Cover plate assembly and in-line filter
By designing external cable heads to form poles on the filter cover assembly, the problems of poor insertion loss and passband suppression under high frequency suppression are solved, achieving out-of-band suppression and low insertion loss of high-performance filters, which are suitable for a variety of RF filter applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2026-03-17
AI Technical Summary
Existing straight-line filters, when required for high-frequency suppression, use high-order or internal poles, which affects insertion loss and results in poor suppression of frequencies near the passband, thus limiting the application scenarios of the filters.
Design cable heads of a specific shape and position on the cover plate assembly of the filter to form external poles. Introduce additional poles through the insulation setting between the cable and the cover plate to enhance out-of-band rejection performance while maintaining low insertion loss and high Q value.
It effectively enhances the filter's suppression of external frequencies, maintains signal transmission efficiency and the filter's original high quality factor, simplifies the manufacturing process, and eliminates the need for complex internal structure adjustments.
Smart Images
Figure CN224006115U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of filter technology, and in particular to a cover plate assembly and a straight-line filter. Background Technology
[0002] A filter is a frequency-selective device. When the insertion loss requirement is very low and the suppression requirement is very high, poles need to be added to the filter. Typically, most linear filters use high-order poles or add internal poles to meet high-frequency suppression requirements. However, this approach affects the filter's insertion loss and results in poor suppression of frequencies near the passband, thus limiting the filter's application scenarios. Utility Model Content
[0003] In view of this, the purpose of this application is to overcome the shortcomings of the prior art and provide a cover plate assembly and a straight-line filter. By improving the cover plate assembly of the straight-line filter, it is possible to generate poles and improve the insertion loss performance of the filter without affecting the Q value of the filter.
[0004] This application provides the following technical solution:
[0005] In a first aspect, embodiments of this application provide a cover plate assembly for a straight-line filter, the cover plate assembly comprising:
[0006] A cover plate has an outer side, an inner side, a front end, and a rear end; wherein the outer side of the cover plate is away from the resonant cavity of the linear filter, the inner side of the cover plate is close to the resonant cavity of the linear filter, the front end of the cover plate is close to the signal input terminal of the linear filter, and the rear end of the cover plate is close to the signal output terminal of the linear filter.
[0007] A cable, with cable heads at both ends, is disposed on a cover plate and insulated from the cover plate; wherein, both cable heads protrude from the inner side of the cover plate, one cable head is located at the front end of the cover plate and the other cable head is located at the rear end of the cover plate, the portion of the cable between the two cable heads is located on the outer side of the cover plate, and the portion of the cable head located on the inner side of the cover plate defines an pole.
[0008] In some embodiments of the first aspect, the length of the cable is L, and the center frequency of the linear filter is V, satisfying:
[0009] .
[0010] In some embodiments of the first aspect, the length of the cable is L, the wavelength corresponding to the center frequency of the straight-line filter is λ, and L = 0.5λ.
[0011] In some embodiments of the first aspect, the cover plate has a centerline, and the two cable heads are located near the centerline.
[0012] In some embodiments of the first aspect, the cover plate has a through-hole through which the cable head passes.
[0013] In some embodiments of the first aspect, the cable is configured in any of the following shapes:
[0014] U-shaped, arc-shaped, M-shaped.
[0015] Secondly, this application also provides a linear filter, the linear filter comprising:
[0016] A cover assembly, wherein the cover assembly is the cover assembly described in any of the above embodiments;
[0017] The housing has multiple resonant cavities and an opening, the multiple resonant cavities and the opening are connected, and a coupling window is provided between adjacent resonant cavities. The multiple resonant cavities are arranged sequentially from the signal input end to the signal output end of the straight-line filter, and the cover plate is connected to the opening end of the housing.
[0018] In some embodiments of the second aspect, one of the cable ends is located in the resonant cavity closest to the signal input end, and the other cable end is located in the resonant cavity closest to the signal output end.
