Tri-modal resonator and waveguide filter comprising such tri-modal resonator

Abstract

The present disclosure relates to a triple-mode resonator (100) comprising a body made of a dielectric material and having a cuboid shape defining three orthogonal axes (x, y, z) substantially aligned with faces of the body, and a conductive coating covering all of the body except for portions of the faces of the body defining at least one coupling aperture (110, 120, 130, 110', 120', 130') through which a signal can be coupled into and / or out of the body, wherein the coupling aperture has a closed shape comprising a first (110a, 120a, 130a) and a second (110c, 120c, 130c) main edge extending along two of the axes, respectively, and a third main edge (110b, 120b, 130b) extending neither parallel nor perpendicular to the first and second main edges, the general shape and dimensions and position of the coupling aperture being mainly determined by the first, second and third main edges, and the coupling aperture being configured in such a way that an input signal introduced therethrough can independently excite the three desired main resonance modes in the triple-mode resonator (100). The present disclosure also relates to a waveguide filter comprising the above triple-mode resonator.

Description

Technical Field

[0001] This disclosure relates generally to the field of filters, and more specifically to a three-mode resonator and a waveguide filter including such a three-mode resonator. Background Technology

[0002] This section provides information to help in a better understanding of aspects of this disclosure. Therefore, the statements in this section should be read in that context and should not be construed as an admission of what is in the prior art or what is not.

[0003] With the development of 5G communication, Multiple-Input Multiple-Output (MIMO) technology is widely used in Sub-6GHz base station products, which require the integration of a large number of filter units (FUs) with antenna units (AUs) or radio units (RUs). To save cost and space, FUs are typically soldered to radio motherboards, low-pass filter (LPF) boards, antenna calibration (AC) boards, or power divider boards, which means there is a great demand for smaller and lighter FUs.

[0004] In traditional base stations, metal cavity filters (FUs) are widely used due to their high Q-factor and power handling performance, but there is still room for improvement in terms of FU size and weight for 5G advanced radio systems. Ceramic waveguide (CWG) filters, formed from ceramic blocks coated with conductive materials (such as silver), are also widely used. The high dielectric constant of ceramics reduces the waveguide wavelength, which makes the physical size of CWG filters smaller than that of conventional metal cavity filters for a given resonant frequency.

[0005] CWG filters, especially multimode CWG filters, are strongly recommended for use in 5G FU due to their high performance, light weight, small size and ease of integration.

[0006] Currently, the Q-factor value of a single-mode CWG filter is lower than that of a metal cavity filter of the same size. To improve the Q-factor value of a single-mode CWG filter, the cavity size must be increased, which contradicts the fundamental design requirement of reducing size.

[0007] Furthermore, it was found that a single multimode cavity can contribute the radio frequency (RF) characteristics provided by multiple single-mode cavities, and the size of a single multimode cavity is larger than that of a single-mode cavity, but smaller than the sum of the sizes of multiple single-mode cavities. That is, for multimode filters, the Q factor can be improved while the overall size can be reduced. Compared to single-mode CWG filters, multimode CWG filters can improve the Q factor by 100%-120% and reduce the size by 30%-50%. The reduced size of multimode CWG filters allows for easier integration with AU, RU, or macro station duplexers. Therefore, multimode CWG filters outperform single-mode CWG filters in achieving a balance between high Q factor values ​​and small size.

[0008] However, existing multimode CWGs have limited bandwidth and therefore cannot be applied to broadband radios that require high-bandwidth filters.

[0009] Another problem with existing multimode CWG filters is that most single-mode CWG filters utilize blind vias or trenches to achieve negative coupling / capacitive coupling. However, this coupling method is neither convenient for multimode coupling nor easy to control the coupling value. Furthermore, current multimode CWG filters suffer from very poor harmonic performance due to their coupling methods. Moreover, they cannot flexibly implement transmission zero setting. Summary of the Invention

[0010] This summary is provided to introduce selected concepts in a simplified form, which will be further described in the detailed description below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0011] One object of this disclosure is to provide an improved solution for waveguide filters that have improved Q-factor values, low insertion loss, high power capacity, and improved harmonic performance.

[0012] According to a first aspect of this disclosure, a three-mode resonator is provided, comprising: a body made of a dielectric material and having a cuboid shape defining three orthogonal axes substantially aligned with the faces of the body; and a conductive coating covering the entire body except for portions of the faces defining at least one coupling aperture, through which signals can be coupled into and / or out of the body. The coupling aperture has a closed shape comprising first and second main edges extending along two of the axes, respectively, and a third main edge extending neither parallel nor perpendicular to the first and second main edges. The general shape, size, and location of the coupling aperture are primarily determined by the first, second, and third main edges. The coupling aperture is configured such that an input signal introduced therethrough can independently excite the three desired principal resonant modes in the three-mode resonator.

