High-temperature superconducting filter and multi-layer stacked three-dimensional integrated design method thereof

Abstract

The invention discloses a high-temperature superconducting filter and a multi-layer stacked three-dimensional integrated design method thereof, and belongs to the technical field of microwave communication, the high-temperature superconducting filter comprises multiple layers of superconducting medium substrates and a high-temperature superconducting thin film layer, air with a certain thickness is arranged between the two layers of superconducting medium substrates, and the high-temperature superconducting thin film layer is arranged between the two layers of superconducting medium substrates. The lower surface of the bottom superconducting medium substrate is grounded; the high-temperature superconducting thin film layer is located on the upper surface of the superconducting medium substrate, a filter circuit is constructed on the high-temperature superconducting thin film layer, and the filter circuit comprises one or more resonator structures, one or more microstrip branch structures and one or more feeder line structures. The resonator structure is connected with the input feeder line and the output feeder line, and the novel double-layer high-temperature superconducting filter with the multiple transmission zero points has the advantages of being low in loss, wide in stop band, high in integration level, multiple in zero point, flexible in design and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave communication, and particularly relates to a high-temperature superconducting filter and a multi-layer stacked three-dimensional integrated design method thereof. Background Art

[0002] With the continuous development of modern wireless communication systems and the increasingly dense spectrum resources, the demand for filters with high selectivity, low loss, and high integration is also increasing day by day. The high-temperature superconducting technology is a high-tech technology that has developed rapidly in recent years. Since its discovery, it has been widely used in the manufacture of microwave filters. Filters applying high-temperature superconducting technology have extremely low passband loss and extremely high frequency interference suppression ability, so they have broad development prospects in the microwave radio frequency field.

[0003] At present, most common superconducting filters are of planar structure, and superconducting filters based on three-dimensional integration have not been published yet. To improve the selectivity of planar superconducting filters, more resonators must be added, which greatly increases the size of the filters and does not meet the current requirements for miniaturization and high integration of radio frequency devices. To solve the contradiction between the selectivity and size of planar superconducting filters, based on this, this work designs a novel multi-layer high-temperature superconducting filter with multiple transmission zeros. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art. The present invention proposes a multi-layer stacked three-dimensional integrated design method for a superconducting filter: stacking multiple superconducting dielectric substrates three-dimensionally, building circuits on the surfaces of multiple superconducting dielectric substrates, and enabling three-dimensional coupling of resonators in different layers through the interlayer air and dielectric substrates, so as to introduce more available layers in the third dimension and make the overall circuit more compact; Design a high-temperature superconducting filter and a multi-layer stacked three-dimensional integrated design method thereof. The filter has the characteristics of high integration, multiple transmission zeros, low loss, wide stopband, and simple design.

[0005] To achieve the purpose of the present invention, the following technical solutions are adopted: The filter includes: superconducting dielectric substrates, and high-temperature superconducting thin film layers. The superconducting dielectric substrates are multi-layered; There is air with a certain thickness between the multi-layer superconducting dielectric substrates. The high-temperature superconducting thin film layer is located on the upper surface of the superconducting dielectric substrates. A filter circuit is constructed on the high-temperature superconducting thin film layer. The filter circuit includes: one or more resonator structures, one or more microstrip stub structures, and one or more feeder structures. The resonator structure is connected to the input feeder and the output feeder.

[0006] Further, the superconducting dielectric substrate can be divided into a top superconducting dielectric substrate, a middle superconducting dielectric substrate, and a bottom superconducting dielectric substrate from top to bottom; one resonator structure forms one resonator.

[0007] Further, the resonator structure includes a first resonator structure, a second resonator structure, a third resonator structure, and a fourth resonator structure.

[0008] Further, the feeder structure includes a first feeder structure and a second feeder structure.

[0009] Further, the first resonator structure and the fourth resonator structure are respectively connected to the feeder structure. The first resonator structure and the fourth resonator structure are symmetric, and have the function of introducing zeros.