[0019] In some embodiments of the second aspect, the straight-line filter further includes a plurality of resonant rods, each of the resonant cavities having a separate resonant rod, and the cable head being located between adjacent resonant rods.
[0020] In some embodiments of the second aspect, the linear filter further includes a fastening screw, the housing has a through hole, the open end of the housing has a fastening threaded hole, the screw portion of the fastening screw passes through the through hole and is threadedly connected to the wall of the fastening threaded hole; wherein, a reinforcing rib is provided inside the housing, the reinforcing rib extends along the extension direction of the fastening threaded hole, the reinforcing rib protrudes from the inner wall of the resonant cavity, and the fastening threaded hole is provided in the reinforcing rib.
[0021] The embodiments of this application have the following advantages:
[0022] This application provides a cover plate assembly that effectively enhances the filter's suppression of unwanted external frequencies by forming poles on the cable ends inside the cover plate. Since the cables between the poles are external, they do not cause additional signal loss within the passband, ensuring signal transmission efficiency. Furthermore, the design of the cables and cover plate ensures that the filter's original high quality factor remains unchanged, maintaining good selectivity and stability. It should be noted that this improvement can be achieved through relatively simple mechanical assembly, without requiring complex internal structural adjustments or redesign.
[0023] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0025] Figure 1 A schematic diagram of a cover plate assembly provided by an embodiment of this application is shown from one perspective.
[0026] Figure 2 This illustration shows a structural schematic diagram from another perspective of a cover plate assembly provided by an embodiment of this application;
[0027] Figure 3 This illustration shows a structural schematic diagram from another perspective of a cover plate assembly provided by an embodiment of this application;
[0028] Figure 4 This illustration shows a schematic diagram of the structure of a straight-line filter provided in an embodiment of this application from one perspective;
[0029] Figure 5 The diagram shows a structural schematic of a housing provided by an embodiment of this application from one perspective;
[0030] Figure 6 A schematic diagram of the response bandwidth of the first test group provided in an embodiment of this application is shown;
[0031] Figure 7 A schematic diagram of the response bandwidth of the second test group provided by an embodiment of this application is shown.
[0032] Explanation of key component symbols:
[0033] 100-Cover plate; 110-Pole hole; 120-Center line; 200-Cable; 210-Cable head; 300-Resonant rod; 400-Housing; 410-Signal input terminal; 420-Signal output terminal; 430-Open end; 440-Resonant cavity; 450-Reinforcing rib; 460-Securing threaded hole. Detailed Implementation
[0034] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0035] It should be noted that when an element is said to be "fixed" to another element, it can be directly on the other element or there may be an intervening element. When an element is said to be "connected" to another element, it can be directly connected to the other element or there may be an intervening element. Conversely, when an element is said to be "directly" on another element, there is no intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.
[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the template description is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.
[0039] In related technologies, a filter is a frequency-selective device. When the insertion loss requirement of the filter is very small and the suppression requirement is very high, poles need to be added to the filter. Typically, most linear filters use high-order poles or add internal poles to meet the high-frequency suppression requirements. However, this approach affects the insertion loss of the filter and results in poor frequency suppression near the passband, thus limiting the application scenarios of the filter.
[0040] As shown in Figures 1 and 2, Figure 3 As shown, in order to solve the above-mentioned technical problems, this application provides a cover plate assembly for a straight-line filter. The cover plate assembly includes a cover plate 100 and a cable 200. The cover plate 100 has an outer side, an inner side, a front end, and a rear end. The outer side of the cover plate 100 is away from the resonant cavity 440 of the straight-line filter, the inner side of the cover plate 100 is close to the resonant cavity 440 of the straight-line filter, the front end of the cover plate 100 is close to the signal input terminal 410 of the straight-line filter, and the rear end of the cover plate 100 is close to the signal output terminal 420 of the straight-line filter.