[0013] In one embodiment of this disclosure, the coupling hole is generally triangular in shape.

[0014] In one embodiment of this disclosure, the third main edge is in the form of an arc-shaped segment.

[0015] In one embodiment of this disclosure, the arc-shaped segment bends toward the inside of the coupling hole, wherein the center of the arc of the arc-shaped segment is the center of the surface in which the arc-shaped segment is located.

[0016] In one embodiment of this disclosure, the third main edge is linear and tilted at an angle of 30° to 60°, preferably 45°, relative to the first or second main edge.

[0017] In one embodiment of this disclosure, the coupling hole further includes a fourth edge that extends obliquely relative to the first and second main edges to intersect the first and second main edges.

[0018] In one embodiment of this disclosure, the fourth edge is located at the corner where the extensions of the first and second main edges intersect.

[0019] In one embodiment of this disclosure, the first and second main edges or their extensions intersect in the region near the right-angle corner of the surface of the body.

[0020] In one embodiment of this disclosure, one end of the first main edge is connected to the end of the third main edge near the first main edge via a fifth edge perpendicular to the first main edge.

[0021] In one embodiment of this disclosure, one end of the second main edge is connected to the end of the third main edge near the second main edge via a sixth edge perpendicular to the second main edge.

[0022] In one embodiment of this disclosure, one or more coupling holes are provided on one surface of the main body as input coupling holes.

[0023] In one embodiment of this disclosure, one or more coupling holes are provided on one surface of the main body as output coupling holes, and the surface where the output coupling holes are located is approximately opposite to the surface where the input coupling holes are located.

[0024] In embodiments of this disclosure, the input coupling hole and the output coupling hole are either mirror images of each other or not mirror images of each other.

[0025] In one embodiment of this disclosure, the dielectric material is ceramic.

[0026] According to a second aspect of this disclosure, a waveguide filter is provided, which includes a three-mode resonator as described above.

[0027] In one embodiment of this disclosure, the waveguide filter further includes: a first single-mode resonator having a body formed of a dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling aperture; and a second single-mode resonator having a body formed of a dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling aperture, and the tri-mode resonator being sandwiched between the first and second single-mode resonators in such a way that the tri-mode resonator is in communication with the first and second single-mode resonators respectively through corresponding coupling apertures on their contact surfaces, and is capable of exciting the three desired principal resonance modes in the tri-mode resonator.

[0028] In one embodiment of this disclosure, the waveguide filter further includes a third single-mode resonator having a body formed of a dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole, and the third single-mode resonator communicating with the first single-mode resonator via a corresponding coupling hole on its abutment surface.

[0029] In one embodiment of this disclosure, the output coupling hole on the third single-mode resonator and the input coupling hole on the first single-mode resonator are in the form of circular slots.

[0030] In one embodiment of this disclosure, on the surface of the third single-mode resonator opposite to the surface where its output coupling hole is located, an input device is connected to the dielectric material in the third single-mode resonator to supply the signal to be filtered.

[0031] In one embodiment of this disclosure, the rotation axis of the input device coincides with the central axis of the circular slot of the third and first single-mode resonators.

[0032] In one embodiment of this disclosure, the third main edge of the coupling hole on the three-mode resonator is in the form of an arc-shaped segment curved toward the inside of the coupling hole, wherein the center of the arc-shaped segment is the center of the surface in which the arc-shaped segment is located, and the rotation axis of the input device extends through the center of the arc-shaped segment.

[0033] In one embodiment of this disclosure, the waveguide filter further includes a fourth single-mode resonator having a body formed of a dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole, and the fourth single-mode resonator communicating with the second single-mode resonator via a corresponding coupling hole on its abutment surface.

[0034] In one embodiment of this disclosure, on the surface of the fourth single-mode resonator opposite to the surface where its input coupling hole is located, an output device is connected to the dielectric material in the fourth single-mode resonator for outputting a filtered signal.

[0035] In one embodiment of this disclosure, the first single-mode resonator and the second single-mode resonator are mirror-symmetric to each other, and / or the third single-mode resonator and the fourth single-mode resonator are mirror-symmetric to each other.

[0036] In one embodiment of this disclosure, the first, second, third, and fourth single-mode resonators and the three-mode resonator are all made of the same dielectric material.

