An ultra-narrowband filter

Abstract

The present application provides an ultra-narrowband filter, comprising a symmetrically arranged input feeder structure and an output feeder structure, and a plurality of symmetrically arranged and sequentially arranged dual-ring resonators; wherein the input feeder structure is slot-coupled with the first of the plurality of dual-ring resonators, and the output feeder structure is slot-coupled with the last of the plurality of dual-ring resonators to provide electromagnetic excitation; and each two adjacent dual-ring resonators in the plurality of dual-ring resonators are slot-coupled to generate an ultra-narrowband under electromagnetic excitation. In the present application, the ultra-narrowband filter is easy to design and implement, and the structure is simple.

Description

Technical Field

[0001] The disclosed embodiments of the present application relate to the field of wireless communication technology, and more particularly, to an ultra-narrowband filter. Background Art

[0002] Radio signals emitted from celestial bodies with narrow spectrum are usually very weak and often drowned out by various interferences. Therefore, in order to receive radio signals emitted from celestial bodies with narrow spectrum, it is of great significance to design ultra-narrowband filters.

[0003] Moreover, with the development of astronomical objects with narrow spectrum, the demand for ultra-narrowband filters is increasing, thus putting forward high requirements for bandpass filters with low insertion loss, ultra-narrow passband and high selectivity.

[0004] Therefore, in order to meet the needs of accurately receiving weak radio source signals emitted by celestial bodies and cope with the complex and changeable electromagnetic noise interference environment, it is of great significance to study and design high-performance ultra-narrowband filters. Summary of the Invention

[0005] According to an embodiment of the present application, an ultra-narrowband filter is proposed to solve the above-mentioned problem.

[0006] According to aspects of the present application, an exemplary ultra-narrowband filter is disclosed. The exemplary ultra-narrowband filter includes a symmetrically arranged input feeder structure and an output feeder structure, and a plurality of symmetrically arranged and sequentially arranged dual-ring resonators; wherein the input feeder structure is slot-coupled with the first dual-ring resonator in the plurality of dual-ring resonators, and the output feeder structure is slot-coupled with the last dual-ring resonator in the plurality of dual-ring resonators to provide electromagnetic excitation; and every two adjacent dual-ring resonators in the plurality of dual-ring resonators are slot-coupled to generate an ultra-narrowband under the action of electromagnetic excitation.

[0007] In some embodiments, each of the plurality of dual ring resonators includes a first ring structure and a second ring structure, wherein the first ring structure and the second ring structure partially overlap, and the second ring structure is nested within the first ring structure.

[0008] In some embodiments, the first ring structure includes a first ring branch and a second ring branch, and both ends of the first ring branch are connected to both ends of the second ring branch to form a closed ring; the second ring structure includes a third ring branch and a fourth ring branch, and both ends of the third ring branch are connected to both ends of the fourth ring branch to form a closed ring; wherein, the first ring branch and the third ring branch are the same ring branch, so that the first ring structure and the second ring structure partially overlap; the fourth ring branch is located within the first ring structure, so that the second ring structure is nested within the first ring structure.

[0009] In some embodiments, the first loop branch line is bent twice, and the second loop branch line is bent twice.

[0010] In some embodiments, within the first ring structure, the fourth ring branch line is bent multiple times in the bending direction of the second ring branch line so that the corresponding portion of the fourth ring branch line is parallel to the corresponding portion of the second ring branch line with a preset gap therebetween.

[0011] In some embodiments, the equivalent impedances of the first loop branch, the second loop branch, the third loop branch, and the fourth loop branch are the same.

[0012] In some embodiments, the multiple dual-ring resonators include a first dual-ring resonator, a second dual-ring resonator, a third dual-ring resonator, a fourth dual-ring resonator, a fifth dual-ring resonator and a sixth dual-ring resonator; wherein the first dual-ring resonator and the sixth dual-ring resonator are symmetrically arranged, and are respectively the first dual-ring resonator and the last dual-ring resonator among the multiple dual-ring resonators; the second dual-ring resonator and the fifth dual-ring resonator are symmetrically arranged; and the third dual-ring resonator and the fourth dual-ring resonator are symmetrically arranged.

