A switching device for coaxial energy transmission window of traveling wave tube

Abstract

The present invention discloses an adapter device for a traveling wave tube coaxial energy transmission window, comprising: a radio frequency coaxial cable and an adapter and a standard radio frequency coaxial connector respectively connected to both ends of the radio frequency coaxial cable, the adapter comprising an inner conductor and an outer conductor respectively connected to the radio frequency coaxial cable, and a nut rotatably sleeved on the outer conductor, the inner conductor being in the shape of a circular tube, and the nut being used for threaded connection with the coaxial energy transmission window of the traveling wave tube. The inner conductor of the adapter of the adapter device of the present invention is a female interface (hole) that can be directly plugged into the inner conductor (pin) of the coaxial energy transmission window, and the outer conductor of the adapter is provided with a rotatable nut that can be connected to a bolt on the outer conductor of the coaxial energy transmission window. Since the nut is located at the end of the slender radio frequency coaxial cable, the operating space for tightening the nut is no longer restricted, so that it can be easily and conveniently connected to the inner and outer conductors of the coaxial energy transmission window.

Description

Technical Field

[0001] The present invention relates to the field of microwave vacuum electronic devices, and more particularly to a switching device for a coaxial energy transmission window of a traveling wave tube. Background Art

[0002] A traveling wave tube is a microwave vacuum electronic device that can amplify signals in different frequency bands. It has the characteristics of high power, wide bandwidth, high gain, and high efficiency. It has been widely used in electronic countermeasures, radar, satellite communications and other fields. Figure 1 As shown, a traveling wave tube (TWT) consists of five main components: an electron gun, a focusing magnetic system, a slow-wave structure, input and output couplers, and a collector. Its operating principle is that the electron gun generates an electron beam of the desired size and current. After exiting the electron gun, the electron beam passes through the elongated slow-wave structure. The high-frequency signal enters the TWT through the input coupler, forming a traveling wave that propagates along the slow-wave structure. The slow-wave structure reduces the phase velocity of the electromagnetic wave to approximately the same speed as the electrons, enabling interaction and energy exchange between the electron beam and the electromagnetic wave. Due to the focusing effect of the magnetic field, the electron beam travels along the slow-wave structure's axis. This process of electron propagation is accompanied by interaction with the electromagnetic wave, converting the electrons' kinetic energy into electromagnetic wave energy, thereby amplifying the input high-frequency signal. The high-frequency signal is output through the output coupler. The electrons, having transferred most of their energy, eventually strike the collector, where they are converted into heat energy.

[0003] Compared to solid-state microwave amplifiers, traditional traveling wave tubes (TWTs) can provide sufficiently high output power, but they require very high operating voltages, making them inconvenient to power and operate in practice. Furthermore, their large size and weight, along with their complex structure, make them difficult to manufacture and repair. Therefore, facing the challenges posed by solid-state microwave amplifiers, there is a growing need for practical, low-voltage, and highly reliable miniaturized TWTs. Microwave power modules (MPMs) utilize a solid-state amplifier as the excitation stage and a TWT as the output stage, integrating the two. Combining the advantages of both solid-state and vacuum devices, they have been widely used in various military and civilian applications, including electronic weapon systems and satellite communications. The development of MPMs also requires the miniaturization of TWTs. Miniaturizing TWTs can expand their applications.

[0004] Miniaturization of a traveling wave tube (TWT) can be achieved by miniaturizing its length (L), thickness (H), and width (W). For example, the length can be achieved by shortening the slow-wave structure, and the thickness can be achieved by reducing the radial dimensions of the electron gun, high-frequency band, and collector. In comparison, miniaturizing the TWT's width is more difficult. Reasonable miniaturization of the TWT's width is essential to fully utilize the MPM's internal space and improve its integration. The TWT's input and output couplers, or the energy transmission structure, play a significant role in determining the TWT's width. Summary of the Invention

[0005] The object of the present invention is to provide a switching cable for a coaxial energy transmission window of a traveling wave tube.

