Branch structure for high-power radio frequency matching

Abstract

The utility model provides a stub structure for high-power radio frequency matching, which consists of a hard feed transmission line and an adjustable vacuum capacitor to form a parallel short-circuit stub. A section of transmission line branch with adjustable length and characteristic impedance is connected in parallel to a 6-inch or 9-inch high-power hard-feed transmission line branch, and an adjustable vacuum capacitor is connected in series, so that the structure effectively increases the adjustment range, improves the tolerance power and impedance matching efficiency of the system, and is suitable for a high-power radio frequency system.

Description

Technical Field

[0001] This utility model relates to the field of high-power wideband radio frequency transmission, and in particular to a spur structure for high-power radio frequency matching. Background Technology

[0002] In existing technologies, RF matching stubs play a crucial role in high-power RF systems. However, traditional short-circuit stubs suffer from limited adjustment range, insufficient voltage and current withstand capabilities, and large structural dimensions. For example, while existing three-stub matching unit designs can achieve good matching performance in certain frequency bands, their adjustment flexibility and reliability still need improvement over a wider frequency range. Therefore, there is an urgent need for an RF matching stub that can provide a wider adjustment range and higher voltage withstand capability while maintaining a compact structure to meet the requirements of high-power applications. Utility Model Content

[0003] In order to overcome the shortcomings of the prior art, the purpose of this utility model is to provide a spur structure for high-power radio frequency matching.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] An innovative stub structure for high-power RF matching combines a hard-fed transmission line and an adjustable vacuum capacitor. Through a unique parallel short-circuit stub design, it significantly improves the impedance adjustment range and the system's power tolerance. Specifically, traditional RF matching devices often face problems in high-power applications, such as limited adjustment range, insufficient voltage withstand capability, and excessively large structural size, resulting in unsatisfactory matching performance over a wide frequency range. To address these issues, this invention employs the following key design solutions.

[0006] Firstly, this invention forms a parallel short-circuit stub structure by connecting an adjustable-length and characteristic-impedance transmission line stub in parallel to a 6-inch or 9-inch transmission line stub. This parallel connection is achieved through a T-shaped structure, allowing for the selection of appropriate length and characteristic impedance according to actual needs, thus achieving more precise impedance matching. This design not only significantly improves adjustment flexibility but also optimizes the matching effect at different operating frequencies by adjusting the stub length, thereby providing broader application possibilities in high-power RF systems.

[0007] Secondly, an adjustable vacuum capacitor is connected in series in this support structure. Traditional RF matching circuits often use fixed capacitors, while the adjustable vacuum capacitor in this invention has a large adjustment range, allowing for flexible adjustment according to system requirements. This design significantly improves the system's impedance regulation capability, especially under high power conditions, ensuring stable operation of the matching circuit over a wider power range. By selecting a high-voltage and high-current-resistance vacuum capacitor, this invention effectively solves the common problem of insufficient voltage and current resistance of spring contacts in traditional supports, significantly improving the power carrying capacity of the entire RF system.

[0008] Furthermore, the spur structure of this invention, while achieving impedance matching and traction, can also be effectively applied to high-power antenna decoupling systems. Traditional RF matching spurs typically operate only under specific conditions, while this invention, through precise control of spur length and impedance, allows it to adapt to a variety of different operating conditions, thus playing a crucial role in a wide range of high-power RF applications. Through this design, this invention not only expands the application scenarios of short-circuit spurs but also provides a new technical solution for matching and decoupling high-power RF systems.

[0009] In summary, this invention, through innovative design of the parallel short-circuit stub and adjustable vacuum capacitor, significantly increases the adjustment range while reducing the impedance transformation size. Furthermore, by selecting a high-performance capacitor, it substantially improves the system's power tolerance, making it suitable for matching and decoupling applications in various high-power RF systems. This stub structure not only demonstrated excellent performance in experiments but also shows great application potential, meeting the future development needs of high-power RF technology.

[0010] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0011] 1. By combining parallel short-circuit stubs and adjustable vacuum capacitors, the impedance adjustment range is significantly expanded.

[0012] 2. The use of high-voltage and high-current capacitors effectively improves the system's power handling capability.

[0013] 3. Compact structure, suitable for space-constrained high-power RF systems.

[0014] 4. It can be applied to impedance matching, impedance pulling, and antenna decoupling scenarios in high-power RF systems. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a high-power support structure;

[0016] Figure 2 A schematic diagram of ADS simulation setup for high-power supports;

[0017] Figure 3 The image shows the simulation results of the high-power support.