[0013] In some embodiments, the gap between the first dual-ring resonator and the second dual-ring resonator and the gap between the sixth dual-ring resonator and the fifth dual-ring resonator are both first gaps, wherein the first gap is used for gap coupling between the first dual-ring resonator and the second dual-ring resonator and gap coupling between the sixth dual-ring resonator and the fifth dual-ring resonator; the gap between the second dual-ring resonator and the third dual-ring resonator and the gap between the fifth dual-ring resonator and the fourth dual-ring resonator are both second gaps, wherein the second gap is used for gap coupling between the second dual-ring resonator and the third dual-ring resonator and gap coupling between the fifth dual-ring resonator and the fourth dual-ring resonator; the gap between the third dual-ring resonator and the fourth dual-ring resonator is a third gap, wherein the third gap is used for gap coupling between the third dual-ring resonator and the fourth dual-ring resonator; wherein the first gap, the second gap and the third gap are different from each other and increase in sequence.

[0014] In some embodiments, each of the input feeder structure and the output feeder structure includes a feeding portion and a coupling portion, wherein one end of the feeding portion is connected to the coupling portion and is at different distances from both ends of the coupling portion, and the other end of the feeding portion serves as an input / output port, and the coupling portion is used to achieve gap coupling with the first dual-ring resonator or the last dual-ring resonator among the multiple dual-ring resonators.

[0015] In some embodiments, the coupling portion includes a first coupling line and a second coupling line connected to each other; wherein the first coupling line is perpendicular to the feeding portion, and the feeding portion is close to one end of the first coupling line; the second coupling line is perpendicular to the first coupling line, and the second coupling line and the feeding portion are located on both sides of the first coupling line.

[0016] The beneficial effects of the present application are as follows: by gap coupling between every two adjacent dual-ring resonators in a plurality of symmetrically arranged and sequentially arranged dual-ring resonators, an ultra-narrow band is generated under the electromagnetic excitation of an input feeder structure and an output feeder structure, which is easy to design and realize an ultra-narrow band and has a simple structure.

[0017] These and other objects of the present application will no doubt become apparent to those skilled in the art after reading the following detailed description of the preferred embodiments illustrated in the drawings and therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 3 is a schematic structural diagram of an ultra-narrowband filter according to an embodiment of the present application.

[0019] Figure 2Schematic diagram of the structure of the dual-ring resonator involved in the ultra-narrowband filter according to an embodiment of the present application.

[0020] Figure 3 is a scattering parameter curve diagram of the ultra-narrowband filter according to an embodiment of the present application. DETAILED DESCRIPTION

[0021] Certain terms used throughout this specification and claims refer to specific components. As will be appreciated by those skilled in the art, electronic equipment manufacturers may use different names to refer to the same component. Components are not distinguished by name herein, but rather by function. In the following specification and claims, the term "including" is an open-ended qualifier and should therefore be interpreted to mean "including but not limited to...". Additionally, the term "coupled" is intended to mean either an indirect electrical connection or a direct electrical connection. Thus, when one device is coupled to another device, such connection may be a direct electrical connection or an indirect electrical connection achieved through other devices and connections.

[0022] like Figure 1 2 is a schematic structural diagram of an ultra-narrowband filter 100 according to an embodiment of the present application. The ultra-narrowband filter 100 includes a symmetrically arranged input feeder structure 110 and an output feeder structure 120, and a plurality of symmetrically arranged and sequentially arranged dual-ring resonators, for example, including six dual-ring resonators, namely, a first dual-ring resonator 130a, a second dual-ring resonator 130b, a third dual-ring resonator 130c, a fourth dual-ring resonator 130d, a fifth dual-ring resonator 130e, and a sixth dual-ring resonator 130f.

[0023] The symmetric arrangement of the input feeder structure 110, the output feeder structure 120, and the multiple dual-ring resonators can be configured based on actual circuit design considerations. In this embodiment, the symmetric arrangement of the input feeder structure 110, the output feeder structure 120, and the symmetric arrangement of the multiple dual-ring resonators can be vertically symmetric, that is, the symmetric direction is vertical. In other embodiments, the symmetric arrangement of the input feeder structure 110, the output feeder structure 120, and the symmetric arrangement of the multiple dual-ring resonators can also be symmetric about an inclined line.

[0024] The dual-ring resonator is a symmetrically arranged structure, including two ring structures, which can achieve weak coupling. When designing an ultra-narrowband bandpass filter, the coupling between the two resonators needs to be weak, so the dual-ring resonator is used to design an ultra-narrowband bandpass filter.