[0010] Further, the left side of the first feeder structure is connected to the input feeder; the right side of the second feeder structure is connected to the output feeder; both the input feeder and the output feeder are 50 Ω feeders.

[0011] Further, the second resonator structure and the third resonator structure are symmetric, and the coupling strength is controlled by controlling parameters such as the distance between adjacent resonator structures.

[0012] Further, the microstrip stub structure includes an upper stub, a lower stub. The microstrip stub structure is a stepped impedance stub structure. The upper stub is connected to the bottom of the third resonator structure. The microstrip stub structure suppresses the parasitic passband outside the passband.

[0013] Further, the first resonator structure, the second resonator structure, the third resonator structure, the fourth resonator structure, the first feeder structure, the second feeder structure, the input feeder, the output feeder, and the microstrip stub structure are all located on the high-temperature superconducting thin film layer on the upper surface of the top superconducting dielectric substrate.

[0014] Further, the fifth resonator structure is located on the high-temperature superconducting thin film layer on the upper surface of the bottom superconducting dielectric substrate and is coupled to the resonator structure of the top superconducting dielectric substrate.

[0015] Further, the second resonator structure and the third resonator structure can be located on the middle superconducting dielectric substrate and are coupled to the resonator structure of the top superconducting dielectric substrate and the resonator structure of the bottom superconducting dielectric substrate.

[0016] Further, the middle superconducting dielectric substrate can construct a new resonator structure and is coupled to the resonator structure of the top superconducting dielectric substrate and the resonator structure of the bottom superconducting dielectric substrate.

[0017] Features and beneficial effects of the present invention: 1. Design a filter using high-temperature superconducting technology. The designed filter has extremely low passband loss and extremely high frequency interference suppression ability through the second feeder structure and microstrip stub structure.

[0018] 2. A novel double-layer high-temperature superconducting filter structure with multiple transmission zeros is proposed for the first time. Use a multi-layer superconducting dielectric substrate, design a circuit on the upper surface of the multi-layer superconducting dielectric substrate, and the upper and lower resonators are coupled through the air between the superconducting dielectric substrates and the superconducting dielectric substrates, providing a new idea for solving the contradiction between the selectivity and size of the current planar superconducting filter structure and improving the integration of the filter.

[0019] 3. It has the characteristics of flexible design, compact structure, high integration, and multiple transmission zeros, and is suitable for the production of high-quality factor high-temperature superconducting thin films. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 Schematic diagram of the 3D structure of the high-temperature superconducting filter in the embodiment of the present invention; Figure 2 Schematic diagram of the specific size structure of the high-temperature superconducting filter in the embodiment of the present invention; Figure 3 Front view of the high-temperature superconducting filter structure in the embodiment of the present invention; Figure 4 Top view of the high-temperature superconducting filter structure in the embodiment of the present invention; Figure 5 Front view of the high-temperature superconducting filter structure in the embodiment of the present invention; Figure 6 Schematic diagram of the high-temperature superconducting filter structure in the embodiment of the present invention and the materials of each part; Figure 7 S-parameter response of the high-temperature superconducting filter in the embodiment of the present invention.

[0021] In the figure: 1. Top superconducting dielectric substrate; 2. Input feeder; 3. Wide part of the first feeder structure; 4. Narrow part of the first feeder structure; 5. First resonator structure; 6. Second resonator structure; 7. Third resonator structure; 8. Fourth resonator structure; 9. Wide part of the second feeder structure; 10. Output feeder; 11. Narrow part of the second feeder structure; 12. Upper stub; 15. Bottom superconducting dielectric substrate; 16. GND. DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Grounding description. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention; a dual-layer high-temperature superconducting filter with multiple transmission zeros proposed by the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments: The high-temperature superconducting filter in this example adopts a two-layer 3D structure, and it is easy to implement three layers and above by the same token.

[0023] Figure 1 Fig. shows a 3D structural schematic diagram of a dual-layer high-temperature superconducting filter with multiple transmission zeros in an embodiment of the present invention. The filter includes: a superconducting dielectric substrate and a high-temperature superconducting thin film layer.

