG. 21, the sixth coupling portion 62 and the seventh coupling portion 63 are bent toward the same side of the connecting portion 61, that is, the sixth coupling portion 62 and the seventh coupling portion 63 are located on the same side of the connecting portion 61, so that the third coupling structure 60 is in a shape similar to the Chinese character "ji".

[0223] In the third coupling structure 60 shown in FIG. 22, the sixth coupling portion 62 is bent toward one side of the connecting portion 61, while the seventh coupling portion 63 is bent toward the other side of the connecting portion 61, that is, the sixth coupling portion 62 and the seventh coupling portion 63 are respectively arranged on opposite sides of the connecting portion 61.

[0224] Based on this, by adopting the above solution, the third coupling structure 60 can be transformed between the structural forms of "the sixth coupling portion 62 and the seventh coupling portion 63 are bent toward the same side of the connecting portion 61" and "the sixth coupling portion 62 is bent toward one side of the connecting portion 61, while the seventh coupling portion 63 is bent toward the other side of the connecting portion 61", so that the coupling relationship realized by the third coupling structure 60 is reversed, that is, the coupling relationship between the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16 is reversed between the capacitive coupling relationship and the inductive coupling relationship. Thus, it is convenient to achieve the required coupling relationship between the TE mode of the fourth resonator 15 and the TE mode of the fifth resonator 16, convenient for the coupling design between the fourth resonator 15 and the fifth resonator 16, convenient for the simulation design of the filter, and can optimize the performance of the filter. Among them, for the structural forms of "the sixth coupling portion 62 and the seventh coupling portion 63 are bent toward the same side of the connecting portion 61" and "the sixth coupling portion 62 is bent toward one side of the connecting portion 61, while the seventh coupling portion 63 is bent toward the other side of the connecting portion 61", specifically which structural form realizes inductive coupling and which realizes capacitive coupling need to be determined by considering other specific settings (such as the settings of ports).

[0225] Of course, in other embodiments, the third coupling structure 60 can adopt other structural designs.

[0226] Referring to FIG. 23, in some embodiments of the present application, at least one group of two adjacent resonators 10 are the sixth resonator 17 and the seventh resonator 18. The sixth resonator 17 has a TM mode resonance mode or a TEM mode resonance mode, and the seventh resonator 18 has a TM mode resonance mode or a TEM mode resonance mode; the filter includes a fourth coupling structure 70, and the fourth coupling structure 70 is arranged in the coupling window 30 between the sixth resonator 17 and the seventh resonator 18, and couples the TM mode or TEM mode of the sixth resonator 17 with the TM mode or TEM mode of the seventh resonator 18.

[0227] It should be noted that at least one set of two adjacent resonators 10 uses a combination of the sixth resonator 17 and the seventh resonator 18. The sixth resonator 17 has a TM mode or a TEM mode, that is, the sixth resonator 17 can support at least the TM mode or the TEM mode within its passband. The sixth resonator 17 can be a TM single-mode resonator, a TEM single-mode resonator, a TM dual-mode resonator, a TE-TM dual-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc. The seventh resonator 18 has a TM mode or a TEM mode, that is, the seventh resonator 18 can support at least the TM mode or the TEM mode within its passband. The seventh resonator 18 can be a TM single-mode resonator, a TEM single-mode resonator, a TM dual-mode resonator, a TE-TM dual-mode resonator, a HE-TM tri-mode resonator, a HE-TE-TM quad-mode resonator, or the first resonator 11 provided in any of the above embodiments of this application, etc.

[0228] The TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18 can be coupled via a fourth coupling structure 70. At least a portion of the fourth coupling structure 70 is disposed in the coupling window 30 between the sixth resonator 17 and the seventh resonator 18.

[0229] The fourth coupling structure 70 may be a metal component, a non-metallic component with a metal layer on its surface, or a non-metallic component. The specific construction, extension path, shape, and dimensions of the fourth coupling structure 70 are not currently limited.

[0230] It should be noted that the fourth coupling structure 70 can couple TM modes with TM modes (or TM modes with TEM modes; or TEM modes with TEM modes). However, due to the different electromagnetic field distributions of the TE and TM modes, the fourth coupling structure 70 may or may not couple TE modes. Whether the fourth coupling structure 70 can achieve coupling between TE modes depends on the specific design requirements of the filter, and the specific structure of the fourth coupling structure 70 can be designed as needed.