[0025] The input feed line structure 110 is slot-coupled with the first dual-ring resonator among the multiple dual-ring resonators, and the output feed line structure 120 is slot-coupled with the last dual-ring resonator among the multiple dual-ring resonators to provide electromagnetic excitation. For example, in an example where the multiple dual-ring resonators include six dual-ring resonators, the input feed line structure 110 is slot-coupled with the first dual-ring resonator 130a, and the output feed line structure 120 is slot-coupled with the sixth dual-ring resonator 130f to provide electromagnetic excitation.

[0026] Every two adjacent dual-ring resonators in the plurality of dual-ring resonators are slot-coupled to generate an ultra-narrowband under electromagnetic excitation. For example, in an example where the plurality of dual-ring resonators includes six dual-ring resonators, the first dual-ring resonator 130a is slot-coupled with the second dual-ring resonator 130b, the second dual-ring resonator 130b is slot-coupled with the third dual-ring resonator 130c, the third dual-ring resonator 130c is slot-coupled with the fourth dual-ring resonator 130d, the fourth dual-ring resonator 130d is slot-coupled with the fifth dual-ring resonator 130e, and the fifth dual-ring resonator 130e is slot-coupled with the sixth dual-ring resonator 130f.

[0027] In this embodiment, by gap coupling between two adjacent dual-ring resonators in a plurality of symmetrically arranged and sequentially arranged dual-ring resonators, an ultra-narrow band is generated under the electromagnetic excitation of the input feeder structure 110 and the output feeder structure 120. This makes it easy to design and implement an ultra-narrow band and has a simple structure.

[0028] As described above, each adjacent two dual-ring resonators in a plurality of dual-ring resonators are gap-coupled to generate an ultra-narrow band under electromagnetic excitation, wherein the dual-ring resonator includes two ring structures. In some embodiments, Figure 2 FIG. 1 is a schematic diagram of the structure of a dual-ring resonator involved in an ultra-narrowband filter 100 according to an embodiment of the present application. Each dual-ring resonator 130 includes a first ring structure 131 and a second ring structure 132 , wherein the first ring structure 131 and the second ring structure 132 partially overlap, and the second ring structure 132 is nested within the first ring structure 131 .

[0029] The first ring structure 131 and the second ring structure 132 partially overlap, that is, the first ring structure 131 and the second ring structure 132 have a common portion, which is used to achieve weak coupling.

[0030] Furthermore, the second ring structure 132 is nested within the first ring structure 131 , that is, the first ring structure 131 surrounds the second ring structure 132 . Thus, when the two dual-ring resonators 130 are gap-coupled, the current intensity radiated to the adjacent dual-ring resonators 130 can be reduced, further achieving weaker coupling.

[0031] It should be noted that Figure 2The structure layout and size of the dual ring resonator in the figure are only for illustration and are not used to limit the present application. Other dual ring resonators may also be used. For example, Figure 2 The dual-ring resonator 130 in FIG. 1 is a vertically symmetrical dual-ring resonator. In other examples, the dual-ring resonator used in this application may also be a dual-ring resonator symmetrically arranged in other directions.

[0032] In some embodiments, as Figure 2 As shown, the first ring structure 131 includes a first ring branch line 1311 and a second ring branch line 1312 , and two ends of the first ring branch line 1311 are connected to two ends of the second ring branch line 1312 to form a closed ring.

[0033] The two ends of the first ring branch line 1311 are connected to the two ends of the second ring branch line 1312 to form a closed loop. That is, one end of the first ring branch line 1311 is connected to one end of the second ring branch line 1312, and the other end of the first ring branch line 1311 is connected to the other end of the second ring branch line 1312. The closed loop formed in this way can be called a first closed loop.

[0034] The first closed loop formed by the first ring branch 1311 and the second ring branch 1312 is a ring, and its electrical length is 360 degrees, wherein the electrical length of the first ring branch 1311 is smaller than the electrical length of the second ring branch 1312, that is, the physical length of the first ring branch 1311 is smaller than the physical length of the second ring branch 1312. This application does not limit the ratio of the electrical lengths of the first ring branch 1311 and the second ring branch 1312, as long as the electrical length of the first ring branch 1311 is smaller than the electrical length of the second ring branch 1312.

[0035] The second ring structure 132 includes a third ring branch line 1321 and a fourth ring branch line 1322 . Two ends of the third ring branch line 1321 are connected to two ends of the fourth ring branch line 1322 to form a closed ring.