[0041] The cable 200 has cable heads 210 at both ends. The cable 200 is disposed on the cover plate 100, and the cable 200 and the cover plate 100 are insulated from each other. The two cable heads 210 protrude from the inner side of the cover plate 100. One cable head 210 is located at the front end of the cover plate 100, and the other cable head 210 is located at the rear end of the cover plate 100. The portion of the cable 200 between the two cable heads 210 is located on the outer side of the cover plate 100, and the portion of the cable head 210 located on the inner side of the cover plate 100 defines a pole.
[0042] In these embodiments, this application provides an improved cover plate assembly for a straight-line filter. This assembly aims to improve the out-of-band rejection performance of the filter while maintaining low insertion loss and a high Q value by introducing additional poles through the addition of a specifically designed cable 200 to the outside of the cover plate 100. The cover plate 100, as part of the filter, has a clearly defined orientation: the outer side is the side away from the resonant cavity 440; the inner side is the side closer to the resonant cavity 440; the front end is closer to the signal input terminal 410; and the rear end is closer to the signal output terminal 420. The cable 200 and its cable ends 210 are improvements of this application, having the following characteristics: each end of the cable 200 has a cable end 210; the cable 200 is insulated from the cover plate 100; the cable ends 210 protrude from the inner side of the cover plate 100, located at the front and rear ends of the cover plate 100 respectively; the middle portion of the cable 200 is located on the outer side of the cover plate 100; and the inner cable ends 210 form poles, affecting the frequency response characteristics of the filter.
[0043] The cable connector 210 can interact with the electromagnetic field inside the filter, generating additional poles at specific frequencies. These poles appear in the out-of-band region of the filter, helping to enhance the suppression of unwanted frequency components. Since the cable 200 and its cable connector 210 are mounted on the cover plate 100, rather than being directly integrated into the filter, the basic electrical characteristics of the filter, such as the Q value, are not significantly altered, nor is the insertion loss in the passband increased.
[0044] Therefore, by forming poles on the cable ends 210 inside the cover plate 100, the filter's suppression of unwanted external frequencies can be effectively enhanced. Since the cable 200 between the poles is external, it does not cause additional loss to the signal within the passband, ensuring signal transmission efficiency. Furthermore, the design of the cable 200 and the cover plate 100 ensures that the filter's original high quality factor remains unchanged, maintaining good selectivity and stability. It should be noted that this improvement can be achieved through relatively simple mechanical assembly, without requiring complex internal structural adjustments or redesign.
[0045] In some embodiments, the length of cable 200 is L, and the center frequency of the linear filter is V, satisfying:
[0046]
[0047] In these embodiments, the relationship between the length of cable 200 and the wavelength of the center frequency of the linear filter is a key design parameter. Specifically, the length of cable 200 and the wavelength corresponding to the center frequency of the filter should satisfy the following conditions:
[0048] The length of cable 200 should fall within the range described above. This specific range is based on electromagnetic theory and practical application requirements, aiming to optimize filter performance and help form an ideal pole at cable end 210, thereby enhancing out-of-band rejection. This length range ensures that the pole appears at the appropriate frequency position for optimal filtering. If cable 200 is too long, it will introduce unwanted resonant modes, leading to additional insertion loss or unwanted frequency response characteristics; while if cable 200 is too short, it will not effectively generate the required pole, weakening the out-of-band rejection effect.
[0049] Clearly, limiting the length of cable 200 to a reasonable range simplifies the design and manufacturing process while ensuring consistent performance and reliability. In practical applications, the specific length of cable 200 needs to be determined based on the center frequency of the specific filter. For example, for a filter operating at different center frequencies, the length of cable 200 will be adjusted accordingly to maintain it within the aforementioned proportional range. Furthermore, the shape of cable 200 can be optimized, such as using L-shapes or circular deformations, to better adapt to the actual installation space, and the dimensions can be further fine-tuned using simulation tools to ensure optimal performance.
[0050] In some embodiments, the length of the cable 200 is L, the wavelength corresponding to the center frequency of the straight filter is λ, and L = 0.5λ is satisfied.