[0037] In one embodiment of this disclosure, all of the resonators are made of ceramic dielectric material.

[0038] In one embodiment of this disclosure, the filter is integrally formed by casting.

[0039] Using the resonator disclosed herein, the Q-factor of the three-mode filter can be significantly improved compared to a cascaded single-mode filter of the same size. Therefore, the improved Q-factor leads to improved insertion loss in the waveguide filter. Furthermore, the proposed coupling structure allows for easy control of cross-coupling. Negative and positive couplings can be more flexibly established, routed, and placed. Desired broadband coupling can also be achieved.

[0040] The waveguide filter disclosed herein enables better near-band attenuation performance with less negative coupling, which is beneficial for near-band spurious emissions and in-band insertion loss. Furthermore, it improves the filter's harmonic parameters. In addition, it simplifies low-pass filter design, thereby improving overall FU performance, particularly insertion loss.

[0041] Furthermore, the multimode CWG filter disclosed herein can be flexibly designed for installation in AUs or macro stations. This improves production efficiency while reducing production costs due to the benefits in both production consistency and accuracy. Attached Figure Description

[0042] These and other objects, features, and advantages of this disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which should be read in conjunction with the accompanying drawings.

[0043] Figure 1 This is a perspective view of the waveguide filter according to this disclosure;

[0044] Figure 2 Is it like this? Figure 1 A perspective view of a portion of the waveguide filter shown;

[0045] Figure 3 Is it like this? Figure 2 A side view of a portion of the waveguide filter shown;

[0046] Figure 4 This is an end view of the three-mode resonator disclosed herein;

[0047] Figure 5 This is an end view of another variation of the three-mode resonator disclosed herein;

[0048] Figure 6 This is a perspective view of another variation of the three-mode resonator disclosed herein;

[0049] Figure 7A It shows the result of, as Figure 4 The electric field in mode 1 excited by the coupling aperture of the three-mode resonator of this disclosure is shown.

[0050] Figure 7B It shows the result of, as Figure 4 The electric field in mode 2 excited by the coupling hole of the three-mode resonator of this disclosure is shown.

[0051] Figure 7C It shows the result of, as Figure 4 The electric field in mode 3 excited by the coupling aperture of the three-mode resonator of this disclosure is shown; and

[0052] Figure 8 The topology of the waveguide filter disclosed herein is shown. Detailed Implementation

[0053] Embodiments of this disclosure are described in detail below with reference to the accompanying drawings. It should be understood that these embodiments are discussed merely to enable those skilled in the art to better understand and implement this disclosure, and not to impose any limitation on the scope of this disclosure. References to features, advantages, or similar language throughout this specification do not imply that all features and advantages achievable through this disclosure should be present in or in any single embodiment of this disclosure. Rather, references to features and advantages should be understood as meaning that a particular feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Furthermore, the features, advantages, and characteristics described in this disclosure may be combined in one or more embodiments in any suitable manner. Those skilled in the art will recognize that this disclosure can be practiced without one or more specific features or advantages of a particular embodiment. In other cases, additional features and advantages may be recognized in some embodiments that may not be present in all embodiments of this disclosure.

[0054] Generally, all terms used herein should be interpreted according to their ordinary meaning in the relevant art, unless explicitly given and / or implied from the context of their use. Unless expressly stated otherwise, all references to "a / an / element, device, component, apparatus, step, etc." should be interpreted as referring to at least one instance of that element, device, component, apparatus, step, etc. Any feature of any embodiment disclosed herein may be applied to any other embodiment, where appropriate. Similarly, any advantage of any embodiment may be applied to any other embodiment, and vice versa. Other objects, features, and advantages of the appended embodiments will become apparent from the following description.

[0055] Figure 1 A perspective view of the waveguide filter 1 of this disclosure, including multiple resonators coupled in series, is shown. Figure 2 A perspective view of some resonators is shown.

[0056] The waveguide filter 1 includes a three-mode resonator 100 and a first single-mode resonator 201 (i.e., a first intermediate resonator) and a second single-mode resonator 202 (i.e., a second intermediate resonator) connected to the three-mode resonator at opposite ends along the y-axis. A third single-mode resonator 301 is coupled to the first intermediate resonator 201 as an input resonator. A fourth single-mode resonator 302 is coupled to the second intermediate resonator 202 as an output resonator. Figure 1In the illustrated embodiment, the input resonator 301 and output resonator 302, as well as the first intermediate resonator 201 and the second intermediate resonator 202, are single-mode resonators, each comprising a body and an external coating of conductive material covering the body. The body has an uncovered portion for providing a coupling aperture that allows coupling between the signal and the body. The input resonator 301 has an input device 401 connected to its body to allow the application of an unfiltered signal, and the output resonator 302 has an output device 402 connected to its body to allow the output of a filtered signal.