[0006] According to one aspect of the present invention, there is provided an adapter device for a coaxial energy transmission window of a traveling wave tube, comprising: a radio frequency coaxial cable and an adapter and a standard radio frequency coaxial connector respectively connected to both ends of the radio frequency coaxial cable, the adapter comprising an inner conductor and an outer conductor respectively connected to the radio frequency coaxial cable, and a nut rotatably sleeved on the outer conductor, the inner conductor being in the shape of a circular tube, and the nut being used for threaded connection with the coaxial energy transmission window of the traveling wave tube.

[0007] Preferably, the nut is configured to be barrel-shaped, and the inner conductor and the outer conductor are both located inside the nut.

[0008] Preferably, the outer conductor is configured to be cylindrical, and the top surface of the cylinder extends radially outward to form an annular boss. The top surface of the nut abuts against the annular boss to press the outer conductor onto the outer conductor of the coaxial energy transmission window.

[0009] Preferably, the height of the nut is 5.8 mm.

[0010] Preferably, the standard radio frequency coaxial connector is a male connector.

[0011] Preferably, the inner conductor is a nickel tube.

[0012] Preferably, there is an interference fit between the nickel tube and the inner conductor of the coaxial energy transmission window.

[0013] The beneficial effects of the present invention are as follows:

[0014] The inner conductor of the adapter of the adapter device of the present invention is a female interface (hole), which can be directly plugged into the inner conductor (needle) of the coaxial energy transmission window. The outer conductor of the adapter is provided with a rotatable nut that can be connected to the bolt on the outer conductor of the coaxial energy transmission window. Since the nut is located at the end of the slender radio frequency coaxial cable, the operating space for tightening the nut is no longer restricted, so that it can be easily and conveniently connected to the inner and outer conductors of the coaxial energy transmission window.

[0015] The nut height of the present invention is set at 5.8mm, which is 64% smaller than the 16mm height of a standard male connector. The adapter device of the present invention not only solves the problem of limited operating space and the inconvenience of tightening the nut, but also reduces the overall height of the energy transmission coupler. This allows the connection from the coaxial energy transmission window to the coaxial cable, which originally required three parts (inner adapter, outer adapter, and standard male connector), to be achieved with only a non-standard coaxial connector. As a result, the energy transmission coupler has achieved a compact size, with the height reduced from the original 30.3mm to 15.15mm, a reduction in size by half. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0017] Figure 1 Shown is a schematic structural diagram of the present invention.

[0018] Figure 2 A schematic structural diagram of the adapter of the present invention is shown.

[0019] Figure 3 A schematic diagram of the connection structure between the adapter and the coaxial energy transmission window of the present invention is shown. DETAILED DESCRIPTION

[0020] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the following detailed description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0021] The connection between RF coaxial cables is generally achieved by connecting a standard male RF connector with a female RF connector. The inner conductor interface of the standard male connector is a solid pin, and the outer conductor interface is a rotatable nut, while the inner conductor interface of the female connector is a hole, and the outer conductor interface is a bolt. The inner conductor is connected by the pin and the hole, and the outer conductor is connected by a thread. The rotatable nut on the male connector is screwed onto the outer conductor bolt of the female connector.

[0022] The coaxial energy transmission window is an important component for energy transmission in microwave electronic devices such as traveling wave tubes, klystrons, backward wave tubes, and magnetrons. It not only ensures that the slow-wave circuit where injection-wave interaction occurs in the microwave device is in a vacuum environment and plays a role in sealing and isolating, but also allows electromagnetic waves to pass smoothly for energy transfer and signal transmission.

