A multi-stage T-type coaxial fixed attenuator in series

Abstract

The present application relates to the technical fields of microwave passive radio frequency attenuator, and more particularly to a multi-stage T-type coaxial fixed attenuator, comprising: a screw sleeve, a clasp, a first shell, a first dielectric, a first inner conductor, a second inner conductor, a second shell, an attenuation chip, a third inner conductor, a fourth inner conductor, a second dielectric and a third shell connected in sequence; the second shell is a horizontal hollow cylindrical structure, and a group of horizontally symmetrical welding grooves and a group of vertically symmetrical impedance compensation grooves are arranged in the second shell; the attenuation chip is a distributed topology structure, and is arranged in the welding grooves of the second shell, and comprises a first attenuation module and a second attenuation module which are the same in structure and connected in series, wherein, any one attenuation module is formed by two T-type circuits in parallel; a single attenuation module comprises a guide sheet arranged in the middle of four corners and four edges, and two resistance films symmetrically distributed on the upper and lower middle parts. The present application improves the electrical performance of the attenuator.

Description

Technical Field

[0001] This invention relates to the field of microwave passive radio frequency attenuators, and in particular to a multi-stage T-type series coaxial fixed attenuator. Background Technology

[0002] A coaxial attenuator is a passive microwave device used to dissipate signal energy. Based on whether the attenuation is adjustable, it is divided into fixed attenuators and adjustable attenuators. It primarily functions by absorbing signals through resistance. When designing the resistor, the circuit design is typically completed by etching thin-film resistors and metal conductive plates onto a chip. For thin-film resistor-type coaxial fixed attenuators, the main specifications include voltage standing wave ratio (S11 or S12), attenuation (S12), and power.

[0003] Conventional RF coaxial attenuators generally come in three types: T-type, π-type, and bridge T-type, each suited to different application scenarios. However, regardless of the type of attenuator, when achieving high attenuation (e.g., attenuation > 30dB), the resistance value becomes extremely extreme (one arm is close to 0, and the other arm has a very high resistance). Furthermore, the large resistance introduces high parasitic inductance / capacitance, which makes the product design and manufacturing process extremely difficult and uncontrollable. Summary of the Invention

[0004] To address this issue, the present invention provides a multi-stage T-type series coaxial fixed attenuator to overcome the problem in the prior art where the theoretical resistance value is too extreme when achieving high attenuation, leading to manufacturing difficulties.

[0005] To achieve the above objectives, the present invention provides a multi-stage T-type series coaxial fixed attenuator, comprising a threaded sleeve, a retaining ring, a first housing, a first dielectric, a first inner conductor, a second inner conductor, a second housing, an attenuation chip, a third inner conductor, a fourth inner conductor, a second dielectric, and a third housing connected in sequence.

[0006] The threaded sleeve is fixed to the first housing by a retaining ring;

[0007] The second shell is a horizontal hollow cylindrical structure, with a set of horizontally symmetrical welding grooves and a set of vertically symmetrical impedance compensation grooves inside.

[0008] The attenuation chip has a distributed topology structure and is located inside the solder groove of the second housing. It includes a first attenuation module and a second attenuation module that are identical in structure and connected in series. Each attenuation module is formed by two T-shaped circuits connected in parallel.

[0009] A single attenuation module includes conductive plates located at the four corners and the center of the four sides, as well as two resistive films symmetrically distributed vertically in the middle.

[0010] It also includes a data monitoring module and a control module. The data monitoring module is located inside the second housing and is used to monitor the key status parameters of the attenuation chip. It includes a temperature sensing unit and a DC resistance measurement unit. The key status parameters include operating temperature and DC resistance.

[0011] The control module is connected to the data monitoring module and is used to determine whether the working status of the attenuator meets the preset standard based on the attenuation status risk index obtained by the data monitoring module, and to issue a warning signal if it does not meet the preset standard.

[0012] Furthermore, the first housing is provided with limiting steps and barbs inside to fix the first medium;

[0013] A limiting step is provided on the first medium to fix the first inner conductor.

[0014] Furthermore, the guide plate in the middle of the left side of the first attenuation module is an input guide plate, and the input guide plate is connected to the second inner conductor by welding;

[0015] The guide plate in the middle of the right side of the second attenuation module is the output guide plate, and the output guide plate is connected to the third inner conductor by welding.