[0057] exist Figure 1 In the waveguide filter 1 shown, a three-mode resonator 100 is sandwiched between a first intermediate resonator 201 and a second intermediate resonator 202. Similar to those single-mode resonators 301, 201, 202, 302, the three-mode resonator 100 includes a body and an external coating made of conductive material covering the body. The body has an uncovered portion for providing a coupling aperture that allows coupling between the signal and the body.

[0058] Typically, for all resonators 301, 201, 100, 202, 302, each of their bodies comprises, or more typically is made of, a solid body formed of a dielectric material with suitable dielectric properties. The dielectric material used for these resonators may be the same or different. In one example, their body is a ceramic block, although this is not required and alternative materials can be used.

[0059] The main bodies of the input resonator 301, output resonator 302, first intermediate resonator 201, and second intermediate resonator 202 can be of any shape. In the illustrated example, the main bodies of the input resonator 301, output resonator 302, first intermediate resonator 201, and second intermediate resonator 202 are each in the form of a rectangular cuboid, defining three orthogonal axes approximately aligned with the faces of the main body, such as... Figure 1 The axes x, y, and z are shown in the figure. In the example shown, the body of the three-mode resonator 100 is a ceramic block in the form of a cuboid (or cube) with faces that are approximately aligned with the three orthogonal axes x, y, and z.

[0060] The conductive materials used for all these resonators can be the same or different. In the illustrated embodiment, silver is chosen for all resonators. Those skilled in the art will readily appreciate that other conductive materials, such as gold, copper, etc., can be used.

[0061] refer to Figure 1-3 All resonators 301, 201, 100, 202, and 302 are coupled in series through the connection of corresponding coupling holes on their contact surfaces. Figure 1In the example shown, the input resonator 301 and the first intermediate resonator 201 abut against each other. The output coupling hole 311a in the outer coating of the input resonator 301 is coaxially aligned with the input coupling hole 311b in the outer coating of the first intermediate resonator 201, thus providing an overlapping opening in the form of a circular slot for transferring electromagnetic energy from the input resonator 301 to the first intermediate resonator 201. Although the coupling holes 311a and 311b are shown as circular slots of the same size, it is readily apparent that their shapes and sizes can be designed differently, as long as the opening 311 defined by their overlap is circular and has a sufficient cross-sectional area for energy transfer.

[0062] Figure 3 Specifically, coupling holes 110, 120, and 130 are shown as input coupling holes on the input surface of the main body of the three-mode resonator 100. Each coupling hole 110, 120, and 130 has a closed shape, comprising first main edges 110a, 120a, and 130a extending along two axes z and x, respectively, and second main edges 110c, 120c, and 130c, extending neither parallel nor perpendicular to the first and second main edges, and third main edges 110b, 120b, and 130b. The general shape, size, and position of each input coupling hole 110, 120, and 130 are primarily determined by the first, second, and third main edges. Furthermore, the input coupling holes on the input surface of the three-mode resonator 100 are configured such that input signals introduced through them can independently excite the three desired principal resonant modes in the three-mode resonator 100. Each main edge of the coupling hole excites one resonant mode independently of the other main edges of the coupling hole. Therefore, each mode can be adjusted individually.

[0063] The term "position" here refers to the position information of the input coupling hole (including each segment of its edge) in a Cartesian coordinate system associated with the surface where the input coupling hole is located.

[0064] On the output surface of the first intermediate resonator 201 opposite to the input surface where the input coupling hole 311b is located, three coupling holes 210, 220, and 230 are provided in the outer coating of the first intermediate resonator 201 as output coupling holes, which are used to connect with the coupling holes 110, 120, and 130 of the three-mode resonator 100 respectively.

[0065] Despite Figure 1The diagram shows that each coupling hole 210, 220, 230 is identical in shape, size, and orientation to the corresponding coupling holes in coupling holes 110, 120, 130. However, those skilled in the art will readily recognize that, provided the coupling holes 110, 120, 130 of the three-mode resonator 100 can be well used to excite three-mode resonance in its body, the coupling holes aligned with each other on the abutment surfaces can be designed differently. For example, the shape, size, and orientation can be different.

