Miniaturized superconducting bandpass filter

Abstract

The utility model aims at providing a miniaturized superconducting band pass filter including medium base plate, left resonator group, right resonator group half wave length resonator, fixed value capacitor, its characterized in that: left resonator group, right resonator group left and right symmetry sets up on medium base plate, left resonator group, right resonator group respectively by same group number's multiple group half wave length resonator is composed, and each group half wave length resonator is side by side set up on medium base plate, is connected respectively through a group small capacitor between each group half wave length resonator in left resonator group, right resonator group, each group half wave length resonator respectively loads a group fixed value capacitor, and the first group half wave length resonator of left resonator group and the last group half wave length resonator of right resonator group respectively are equipped with port. The utility model can keep electrical performance while realizing size reduction significantly, improves internal space utilization, increases tuning flexibility, and through composite structure design, performance and size are taken into account, which is beneficial to industrialization.

Description

Technical Field

[0001] This utility model relates to the field of microwave radio frequency filter technology, specifically to a miniaturized superconducting bandpass filter. Background Technology

[0002] Filters are essential components in the radio frequency (RF) field. They filter signals, removing noise, interference, and other unwanted frequency components, thereby improving signal quality and stability. Compared to traditional microstrip filters, superconducting filters offer advantages such as low loss, high suppression, and good frequency selectivity, significantly improving the communication quality of communication systems. Therefore, they are widely used in specialized communication fields such as electronic warfare, radio astronomy, and deep space exploration.

[0003] Superconducting filters, due to their extremely low insertion loss and high selectivity, have important applications in wireless communication, satellite systems, and quantum computing. With the increasing demand for device miniaturization, how to reduce filter size while maintaining performance has become a research hotspot. Traditional superconducting filters typically rely on λ / 4 transmission line resonators, resulting in relatively large sizes, typically tens of millimeters, which is difficult to meet the requirements of modern compact devices.

[0004] Currently, the design of miniaturized superconducting filters mainly includes traditional λ / 2 resonator superconducting filters, helical resonator or interdigital superconducting filters, multilayer LTCC integrated superconducting filters, and capacitor-loaded superconducting filters. Traditional λ / 2 resonator superconducting filters use half-wavelength superconducting microstrip lines or coplanar waveguide resonators, utilizing high-temperature superconducting materials to reduce losses. The disadvantage is their large size, especially at low frequencies, where individual resonators are relatively long and typically require large physical spacing or additional matching networks, affecting integration and making it difficult to meet the miniaturization requirements of modern communication equipment. Helical resonator or interdigital superconducting filters increase the electrical length and shorten the physical size of the resonator through helical or interdigital structures. The disadvantage is high fabrication difficulty, and the helical structure can introduce unnecessary spurious modes, affecting out-of-band suppression characteristics. Multilayer LTCC integrated superconducting filters use low-temperature co-fired ceramic (LTCC) technology to achieve multilayer stacking, reducing planar size. The disadvantage is low interlayer coupling efficiency, and traditional vertical interconnects (such as cylindrical vias) introduce additional parasitic inductance, deteriorating filter bandwidth and in-band flatness. Capacitor-loaded superconducting filters shorten the electrical length of the resonator by loading with lumped capacitance; however, the coupling coefficient is difficult to adjust flexibly, resulting in limited bandwidth design. Utility Model Content

[0005] In view of the technical problems existing in the background art, the present invention aims to provide a miniaturized superconducting bandpass filter. This filter can significantly reduce its size while maintaining electrical performance, improve the utilization rate of internal space, increase tuning flexibility, and is relatively easy to manufacture, which is conducive to industrialization. In addition, the bending structure has a higher tolerance for processing errors, which can greatly reduce the possibility of excessive differences between the actual product and the simulation due to processing problems, and has good application prospects.

[0006] To solve the above problems, the technical solution of this utility model is as follows: A miniaturized superconducting bandpass filter includes a dielectric substrate, a left resonator group, a right resonator group of half-wavelength resonators, and a fixed capacitor. The left and right resonator groups are symmetrically arranged on the dielectric substrate. Each group consists of multiple sets of half-wavelength resonators of the same number, arranged side-by-side on the dielectric substrate. Each set of half-wavelength resonators in the left and right resonator groups is connected to the other group via a small capacitor. A fixed capacitor is loaded into each set of half-wavelength resonators. Ports are provided on the first set of half-wavelength resonators in the left resonator group and the last set of half-wavelength resonators in the right resonator group.

