Spiral filter
By optimizing the parameters and structural design of the helical resonator, the shortcomings of existing filters in terms of multi-frequency selectivity and insertion loss are solved, realizing a high-performance, low-loss miniaturized helical filter suitable for satellite communication at frequencies of 240MHz, 320MHz and 400MHz.
Patent Information
- Application Number
- CN202423270619.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-12-30
AI Technical Summary
Existing LC filters and SAW filters exhibit significant limitations in several specific frequency-selective applications, exhibiting high insertion loss and insufficient out-of-band signal suppression, while cavity filters suffer from large size and complex manufacturing.
The design utilizes helical filters suitable for frequencies of 240MHz, 320MHz, and 400MHz. By optimizing the parameters of the helical resonator (such as the diameter of the coil wire, the total number of turns of the helical tube, and the pitch), and combining the use of copper sheets and tuning screws, high selectivity and low insertion loss are achieved.
They exhibit excellent selectivity at their respective operating frequencies, minimize insertion loss, effectively suppress out-of-band signals, ensure efficient transmission of high-frequency signals, reduce energy loss, and are small in size, making them suitable for multi-frequency communication.
Smart Images
Figure CN223625199U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of satellite communication technology, and in particular to a spiral filter. Background Technology
[0002] In modern satellite communication systems, real-time communication between ground stations and satellites is crucial. Especially in the communication applications of the Tianqi satellite, three frequency bands—240MHz, 320MHz, and 400MHz—are used for different communication tasks: 240MHz for high-speed uplink, 320MHz for high-speed downlink, and 400MHz for low-speed uplink and downlink. To enhance communication efficiency and ensure that data transmission at these different rates can occur simultaneously within the same ground station without interference, high-performance filters are needed to address signal isolation issues between the frequency bands.
[0003] Currently, LC filters and surface acoustic wave (SAW) filters are widely used in RF circuit design. However, these filters exhibit significant limitations when dealing with applications requiring strict selectivity for multiple specific frequencies. For example, they typically introduce insertion loss exceeding 1.5 dB and achieve only about 60 dB of signal suppression outside their operating frequency band, which is clearly insufficient to meet today's complex and ever-changing communication demands. Furthermore, achieving higher performance standards may require cavity filters, but this solution often comes with drawbacks such as large size and complex manufacturing processes. Utility Model Content
[0004] In view of the above problems of the prior art, this application provides a spiral filter that is suitable for three frequency points: 240MHz, 320MHz or 400MHz. Each spiral filter exhibits excellent selectivity at its respective operating frequency point, and the suppression of the other two out-of-band frequencies can reach more than 60dB, with an insertion loss of only 0.6dB.
[0005] To achieve the above objectives, the first aspect of this application provides a spiral filter suitable for a 240MHz frequency point, including a housing;
[0006] The outer casing contains three helical resonant cavities, wherein the diameter of the coil wire in each helical resonant cavity is set to 0.195 cm, the total number of turns of the helical tube is set to 6.66, and the pitch is set to 0.39 cm.
[0007] The top of the outer casing has two slits for accommodating copper sheets, which are inserted into the slits; the copper sheets are located 1.08 cm from the grounding end of the spiral tube.
[0008] The inner ends of the housing are also provided with an input tap and an output tap, which are respectively connected to the grounding end of the spiral tube at 0.3 turns.
[0009] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 240MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0010] To achieve the above objectives, a second aspect of this application provides a spiral filter suitable for a 320MHz frequency point, including a housing;
[0011] The outer casing contains three helical resonant cavities, wherein the diameter of the coil wire in each helical resonant cavity is 0.26 cm, the total number of turns of the helical tube is 5, and the pitch is 0.52 cm.
[0012] The top of the outer casing has two slits for accommodating copper sheets, which are inserted into the slits; the copper sheets are located 0.93 cm from the grounding end of the spiral tube.
[0013] The inner ends of the housing are also provided with an input tap and an output tap, which are respectively connected to the grounding end of the spiral tube at 0.25 turns.
[0014] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 320MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0015] To achieve the above objectives, a third aspect of this application provides a spiral filter suitable for a 400MHz frequency point, including a housing;
[0016] The outer casing contains three helical resonant cavities, wherein the diameter of the coil wire in each helical resonant cavity is 0.33 cm, the total number of turns of the helical tube is 4, and the pitch is 0.65 cm.