[0066] Figure 4 and Figure 5 Some variations of the input coupling holes 110, 120, 130, 110', 120', and 130' of the three-mode resonator 100 of this disclosure are shown. For example... Figure 4 and Figure 5 As shown, the input coupling holes 110, 120, 130, 110', 120', and 130' are approximately triangular in shape. The first main edges 110a, 120a, 130a, and 130'a of each input coupling hole intersect with the second main edges 110c, 120c, 130c, and 130'c in the region near the right-angle corner of the input surface of the tri-mode resonator 100. The third main edges 110b and 110'b are in the form of arc-shaped segments. The arc-shaped segments bend inward toward the coupling holes 110 and 110', and their center is the center of the input surface of the tri-mode resonator 100 where the arc-shaped segments are located.

[0067] exist Figure 5 In the illustrated embodiment, each of the input coupling holes 110' and 120' includes a fourth edge 110'd and 120'd, which extends obliquely relative to the first main edges 110'a and 120'a and the second main edges 110'c and 120', respectively, at its ends intersecting the first main edges 110'a and 120'a and the second main edges 110'c and 120'c. The fourth edges 110'd and 120'd are located at the corner where the extensions of the first main edges 110'a and 120'a intersect with the extensions of the second main edges 110'c and 120'c. That is, the fourth edges 110'd and 120'd are chamfered. In the illustrated example, the extensions of the first main edges 110'a, 120'a and the second main edges 110'c, 120'c of the single input coupling hole intersect in the region near the right-angle corner of the input surface of the tri-mode resonator 100 disclosed herein.

[0068] Moreover, in Figure 4 and 5In the input coupling holes 110, 120, 130, 110', 120', 130' shown, one end of the first main edge 110a, 120a, 130a, 110'a, 120'a, 130'a is connected to the end of the third main edge 110b, 120b, 130b, 110'b, 120'b, 130'e near the first main edge via the fifth edge 110e, 120e, 130e, 110'e, 120'e, 130'e perpendicular to the first main edge. One end of the second primary edges 110c, 120c, 130c, 110'c, 120'c, 130'c is connected to the end of the third primary edges 110b, 120b, 130b, 110'b, 120'b, 130'b near the second primary edge via the sixth edges 110f, 120f, 130f, 110'f, 120'f, 130'f perpendicular to the second primary edges.

[0069] like Figure 4 and 5 As shown, none of the input coupling holes 110, 120, 130, 110', 120', and 130' of the three-mode resonator 100 are precisely triangular. However, they can be considered approximately triangular, and those skilled in the art will readily recognize that these input coupling holes of the three-mode resonator can be configured to be precisely triangular or other shapes that can be derived from triangular or polygonal shapes or similar geometries, as long as the three principal resonant modes required can be independently excited in the resonator by the input signal introduced through the input coupling holes. Furthermore, although three coupling holes are shown on the input surface of the resonator, the number of input coupling holes can be varied according to actual needs. For example, only one input coupling hole or more may be provided on the input surface of the resonator body. The arrangement of the input coupling holes can be changed accordingly, as long as the three principal resonant modes can be independently excited in the body of the three-mode resonator as needed.

[0070] Return to reference Figure 1 Three coupling holes 111, 121, and 131 are provided as output coupling holes on the surface of the main body of the three-mode resonator 100 that is substantially opposite to the surfaces containing the input coupling holes 110, 120, and 130. In the illustrated example, the output coupling holes 111, 121, and 131 are configured and distributed in almost the same manner as the input coupling holes 110, 120, and 130, such that they can be considered to be substantially mirror-symmetrical to each other with respect to the plane of symmetry of the three-mode resonator 100 perpendicular to the y-axis. However, it is not mandatory that the placement and / or shape and / or size and / or orientation of the output coupling holes 111, 121, and 131 be exactly the same as those of the input coupling holes 110, 120, and 130. Other configurations of the output coupling holes of the three-mode resonator 100 will be conceived by those skilled in the art (e.g., Figure 6 The configuration / arrangement of the output coupling holes shown can be as long as they can output signals filtered by the three-mode resonance within the resonator 100.

[0071] Similar to the first intermediate resonator 201, the second intermediate resonator 202 includes three input coupling holes 211, 221, and 231 disposed on its surface abutting the output surface of the tri-mode resonator 100, and an output coupling hole 312b in the form of a circular slot. The signal output from the tri-mode resonator 100 is introduced into the second intermediate resonator 202 via the input coupling holes 211, 221, and 231, and finally exits via its output coupling hole 312b. An input coupling hole 312a is provided in the output resonator 302 to communicate with the output coupling hole 312b. Although both coupling holes 312a and 312b are shown as circular slots of the same size, it is readily apparent that their shapes and sizes could be designed differently, provided that the opening 312 defined by the overlap of the output coupling hole 312b and the input coupling hole 312a is circular and has a sufficient cross-sectional area for energy transfer.