[0007] Each half-wavelength resonator consists of a metal strip and a fixed capacitor. The two ends of the metal strip are positioned opposite each other and connected to one end of the fixed capacitor.

[0008] The metal strip is symmetrically arranged with the center line of the fixed capacitor as the boundary. Both sides of the strip have a multi-level bending topology. Each bending unit consists of a bending segment and two connecting segments. Adjacent bending segments are connected by their respective connecting segments to form a continuous bending path.

[0009] The width of the metal strip is 0.1-0.3 mm.

[0010] The metal strip is made of copper.

[0011] The left and right resonator groups each contain two sets of half-wavelength resonators.

[0012] The spacing between the left and right resonator groups is 0.03-0.05 mm; within the left and right resonator groups, the spacing between adjacent half-wavelength resonators is 0.10-0.12 mm.

[0013] The capacitance of the fixed capacitor is 23-27pF.

[0014] The capacitance of the small capacitor is 1.3-1.7pF.

[0015] The dielectric substrate is made of MgO material with a thickness of 0.4-0.6 mm and a dielectric constant of 9.78.

[0016] The beneficial effects of this utility model are as follows:

[0017] The miniaturized superconducting bandpass filter of this application improves the disadvantage of large size of traditional λ / 2 resonator superconducting filters through composite structure design. While ensuring high Q value and excellent selectivity, it significantly reduces the physical size of the filter and improves the utilization efficiency of the internal space of the resonator.

[0018] This invention employs a distributed lumped capacitance optimization design, overcoming the shortcomings of existing technologies. Experimental verification shows that it can extend the first parasitic passband suppression from around 2f0 (30-40dB) to above 7f0 (suppression ratio improved to >50dB), while maintaining the stability of the center frequency.

[0019] This invention addresses the weakening of magnetic coupling caused by increasing the capacitance value by innovatively introducing an adjustable compensation capacitor at the adjacent end of the half-wavelength resonator, which restores the 3dB bandwidth to more than 90% of the design value. It balances performance with miniaturization requirements and has a simple manufacturing process, making it a promising application. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the miniaturized superconducting bandpass filter of this utility model;

[0021] Figure 2 The simulation diagram of the S-parameters of the miniaturized superconducting bandpass filter of this utility model is shown.

[0022] The names and numbers of the parts in the diagram are as follows:

[0023] 1 is a half-wavelength resonator, 2 is a fixed capacitor, 3 is a small capacitor, 4 is a port, 5 is a metal strip, 6 is a bend, and 7 is a connecting section. Detailed Implementation

[0024] The following description, in conjunction with the accompanying drawings, details the implementation methods and embodiments of this utility model and their working processes. Example 1

[0025] Referring to the accompanying drawings, a miniaturized superconducting bandpass filter in this embodiment includes a dielectric substrate, a left resonator group, a right resonator group, half-wavelength resonators 1, and fixed capacitors 2. The left and right resonator groups are symmetrically arranged on the dielectric substrate. Each group consists of multiple sets of half-wavelength resonators 1 with the same number of sets, arranged side-by-side on the substrate. Each set of half-wavelength resonators 1 in the left and right resonator groups is connected by a small capacitor 3. A fixed capacitor 2 is loaded within each set of half-wavelength resonators 1. Ports 4 are provided on the first set of half-wavelength resonators 1 in the left resonator group and the last set of half-wavelength resonators 1 in the right resonator group. While ensuring high Q-value and excellent selectivity, the filter's physical size is significantly reduced, while improving the utilization efficiency of the resonator's internal space. A distributed lumped capacitor optimization design is adopted, extending the parasitic passband to above 7f0 and improving the suppression ratio to >50dB, while maintaining center frequency stability.

[0026] Each half-wavelength resonator 1 consists of a metal strip 5 and a fixed capacitor 2. The two ends of the metal strip are positioned opposite each other and are connected to one end of the fixed capacitor 2 respectively.

[0027] The metal strip 5 is symmetrically arranged on the left and right sides with the center line of the fixed capacitor 2 as the boundary. Both sides of the strip have a multi-level bending topology. Each bending unit consists of a bending segment 6 and two connecting segments 7. Adjacent bending segments 6 are connected by their respective connecting segments 7 to form a continuous bending path.

[0028] The width of the metal strip 5 is 0.2 mm.