[0231] By adopting the above scheme, the adjacent sixth resonator 17 and seventh resonator 18 can be coupled through the fourth coupling structure 70, thereby achieving coupling between the TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18. This facilitates the construction of the required coupling relationship between the adjacent sixth resonator 17 and seventh resonator 18 via the fourth coupling structure 70, achieving the desired coupling strength and relationship. This simplifies filter simulation design and performance optimization.

[0232] Of course, in other embodiments, the TM mode or TEM mode of the sixth resonator 17 and the TM mode or TEM mode of the seventh resonator 18 can be coupled directly through the larger coupling window 30, or through the coupling window 30 and the dielectric 50, thus omitting the fourth coupling structure 70.

[0233] Please refer to Figure 23. In some embodiments of this application, the fourth coupling structure 70 is a coupling rib with both ends grounded, so that the TM mode or TEM mode of the sixth resonator 17 is inductively coupled to the TM mode or TEM mode of the seventh resonator 18.

[0234] It should be noted that the fourth coupling structure 70 is a coupling rib, which is a metal component. Both ends of the coupling rib are grounded, enabling inductive coupling. The ends of the coupling rib can be directly connected to the housing component of the resonator 10, or indirectly connected to the housing component of the resonator 10 via other metal components to achieve grounding. When the resonator element 14 of the resonator 10 is a metal resonator element, the coupling rib can also be directly connected to the resonator element 14.

[0235] By adopting the above scheme, the fourth coupling structure 70 can be made into a coupling rib with both ends grounded, so that the TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18 can establish the required inductive coupling relationship through the coupling rib. Compared with other structural types of the fourth coupling structure 70, the coupling rib has a simplified and optimized structure, is easy to process and assemble, and can easily achieve the required inductive coupling relationship, thus achieving better coupling effect. Therefore, the structural design of the fourth coupling structure 70 can be simplified and optimized, which can facilitate the simulation design of the filter and optimize the performance of the filter.

[0236] As shown in Figure 23, in some embodiments, only one coupling window 30 may be provided between the sixth resonator 17 and the seventh resonator 18. The coupling window 30 facilitates the establishment of a coupling relationship between the resonant modes of the sixth resonator 17 and the seventh resonator 18, whose electromagnetic field distributions are similar. The coupling window 30 can also be used to pass through the fourth coupling structure 70.

[0237] In other embodiments, two coupling windows 30 may be provided between the sixth resonator 17 and the seventh resonator 18. One coupling window 30 facilitates the establishment of a coupling relationship between the resonant modes of the sixth resonator 17 and the seventh resonator 18, whose electromagnetic field distributions are similar. The other coupling window 30 is dedicated to the passage of the fourth coupling structure 70. This arrangement facilitates the optimization of the position of the coupling window 30 dedicated to the passage of the fourth coupling structure 70, thereby optimizing the layout of the fourth coupling structure 70. It is particularly beneficial in cases where the fourth coupling structure 70 is a coupling rib, thus shortening the extension length of the coupling rib. This facilitates the molding and assembly of the fourth coupling structure 70, and reduces the material consumption and cost of the fourth coupling structure 70.

[0238] Please refer to Figure 23. In some embodiments of this application, the fourth coupling structure 70 is a flying rod, which capacitively couples the TM mode or TEM mode of the sixth resonator 17 with the TM mode or TEM mode of the seventh resonator 18.

[0239] It should be noted that the fourth coupling structure 70 is a fly rod. The fly rod achieves capacitive coupling, meaning it allows the TM or TEM mode of the sixth resonator 17 to be capacitively coupled with the TM or TEM mode of the seventh resonator 18. The fly rod is a metal component, insulated and mounted on the coupling window 30, or insulated and mounted on the housing of the sixth resonator 17 and / or the seventh resonator 18. The specific construction, extension path, shape, and size of the fly rod are not limited.