[0072] In the illustrated example, the rotation axis of the input device 401 coincides with the central axis of the circular opening 311. Preferably, the rotation axis of the input device 401 extends through the center of the arc of the third main edges 110b, 110'b, which are in the form of arcuate segments. Figure 1 In a preferred embodiment shown, the first intermediate resonator 201 and the second intermediate resonator 202 are configured and aligned in such a way that they are mirror-symmetric to each other with respect to the plane of symmetry of the tri-mode resonator 100 perpendicular to the y-axis direction, and / or the input resonator 301 and the output resonator 302 are configured and aligned in such a way that they are mirror-symmetric to each other with respect to the plane of symmetry of the tri-mode resonator 100 perpendicular to the y-axis direction. Figure 1 As shown, the input device 401 and the output device 402 are arranged approximately coaxially.

[0073] To better understand this disclosure, the working principle and technical advantages of waveguide filter 1 are described as follows:

[0074] The electric field (in mode 2) generated inside the input resonator 301 by the input device 401 is along the y-axis and perpendicular to the xoz plane, as shown below. Figure 7B As shown. The first intermediate resonator 201 serves as a mode switching section via a connection associated with its input coupling aperture 311b and output coupling apertures 210, 220, 230. Three main resonant modes, namely mode 1 (e.g., mode 2), can be excited in the three-mode resonator 100 via input coupling apertures 110, 120, 130. Figure 7A As shown), Mode 2 (as shown) Figure 7B (as shown) and Mode 3 (as shown) Figure 7C (As shown).

[0075] Specifically, the first main edges 110a, 120a, and 130a are primarily responsible for coupling mode 2 from the input resonator 301 (first intermediate resonator) to mode 1 in the three-mode resonator 100, such as... Figure 7A As shown, the length and position of the first main edges 110a, 120a, and 130a define the coupling strength from mode 2 in the input resonator 301 (and / or the first intermediate resonator) to mode 1 in the tri-mode resonator 100. Furthermore, the positions of the first main edges 110a, 120a, and 130a define the sign of the coupling. That is, by changing the positions of the first main edges 110a, 120a, and 130a, the sign of the coupling can be adjusted to be positive or negative. Moreover, the first main edges 110a, 120a, and 130a can be precisely designed to adjust the cross-coupling between modes 1 within the tri-mode resonator 100.

[0076] The second primary edges 110c, 120c, and 130c are mainly responsible for coupling mode 2 from the input resonator 301 (and / or the first intermediate resonator) to mode 3 in the three-mode resonator 100, such as... Figure 7C As shown, the coupling strength can be adjusted by changing the length and position of the second main edges 110c, 120c, and 130c. Furthermore, the positions of the second main edges 110c, 120c, and 130c define the sign of the coupling. By changing the position of the second main edges, the sign of the coupling can be adjusted to positive or negative. Moreover, the second main edges 110c, 120c, and 130c can be precisely designed to adjust the cross-coupling between modes 3 within the three-mode resonator 100.

[0077] The third main edges 110b, 120b, and 130b are primarily responsible for coupling mode 2 from the input resonator 301 (and / or the first intermediate resonator) to mode 2 in the three-mode resonator 100, such as... Figure 7B As shown. The third main edges 110b, 120b, and 130b can be precisely designed to adjust the cross-coupling between modes 2 within the three-mode resonator 100. This is achieved by arranging the input device 401 in such a way that its axis of rotation coincides with the central axis of the circular opening 311 and extends through the arc centers of the third main edges 110b and 110'b in the form of arcuate segments, as... Figure 1 As shown, the coupling efficiency can be adjusted. To reduce the coupling efficiency, the third main edge of the input coupling aperture of the three-mode resonator 100 can be changed to a line, as shown below. Figure 4 and 5Lines 120b, 130b, 120'b, and 130'b are shown in the diagram. In a preferred embodiment, the third primary edge of the line is tilted at an angle of 45° or approximately 45° (e.g., 30° to 60°, or 20° to 70°) relative to the x or z axis. Furthermore, the coupling strength can be varied by changing the position and shape of the third primary edges 110b, 120b, 130b, 110'b, 120'b, and 130'b.