[0016] Furthermore, the upper and lower conductive plates of the attenuation chip are grounding conductive plates, and the grounding conductive plates are welded to the solder groove of the second housing.

[0017] Furthermore, the third housing is provided with limiting steps and barbs inside to fix the second medium;

[0018] The second medium is provided with a limiting step for fixing the fourth inner conductor.

[0019] Furthermore, the first inner conductor is connected to the second inner conductor, and the third inner conductor is connected to the fourth inner conductor via a plug-in structure.

[0020] Furthermore, the first housing and the third housing are connected by a threaded structure.

[0021] Furthermore, the width of the impedance compensation groove is 1 / 4 of the width of the second housing.

[0022] Furthermore, the attenuation state risk index is determined by both the operating temperature and the DC resistance.

[0023] Furthermore, the control module determines whether the attenuator's operating state meets a preset standard based on the attenuation state risk index, wherein...

[0024] If the attenuation state risk index is less than the preset risk index, then the attenuator's working state is determined to meet the preset standard.

[0025] If the attenuation state risk index is greater than or equal to the preset risk index, the attenuator's operating state is determined to be inconsistent with the preset standard, and a warning signal is issued.

[0026] Compared with existing technologies, the beneficial effects of this invention are that, through the design of a distributed multi-level T-shaped topology, the total attenuation is decomposed and borne collaboratively by multiple resistors, so that the resistance value of a single resistor does not need to tend to the theoretical extreme value. This fundamentally solves the industry problem of high processing difficulty, poor precision control, and high cost caused by excessively extreme resistance values ​​in high attenuation designs, significantly improving product manufacturability and yield.

[0027] Furthermore, this invention, through a specific "parallel first, series later" two-stage structure, distributes the total attenuation across multiple resistors, effectively dispersing parasitic parameters and significantly reducing the parasitic inductance and capacitance of the overall circuit. This allows the attenuator to maintain a flatter attenuation curve and a better voltage standing wave ratio in the microwave band, thereby achieving a wider operating bandwidth and more stable high-frequency response characteristics.

[0028] Furthermore, by integrating a data monitoring module and a control module, this invention enables real-time monitoring of key state parameters such as the operating temperature and DC resistance of the attenuation chip. Based on this, the calculated attenuation state risk index can provide early warning and intelligent diagnosis of attenuator performance degradation, upgrading traditional passive devices into intelligent components with self-sensing capabilities, thereby improving the overall reliability and maintainability of the system. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of a multi-stage T-type series coaxial fixed attenuator according to an embodiment of the present invention;

[0030] Figure 2 for Figure 1 A sectional view;

[0031] Figure 3 for Figure 1 Exploded view;

[0032] Figure 4 This is a schematic diagram of the attenuation chip structure according to an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the circuit structure of the attenuation chip according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the second housing in an embodiment of the present invention;

[0035] Figure 7 Performance test diagram of a conventional 20dB attenuator;

[0036] Figure 8 This is a performance test diagram of the 20dB multi-stage T-type series coaxial fixed attenuator of this invention.

[0037] Figure 9 The attenuation performance test diagram for a conventional 40dB attenuator;

[0038] Figure 10 This is a performance test diagram of the 40dB multi-stage T-type series coaxial fixed attenuator of this invention.

[0039] In the diagram: 1. Screw sleeve; 2. Buckle ring; 3. First housing; 4. First dielectric; 5. First inner conductor; 6. Second inner conductor; 7. Second housing; 71. Solder groove; 72. Impedance compensation groove; 8. Attenuation chip; 81. First attenuation module; 811. Input guide plate; 812. Output guide plate; 82. Second attenuation module; 83. Grounding guide plate; 84. Resistive film; 9. Third inner conductor; 10. Fourth inner conductor; 11. Second dielectric; 12. Third housing. Detailed Implementation