[0240] By adopting the above scheme, the fourth coupling structure 70 can be made into a flybar, facilitating the establishment of the required capacitive coupling relationship between the TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18 via the flybar. This simplifies and optimizes the structural design of the fourth coupling structure 70, making it easier for the TM or TEM mode of the sixth resonator 17 and the TM or TEM mode of the seventh resonator 18 to achieve the required capacitive coupling relationship and achieve better coupling effect. This, in turn, facilitates the simulation design of the filter and optimizes its performance.

[0241] It should be noted that, for the second coupling structure 40, the third coupling structure 60, the fourth coupling structure 70 and the medium 50 provided in the above embodiments of this application, only one of them can be set in the same coupling window 30 according to specific coupling requirements, or any few or all of them can be set in the same coupling window 30.

[0242] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A filter, comprising a first resonator, wherein the first resonator has at least two resonant modes: a TE mode and a TM mode, wherein, The first resonator includes a resonator housing and a dielectric resonator disposed within the resonator housing, the dielectric resonator being connected to a first wall of the resonator housing; the filter further includes a first coupling structure disposed within the resonator housing, the first coupling structure including a first coupling portion parallel to and spaced from the first wall, and a second coupling portion connected between one end of the first coupling portion and the first wall, the first coupling structure being used to couple the TE mode and TM mode of the first resonator.

2. The filter as claimed in claim 1, wherein, The first coupling structure is disposed between the dielectric resonator and the first wall; Along the axial direction of the dielectric resonator, at least a portion of the projection of the first coupling portion and at least a portion of the projection of the second coupling portion fall within the projection of the dielectric resonator.

3. The filter as described in claim 1, wherein, The first coupling structure changes the coupling polarity between the TE mode and the TM mode of the first resonator by placing the second coupling part at one end of the first coupling part in a counterclockwise direction or at one end of the first coupling part in a clockwise direction.

4. The filter as described in claim 1, wherein, The first coupling portion extends circumferentially along the dielectric resonator.

5. The filter as claimed in claim 1, wherein, The second coupling portion extends along the axial direction of the dielectric resonator.

6. The filter as claimed in claim 1, wherein, The area of ​​the side of the first coupling portion facing the dielectric resonator is greater than or equal to the area of ​​the side of the first coupling portion facing the first wall.

7. The filter as claimed in claim 1, wherein, The first coupling structure includes a third coupling portion connected to the end of the first coupling portion away from the second coupling portion. The end of the third coupling portion away from the first coupling portion extends beyond the outer peripheral surface of the dielectric resonator and is connected to the resonator housing.

8. The filter as claimed in claim 1, wherein, In the same first resonator, there are multiple first coupling structures, and the second coupling part of each first coupling structure is disposed at one end of the first coupling part in the counterclockwise direction, or the second coupling part of each first coupling structure is disposed at one end of the first coupling part in the clockwise direction.

9. The filter as claimed in claim 8, wherein, Each of the first coupling structures is replicated by rotating around the central axis of the dielectric resonator.

10. The filter as claimed in any one of claims 1-9, wherein, The filter includes at least two resonators, and a coupling window connecting the interior of each other is provided between two adjacent resonators.

11. The filter of claim 10, wherein, At least one pair of adjacent resonators are a second resonator and a third resonator, the second resonator has a TE mode resonant mode, the third resonator has a TM mode resonant mode or a TEM mode resonant mode, and the coupling window between the second resonator and the third resonator is a first coupling window; The filter includes a second coupling structure with both ends grounded, at least a portion of which is located within the first coupling window. The second coupling structure couples the TE mode of the second resonator with the TM mode or TEM mode of the third resonator.

12. The filter as claimed in claim 11, wherein, The second coupling structure is disposed within the third resonator, and the second coupling structure intersects the circumferential direction of the resonator element of the third resonator to couple the TM mode or TEM mode of the third resonator; One end of the second coupling structure extends to the first coupling window and intersects the radial direction of the resonator of the second resonator to couple the TE mode of the second resonator.

13. The filter as claimed in claim 12, wherein, The end of the second coupling structure near the resonator of the third resonator is connected to the base of the third resonator.