[0051] When the length of cable 200 is precisely set to half the wavelength of the center frequency of the straight-line filter, i.e., 0.5λ, half-wavelength elements are often used in antenna and microwave engineering to achieve specific reactive characteristics or resonant conditions. At this length, cable 200 can operate as an open-circuit transmission line, forming a high-impedance node at its end, thereby affecting the electromagnetic field distribution inside the filter. This helps to introduce the desired pole at the cable head 210 location to enhance out-of-band rejection performance.
[0052] In other words, a cable length of 0.5λ and 200mm ensures that the poles occur at the optimal frequency, guaranteeing effective suppression of out-of-band signals without affecting signal quality within the passband. Furthermore, this length helps reduce unnecessary energy reflection and loss, maintaining low insertion loss, which is crucial for high-performance filters. It effectively improves the filter's out-of-band rejection capability while maintaining low insertion loss and a high Q value, making it suitable for various high-performance RF filter applications.
[0053] like Figure 3 As shown, in some embodiments, the cover plate 100 has a center line 120, and two cable heads 210 are located near the center line 120.
[0054] In these embodiments, the cover plate 100 has a center line 120, with two cable heads 210 arranged close to this center line 120. This not only helps optimize the electrical performance of the filter but also simplifies the manufacturing and assembly process.
[0055] Placing the two cable ends 210 near the centerline 120 of the cover plate 100 ensures the symmetry and uniformity of the electromagnetic field distribution inside the filter. This symmetrical structure helps reduce unwanted phase differences and imbalances, thereby improving the overall performance of the filter. The cable ends 210, closer to the centerline 120, can more effectively interact with the signal path inside the filter, introducing desired poles at specific frequencies to enhance out-of-band rejection without affecting passband performance.
[0056] The symmetrical arrangement of the cable heads 210 generates more uniform and stable reactive characteristics within the filter, which helps optimize the frequency response throughout the passband and ensures the quality of signal transmission. Because the cable heads 210 are close to the neutral line 120, the distance between them is minimized, reducing potential parasitic coupling or interference and further improving the stability and selectivity of the filter.
[0057] Furthermore, the symmetrical design makes the manufacturing process more intuitive and easier to control, reducing complexity and errors in production and improving product consistency and reliability. Additionally, the symmetrical structure facilitates installation and subsequent commissioning, as engineers can quickly locate and adjust the position of the cable head 210 based on the centerline 120, ensuring that each filter achieves its expected performance specifications.
[0058] It should be noted that the centerline 120 of the cover plate 100 refers to the central axis along the length of the cover plate 100, which is usually located between the front and rear ends and is perpendicular to the signal input terminal 410 and the output terminal. This provides a clear reference position for the cable head 210.
[0059] like Figure 1 As shown, in some embodiments, the cover plate 100 has a through-hole 110 through which the cable head 210 passes.
[0060] In these embodiments, the cover plate 100 has through-hole pole holes 110 through which cable heads 210 pass, facilitating manufacturing and assembly.
[0061] The pole hole 110 is a channel specifically designed for the cable head 210, allowing it to penetrate from the outside to the inside of the cover plate 100. In this way, the cable head 210 can directly interact with the signal path inside the filter, introducing the desired pole at a specific frequency. The pole hole 110 ensures good insulation between the cable head 210 and the cover plate 100 while providing the necessary electromagnetic coupling path, enabling the cable head 210 to effectively influence the frequency response characteristics of the filter.
[0062] By passing the cable head 210 through the pole hole 110, the position and intensity of the pole can be controlled more precisely, thereby achieving effective suppression of out-of-band frequencies without affecting the performance within the passband.
[0063] Furthermore, compared to directly pasting or fixing the cable head 210 to the inside of the cover plate 100, using the pole hole 110 for installation is simpler, faster, and more reliable, which helps to improve production efficiency and reduce manufacturing costs.
