V-band narrow-passband superconducting filter
The 1/4 wave single-spiral resonator structure with interdigitated grounding in a V-frequency band superconducting filter addresses the compactness and performance challenges, achieving high band rejection and efficient substrate utilization.
Patent Information
- Application Number
- CN202411822886.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-03-21
AI Technical Summary
Current designs for V-frequency band superconducting filters face challenges in achieving a compact structure with high microwave performance due to the limited area of superconducting thin-film substrates and the need for weak coupling between resonator units, which results in larger resonator lengths and occupancies, especially for lower frequency bands like V, U, and L frequencies.
The design incorporates a 1/4 wave single-spiral resonator structure with multiple units in a parallel cascaded arrangement on a superconducting thin-film substrate, utilizing a higher dielectric constant material like aluminum oxide to reduce line length and width, and incorporating an interdigitated grounding structure to minimize coupling, leading to a more compact and efficient filter configuration.
This approach results in a significantly reduced footprint, improved microwave performance, and enhanced frequency selectivity, with measured band rejection exceeding 100 dB and reduced material usage, allowing for more efficient utilization of substrate space.
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Figure CN119674480A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of microwave communication technology, and in particular to a V-band narrow-passband superconducting filter. Background Art
[0002] With the rapid development of wireless communication technology, more and more communication frequency bands are being developed and utilized, and the electromagnetic environment in space has become very complex. The performance requirements of microwave filters for high-performance microwave receiver front ends are also getting higher and higher. The ideal microwave filter has a rectangular filtering characteristic, which can filter out the signals of the required frequency band and completely filter out the signals of the remaining frequency bands. Due to factors such as the microwave loss of metal materials, the filtering performance of the actual microwave filter is far behind that of the ideal filter. The surface resistance of high-temperature superconducting materials in the microwave frequency band is two to three orders of magnitude smaller than that of conventional metal materials, which is close to the effect of zero resistance. Therefore, the resonators and filters designed and manufactured with high-temperature superconducting thin film materials can simultaneously achieve a series of advantages such as extremely small insertion loss in the passband, extremely narrow relative bandwidth, extremely high band edge steepness, and extremely large out-of-band suppression, which can greatly improve the frequency selectivity and sensitivity of microwave receivers.
[0003] The main difficulties in designing narrow-band microwave filters include high-quality resonator units, weak coupling between adjacent resonators, and weak parasitic coupling between non-adjacent resonators. At present, the weak-coupled resonator design method is mainly used in the design of narrow-band filters. The research on weak-coupled resonator structures mainly includes hairpin resonators, spiral resonators, open ring resonators, step impedance resonators, clip resonators, and their combinations and deformations.
[0004] Due to the limited single-piece area of commonly used superconducting thin film substrates, the above-mentioned common weakly coupled resonator structures usually require thinner line widths and spacings and more winding turns to achieve in low frequency bands such as V / U / L. Therefore, for low frequency bands such as the V band, U band, and L band, the design of narrow passband superconducting filters still has the difficulty of achieving a compact structure. Compared with the U band and L band, the V band has a lower frequency, and the resonator line length and occupied area are relatively larger. Therefore, there is an urgent need for a V-band narrow passband superconducting filter with a more compact structure and higher microwave performance. Summary of the invention
[0005] The purpose of the present application is to provide a V-band narrow-passband superconducting filter with a more compact structure and higher microwave performance.
[0006] To achieve the above objectives, this application provides the following solutions:
[0007] The present application provides a V-band narrow-passband superconducting filter, comprising a monomer component and a superconducting thin film substrate.
[0008] The monomer component includes a plurality of resonator units; the plurality of resonator units are arranged in parallel and cascaded manner on a side surface of the superconducting thin film substrate; a hollow blank structure is arranged inside each of the resonator units, and a plurality of coils are arranged outside the hollow blank structure, and the plurality of coils are a 1 / 4 wavelength single helical structure.
[0009] Optionally, the number of the resonator units is 8.
[0010] Optionally, the substrate material used for the resonator unit is lanthanum aluminate.
[0011] Optionally, the line width of the coil is 10 um.
[0012] Optionally, the V-band narrow-bandpass superconducting filter further includes a grounding strip; the grounding strip is arranged around the plurality of resonator units and has a first set distance from the resonator units.