[0036] The two ends of the third ring branch line 1321 are connected to the two ends of the fourth ring branch line 1322 to form a closed loop, that is, one end of the third ring branch line 1321 is connected to one end of the fourth ring branch line 1322, and the other end of the third ring branch line 1321 is connected to the other end of the fourth ring branch line 1322, thus forming a closed loop, which can be called a second closed loop.

[0037] The second closed loop formed by the third ring branch line 1321 and the fourth ring branch line 1322 is a ring, and its electrical length is 360 degrees, wherein the electrical length of the third ring branch line 1321 is smaller than the electrical length of the fourth ring branch line 1322, that is, the physical length of the third ring branch line 1321 is smaller than the physical length of the fourth ring branch line 1322. This application does not limit the ratio of the electrical lengths of the third ring branch line 1321 and the fourth ring branch line 1322, as long as the electrical length of the third ring branch line 1321 is smaller than the electrical length of the fourth ring branch line 1322.

[0038] The first ring branch line 1311 and the third ring branch line 1321 are the same ring branch line, so that the first ring structure 131 and the second ring structure 132 partially overlap.

[0039] The fourth ring branch 1322 is located within the first ring structure 131, so that the second ring structure 132 is nested within the first ring structure 131. In other words, the fourth ring branch 1322 is located within the first closed loop, that is, the fourth ring branch 1322 is surrounded by the first closed loop.

[0040] The electrical length of the first ring branch 1311 is less than the electrical length of the second ring branch 1312, and the electrical length of the third ring branch 1321 is less than the electrical length of the fourth ring branch 1322. In some examples, the ratio of the electrical lengths of the first ring branch 1311 to the second ring branch 1312 is greater than the ratio of the electrical lengths of the third ring branch 1321 to the fourth ring branch 1322. When the first ring branch 1311 and the third ring branch 1321 are the same ring branch, the electrical length of the second ring branch 1312 is less than the electrical length of the fourth ring branch 1322. In other words, the physical length of the second ring branch 1312 is less than the physical length of the fourth ring branch 1322.

[0041] Furthermore, in some embodiments, Figure 2 As shown, the first loop branch line 1311 is bent twice, and the second loop branch line 1312 is bent twice.

[0042] One bending process means that the first loop branch line 1311 or the second loop branch line 1312 is bent 90 degrees, so that a part of the first loop branch line 1311 or the second loop branch line 1312 is arranged perpendicular to the other part.

[0043] The two bending processes of the first loop branch line 1311 are both in the same direction, that is, the bending processes are in the same direction, for example, vertically upward. After the two bending processes of the first loop branch line 1311, both ends of the first loop branch line 1311 are vertically upward.

[0044] Similarly, the two bending processes of the second loop branch line 1312 are both in the same direction, that is, the bending processes are in the same direction, for example, vertically downward. After the two bending processes of the second loop branch line 1312, both ends of the second loop branch line 1312 are vertically downward.

[0045] At this point, after the two bending processes, the first closed loop formed by the first loop branch 1311 and the second loop branch 1312 is a square loop. It should be noted that the square shape of the first closed loop can be determined based on actual design conditions. For example, the square shape can be a rectangular loop or a square loop, and this application does not make specific limitations on this.

[0046] As described above, the fourth ring branch line 1322 is located within the first ring structure 131, and the electrical length of the fourth ring branch line 1322 is greater than the electrical length of the second ring branch line 1312. In some embodiments, within the first ring structure 131, the fourth ring branch line 1322 is bent multiple times in the bending direction of the second ring branch line 1312, so that the corresponding part of the fourth ring branch line 1322 is parallel to the corresponding part of the second ring branch line 1312 with a preset gap between them.

[0047] like Figure 2 As shown, according to the bending direction of the second loop branch 1312, for example, vertically downward, the end of the fourth loop branch 1322 connected to the third loop branch 1321 or the first loop branch 1311 is bent multiple times in sequence from the connection point, first bending horizontally to the right by a first preset length, then bending vertically upward by a second preset length, then bending horizontally to the right by a first preset length, and so on, until the other end of the fourth loop branch 1322 connected to the third loop branch 1321 or the first loop branch 1311. The first preset length is the preset gap.