[0024] The superconducting dielectric substrate includes a top superconducting dielectric substrate 1, a bottom superconducting dielectric substrate 15, and the lower surface of the bottom superconducting dielectric substrate 15 is connected to GND16.

[0025] The high-temperature superconducting thin film layer is located on the upper surface of the multi-layer superconducting dielectric substrate. A filter circuit is constructed in the two high-temperature superconducting thin film layers. The filter circuit includes: a first resonator structure 5, a second resonator structure 6, a third resonator structure 7, a fourth resonator structure 8, a fifth resonator structure, a first feeder structure, a second feeder structure, and an input / output 50Ω feeder, and a microstrip stub structure. Among them: the first resonator structure 5, the second resonator structure 6, the third resonator structure 7, the fourth resonator structure 8, the first feeder structure, the second feeder structure, the input feeder 22, and the microstrip stub structure are all located on the high-temperature superconducting thin film layer of the superconducting dielectric substrate. Among them, the first resonator structure 5 and the fourth resonator structure 8 are respectively connected to the feeder, and the two are symmetric, having the function of introducing zeros; the second resonator structure 6 and the third resonator structure 7 are symmetric, and the coupling strength is controlled by controlling parameters such as the distance between adjacent resonator structures; the microstrip stub structure is connected to the bottom of the third resonator structure 7, playing a role in suppressing the parasitic passband; the fifth resonator structure is located on the high-temperature superconducting thin film layer of the superconducting dielectric substrate and is coupled to the upper resonator structure through the superconducting dielectric substrate. The lower surface of the superconducting dielectric substrate is connected to GND16.

[0026] The second resonator structure 6, the third resonator structure 7, the fifth resonator structure, and the microstrip stub structure are all left-right symmetric structures.

[0027] It should be noted that the sizes W6 and RW7 of the second resonator structure 6 and the third resonator are not equal, and the line width of the fifth resonator is equal everywhere.

[0028] It should be noted that the upper stub 12 of the microstrip stub structure is connected to the third resonator structure 7. The microstrip stub structure forms a stepped impedance structure, which has the function of suppressing the second harmonic.

[0029] It should be noted that the first resonator structure 5 is connected to the narrow part 4 of the first feeder structure, and the fourth resonator structure 8 is connected to the narrow part 11 of the second feeder structure. Connecting the resonator structure to the feeder structure can not only generate coupling with other resonators, but also play a role in introducing zeros.

[0030] It should be noted that the line widths of the first resonator structure 5 and the fourth resonator structure 8 are not equal everywhere.

[0031] It should be noted that the line widths of the first feeder structure and the second feeder structure are not equal everywhere, and their line widths are also not equal to the line width of the input / output 50Ω feeder.

[0032] It should be noted that the fifth resonator structure is coupled to other resonator structures through the air between two dielectric plates and the superconducting dielectric substrate.

[0033] Figure 2 The top view of the double-layer high-temperature superconducting filter structure with multiple transmission zeros in the embodiment of the present invention is shown. The specific parameter names are marked in the figure, which are the same as the length and width of the superconducting dielectric substrate. In this embodiment, its overall shape is rectangular, and corresponding filter circuits can also be formed with other dimensions. At the same time, it is worth noting that the relevant simulation tool used in the present invention is Sonnet EM, the superconducting substrate used is MgO / YBCO, the dielectric constant of the substrate is 9.73, and this embodiment is only one of the solutions.

[0034] The length, width, and the relative positions of the first resonator structure 5, the second resonator structure 6, the third resonator structure 7, the fourth resonator structure 8, the fifth resonator structure, the microstrip stub structure mainly determine the number and spectral positions of the mode frequencies of the filter.

[0035] The number of turns of the first resonator structure 5 and the fourth resonator structure 8 determines the number of out-of-band zeros; the dimensions L13, W13, L12, W12 of the microstrip stub structure affect the effect of suppressing the second harmonic.

[0036] The length and width of the narrow part 4 of the first feeder structure and the narrow part 11 of the second feeder structure mainly affect the intensity of coupling and excitation.