[0013] Optionally, the ground ends of the outer coils of the plurality of resonator units are connected to the ground bar in an up-and-down staggered orientation.
[0014] Optionally, the V-band narrow-bandpass superconducting filter further includes a first feeder position and a second feeder position; the first feeder position and the second feeder position are respectively connected to the outer coil of the resonator unit arranged at both ends.
[0015] Optionally, the length of the resonator unit is 2.6 mm, and the width of the resonator unit is 1.1 mm.
[0016] Optionally, the size of the superconducting thin film substrate is 20*4mm.
[0017] Optionally, the coil lines have a spacing of 10 um.
[0018] According to the specific embodiments provided in this application, this application discloses the following technical effects:
[0019] The present application provides a V-band narrow passband superconducting filter, comprising a monomer component and a superconducting film substrate, wherein the monomer component comprises a plurality of resonator units; the plurality of resonator units are arranged in parallel and cascaded on a side surface of the superconducting film substrate; a hollow blank structure is arranged inside each of the resonator units, and a plurality of coils are arranged outside the hollow blank structure, and the plurality of coils are 1 / 4 wavelength single helix structures. By adopting a 1 / 4 wavelength single helix structure, the structure of the resonator unit is made more compact, and thus, in the case of a more compact structure, a multi-section resonator unit is adopted, so that the microwave performance of the V-band narrow passband superconducting filter is higher. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0021] Figure 1 It is a schematic diagram of a resonator with a larger existing size;
[0022] Figure 2 A schematic diagram of the structure of a resonator unit provided in one embodiment of the present application;
[0023] Figure 3 The existing 6-section superconducting filter simulation design diagram provided in one embodiment of the present application;
[0024] Figure 4 A schematic diagram of the structure of a V-band narrow-passband superconducting filter provided in one embodiment of the present application;
[0025] Figure 5 A schematic diagram showing a comparison of the placement of a superconducting filter provided in one embodiment of the present application on a two-inch substrate;
[0026] Figure 6 A schematic diagram showing the comparison between the measured results and the simulated design of S11 and S21 within the passband of a V-band narrow-passband superconducting filter provided in one embodiment of the present application;
[0027] Figure 7 A schematic diagram of an S21 transmission curve within the passband of a V-band narrow-passband superconducting filter provided in an embodiment of the present application;
[0028] Figure 8 A schematic diagram of the effects of photolithography and dry etching provided in one embodiment of the present application.
[0029] Reference numerals:
[0030] First feed line position—1, second feed line position—2, superconducting thin film substrate—3, resonator unit—4, grounding bar—5, grounding terminal—6. DETAILED DESCRIPTION
[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0033] For low frequency bands such as V band, U band and L band, the design of narrow passband superconducting filters still has the difficulty of achieving compact structure: a) Compared with high frequency bands above S band, the microstrip line length corresponding to 1 / 2 and 1 / 4 wavelength is many times larger, and the area occupied by the resonator is also many times larger. It is difficult to place more units on the commonly used 2-inch and 3-inch substrates; b) The coupling between adjacent and non-adjacent resonators must be weak enough, which usually means that the resonator spacing must be large enough, resulting in the entire filter design occupying a larger area; c) Compared with high frequency bands above S band, the design graphics are more complex, the simulation design has a larger amount of calculation, and the initial design and subsequent optimization are more difficult.
[0034] In view of the above problems, the present application proposes a V-band narrow passband superconducting filter, which is composed of multiple resonator units 4 with narrow and long single spiral structures with finer lines and spacing and thus a more compact structure. The resonator units 4 and the filter circuit as a whole adopt a more compact design.
[0035] In an exemplary embodiment, Figure 4 As shown, a V-band narrow-passband superconducting filter is provided, comprising a first feed line position 1, a second feed line position 2, a monomer component and a superconducting thin film substrate 3.
[0036] The monomer assembly includes a plurality of resonator units 4; the plurality of resonator units 4 are arranged in parallel and cascaded on a side surface of a superconducting thin film substrate 3; a hollow blank structure is arranged inside each resonator unit 4, and a multi-turn coil is arranged outside the hollow blank structure, and the multi-turn coil is a 1 / 4 wavelength single helical structure. The first feeder position 1 and the second feeder position 2 are respectively connected to the outer coils of the resonator units 4 arranged at both ends.