[0078] Figure 8 As shown Figure 1 The corresponding topology of waveguide filter 1 is shown. For better illustration, the three-mode resonator 100 can be considered to include three effective cavities #3, #4, and #5, used for resonance in modes 1, 2, and 3, respectively. Furthermore, the single-mode resonators 301, 201, 202, and 302 can be considered to include cavities #1, #2, #6, and #7, respectively, used for single-mode resonance therein. A seven-pole topology with two pairs of symmetrical zeros is provided, wherein eight main couplings (i.e., between cavities #1 and #2, between cavities #2 and #3, between cavities #3 and #6, between cavities #2 and #4, between cavities #4 and #6, between cavities #2 and #5, between cavities #5 and #6, and between cavities #6 and #7) are provided from the corresponding coupling holes on the abutment surfaces of the resonators. With this topology, the main couplings and cross couplings can be freely manipulated to achieve the desired transmission function. Capacitive coupling / negative cross coupling with a small coupling value is provided between cavities #2 and #5. Figure 8 As shown in the topology, the cross-coupling between mode 1 and mode 2 in the three-mode resonator 100, between mode 1 and mode 3 in the three-mode resonator 100, and between mode 2 and mode 3 in the three-mode resonator 100 must be bridged by the first intermediate resonator 201 and the second intermediate resonator 202, respectively.

[0079] In summary, the waveguide filter disclosed herein can provide efficient strong primary / negative / capacitive coupling, thereby allowing for flexible implementation of coupling values ​​and shapes.

[0080] If the same dielectric material, such as ceramic, is chosen for the body of all resonators in waveguide filter 1, waveguide filter 1 can be integrally cast. This eliminates the assembly step required to connect all resonators in series, thereby improving production efficiency.

[0081] Despite Figure 1 The diagram illustrates five resonators coupled to form a filter, but the number of resonator / filter poles can be varied, thus affecting the filter's near-band attenuation / selectivity as expected. For filters of the same order, the number of zeros or the amount of cross-coupling greatly helps optimize the filter's near-band attenuation performance.

[0082] The terms "one embodiment," "another embodiment," etc., used in this disclosure indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such terms do not necessarily refer to the same embodiment. Additionally, when a specific feature, structure, or characteristic is described in connection with one embodiment, it is believed that implementing such a feature, structure, or characteristic in conjunction with other embodiments is within the understanding of those skilled in the art, whether explicitly described or not.

[0083] It should be understood that the term "and / or" includes any and all combinations of one or more of the related listed terms.

[0084] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should be further understood that the terms “comprises,” “comprising,” “has,” “having,” “includes,” and / or “including,” when used herein, specify the presence of the stated feature, element, and / or component, but do not exclude the presence or addition of one or more other features, elements, components, and / or combinations thereof. The terms “connect,” “connects,” “connecting,” and / or “connected” as used herein cover direct and / or indirect connections between two elements.

[0085] This disclosure includes any novel feature or combination of features expressly disclosed herein, or any generalization thereof. Various modifications and adjustments to the foregoing exemplary embodiments of this disclosure will be apparent to those skilled in the art when read in conjunction with the accompanying drawings, in light of the foregoing description. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure.

Claims

1. A three-mode resonator (100), comprising: The body is made of a dielectric material and has a cuboid shape that defines three orthogonal axes (x, y, z) that are generally aligned with the faces of the body; and A conductive coating covers the entire body except for the portion defining at least one coupling hole (110, 120, 130, 110', 120', 130') on the surface of the body, through which signals can be coupled into and / or out of the body. The coupling aperture has a closed shape comprising two first main edges (110a, 120a, 130a) and a second main edge (110c, 120c, 130c) extending along the axis, respectively, and a third main edge (110b, 120b, 130b) extending neither parallel to nor perpendicular to the first and second main edges. The overall shape, size, and position of the coupling aperture are primarily determined by the first, second, and third main edges. The coupling aperture is configured such that an input signal introduced through it can independently excite the three main resonant modes required in the three-mode resonator (100). The third main edge (110b, 110'b) is in the form of an arcuate segment. The coupling aperture also includes a fourth edge (110'd, 120'd) extending obliquely relative to the first and second main edges to intersect them.

2. The three-mode resonator (100) according to claim 1, wherein, The coupling holes (110, 120, 130, 110', 120', 130') are roughly triangular in shape.

3. The three-mode resonator (100) according to claim 1, wherein, The arc-shaped section bends toward the inside of the coupling hole, and the center of the arc of the arc-shaped section is the center of the surface in which the arc-shaped section is located.

4. The three-mode resonator (100) according to claim 1, wherein, The fourth edge (110'd, 120'd) is located at the corner where the extensions of the first and second main edges intersect.