[0064] It should be noted that the diameter of the pole hole 110 needs to be designed according to the actual size of the cable head 210, so as to ensure that the cable head 210 can pass through smoothly, while avoiding excessive size that may cause unnecessary electromagnetic leakage or coupling.
[0065] To ensure good insulation between the cable head 210 and the cover plate 100, appropriate insulating material or coating can be added around the pole hole 110 to prevent current leakage or short circuits. Alternatively, the outer layer of the cable 200 can be an insulating layer.
[0066] For example, the shape of the pole hole 110 is set to be circular, elliptical, etc.
[0067] For example, the cable 200 and the pole hole 110 can be fixed by welding, bonding, interference fit or other methods.
[0068] like Figure 1 As shown, in some embodiments, the cable 200 is configured in any of the following shapes: U-shaped, arc-shaped, or M-shaped.
[0069] like Figure 4 and Figure 5 As shown, in some embodiments, this application also provides a straight-line filter, which includes a cover plate assembly and a housing 400, wherein the cover plate assembly is any of the cover plate assemblies described in the above embodiments;
[0070] The housing 400 has multiple resonant cavities 440 and an opening 430. The multiple resonant cavities 440 and the opening 430 are connected and arranged in communication. A coupling window is provided between adjacent resonant cavities 440. The multiple resonant cavities 440 are arranged sequentially from the signal input terminal 410 to the signal output terminal 420 of the straight-line filter. The cover plate 100 is connected to the opening 430 of the housing 400.
[0071] In these embodiments, the filter is designed to improve overall performance, particularly in terms of high suppression and low insertion loss, by combining an optimized cover plate assembly with a housing 400 of a specific structure.
[0072] As previously described, the cover plate assembly includes elements such as a centerline 120, a cable 200, and a cable head 210 passing through a pole hole 110. These designs ensure that the filter can introduce the desired poles to enhance out-of-band suppression.
[0073] The housing 400 is the main structural component of the filter, containing multiple resonant cavities 440 and openings 430, with coupling windows between adjacent resonant cavities 440. Each resonant cavity 440 is an independent electromagnetic field region used to selectively amplify or attenuate signals within a specific frequency range. The presence of multiple resonant cavities 440 allows the filter to achieve more complex frequency response characteristics. The openings 430 on the housing 400 are designed for mounting cover assemblies, ensuring that cable heads 210 can penetrate into the interior and interact with the resonant cavities 440.
[0074] The coupling window, set between adjacent resonant cavities 440, allows signals to be transmitted from one resonant cavity 440 to another while controlling the electromagnetic coupling strength between different resonant cavities 440. The design of the coupling window is crucial for determining the filter's passband width, insertion loss, and other key parameters.
[0075] The resonant cavity 440 is arranged sequentially from the signal input terminal 410 to the signal output terminal 420 to form a continuous signal path, ensuring that the signal passes through the entire filter in the expected manner.
[0076] Clearly, by introducing poles through the cover plate assembly, the filter can generate additional zeros or poles outside the band, thereby significantly improving its ability to suppress unwanted frequency components. Since the cable 200 is external, it does not cause additional loss to the signal within the passband, ensuring signal transmission efficiency. The design of the cable 200 and cover plate 100 ensures that the filter's original high quality factor remains unchanged, maintaining good selectivity and stability.
[0077] like Figure 5 As shown, in some embodiments, one cable head 210 is located in the resonant cavity 440 closest to the signal input terminal 410, and the other cable head 210 is located in the resonant cavity 440 closest to the signal output terminal 420.
[0078] In these embodiments, not only are the electrical performance of the filter optimized, but its out-of-band rejection capability is also enhanced. Placing the cable end 210 in the resonant cavity 440 closest to the signal input terminal 410 and the signal output terminal 420, respectively, ensures direct interaction with signals entering and leaving the filter. This arrangement helps introduce poles on the cable end 210, thereby affecting the frequency response characteristics of the entire filter.
[0079] In this way, additional poles can be introduced at both ends of the filter's passband to enhance the suppression of out-of-band frequency components without affecting the performance within the passband.