[0037] The substrate material used in the existing resonator is magnesium oxide, and its dielectric constant is about 9.8. In order to make the V-band narrow-bandpass superconducting filter structure more compact, as an optional implementation, the resonator unit 4 uses a substrate material with a higher dielectric constant, specifically lanthanum aluminate with a dielectric constant of about 24, so that the line length is greatly shortened, and the area occupied by the resonator unit 4 with the same line width can be reduced by nearly half.
[0038] Optionally, the number of resonator units 4 is eight.
[0039] The resonator unit 4 in the present application adopts a more compact outer-end grounded 1 / 4 wavelength single helix structure, maximizes the aspect ratio, and the coil is wound more tightly; Figure 2As shown, the optical dry etching process accuracy of the resonator unit 4 in the present application is improved from the original 10um to 1um, and the effect after optical and dry etching is as follows Figure 8 As shown, the straightness and uniformity of the lines are also significantly improved. Therefore, the minimum line width and spacing of the lines can be reduced from 40um to 10um, and the area occupied by the resonator unit 4 can be reduced by more than ten times.
[0040] The line width and spacing of the coil of the resonator unit 4 in the present application are 10um, that is, L1 is 10um, the length L2 of the resonator unit 4 is 2.6mm, the width L3 of the resonator unit 4 is 1.1mm, and Figure 1 Compared with the 1 / 2 wavelength single helical resonator with the same center frequency, 40um line width and line spacing ( Figure 1 The length of the 1 / 2 wavelength single helical resonator is 9.72 and the width is 3.54), and the area occupied by the single resonator unit 4 in the present application is reduced by more than ten times; Figure 3 , Figure 4 and Figure 5 As shown, the resonator unit 4 of the V-band narrow-bandpass superconducting filter of the present application adopts a multi-section cascade arrangement and a multi-filter circuit placement effect, which is also more compact; compared with several other common weakly coupled resonator structures, under the same substrate material, the same line width and line spacing, the resonator unit 4 of the present application has a more compact structure.
[0041] The V-band narrow-band superconducting filter also includes a grounding strip 5; the grounding strip 5 is arranged around the plurality of resonator units 4 and has a first set distance from the resonator units 4; the grounding strip 5 includes a top strip, a bottom strip and a middle block structure; the top strip and the bottom strip are parts arranged at the top and bottom of the superconducting film substrate 3; the top strip and the bottom strip are parallel to the short side of the resonator unit 4; the middle block structure includes a plurality of middle strips arranged in parallel; the middle strip is parallel to the long side of the resonator unit 4; the left edge of the superconducting film substrate 3 is close to the left edge of the superconducting film substrate 3. The middle bar and the middle bar near the right end boundary of the superconducting thin film substrate 3 are named as the left edge bar and the right edge bar respectively; the left edge bar and the right edge bar are both composed of the first bar and the second bar; a second set distance is set between the first bar and the second bar, the first feeder position 1 passes through the area between the first bar and the second bar of the left edge bar and is connected to the resonator unit 4 near the left edge bar, and the second feeder position 2 passes through the area between the first bar and the second block of the right edge bar and is connected to the resonator unit 4 near the right edge bar.
[0042] Adding the grounding strip 5 can weaken the coupling strength between the resonator units 4 and effectively shorten the spacing between the resonator units 4. The same first set distance is left between each resonator unit 4 and the grounding strip 5, so that the coupling strength between the resonator units 4 is appropriate and the spacing can be shortened by more than half compared with the original, thereby making the V-band narrow-band superconducting filter structure more compact.
[0043] The grounding ends 6 of the outer coils of the multiple resonator units 4 are connected to the grounding strip 5 in an up-and-down staggered orientation. The grounding ends 6 are placed in a reasonable orientation and the up-and-down staggered arrangement of the grounding ends 6 can well suppress the frequency doubling resonance peak.