[0018] In the diagram: 1-Transmission line branch, 2-Parallel short-circuit branch, 3-Variable vacuum capacitor. Detailed Implementation

[0019] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0020] Reference Figure 1-3 In practical implementation, the spur structure of this invention achieves efficient matching for high-power RF systems by connecting a transmission line spur with adjustable length and characteristic impedance in parallel to a 6-inch or 9-inch main transmission line spur, and then connecting an adjustable vacuum capacitor in series after the spur. By adjusting the length and characteristic impedance of the spur, the matching effect can be optimized in different operating frequency bands, ensuring stable operation of the RF system under high-power conditions.

[0021] Typically, the design of coaxial transmission lines is mainly considered from the following three aspects: 1) highest withstand voltage; 2) largest power capacity; 3) minimum high-frequency loss.

[0022] Typically, the design of coaxial transmission lines is mainly considered from the following three aspects: 1) highest withstand voltage; 2) largest power capacity; 3) minimum high-frequency loss.

[0023] Under different conditions, such as optimal performance and minimum high-frequency loss, the corresponding characteristic impedance value of the coaxial line can be determined.

[0024] Highest withstand voltage for coaxial transmission lines:

[0025] The electric field strength between the inner and outer conductors of a coaxial line can be written as:

[0026] When r = a (radius of the inner conductor), Ea = Emax is strongest. Let b / a = x, the electric field strength Ea at the surface of the inner conductor is:

[0027]

[0028] Therefore, when the coaxial cable has the maximum withstand voltage, the characteristic impedance of the coaxial cable is:

[0029]

[0030] Maximum power capacity:

[0031] The surface electric field strength of the inner conductor is the most important factor limiting the power transmission capacity. When the maximum electric field strength reaches the breakdown electric field strength, i.e., Ea = Emax, the power at this point is the breakdown power of the coaxial line (that is, the maximum transmission power), P = Pmax.

[0032]

[0033] To find the extreme value of Pmax, let dPmax / dx = 0, then:

[0034] Therefore, under the condition of maximum power capacity of the transmission line, its characteristic impedance is:

[0035]

[0036] Coaxial cable has the lowest high-frequency loss:

[0037] High-frequency losses exist on the surfaces of the inner and outer conductors of the coaxial line (not considering conductor dielectric losses):

[0038]

[0039] Let rs be the surface resistance of the inner conductor. Setting dα / dx = 0, we get:

[0040] xlnx-x-1=0, b / a=x=3.59,

[0041] In China, coaxial transmission lines typically have two standard characteristic impedances: 75Ω and 50Ω. The 75Ω characteristic impedance is primarily chosen to minimize ohmic loss. For minimum attenuation and maximum power capacity, the ratio of the inner to outer conductor dimensions of the coaxial line is: Therefore, the characteristic impedance of the corresponding coaxial transmission line is 50Ω.

[0042] Once the characteristic impedance is determined, the required stub length L can be obtained through ADS simulation.

[0043] When selecting capacitors, you can refer to the specific technical parameters of adjustable vacuum capacitors in China. You can choose capacitors with a large parameter margin. Although the size will increase a bit, the overall structure will be much smaller.

[0044] This spur structure has been successfully applied in high-power radio frequency antenna decoupling systems, demonstrating its superior performance and reliability. Although the illustrative specific embodiments of this utility model have been described above to enable those skilled in the art to understand this utility model, it should be understood that this utility model is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of this utility model as defined and determined by the appended claims. All utility model creations utilizing the concept of this utility model are within the scope of protection.

[0045] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment have been appropriately combined to form other embodiments that are easy for those skilled in the art to understand.

Claims

1. A spur structure for high-power radio frequency matching, characterized in that: It includes a hard-feed transmission line stub and a parallel short-circuit stub. The parallel short-circuit stub is connected in parallel to the transmission line stub through a T-shaped structure, and an adjustable vacuum capacitor is connected in series after the transmission line stub.

2. The spur structure for high-power radio frequency matching according to claim 1, characterized in that: The length and characteristic impedance of the parallel short-circuit branch are selected according to actual needs.

3. The spur structure for high-power radio frequency matching according to claim 1, characterized in that: The transmission line segment is a 6-inch or 9-inch transmission line segment.

Images