[0080] The input pole is a pole located at the cable head 210 closest to the signal input terminal 410. This pole can help improve the filter's suppression of out-of-band signals in the low-frequency range.
[0081] The output pole can also be formed at the cable head 210, which is closest to the signal output terminal 420, which helps to improve the suppression of out-of-band signals in the high-frequency band.
[0082] The two cable ends 210 are located in the resonant cavities 440 at the input and output ends, respectively, which can generate additional zeros or poles outside the filter's band, thereby significantly improving the suppression capability for unwanted frequency components. Since the cable 200 between the poles is formed externally, it does not cause additional loss to the signal within the passband, ensuring signal transmission efficiency.
[0083] like Figure 5 As shown, in some embodiments, the straight-line filter also includes multiple resonant rods 300, each resonant cavity 440 having a separate resonant rod 300, and the cable head 210 being located between adjacent resonant rods 300.
[0084] In these embodiments, each resonant cavity 440 is provided with a resonant rod 300 for adjusting the resonant frequency and quality factor (Q value) of the resonant cavity 440. The resonant rod 300 can enhance the signal response within a specific frequency range while attenuating signals at other frequencies, thereby achieving more precise frequency selection.
[0085] Placing the cable end 210 between adjacent resonant rods 300 ensures effective interaction with the electromagnetic field within the resonant cavity 440, introducing the desired poles at specific frequencies. This arrangement helps optimize out-of-band suppression without affecting passband performance.
[0086] The cable connector 210 is located between adjacent resonant rods 300, allowing the introduction of additional poles without interfering with the operation of the resonant rods 300, thus further enhancing the out-of-band rejection effect. The combined use of the resonant rods 300 and the cable connector 210 can generate more zeros or poles outside the filter's band, significantly improving the suppression capability for unwanted frequency components. Since the cable 200 between the poles is formed externally, and the cable connector 210 does not directly interfere with the operation of the resonant rods 300, it does not cause additional signal loss within the passband, ensuring signal transmission efficiency.
[0087] Furthermore, the presence of the resonant rod 300 allows for fine-tuning of the filter's frequency response characteristics by adjusting its parameters without changing the position or length of the cable head 210, simplifying the debugging process.
[0088] like Figure 4 and Figure 5As shown, in some embodiments, the straight-line filter further includes a fastening screw, the housing 400 has a through hole, the open end 430 of the housing 400 has a fastening threaded hole 460, the screw portion of the fastening screw passes through the through hole and is threadedly connected to the hole wall of the fastening threaded hole 460; wherein, a reinforcing rib 450 is provided inside the housing 400, the reinforcing rib 450 extends along the extension direction of the fastening threaded hole 460, the reinforcing rib 450 protrudes from the inner wall of the resonant cavity 440, and the fastening threaded hole 460 is provided in the reinforcing rib 450.
[0089] In these embodiments, fastening screws are used to securely connect the cover plate 100 to the housing 400, ensuring tight contact between the cover plate 100 and the housing 400 to maintain good electromagnetic sealing. Through holes in the housing 400 allow the screw shank to pass through, while threaded fastening holes 460 provide threaded connection points, enabling the screw to be secured in place.
[0090] The reinforcing rib 450, located inside the housing 400, is arranged along the extension direction of the fastening threaded hole 460 and protrudes from the inner wall of the resonant cavity 440. The presence of the reinforcing rib 450 not only enhances the structural strength of the housing 400, but also provides additional support for the fastening threaded hole 460, preventing deformation or damage caused by long-term use or external stress.
[0091] The reinforcing rib 450 improves the overall rigidity of the housing 400, enabling the filter to maintain stable performance under vibration. Furthermore, while ensuring the connection strength of the threaded hole 460 and the fastening screw, the wall thickness of the housing 400 can be reduced, thereby reducing the size and weight of the filter.