14. The filter as claimed in claim 11, wherein, The second coupling structure includes a fourth coupling part and a fifth coupling part that are bent and connected in sequence; The fourth coupling part is disposed in the first coupling window, or extends from the first coupling window into the second resonator. The fourth coupling part intersects the radial direction of the resonant element of the second resonator to couple the TE mode of the second resonator. The fifth coupling part is disposed inside the third resonator and intersects with the circumferential direction of the resonator of the third resonator to couple the TM mode or TEM mode of the third resonator.

15. The filter as claimed in claim 11, wherein, The second coupling structure is disposed in the first coupling window and intersects the center line connecting the second resonator and the third resonator; along the axial direction of the resonator of the third resonator, the second coupling structure is disposed on the same side as the connection end of the resonator of the third resonator.

16. The filter of claim 11, wherein, The second coupling structure is mirrored along the center line connecting the second resonator and the third resonator to reverse the coupling polarity between the TE mode of the second resonator and the TM or TEM mode of the third resonator.

17. The filter of claim 10, wherein, The filter includes a dielectric element disposed in the coupling window.

18. The filter of claim 17, wherein, The medium is in the shape of a cuboid block or a cylinder.

19. The filter of claim 17, wherein, The medium is a solid structure; Alternatively, the filter includes a coupling adjustment structure disposed on one side of the dielectric element along its own height direction, and the dielectric element has an opening on the side facing the coupling adjustment structure, the opening being correspondingly disposed to the coupling adjustment structure, and the opening allowing the coupling adjustment structure to pass through it.

20. The filter of claim 17, wherein, The medium component is formed independently; And / or, the dielectric constant of the dielectric element is 30 to 40.

21. The filter of claim 17, wherein, At least one pair of adjacent resonators are a fourth resonator and a fifth resonator, the fourth resonator having a TE mode resonance mode, the fifth resonator having a TE mode resonance mode, and the TE modes of the fourth resonator and the fifth resonator being capacitively coupled to the dielectric through the coupling window.

22. The filter of claim 17, wherein, At least one pair of adjacent resonators are a sixth resonator and a seventh resonator, wherein the sixth resonator has a TM mode resonant mode or a TEM mode resonant mode, and the seventh resonator has a TM mode resonant mode or a TEM mode resonant mode. The TM or TEM mode of the sixth resonator is inductively coupled to the TM or TEM mode of the seventh resonator through the coupling window, and the coupling strength between them is adjusted by the dielectric material; or, the TM or TEM mode of the sixth resonator is capacitively coupled to the TM or TEM mode of the seventh resonator through the dielectric material.

23. The filter of claim 10, wherein, At least one pair of adjacent resonators are a fourth resonator and a fifth resonator, wherein the fourth resonator has a TE mode resonant mode and the fifth resonator has a TE mode resonant mode; The filter includes a third coupling structure disposed in the coupling window between the fourth resonator and the fifth resonator, and couples the TE mode of the fourth resonator with the TE mode of the fifth resonator.

24. The filter as claimed in claim 23, wherein, The third coupling structure includes a connecting part, a sixth coupling part bent and connected to one end of the connecting part, and a seventh coupling part bent and connected to the other end of the connecting part. The sixth coupling portion and the seventh coupling portion are bent toward the same side of the connecting portion; Alternatively, the sixth coupling portion may be bent toward one side of the connecting portion, and the seventh coupling portion may be bent toward the other side of the connecting portion.

25. The filter of claim 10, wherein, At least one pair of adjacent resonators are a sixth resonator and a seventh resonator, wherein the sixth resonator has a TM mode resonant mode or a TEM mode resonant mode, and the seventh resonator has a TM mode resonant mode or a TEM mode resonant mode. The filter includes a fourth coupling structure disposed in the coupling window between the sixth resonator and the seventh resonator, and couples the TM mode or TEM mode of the sixth resonator with the TM mode or TEM mode of the seventh resonator.

26. The filter of claim 25, wherein, The fourth coupling structure is a coupling rib with both ends grounded, which enables the TM mode or TEM mode of the sixth resonator to be inductively coupled to the TM mode or TEM mode of the seventh resonator.

27. The filter of claim 25, wherein, The fourth coupling structure is a flying rod, which capacitively couples the TM mode or TEM mode of the sixth resonator with the TM mode or TEM mode of the seventh resonator.

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