[0040] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0041] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0042] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the determination of the above-mentioned parameters for any single item in this invention can be achieved by selecting the value with the highest percentage based on the data distribution as the preset standard parameter, using weighted summation to obtain the value as the preset standard parameter, substituting each historical data point into a specific formula and using the value obtained from that formula as the preset standard parameter, or other selection methods, as long as the invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0043] Please see Figures 1 to 3The figures shown are a schematic diagram, a cross-sectional view, and an exploded view of the multi-stage T-type series coaxial fixed attenuator according to an embodiment of the present invention. The multi-stage T-type series coaxial fixed attenuator according to an embodiment of the present invention includes a screw sleeve 1, a retaining ring 2, a first housing 3, a first dielectric 4, a first inner conductor 5, a second inner conductor 6, a second housing 7, an attenuation chip 8, a third inner conductor 9, a fourth inner conductor 10, a second dielectric 11, and a third housing 12 connected in sequence. The screw sleeve 1 is fixed to the first housing 3 by the retaining ring 2. The first housing 3 is provided with a limiting step and barbs inside for fixing the first dielectric 4. The first dielectric 4 is provided with a limiting step for fixing the first inner conductor 5. The third housing 12 is provided with a limiting step and barbs inside for fixing the second dielectric 11. The second dielectric 11 is provided with a limiting step for fixing the fourth inner conductor 10.

[0044] Specifically, the first inner conductor 5 and the second inner conductor 6, and the third inner conductor 9 and the fourth inner conductor 10 are all connected by a plug-in structure.

[0045] Specifically, the first housing 3 and the third housing 12 are connected by a threaded structure.

[0046] Please see Figure 4 As shown, it is a schematic diagram of the structure of the attenuation chip 8 in an embodiment of the present invention. The attenuation chip 8 in this embodiment of the present invention has a distributed topology structure and is disposed inside the solder groove 71 of the second housing 7. It includes a first attenuation module 81 and a second attenuation module 82 with the same structure and connected in series. Each attenuation module is formed by two T-shaped circuits connected in parallel. A single attenuation module includes conductive plates disposed at the four corners and the middle of the four sides, and two resistive films 84 disposed in the middle and symmetrically distributed vertically.

[0047] Please see Figure 5 The diagram shown is a schematic of the circuit structure of the attenuation chip 8 in an embodiment of the present invention. The present invention proposes an innovative distributed T-type topology circuit. Through a specific "parallel first, series later" two-stage structure, the total attenuation is distributed across multiple resistors, thereby solving the design challenge of high attenuation. The distributed topology consists of three stages:

[0048] 1. Basic Unit: Traditional T-type attenuation circuit, composed of resistors Ra / Rb / Rc;

[0049] 2. First-level combination (modular): Two basic units are connected in parallel to form an equivalent attenuation module. After parallel connection, the equivalent resistance of the attenuation module is:

[0050] ;

[0051] ;

[0052] .

[0053] 3. Second-stage combination (system integration): Connect the two modules mentioned above in series to form a complete attenuation circuit, see details below. Figure 5 .

[0054] Specifically, through the aforementioned specific secondary structure and by setting the resistance value of the basic unit according to the following rules, the impedance characteristics of the entire distributed network can be made completely equivalent to a traditional T-type network with a target attenuation. The specific derivation process is as follows:

[0055] Let the resistances of the target conventional T-network be Ra_theory and Rc_theory (for a symmetrical T-network, Ra_theory = Rb_theory).

[0056] Let the resistances of a practical traditional T-type network be Ra_actual and Rc_actual (for a symmetrical T-type network, Ra_actual = Rb_actual).

[0057] The equivalent resistance of the first-stage combination after parallel connection is:

[0058] ;

[0059] After the two modules are connected in series, forming the second-stage combination, the series resistance from the port perspective is:

[0060] ;

[0061] The parallel resistance is:

[0062] ;

[0063] For this distributed network to be equivalent to a traditional network, the following must be satisfied:

[0064] ;

[0065] ;

[0066] Therefore, the actual resistance value of each basic unit should be twice the traditional theoretical value.

[0067] Therefore, in this invention, the resistance calculation formula is:

[0068] ;

[0069] ;

[0070] .

[0071] Specifically, this invention distributes power across multiple resistors using a distributed topology, while the all-welded structure provides an efficient vertical heat dissipation path for these distributed heat sources, together ensuring the device's high power capacity. The distributed topology reduces parasitic effects within the chip from a circuit principle perspective, while the all-welded structure provides an ultra-low inductance ground loop from a packaging perspective. Together, they ensure excellent and flat attenuation characteristics and impedance matching characteristics of the attenuator across the entire frequency band.