[0092] Additionally, the following comparative test is provided:
[0093] First test group: Out-of-band performance testing of traditional straight-line filters, filter response bandwidth as follows: Figure 6 As shown;
[0094] Second test group: Out-of-band performance testing of the straight-line filter provided in this application, the filter response bandwidth is as follows: Figure 7 As shown.
[0095] in, Figure 6 and Figure 7 In the diagram, the horizontal axis represents frequency, and the vertical axis represents attenuation.
[0096] Clearly, the passband of the filter in the first test group is 1800MHz, and the high-frequency suppression at 1850MHz is 40dB.
[0097] The filter passband of the second test group is 1800MHz, which can easily achieve high-frequency suppression of more than 90dB at 1850MHz.
[0098] In other words, the filter design proposed in this application improves high-frequency suppression by 50dB compared with traditional design schemes, resulting in superior overall filter performance.
[0099] In all examples shown and described herein, any specific values should be interpreted as merely exemplary and not as limitations; therefore, other examples of exemplary embodiments may have different values.
[0100] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0101] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these modifications and improvements all fall within the protection scope of this application.
Claims
1. A cover plate assembly for a direct flow filter, the cover plate assembly comprising: The cover plate assembly comprises: a cover plate having an outer side, an inner side, a front end and a rear end; wherein the outer side of the cover plate faces away from the resonant cavity of the straight-line filter, the inner side of the cover plate is close to the resonant cavity of the straight-line filter, the front end of the cover plate is close to the signal input end of the straight-line filter, and the rear end of the cover plate is close to the signal output end of the straight-line filter; a cable having cable heads at both ends, the cable being arranged on the cover plate and being insulated between the cable and the cover plate; wherein both of the cable heads are protruding on the inner side of the cover plate, one of the cable heads is located at the front end of the cover plate, the other cable head is located at the rear end of the cover plate, the part of the cable between the two cable heads is located on the outer side of the cover plate, and the part of the cable head located on the inner side of the cover plate defines a pole point.
2. The cover plate assembly of claim 1, wherein, The length of the cable is L, and the center frequency of the straight-line filter is V, satisfying:
3. The cover plate assembly of claim 2, wherein, The length of the cable is L, and the wavelength corresponding to the center frequency of the straight-line filter is λ, and satisfying: L=0.5λ.
4. The cover plate assembly of claim 1, wherein, The cover plate has a center line, and both of the cable heads are close to the center line.
5. The cover plate assembly of claim 1, wherein, The cover plate has a pole point hole passing through, and the cable head is arranged in the pole point hole.
6. The cover plate assembly of claim 1, wherein, The shape of the cable is arranged as any one of the following: U-shaped, arc-shaped, M-shaped.
7. A direct flow filter characterized by The straight-line filter comprises: a cover plate assembly as claimed in any one of claims 1 to 6; a shell having a plurality of resonant cavities and an open end, the plurality of resonant cavities and the open end being arranged in communication, a coupling window being arranged between adjacent resonant cavities, the plurality of resonant cavities being arranged in sequence from the signal input end to the signal output end of the straight-line filter, and the cover plate being connected to the open end of the shell.
8. The inline filter of claim 7, wherein, One of the cable heads is located in the resonant cavity closest to the signal input end, and the other cable head is located in the resonant cavity closest to the signal output end.
9. The inline filter of claim 8, wherein, The straight-line filter further comprises a plurality of resonant rods, each resonant rod being arranged separately in each resonant cavity, and the cable heads being located between adjacent resonant rods.
10. The inline filter of claim 9, wherein, The straight-line filter further comprises a fastening screw, the shell has a through hole, the open end of the shell has a fastening threaded hole, the threaded part of the fastening screw is arranged in the through hole and is threadedly connected with the hole wall of the fastening threaded hole; wherein a reinforcing rib is arranged in the shell, the reinforcing rib is arranged in extension along the extension direction of the fastening threaded hole, the reinforcing rib protrudes from the inner wall of the resonant cavity, and the fastening threaded hole is arranged on the reinforcing rib.