5. The three-mode resonator (100) according to any one of claims 1-4, wherein, The first main edge (110a, 120a, 130a) and the second main edge (110c, 120c, 130c) or their extensions intersect in the area near the right-angle corner of the surface of the body.

6. The three-mode resonator (100) according to any one of claims 1-4, wherein, One end of the first main edge (110a, 120a, 130a) is connected to the end of the third main edge (110b, 120b, 130b) near the first main edge via a fifth edge (110e, 120e, 130e) perpendicular to the first main edge (110a, 120a, 130a).

7. The three-mode resonator (100) according to any one of claims 1-4, wherein, One end of the second main edge (110c, 120c, 130c) is connected to the end of the third main edge (110b, 120b, 130b) near the second main edge via a sixth edge (110f, 120f, 130f) perpendicular to the second main edge.

8. The three-mode resonator (100) according to any one of claims 1-4, wherein, One or more coupling holes (110, 120, 130, 110', 120', 130') are provided as input coupling holes on one side of the main body.

9. The three-mode resonator (100) according to claim 8, wherein, One or more coupling holes (111, 121, 131) are provided as output coupling holes on one side of the main body, and the side where the output coupling hole is located is approximately opposite to the side where the input coupling hole is located.

10. The three-mode resonator (100) according to claim 9, wherein, The input coupling holes (110, 120, 130) and the output coupling holes (111, 121, 131) are either mirror images of each other or not mirror images of each other.

11. The three-mode resonator (100) according to any one of claims 1-4, wherein, The dielectric material is ceramic.

12. A waveguide filter (1) comprising a three-mode resonator (100) according to any one of claims 1-11.

13. The waveguide filter (1) according to claim 12, wherein, The waveguide filter further includes: a first single-mode resonator (201) having a body formed of dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole; and a second single-mode resonator (202) having a body formed of dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole, and the three-mode resonator (100) being sandwiched between the first and second single-mode resonators in such a way that the three-mode resonator is connected to the first and second single-mode resonators respectively through corresponding coupling holes on their contact surfaces, and is capable of exciting the three desired principal resonance modes in the three-mode resonator.

14. The waveguide filter (1) according to claim 13, wherein, The waveguide filter further includes a third single-mode resonator (301) having a body formed of dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole, and the third single-mode resonator (301) communicating with the first single-mode resonator (201) via a corresponding coupling hole on its contact surface.

15. The waveguide filter (1) according to claim 14, wherein, The output coupling hole (311a) on the third single-mode resonator and the input coupling hole (311b) on the first single-mode resonator are in the form of circular slots.

16. The waveguide filter (1) according to claim 15, wherein, On the surface of the third single-mode resonator (301) opposite to the surface where its output coupling hole is located, the input device (401) is connected to the dielectric material in the third single-mode resonator to supply the signal to be filtered.

17. The waveguide filter (1) according to claim 16, wherein, The rotation axis of the input device (401) coincides with the central axis of the circular slot (311) of the third and first single-mode resonators.

18. The waveguide filter (1) according to claim 16, wherein, The third main edge (110b, 120b, 130b) of the coupling hole on the three-mode resonator (100) is in the form of an arc-shaped segment curved toward the inside of the coupling hole, wherein the center of the arc-shaped segment is the center of the surface in which the arc-shaped segment is located, and the rotation axis of the input device (401) extends through the center of the arc-shaped segment.

19. The waveguide filter (1) according to any one of claims 16-18, wherein, The waveguide filter further includes a fourth single-mode resonator (302) having a body formed of dielectric material and an external conductive coating covering the body, the body having an uncovered portion defining a coupling hole, and the fourth single-mode resonator (302) communicating with the second single-mode resonator (202) via a corresponding coupling hole on its contact surface.

20. The waveguide filter (1) according to claim 19, wherein, On the surface of the fourth single-mode resonator (302) opposite to the surface where its input coupling hole is located, the output device (402) is connected to the dielectric material in the fourth single-mode resonator (302) for outputting a filtered signal.

21. The waveguide filter (1) according to claim 20, wherein, The first single-mode resonator (201) and the second single-mode resonator (202) are mirror images of each other, and / or the third single-mode resonator (301) and the fourth single-mode resonator (302) are mirror images of each other.

22. The waveguide filter (1) according to claim 21, wherein, The first, second, third, and fourth single-mode resonators and the three-mode resonator have a body made of the same dielectric material.

23. The waveguide filter (1) according to claim 22, wherein, The dielectric material is ceramic.

24. The waveguide filter (1) according to claim 22 or 23, wherein, The filter is integrally formed by casting.

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