[0072] Please see Figure 6 As shown, this is a schematic diagram of the structure of the second housing 7 in an embodiment of the present invention. The second housing 7 in this embodiment of the present invention is a horizontal hollow cylindrical structure, with a set of horizontally symmetrical solder grooves 71 and a set of vertically symmetrical impedance compensation grooves 72 inside. The guide piece in the middle left side of the first attenuation module 81 is an input guide piece 811, which is connected to the second inner conductor 6 by welding. The guide piece in the middle right side of the second attenuation module 82 is an output guide piece 812, which is connected to the third inner conductor 9 by welding. The guide pieces on the upper and lower sides of the attenuation chip 8 are grounding guide pieces 83, which are welded to the solder grooves 71 of the second housing 7.

[0073] Specifically, the width of the impedance compensation groove 72 is 1 / 4 of the width of the second housing 7.

[0074] Specifically, the impedance compensation slot 72 is used to compensate for the impedance matching discontinuity that occurs when the signal transitions from the coaxial line to the attenuation chip 8.

[0075] Specifically, the above design creates a fully welded interconnect structure of "inner conductor-chip-body," forming a low thermal resistance / low parasitic inductance packaging system. As a small module, the chip package interconnect structure is detachable and easy to assemble, improving production efficiency. Furthermore, when customer products malfunction, only the chip package module needs to be replaced, without replacing the entire attenuator.

[0076] Specifically, the multi-stage T-type series coaxial fixed attenuator of the present invention further includes a data monitoring module and a control module, wherein...

[0077] The data monitoring module is located inside the second housing 7 and is used to monitor the key status parameters of the attenuation chip 8. It includes a temperature sensing unit and a DC resistance measurement unit, wherein the key status parameters include operating temperature and DC resistance.

[0078] The control module is connected to the data monitoring module and is used to determine whether the working status of the attenuator meets the preset standard based on the attenuation status risk index obtained by the data monitoring module, and to issue a warning signal if it does not meet the preset standard.

[0079] Specifically, the temperature sensing unit may be, for example, a surface-mount digital temperature sensor, and the DC resistance measuring unit may be, for example, a high-precision resistance measuring circuit. The specifics are not limited, as long as they can measure the real-time operating temperature and DC resistance of the attenuation chip 8.

[0080] Specifically, the degradation state risk index is determined by both the operating temperature and the DC resistance, and is calculated using the following formula:

[0081] ;

[0082] In the formula, H is the attenuation state risk index, k is the proportionality constant, set to k=1, Ra is the real-time DC resistance, Rb is the reference DC resistance, α is the resistance influence factor, set to α=1.5, β is the temperature influence factor, set to β=0.1, Ta is the real-time temperature, and Tb is the reference temperature, set to Tb=25℃.

[0083] In this embodiment of the invention, Rb needs to measure and record the DC resistance value of the attenuation chip in an environment of 25°C before the attenuator is used.

[0084] Specifically, the control module determines whether the attenuator's operating status meets a preset standard based on the attenuation state risk index.

[0085] If the attenuation state risk index is less than the preset risk index, then the attenuator's working state is determined to meet the preset standard.

[0086] If the attenuation state risk index is greater than or equal to the preset risk index, the attenuator's operating state is determined to be inconsistent with the preset standard, and a warning signal is issued.

[0087] In this embodiment of the invention, the preset risk index is set to 1.1, but the value is not limited to this. Those skilled in the art can adjust the value according to actual needs.

[0088] Please see Figure 7 , Figure 8 As shown, the graphs are performance test charts for a conventional 20dB attenuator and a 20dB attenuator according to the present invention, respectively. By comparison, it can be seen that the attenuation (S12) range of the conventional 20dB attenuator is 20dB±1.5dB within 18GHz, while the attenuation (S12) curve of the new 20dB attenuator is flatter, within 20dB±1.0dB, and has superior high-frequency performance. For attenuators with low attenuation, the present invention can optimize their electrical performance, making the attenuation curve flatter.