[0029] The metal strip 5 is made of copper.

[0030] The left and right resonator groups are each equipped with two sets of half-wavelength resonators 1.

[0031] The spacing between the left and right resonator groups is 0.04 mm; within the left and right resonator groups, the spacing between adjacent half-wavelength resonators 1 is 0.11 mm.

[0032] The capacitance of the fixed capacitor is 25pF.

[0033] The capacitance of the small capacitor 3 is 1.5pF.

[0034] The dielectric substrate is made of MgO material with a thickness of 0.5 mm and a dielectric constant of 9.78. Example 2

[0035] Simulation experiments were conducted using the miniaturized superconducting bandpass filter from Example 1.

[0036] In the SONNET 16 system, a 0.5mm thick MgO substrate with a dielectric constant of 9.78 was used for modeling and simulation. The center frequency of the filter phase shifter is f0 = 144MHz. The dashed line represents the S11 return loss, and the solid line represents the S21 insertion loss. Within the passband, |S 11 |<-21.2dB,|S 21 The loss is -0.03dB, achieving near-lossless transmission performance.

[0037] The working process of this utility model is as follows:

[0038] The filter consists of a left resonator group and a right resonator group, which are symmetrically arranged on a dielectric substrate. The left resonator group and the right resonator group each consist of two sets of half-wavelength resonators. Each set of half-wavelength resonators in the left resonator group and the right resonator group is connected to each other through a set of small capacitors. The first set of half-wavelength resonators in the left resonator group and the last set of half-wavelength resonators in the right resonator group are respectively provided with ports.

[0039] Electrical coupling is used to feed power to the half-wavelength resonators from both ends. Energy is primarily transferred between the resonators via magnetic coupling. However, due to the small spacing, the energy transfer capacity of magnetic coupling is limited, failing to achieve the coupling strength required for the designed bandwidth. Therefore, some energy is transferred through small capacitors between the resonators to compensate for the insufficient coupling strength. Due to external coupling issues, the resonant frequencies of the two external resonators are lower than those of the two internal resonators. The internal resonators undergo an additional fold to ensure that the resonant frequencies of all four resonators are consistent.

Claims

1. A miniaturized superconducting bandpass filter, comprising a dielectric substrate, a left resonator group, a right resonator group, a half-wavelength resonator (1), and a fixed capacitor (2), characterized in that: The left and right resonator groups are symmetrically arranged on the dielectric substrate. The left and right resonator groups are each composed of multiple half-wavelength resonators (1) with the same number of groups. Each half-wavelength resonator (1) is arranged side by side on the dielectric substrate. Each half-wavelength resonator (1) in the left resonator group and the right resonator group is connected to each other through a small capacitor (3); Each half-wavelength resonator (1) is loaded with a set of fixed capacitors (2); the first half-wavelength resonator (1) of the left resonator group and the last half-wavelength resonator (1) of the right resonator group are respectively provided with ports (4).

2. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: Each half-wavelength resonator (1) consists of a metal strip (5) and a fixed capacitor (2). The two ends of the metal strip are set opposite to each other and are connected to one end of the fixed capacitor (2).

3. The miniaturized superconducting bandpass filter according to claim 2, characterized in that: The metal strip (5) is symmetrically arranged on the left and right sides with the center line of the fixed capacitor (2) as the boundary. Both sides of the strip have a multi-level bending topology. Each bending unit consists of a bending segment (6) and two connecting segments (7). Adjacent bending segments (6) are connected by their respective connecting segments (7) to form a continuous bending path.

4. The miniaturized superconducting bandpass filter according to claim 2, characterized in that: The width of the metal strip (5) is 0.1-0.3 mm.

5. The miniaturized superconducting bandpass filter according to claim 2, characterized in that: The metal strip (5) is made of copper.

6. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: The left and right resonator groups are respectively equipped with two sets of half-wavelength resonators (1).

7. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: The spacing between the left and right resonator groups is 0.03-0.05 mm; in the left and right resonator groups, the spacing between adjacent half-wavelength resonators (1) is 0.10-0.12 mm.

8. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: The capacitance of the fixed capacitor is 23-27pF.

9. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: The capacitance of the small capacitor (3) is 1.3-1.7pF.

10. The miniaturized superconducting bandpass filter according to claim 1, characterized in that: The dielectric substrate is made of MgO material with a thickness of 0.4-0.6 mm and a dielectric constant of 9.78.

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