[0048] Among them, the first preset length and the second preset length can be determined according to the actual design situation, so that the parts of the multiple second preset lengths of the fourth ring branch 1322 are separated by a preset gap, and the corresponding second preset length of the fourth ring branch 1322 is also separated by a preset gap from the part after the bending process of the second ring branch 1312. It can be understood that the fourth ring branch 1322 is bent multiple times in the bending direction of the second ring branch 1312, that is, the fourth ring branch 1322 is folded. Through the multiple bending processes of the fourth ring branch 1322, a certain current intensity when the gaps of two adjacent dual ring resonators are coupled can be further reduced, and a weaker coupling can be further achieved. In addition, the multiple bending processes of the fourth ring branch 1322 greatly reduce the size of the ultra-narrowband filter 100, achieve miniaturization, and reduce the production cost.

[0049] It should be noted that the fourth ring branch line 1322 undergoes multiple bending processes in the bending direction of the second ring branch line 1312, and each bending process is a 90-degree bend, and the bending direction described above is only for illustration and is not used to limit this application.

[0050] As described above, the first ring structure 131 includes a first ring branch 1311 and a second ring branch 1312, and the second ring structure 132 includes a third ring branch 1321 and a fourth ring branch 1322. In some embodiments, the equivalent impedances of the first ring branch 1311, the second ring branch 1312, the third ring branch 1321, and the fourth ring branch 1322 are the same.

[0051] The equivalent impedances of the first ring branch line 1311, the second ring branch line 1312, the third ring branch line 1321 and the fourth ring branch line 1322 are the same. Figure 2 As shown, the physical widths of the first ring branch line 1311 , the second ring branch line 1312 , the third ring branch line 1321 and the fourth ring branch line 1322 are the same.

[0052] As described above, the multiple dual-ring resonators that are symmetrically arranged and arranged in sequence, for example, include six dual-ring resonators 130, namely a first dual-ring resonator 130a, a second dual-ring resonator 130b, a third dual-ring resonator 130c, a fourth dual-ring resonator 130d, a fifth dual-ring resonator 130e, and a sixth dual-ring resonator 130f. In some embodiments, the first dual-ring resonator 130a and the sixth dual-ring resonator 130f are symmetrically arranged, and are the first and last dual-ring resonators in the multiple dual-ring resonators, respectively; the second dual-ring resonator 130b and the fifth dual-ring resonator 130e are symmetrically arranged; and the third dual-ring resonator 130c and the fourth dual-ring resonator 130d are symmetrically arranged.

[0053] Furthermore, the gap between the first dual-ring resonator 130a and the second dual-ring resonator 130b and the gap between the sixth dual-ring resonator 130f and the fifth dual-ring resonator 130e are both first gaps, wherein the first gaps are used for gap coupling between the first dual-ring resonator 130a and the second dual-ring resonator 130b and gap coupling between the sixth dual-ring resonator 130f and the fifth dual-ring resonator 130e.

[0054] The gap between the second dual-ring resonator 130b and the third dual-ring resonator 130c and the gap between the fifth dual-ring resonator 130e and the fourth dual-ring resonator 130d are both second gaps, wherein the second gaps are used for gap coupling between the second dual-ring resonator 130b and the third dual-ring resonator 130c and the gap coupling between the fifth dual-ring resonator 130e and the fourth dual-ring resonator 130d;

[0055] The gap between the third dual-ring resonator 130c and the fourth dual-ring resonator 130d is a third gap, wherein the third gap is used for gap coupling between the third dual-ring resonator 130c and the fourth dual-ring resonator 130d;

[0056] The first gap, the second gap and the third gap are different from each other and increase in sequence.

[0057] It is understandable that the specific values of the first gap, the second gap and the third gap are calculated according to the design principle of the bandpass filter according to the actual design situation, and will not be explained here.

[0058] As described above, the input feeder structure 110 and the output feeder structure 120 are symmetrically arranged. In some embodiments, each of the input feeder structure 110 and the output feeder structure 120 includes a feeding portion P1 and a coupling portion P2, wherein one end of the feeding portion P1 is connected to the coupling portion P2 and is at different distances from the two ends of the coupling portion P2, the other end of the feeding portion P1 serves as an input / output port, and the coupling portion P2 is used to achieve gap coupling with the first dual-ring resonator or the last dual-ring resonator among the multiple dual-ring resonators.

[0059] The feeder P1 is a feeder line, one end of which is used for tap coupling and the other end serves as an input / output port. The other end of the feeder P1 serves as the input port, receiving electromagnetic signals, while the other end of the feeder P1 serves as the output port, receiving electromagnetic signals. Note that the arrangement of the input and output ports is for illustrative purposes only; the input and output ports can be reversed.