[0037] The dimensions of the wide part 3 of the first feeder structure and the wide part 9 of the second feeder structure and the dimensions of the first resonator structure 5 and the fourth resonator structure 8 jointly affect the introduction of zeros and the spectral positions of the mode frequencies of these two resonators.

[0038] Figure 3 、 Figure 4 、Figure 5 The front view, top view and side view of the double-layer high-temperature superconducting filter structure with multiple transmission zeros in the embodiments of the present invention are shown. The overall structure includes multiple superconducting dielectric substrates, high-temperature superconducting thin film layers on the upper surfaces of the multiple superconducting dielectric substrates respectively, GND16 on the lower surface of the bottom superconducting dielectric substrate 15, air layers between two superconducting dielectric substrates, and an air layer above the top superconducting dielectric substrate 1.

[0039] It should be noted that there are air layers with a certain thickness between the multiple superconducting dielectric substrates.

[0040] Figure 6 The materials of each part of the double-layer high-temperature superconducting filter structure with multiple transmission zeros in the embodiments of the present invention are shown. All the multiple superconducting dielectric substrates use MgO / YBCO materials with a dielectric constant of 9.73. The filter circuit is located in the high-temperature superconducting thin film layers on the upper surfaces of the multiple superconducting dielectric substrates respectively. The lower surface of the superconducting dielectric substrate is grounded. The spaces between the multiple superconducting dielectric substrates and above the superconducting dielectric substrates are all air.

[0041] Figure 7 The S-parameter response of the double-layer high-temperature superconducting filter with multiple transmission zeros of the present invention is shown. It can be seen from the figure that the passband range below -3dB of the filter of the present invention is 4.11 GHz - 5.25 GHz, and the absolute bandwidth is 1.14 GHz. The overall passband bandwidth has no deviation from the performance of the Figure 7 shown structure. Moreover, the highest value of S11 in the overall passband is -20.75 dB, indicating that the filter of the present invention has the performance of lower return loss in the passband. Except for the maximum value of S21, which is -20.4 dB, the rest of the stopband part is less than -21 dB, and there are up to 10 stopband transmission zeros, which shows that the filter designed by using the design method of the present invention has good performance and engineering practical value.

[0042] In summary, the double-layer high-temperature superconducting filter with multiple transmission zeros in the embodiments of the present invention has good performance and obvious engineering practical value; the present invention controls the spectral position of the mode frequency by adjusting the sizes and relative positions of the first resonator structure 5, the second resonator structure 6, the third resonator structure 7, the fourth resonator structure 8, the fifth resonator structure and the first feeder structure and the second feeder structure. The passband width and position have the characteristics of being flexibly controllable, and at the same time, the design difficulty of the high-temperature superconducting double-layer filter is further reduced; in addition, the structure of the present invention is compact, small in volume, flexible in design, high in integration, with multiple transmission zeros, and convenient for circuit processing; it is suitable for being made of high-temperature superconducting thin films with high quality factors.

[0043] The above has introduced the embodiments of the present invention in detail. Specific examples are used in this article to illustrate the principle and The embodiments have been described above. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A high temperature superconducting filter, characterized in that: include: A superconducting dielectric substrate and a high-temperature superconducting thin film layer. The superconducting dielectric substrate is multi-layered. There is a certain thickness of air between two layers of the superconducting dielectric substrate. The lower surface of the bottom superconducting dielectric substrate (15) is grounded. The high-temperature superconducting thin film layer is located on the upper surface of the superconducting dielectric substrate. A filter circuit is constructed on the high-temperature superconducting thin film layer. The filter circuit includes: one or more resonator structures, one or more microstrip branch structures, and one or more feeder structures. The resonator structure connects the input feeder (2) and the output feeder (10).