[0044] Figure 4 Among them, L4 is 20mm, L5 is 4mm, that is, the size of the superconducting thin film substrate 3 is 20*4mm, and only Figure 3 The substrate area of the existing 6-section superconducting filter (size 39*13mm) is about 1 / 6 of that shown. Figure 5 As shown in (a), a two-inch substrate can only hold two Figure 3 The existing 6-section superconducting filter shown in FIG. Figure 5 As shown in (b), a two-inch substrate can hold a full set of 18 Figure 4 In the V-band narrow-passband superconducting filter shown, the utilization rate of the superconducting thin film substrate 3 is increased by 8 times, which can greatly save material costs.
[0045] like Figure 6 As shown, the simulated design of S11 reflection coefficient in the passband is better than -20dB, and the measured result after tuning is better than -15dB; the measured curve of S21 shows that the out-of-band suppression reaches -80dB at f0±1MHz, and the farther out-of-band suppression exceeds -100dB.
[0046] like Figure 7 As shown, m1 is the fundamental frequency f0 position, about 180MHz; m2, m3 and m4 are the positions with the worst suppression at the far end of the high end outside the passband, all of which are better than -80dB, and the m2 position exceeds the second frequency, and the m3 and m4 positions exceed the third frequency; the S21 measured results also show that the suppression of the remaining positions from the far end of the high end outside the passband to more than the fifth frequency exceeds -100dB.
[0047] like Figure 6 and Figure 7 The comparison results of the simulation design and the measured results show that the two resonator units 4 added to the V-band narrow-passband superconducting filter in this application improve the out-of-band suppression of the main indicator to more than 100dB ( Figure 3The existing 6-section filter shown is less than 70dB); the resonator unit 4 is arranged in a reasonable direction, and the far-end second to fifth frequencies of the high end of the passband are well suppressed; since the sensitivity of the fine line end is greatly reduced, the accuracy of major indicators such as center frequency f0, bandwidth BW and in-band standing wave is also improved; while nonlinear indicators such as in-band insertion loss, power resistance and P-1 have almost no change.
[0048] Several other common weakly coupled resonator shapes are used to realize the design and production of a V-band 8-section narrow-bandpass superconducting filter. Under the conditions of the same substrate material, the same frequency and bandwidth, the same line width and line spacing, the compactness of a single resonator and the entire filter cannot be compared with the narrow, long and tightly wound single spiral resonator unit 4 used in the present application. The V-band narrow-bandpass superconducting filter structure provided by the present application is more compact than the common weakly coupled resonator shapes, saving material costs.
[0049] Based on the above settings, the present application realizes the simulation design of a V-band 8-section narrow-passband superconducting filter with a higher number of sections on a smaller substrate area.
[0050] The process and packaging of the V-band narrow-band superconducting filter also adopted various miniaturization methods, including: the accuracy of the optical dry etching process was improved from the original 10um to 1um, and the line straightness and uniformity were also significantly improved.
[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0052] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.
Claims
1. A V-band narrow-passband superconducting filter, characterized in that: The V-band narrow-passband superconducting filter comprises a monomer component and a superconducting thin film substrate; The monomer component includes a plurality of resonator units; the plurality of resonator units are arranged in parallel and cascaded manner on a side surface of the superconducting thin film substrate; a hollow blank structure is arranged inside each of the resonator units, and a plurality of coils are arranged outside the hollow blank structure, and the plurality of coils are a 1 / 4 wavelength single helical structure.
2. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The number of the resonator units is eight.
3. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The substrate material used in the resonator unit is lanthanum aluminate.
4. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The line width of the coil is 10um.
5. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The V-band narrow-passband superconducting filter further includes a grounding strip; the grounding strip is arranged around the plurality of resonator units and has a first set distance from the resonator units.
6. The V-band narrow-passband superconducting filter according to claim 5, characterized in that: The ground ends of the outer coils of the plurality of resonator units are connected to the ground bar in an up-and-down staggered orientation.
7. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The V-band narrow-passband superconducting filter further includes a first feeder position and a second feeder position; the first feeder position and the second feeder position are respectively connected to the outer coils of the resonator units arranged at both ends.
8. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The length of the resonator unit is 2.6 mm, and the width of the resonator unit is 1.1 mm.
9. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The size of the superconducting thin film substrate is 20*4mm.
10. The V-band narrow-passband superconducting filter according to claim 1, characterized in that: The spacing between the coil lines is 10um.