[0060] The coupling portion P2 is slot-coupled with the first or last dual-ring resonator among the multiple dual-ring resonators. For example, the coupling portion P2 of the input feeder structure 110 is slot-coupled with the first dual-ring resonator 130a, and the coupling portion P2 of the output feeder structure 120 is slot-coupled with the sixth dual-ring resonator 130f. The slot coupling between the coupling portion P2 of the input feeder structure 110 and the first dual-ring resonator 130a and the slot coupling between the coupling portion P2 of the output feeder structure 120 and the sixth dual-ring resonator 130f require the same slot. Specifically, the slots required for these two slot couplings are determined based on actual design conditions and are not described in detail here.

[0061] The equivalent impedance of the feeding portion P1 is 50 ohms, and the equivalent impedance of the coupling portion P2 may be greater than 50 ohms. In other words, the physical width of the coupling portion P2 is smaller than the physical width of the feeding portion P1.

[0062] In some embodiments, the coupling portion P2 includes a first coupling line P21 and a second coupling line P22 connected to each other; wherein the first coupling line P21 is perpendicular to the feeding portion P1, and the feeding portion P1 is close to one end of the first coupling line P21; the second coupling line P22 is perpendicular to the first coupling line P21, and the second coupling line P22 and the feeding portion P1 are located on both sides of the first coupling line P21.

[0063] The second coupling line P22 and the first coupling line P21 are perpendicular to each other as the second loop branch 1312 is bent, wherein the first coupling line P21 corresponds to the bent portion of the second loop branch 1312, that is, the length of the first coupling line P21 is the same as the length of the corresponding portion of the second loop branch 1312.

[0064] The second coupling line P22 and the feeding portion P1 are located on both sides of the first coupling line P21 . For example, the feeding portion P1 is located on the left side of the first coupling line P21 , and the second coupling line P22 is located on the right side of the first coupling line P21 .

[0065] The equivalent impedance of the second coupling line P22 is smaller than the equivalent impedance of the first coupling line P21, and both the equivalent impedance of the second coupling line P22 and the equivalent impedance of the first coupling line P21 are greater than the equivalent impedance of the feeding portion P1, i.e., 50 ohms. In other words, the physical width of the second coupling line P22 is greater than the physical width of the first coupling line P21, and both the physical width of the first coupling line P21 and the physical width of the second coupling line P22 are smaller than the physical width of the feeding portion P1.

[0066] As described above, the ultra-narrowband filter 100 includes a symmetrically arranged input feeder structure 110 and an output feeder structure 120, as well as a plurality of symmetrically arranged and sequentially arranged dual-ring resonators. In some embodiments, the ultra-narrowband filter 100 uses a dielectric substrate to manufacture the ultra-narrowband filter 100. The dielectric substrate can be a high-temperature superconducting dielectric substrate made of magnesium oxide. The upper and lower surfaces of the high-temperature superconducting dielectric substrate are made of yttrium barium copper oxide superconducting thin films with a dielectric constant of 9.78 and a thickness of 0.5 mm. In this case, the ultra-narrowband filter 100 has low loss and a high quality factor, thereby achieving better results in applications such as ultra-narrowband filters 100, being stable in use, and having a long service life. Of course, within the scope of understanding of those skilled in the art, the dielectric substrate can also use dielectric substrates with other parameters to manufacture the ultra-narrowband filter 100, which is not limited here.

[0067] like Figure 3Figure 2 shows a scattering parameter curve for the ultra-narrowband filter 100 according to an embodiment of the present application. For the ultra-narrowband filter 100 of the embodiment described above, when fabricated using a high-temperature superconducting dielectric substrate, the center frequency of its bandpass filter is located at 1971 MHz, the insertion loss within the frequency band is less than 0.1 dB, and the return loss is greater than 20 dB.

[0068] The ultra-narrowband filter 100 made of a high-temperature superconducting dielectric substrate can be applied to radio astronomy spectrum observation, for example, a radio frequency device in spectrum observation. In other words, the radio frequency device can include the ultra-narrowband filter 100 made of a high-temperature superconducting dielectric substrate.

[0069] It is easy for a person skilled in the art to know that many modifications and variations can be made to the apparatus and method while maintaining the teaching content of the present application.Therefore, the above disclosure should be considered as being limited only by the scope of the appended claims.