2. A high temperature superconducting filter according to claim 1, characterized in that: The resonator structure comprises: a first resonator structure (5), a second resonator structure (6), a third resonator structure (7), a fourth resonator structure (8), and a fifth resonator structure, wherein the first resonator structure (5) and the fourth resonator structure (8) are respectively connected to the feeder structure, the first resonator structure (5) and the fourth resonator structure (8) are in a symmetrical relationship and have the function of introducing a zero point, the second resonator structure (6) and the third resonator structure (7) are in a symmetrical relationship, and the coupling strength is controlled by controlling parameters such as the distance between adjacent resonator structures.

3. A high temperature superconducting filter as claimed in claim 2, characterized in that: The superconducting dielectric substrate can be divided from top to bottom into a top superconducting dielectric substrate (1), a middle superconducting dielectric substrate, and a bottom superconducting dielectric substrate (15); the bottom surface of the bottom superconducting dielectric substrate (15) is connected to GND (16), and the feeder structure includes a first feeder structure and a second feeder structure.

4. A high temperature superconducting filter as claimed in claim 3, characterized in that: The first resonator structure (5), the second resonator structure (6), the third resonator structure (7), the fourth resonator structure (8), the first feeder structure, the second feeder structure, the input feeder (2), the output feeder (10) and the microstrip branch structure are all located in the high-temperature superconducting film layer of the top superconducting dielectric substrate (1); the fifth resonator structure is located in the high-temperature superconducting film layer on the upper surface of the bottom superconducting dielectric substrate (15) and is coupled with the resonator structure of the top superconducting dielectric substrate (1); the middle superconducting dielectric substrate can construct a new resonator structure and is coupled with the resonator structure of the top superconducting dielectric substrate (1) and the resonator structure of the bottom superconducting dielectric substrate (15).

5. A high temperature superconducting filter as claimed in claim 4, characterized in that: The microstrip branch structure is a step impedance branch structure, comprising an upper branch (12) and a lower branch, wherein the upper branch (12) is connected to the bottom of the third resonator structure (7), and the microstrip branch structure suppresses parasitic passbands outside the passband.

6. A high temperature superconducting filter as claimed in claim 5, characterized in that: The first feeder structure comprises a first feeder structure wide portion (3) and a first feeder structure narrow portion (4); the second feeder structure comprises a second feeder structure wide portion (9) and a second feeder structure narrow portion (11); the first resonator structure (5) is connected to the first feeder structure narrow portion (4); the fourth resonator structure (8) is connected to the second feeder structure narrow portion (11); the resonator structure connected to the feeder structure can not only generate coupling with other resonators, but also play a role in introducing a zero point.

7. A multi-layer stacked three-dimensional integrated design method, characterized in that: Using the high-temperature superconducting filter of any one of claims 1 to 6, multiple superconducting dielectric substrates are three-dimensionally stacked, circuits are built on the surfaces of multiple superconducting dielectric substrates, and different layers of resonators are three-dimensionally coupled through interlayer air and dielectric substrates, thereby introducing more available layers in the third dimension, making the overall circuit more compact.

8. The multi-layer stacked three-dimensional integrated design method according to claim 7, characterized in that: The length, width, microstrip branch structure, and relative positions of the first resonator structure (5), the second resonator structure (6), the third resonator structure (7), the fourth resonator structure (8), and the fifth resonator structure mainly determine the number and spectral positions of the mode frequencies of the filter.

9. A multi-layer stacked three-dimensional integrated design method according to claim 8, characterized in that: The length and width of the narrow portion (4) of the first feed line structure and the narrow portion (11) of the second feed line structure mainly affect the strength of coupling and excitation, and the size of the wide portion (3) of the first feed line structure and the wide portion (9) of the second feed line structure together with the size of the first resonator structure (5) and the fourth resonator structure (8) jointly affect the introduction of zero points and the spectral positions of the two resonator mode frequencies.

10. A multi-layer stacked three-dimensional integrated design method according to claim 9, characterized in that: The spectral position of the mode frequency is controlled by adjusting the sizes and relative positions of the first resonator structure (5), the second resonator structure (6), the third resonator structure (7), the fourth resonator structure (8), the fifth resonator structure and the first feed line structure and the second feed line structure.

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