[0017] The top of the outer casing has two slits for accommodating copper sheets, which are inserted into the slits; the copper sheets are located 0.83 cm from the grounding end of the spiral tube.
[0018] The inner end of the casing is also provided with an input tap and an output tap, which are respectively connected to the grounding end of the spiral tube at 0.18 turns.
[0019] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 400MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0020] In some embodiments, the internal height of the helical resonant cavity is set to 4.33 cm, the average diameter of the helical tube is set to 1.72 cm, and the length of the helical tube is set to 2.58 cm.
[0021] In some embodiments, the helical resonant cavity is a square-cavity helical resonator with a side length of 2.6 cm.
[0022] In some embodiments, the housing includes an upper structural shell and a lower structural shell; the upper structural shell and the lower structural shell are fixedly connected by screws;
[0023] The gap is formed in the upper structural shell.
[0024] In some embodiments, each of the spiral tubes in the spiral resonant cavity is provided with a tuning screw at its open end, and the tuning screw is installed through the top of the housing.
[0025] In some embodiments, after the grounding end of each of the spiral tubes in the spiral resonant cavity is wound into a circle, the grounding end of the spiral tube is fixed to the bottom of the housing by screws and nuts.
[0026] In some embodiments, the outer ends of the housing are provided with SMA connectors for connecting external devices.
[0027] In some embodiments, the dimensions of the housing are 87mm*46mm*52.6mm. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the structure of a spiral resonant cavity provided in this application;
[0029] Figure 2 This is a schematic diagram of the structure of a spiral filter provided in this application;
[0030] Figure 3 This is a side view of a spiral filter provided in this application;
[0031] It should be understood that the dimensions and shapes of the blocks in the above structural diagrams are for reference only and should not constitute an exclusive interpretation of the embodiments of the present invention. The relative positions and inclusion relationships between the blocks presented in the structural diagrams are only schematic representations of the structural relationships between the blocks, and are not intended to limit the physical connection methods of the embodiments of the present invention. Detailed Implementation
[0032] The technical solutions provided in this application will be further described below with reference to the accompanying drawings and embodiments. It should be understood that the system architecture and business scenarios provided in the embodiments of this application are mainly for illustrating possible implementations of the technical solutions of this application and should not be construed as the sole limitation on the technical solutions of this application. Those skilled in the art will recognize that the technical solutions provided in this application are equally applicable to similar technical problems as system architectures evolve and new business scenarios emerge.
[0033] 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. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application. To accurately describe the technical content of this application and to accurately understand the invention, the following explanations or definitions of the terms used in this specification are provided before describing specific embodiments.
[0034] This application provides a spiral filter suitable for a 240MHz frequency point; see also... Figure 1 and Figure 2 As shown, it includes the outer casing 1;
[0035] The outer casing 1 contains three helical resonant cavities, wherein the diameter of the coil wire in each helical resonant cavity is 0.195 cm, the total number of turns of the helical tube is 6.66, and the pitch is 0.39 cm.
[0036] The top of the outer casing 1 has two slots for accommodating copper sheets 2, and the copper sheets 2 are inserted into the slots; the copper sheets 2 are located 1.08 cm from the grounding end of the spiral tube.
[0037] like Figure 3 As shown, the inner ends of the outer casing 1 are also provided with an input tap 3 and an output tap 4, and the input tap 3 and the output tap 4 are respectively connected to the grounding end of the spiral tube at 0.3 turns.
[0038] It should be noted that the spiral resonator mentioned above is a square-cavity spiral resonator, see [link / reference]. Figure 1As shown, the specific meanings of each parameter of the square cavity helical resonator are as follows: S: inner side length of the square cavity (cm), d: average diameter of the helical tube (cm), H: inner height of the square cavity (cm), b: length of the helical tube (cm), Φ0: diameter of the wire used to wind the helical tube (cm), τ: pitch (cm), N: total number of turns of the helical tube (turns), n0: number of turns per unit length (turns / cm).
[0039] Furthermore, if the performance of the spiral filter does not meet expectations during actual testing, the coupling effect of the spiral filter can be improved by fine-tuning the position of the copper plate 2, that is, changing its depth between the two spiral resonant cavities, thereby improving its performance.