Claims

1. An ultra-narrowband filter, characterized in that: include: A symmetrically arranged input feeder structure and output feeder structure and a plurality of symmetrically arranged and sequentially arranged dual-ring resonators; The input feeder structure is coupled to the slot of the first dual-ring resonator among the multiple dual-ring resonators, and the output feeder structure is coupled to the slot of the last dual-ring resonator among the multiple dual-ring resonators to provide electromagnetic excitation; Every two adjacent dual-ring resonators in the plurality of dual-ring resonators are gap-coupled to generate an ultra-narrow band under electromagnetic excitation; Each of the plurality of dual-ring resonators includes a first ring structure and a second ring structure, wherein the first ring structure and the second ring structure partially overlap, and the second ring structure is nested within the first ring structure so that the first ring structure surrounds the second ring structure, and a physical length of the first ring structure is smaller than a physical length of the second ring structure; The first ring structure includes a first ring branch line and a second ring branch line, and two ends of the first ring branch line are connected to two ends of the second ring branch line to form a closed ring; The second ring structure includes a third ring branch line and a fourth ring branch line, and two ends of the third ring branch line are connected to two ends of the fourth ring branch line to form a closed ring; wherein the first ring branch and the third ring branch are the same ring branch, so that the first ring structure and the second ring structure partially overlap; The fourth ring branch is located within the first ring structure, and the physical length of the second ring branch is smaller than the physical length of the fourth ring branch, so that the second ring structure is nested within the first ring structure.

2. The ultra-narrowband filter according to claim 1, wherein The first loop branch line is bent twice, and the second loop branch line is bent twice.

3. The ultra-narrowband filter according to claim 2, wherein: In the first ring structure, the fourth ring branch line is bent multiple times in the bending direction of the second ring branch line, so that the corresponding part of the fourth ring branch line is parallel to the corresponding part of the second ring branch line with a preset gap therebetween.

4. The ultra-narrowband filter according to claim 1, wherein The equivalent impedances of the first loop branch line, the second loop branch line, the third loop branch line, and the fourth loop branch line are the same.

5. The ultra-narrowband filter according to any one of claims 1 to 4, wherein: The plurality of dual-ring resonators include a first dual-ring resonator, a second dual-ring resonator, a third dual-ring resonator, a fourth dual-ring resonator, a fifth dual-ring resonator, and a sixth dual-ring resonator; The first dual-ring resonator and the sixth dual-ring resonator are symmetrically arranged, and are respectively the first dual-ring resonator and the last dual-ring resonator among the multiple dual-ring resonators; The second dual-ring resonator and the fifth dual-ring resonator are symmetrically arranged; The third dual-ring resonator and the fourth dual-ring resonator are symmetrically arranged.

6. The ultra-narrowband filter according to claim 5, wherein: The gap between the first dual-ring resonator and the second dual-ring resonator and the gap between the sixth dual-ring resonator and the fifth dual-ring resonator are both first gaps, wherein the first gap is used for gap coupling between the first dual-ring resonator and the second dual-ring resonator and gap coupling between the sixth dual-ring resonator and the fifth dual-ring resonator; The gap between the second dual-ring resonator and the third dual-ring resonator and the gap between the fifth dual-ring resonator and the fourth dual-ring resonator are both second gaps, wherein the second gap is used for gap coupling between the second dual-ring resonator and the third dual-ring resonator and gap coupling between the fifth dual-ring resonator and the fourth dual-ring resonator; The gap between the third dual-ring resonator and the fourth dual-ring resonator is a third gap, wherein the third gap is used for gap coupling between the third dual-ring resonator and the fourth dual-ring resonator; The first gap, the second gap and the third gap are different from each other and increase in sequence.

7. The ultra-narrowband filter according to any one of claims 1 to 4, wherein: Each of the input feeder structure and the output feeder structure includes a feeding portion and a coupling portion, wherein one end of the feeding portion is connected to the coupling portion and is at different distances from both ends of the coupling portion, the other end of the feeding portion serves as an input / output port, and the coupling portion is used to achieve gap coupling with the first dual-ring resonator or the last dual-ring resonator among the multiple dual-ring resonators.

8. The ultra-narrowband filter according to claim 7, wherein: The coupling portion includes a first coupling line and a second coupling line connected to each other; Wherein, the first coupling line is perpendicular to the feeding portion, and the feeding portion is close to one end of the first coupling line; The second coupling line and the first coupling line are perpendicular to each other, and the second coupling line and the feeding portion are located on both sides of the first coupling line.

Images