[0089] Please see Figure 9 , Figure 10As shown, the graphs are the attenuation performance test charts of a conventional 40dB attenuator and the performance test charts of a 40dB attenuator according to the present invention, respectively. The comparison shows that the embodiment of the present invention has a significant effect on suppressing high-frequency parasitic effects. Figure 9 As shown, the attenuation curve of a traditional 40dB attenuator exhibits an upward drifting trend at high frequencies (>15GHz) due to parasitic effects. Specifically, at 5GHz, the attenuation value can still be maintained at around 42dB, but when the frequency rises to 18GHz, the attenuation value decreases to around 37dB, a difference of 42-37=5dB, indicating a significant parasitic effect. Figure 10 As shown, after optimization by this invention, the high-frequency parasitic effect of the 40dB attenuator is significantly suppressed. Specifically, at 5GHz, the attenuation value is approximately 40.9dB, and at 18GHz, the attenuation value is approximately 40.4dB, with a difference of 40.9-40.4=0.5dB. The attenuation curve is 10 times flatter, demonstrating a significant optimization effect. The attenuator optimized by this invention can achieve an attenuation error of 40dB±1dB at high attenuation values.

[0090] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0091] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A multi-stage T-type series coaxial fixed attenuator, characterized in that, It includes a screw sleeve, a retaining ring, a first housing, a first dielectric, a first inner conductor, a second inner conductor, a second housing, an attenuation chip, a third inner conductor, a fourth inner conductor, a second dielectric, and a third housing connected in sequence. The threaded sleeve is fixed to the first housing by a retaining ring; The second shell is a horizontal hollow cylindrical structure, with a set of horizontally symmetrical welding grooves and a set of vertically symmetrical impedance compensation grooves inside. The attenuation chip has a distributed topology structure and is located inside the solder groove of the second housing. It includes a first attenuation module and a second attenuation module that are identical in structure and connected in series. Each attenuation module is formed by two T-shaped circuits connected in parallel. A single attenuation module includes conductive plates located at the four corners and the center of the four sides, as well as two resistive films symmetrically distributed vertically in the middle. It also includes a data monitoring module and a control module. The data monitoring module is located inside the second housing and is used to monitor the key status parameters of the attenuation chip. It includes a temperature sensing unit and a DC resistance measurement unit. The key status parameters include operating temperature and DC resistance. The control module is connected to the data monitoring module and is used to determine whether the working status of the attenuator meets the preset standard based on the attenuation status risk index obtained by the data monitoring module, and to issue a warning signal if it does not meet the preset standard.

2. The multi-stage T-type series coaxial fixed attenuator according to claim 1, characterized in that, The first housing is provided with a limiting step and barbs inside to fix the first medium; A limiting step is provided on the first medium to fix the first inner conductor.

3. The multi-stage T-type series coaxial fixed attenuator according to claim 2, characterized in that, The guide plate in the middle left side of the first attenuation module is the input guide plate, and the input guide plate is connected to the second inner conductor by welding. The guide plate in the middle of the right side of the second attenuation module is the output guide plate, and the output guide plate is connected to the third inner conductor by welding.

4. The multi-stage T-type series coaxial fixed attenuator according to claim 3, characterized in that, The upper and lower conductive plates of the attenuation chip are grounding conductive plates, and the grounding conductive plates are welded to the solder groove of the second housing.

5. The multi-stage T-type series coaxial fixed attenuator according to claim 4, characterized in that, The third housing is provided with limiting steps and barbs inside to fix the second medium; The second medium is provided with a limiting step for fixing the fourth inner conductor.

6. The multi-stage T-type series coaxial fixed attenuator according to claim 5, characterized in that, The first inner conductor is connected to the second inner conductor, and the third inner conductor is connected to the fourth inner conductor via a plug-in structure.

7. The multi-stage T-type series coaxial fixed attenuator according to claim 6, characterized in that, The first housing and the third housing are connected by a threaded structure.

8. The multi-stage T-type series coaxial fixed attenuator according to claim 7, characterized in that, The width of the impedance compensation groove is 1 / 4 of the width of the second housing.

9. The multi-stage T-type series coaxial fixed attenuator according to claim 8, characterized in that, The attenuation state risk index is determined by both the operating temperature and the DC resistance.

10. The multi-stage T-type series coaxial fixed attenuator according to claim 9, characterized in that, The control module determines whether the attenuator's operating status meets a preset standard based on the attenuation status risk index. If the attenuation state risk index is less than the preset risk index, then the attenuator's working state is determined to meet the preset standard. If the attenuation state risk index is greater than or equal to the preset risk index, the attenuator's operating state is determined to be inconsistent with the preset standard, and a warning signal is issued.

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