[0040] In addition, the positions of input tap 3 and output tap 4 can be adjusted according to actual needs, which helps to minimize insertion loss and improve the efficiency of the spiral filter.
[0041] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 240MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0042] This application also provides a spiral filter suitable for a 320MHz frequency point, see [link to relevant documentation]. Figure 1 and Figure 2 As shown, it includes the outer casing 1;
[0043] The outer casing 1 is provided with three spiral resonant cavities, wherein the diameter of the coil wire in each spiral resonant cavity is set to 0.26 cm, the total number of turns of the spiral tube is set to 5, and the pitch is set to 0.52 cm.
[0044] The top of the outer casing 1 has two slits for accommodating copper sheets 2, and the copper sheets 2 are inserted into the slits; the copper sheets 2 are located 0.93cm from the grounding end of the spiral tube;
[0045] like Figure 3 As shown, the inner ends of the outer casing 1 are also provided with an input tap 3 and an output tap 4, and the input tap 3 and the output tap 4 are respectively connected to the grounding end of the spiral tube at 0.25 turns.
[0046] The aforementioned spiral resonant cavity is a square-cavity spiral resonator, see [link to relevant documentation]. Figure 1 As shown, the specific meanings of each parameter of the square cavity spiral resonator, the adjustment of the position of copper plate 2, and the adjustment of the positions of input tap 3 and output tap 4 are all described above. Repeated descriptions will not be repeated here.
[0047] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 320MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0048] This application also provides a spiral filter suitable for a 400MHz frequency point, see [link to relevant documentation]. Figure 1 and Figure 2 As shown, it includes the outer casing 1;
[0049] The outer casing 1 contains three spiral resonant cavities, wherein the diameter of the coil wire in each spiral resonant cavity is 0.33 cm, the total number of turns of the spiral tube is 4, and the pitch is 0.65 cm.
[0050] The top of the outer casing 1 has two slots for accommodating copper sheets 2, and the copper sheets 2 are inserted into the slots; the copper sheets 2 are located 0.83 cm from the grounding end of the spiral tube.
[0051] like Figure 3 As shown, the inner ends of the outer casing 1 are also provided with an input tap 3 and an output tap 4, and the input tap 3 and the output tap 4 are respectively connected to the grounding end of the spiral tube at 0.18 turns.
[0052] The aforementioned spiral resonant cavity is a square-cavity spiral resonator, see [link to relevant documentation]. Figure 1 As shown, the specific meanings of each parameter of the square cavity spiral resonator, the adjustment of the position of copper plate 2, and the adjustment of the positions of input tap 3 and output tap 4 are all described above. Repeated descriptions will not be repeated here.
[0053] Thus, by designing the parameters of the helical resonant cavity (coil wire diameter, total number of turns of the helical tube, pitch), the helical filter can exhibit excellent selectivity at the 400MHz frequency point, effectively suppress out-of-band signals, and at the same time minimize insertion loss. Minimizing insertion loss ensures efficient transmission of high-frequency signals and reduces energy loss.
[0054] The following will further introduce the specific structure and technical details of the spiral filter. Regardless of whether it is designed for 240MHz, 320MHz or 400MHz frequency points, each spiral filter adopts the same structure as follows.
[0055] In some embodiments, the internal height of the helical resonant cavity is set to 4.33 cm, the average diameter of the helical tube is set to 1.72 cm, and the length of the helical tube is set to 2.58 cm.
[0056] In some embodiments, the helical resonant cavity is a square-cavity helical resonator with a side length of 2.6 cm.
[0057] Thus, the square cavity design helps achieve a more uniform electromagnetic field distribution. Optimized electromagnetic field distribution reduces energy leakage and unnecessary losses, enhancing signal processing capabilities. Furthermore, standardized dimensions and shape help ensure consistency across each product, reducing manufacturing tolerances and improving product quality.
[0058] In some embodiments, the outer shell 1 includes an upper structural shell 5 and a lower structural shell 6; the upper structural shell 5 and the lower structural shell 6 are fixedly connected by screws; the cross-sectional area of the upper structural shell 5 is Z-shaped;
[0059] The gap is formed in the upper structural shell 5.
[0060] Thus, the outer shell 1, consisting of an upper structural shell 5 and a lower structural shell 6, and connected by screws, not only facilitates disassembly and maintenance but also provides robust mechanical support.
[0061] In some embodiments, each of the spiral tubes in the spiral resonant cavity is provided with a tuning screw 7 at its open end, and the tuning screw 7 is installed through the top of the housing 1.
[0062] Thus, since tolerances are unavoidable in the manufacturing process, the tuning screw 7 provides a simple and effective means to compensate for these errors, ensuring that each production batch meets design specifications. In other words, the tuning screw 7 allows for fine-tuning of the frequency response of the spiral filter without altering its physical structure, ensuring that the spiral filter achieves optimal performance within the target frequency band.
[0063] In some embodiments, after the grounding end of each of the spiral tubes in the spiral resonant cavity is wound into a circle, the grounding end of the spiral tube is fixed to the bottom of the housing 1 by screws and nuts.
[0064] Thus, the combination of screws and nuts provides robust mechanical support, preventing loosening due to vibration or impact, and ensuring stability and reliability for long-term use.
[0065] In some embodiments, the outer ends of the housing 1 are provided with SMA connectors 8 for connecting external devices.
[0066] Thus, the SMA connector 8, as a widely accepted standard RF connector, ensures that the spiral filter is compatible with RF devices from various manufacturers, greatly facilitating integration and maintenance.
[0067] In some embodiments, the dimensions of the outer casing 1 are 87mm*46mm*52.6mm.
[0068] Of course, in practical applications, the outer shell 1 can also be set to other sizes, without being specifically limited here, in order to meet the needs of different scenarios and improve design flexibility.
[0069] Thus, the miniaturized housing size significantly reduces the space occupied by the helical filter, making it easier to install in limited spaces, such as communication base stations, satellite receiving equipment, or portable electronic devices.
[0070] The working principle of one of the spiral filters mentioned above will be explained in detail below:
[0071] This application provides a helical filter structure that, by adopting the same housing design 1 and precisely adjusting the key parameters of the helical resonant cavity (such as the coil wire diameter, the total number of turns of the helical tube, and the pitch), successfully designs a high-performance helical filter suitable for three frequency points: 240MHz, 320MHz, and 400MHz. This design not only meets the application requirements of different frequency points but also exhibits excellent selectivity and low insertion loss at each operating frequency.
[0072] After testing and verification, the specific performance indicators of the spiral filters at each frequency point are as follows:
[0073] The insertion loss of the spiral filter suitable for 240MHz is about 0.6dB, the 1dB operating bandwidth is 12MHz, the input-output VSWR is less than 1.2, the suppression at 320MHz is above 60dB, and the suppression at 400MHz is above 80dB.
[0074] The insertion loss of the spiral filter suitable for 320MHz is about 0.6dB, the 1dB operating bandwidth is 14MHz, the input-output VSWR is less than 1.2, the suppression at 240MHz is above 80dB, and the suppression at 400MHz is above 60dB.
[0075] The insertion loss of the suitable 400MHz spiral filter is about 0.6dB, the 1dB operating bandwidth is 15MHz, the input-output VSWR is less than 1.2, the suppression is above 80dB at 240MHz and above 60dB at 320MHz.
[0076] In summary, the spiral filters provided in this application, applicable to 240MHz, 320MHz, or 400MHz, exhibit excellent selectivity at their respective operating frequencies. The suppression of the other two out-of-band frequencies can reach over 60dB, ensuring that the operating paths corresponding to the three frequencies can operate simultaneously at the same address without interference. Each spiral filter has an insertion loss of only 0.6dB, significantly reducing the impact of the spiral filter on the original received or transmitted signals.
[0077] In addition, the spiral filter is small in size (length, width and height dimensions are 87mm*46mm*52.6mm), which significantly reduces the complexity of the layout and is conducive to enabling spiral filters at three frequencies to work simultaneously without interfering with each other at the same address.
[0078] The terms "first, second, third, etc." or similar terms such as module A, module B, module C, etc., used in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of objects. It is understood that a specific order or sequence may be interchanged where permitted so that the embodiments of this application described herein can be implemented in an order other than that illustrated or described herein.
[0079] The term "comprising" as used in the specification and claims should not be construed as limiting itself to what follows; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned feature, integral, step, or component, but does not exclude the presence or addition of one or more other features, integrals, steps, or components, or groups thereof. Thus, the statement "device comprising means A and B" should not be limited to a device consisting solely of components A and B.
[0080] The terms "an embodiment" or "an embodiment" as used in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in at least one embodiment of this application. Therefore, the terms "in one embodiment" or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, the particular features, structures, or characteristics can be combined in any suitable manner, as will be apparent to those skilled in the art from this disclosure.
[0081] Note that the above are merely preferred embodiments and the technical principles employed in this application. Those skilled in the art will understand that this application is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of this application. Therefore, although this application has been described in detail through the above embodiments, this application is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of this application, all of which fall within the scope of protection of this application.
Claims
1. A spiral filter, characterized in that, Suitable for 240MHz frequency, including housing (1); The outer shell (1) is provided with three spiral resonant cavities, wherein the diameter of the coil wire in each spiral resonant cavity is set to 0.195cm, the total number of turns of the spiral tube is set to 6.66 turns, and the pitch is set to 0.39cm. The top of the outer casing (1) has two slits for accommodating copper sheets (2), and the copper sheets (2) are inserted into the slits; the copper sheets (2) are located 1.08 cm from the grounding end of the spiral tube; The inner ends of the outer casing (1) are also provided with an input tap (3) and an output tap (4), and the input tap (3) and the output tap (4) are respectively connected to the grounding end of the spiral tube at 0.3 turns.
2. A spiral filter, characterized in that, Suitable for 320MHz frequency, including housing (1); The outer shell (1) is provided with three spiral resonant cavities, wherein the diameter of the coil wire in each spiral resonant cavity is set to 0.26 cm, the total number of turns of the spiral tube is set to 5, and the pitch is set to 0.52 cm. The top of the outer shell (1) has two slits for accommodating copper sheets (2), and the copper sheets (2) are inserted into the slits; the copper sheets (2) are located 0.93 cm from the grounding end of the spiral tube; The inner ends of the outer casing (1) are also provided with an input tap (3) and an output tap (4), and the input tap (3) and the output tap (4) are respectively connected to the grounding end of the spiral tube at 0.25 turns.
3. A spiral filter, characterized in that, Suitable for 400MHz frequency, including housing (1); The outer shell (1) is provided with three spiral resonant cavities, wherein the diameter of the coil wire in each spiral resonant cavity is set to 0.33cm, the total number of turns of the spiral tube is set to 4, and the pitch is set to 0.65cm. The top of the outer casing (1) has two slits for accommodating copper sheets (2), and the copper sheets (2) are inserted into the slits; the copper sheets (2) are located 0.83 cm from the grounding end of the spiral tube; The inner ends of the outer casing (1) are also provided with an input tap (3) and an output tap (4), and the input tap (3) and the output tap (4) are respectively connected to the grounding end of the spiral tube at 0.18 turns.
4. The spiral filter according to any one of claims 1 to 3, characterized in that, The internal height of the spiral resonant cavity is set to 4.33cm, the average diameter of the spiral tube is set to 1.72cm, and the length of the spiral tube is set to 2.58cm.
5. The spiral filter according to any one of claims 1 to 3, characterized in that, The spiral resonant cavity is a square-cavity spiral resonator with a side length of 2.6 cm.
6. The spiral filter according to any one of claims 1 to 3, characterized in that, The outer shell (1) includes an upper structural shell (5) and a lower structural shell (6); the upper structural shell (5) and the lower structural shell (6) are fixedly connected by screws; The gap is formed in the upper structural shell (5).
7. The spiral filter according to any one of claims 1 to 3, characterized in that, Each of the spiral tubes in the spiral resonant cavity is provided with a tuning screw (7) at the open end, and the tuning screw (7) is installed through the top of the outer shell (1).
8. The spiral filter according to any one of claims 1 to 3, characterized in that, After the grounding end of each of the spiral tubes in the spiral resonant cavity is wound into a circle, the grounding end of the spiral tube is fixed to the bottom of the outer shell (1) by screws and nuts.
9. The spiral filter according to any one of claims 1 to 3, characterized in that, The outer ends of the housing (1) are provided with SMA connectors (8) for connecting external devices.
10. The spiral filter according to any one of claims 1 to 3, characterized in that, The outer shell (1) has a length, width and height of 87mm*46mm*52.6mm.