[0023] The coaxial energy transmission window on the helical traveling wave tube is connected to the external circuit by connecting to the RF coaxial cable. However, in order to achieve vacuum sealing of the traveling wave tube, the inner conductor of the coaxial energy transmission window must be a solid needle, which is consistent with the inner conductor of the standard male RF connector. If the outer conductor interface of the coaxial energy transmission window is designed as a rotatable nut according to the standard male connector, since the coaxial energy transmission window is close to the high-frequency band of the traveling wave tube, in order to achieve miniaturization of the traveling wave tube and reduce the lateral size, the operating space left for tightening the nut will be limited, which will cause inconvenience in bolting with the outer conductor of the standard female RF connector. Therefore, the outer conductor of the coaxial energy transmission window is designed as a fixed bolt interface. However, the inner conductor of the coaxial energy transmission window is a needle and the outer conductor is a bolt, and it cannot be directly connected to either the standard male connector (inner conductor is a needle, outer conductor is a nut) or the standard female connector (inner conductor is a hole, outer conductor is a bolt).

[0024] In order to solve the problem of connecting the coaxial energy transmission window with the standard RF connector, the existing technology is to install an internal adapter and an external adapter on the coaxial energy transmission window to convert the coaxial energy transmission window into the inner and outer conductor interfaces of the standard female connector to achieve connection with the inner and outer conductors of the standard male connector.

[0025] One end of the external adapter is a nut that can be matched with the bolt of the outer conductor of the coaxial energy transmission window, and the other end is a bolt that can be matched with the nut of the outer conductor of the standard male head. After the coaxial energy transmission window is added with the external adapter, it can be connected to the outer conductor of the standard male head connector.

[0026] The inner adapter is a slender nickel tube with the same dimensions as the inner conductor of a standard female connector. One end of the tube is welded to the inner conductor (window pin) of the coaxial power transmission window, while the other end is inserted into the center hole of the outer adapter and plugged into the inner conductor of a standard male connector. The coaxial power transmission window, combined with these inner and outer adapters, can connect to the inner and outer conductors of a standard male connector. However, this design increases the overall height of the coaxial power transmission coupler, hindering the miniaturization of the traveling wave tube. Furthermore, because the inner adapter nickel tube is a solid, non-elastic, round tube, repeated insertion and insertion can easily cause the inner conductor of the slender nickel tube to loosen or even crack, resulting in a loose connection with the standard male connector, affecting the RF signal input to the traveling wave tube and causing unstable test performance. Furthermore, because one end of the inner adapter nickel tube is brazed to the inner conductor (window pin) of the traveling wave tube's coaxial power transmission window at a high temperature of 800°C, it cannot be detached and replaced, directly affecting the effective use of the traveling wave tube and even rendering it useless.

[0027] In order to ensure the flexible and reliable connection of the coaxial energy transmission window and reduce its size, Figure 1An embodiment of the present invention's adapter device for a traveling wave tube coaxial energy transmission window is shown. The adapter device includes an RF coaxial cable 10, an adapter 20, and a standard RF coaxial connector 30, respectively connected to both ends of the RF coaxial cable 10. The adapter 20 can be directly connected to the coaxial energy transmission window, while the standard RF coaxial connector 30 can be connected to an external RF cable. It is understood that the standard RF coaxial connector 30 can be either a male or female connector. In this embodiment, the standard RF coaxial connector 30 is a male connector, facilitating connection to an external coaxial cable.

[0028] like Figure 2 As shown, the adapter 20 includes an inner conductor 21, an outer conductor 22, and a nut 23. The inner conductor 21 is in the shape of a circular tube. The inner conductor 21 and the outer conductor 22 are respectively connected to the RF coaxial cable 10. The nut 23 is rotatably sleeved on the outer side of the outer conductor 22. The circular tubular inner conductor 21 can be plugged into the inner conductor of the coaxial energy transmission window, and the nut 23 can be threadedly connected to the outer conductor of the coaxial energy transmission window, thereby connecting the coaxial energy transmission window to the adapter 20. This type of adapter is a non-standard RF coaxial connector, and the dimensions of its inner conductor 21 and outer conductor 22 correspond to the dimensions of the coaxial energy transmission window.

[0029] The inner conductor 21 of the adapter 20 is a female interface (hole), which can be directly plugged into the inner conductor (needle) of the coaxial energy transmission window. The outer conductor 22 of the adapter 20 is provided with a rotatable nut 23 that can be connected to the bolt on the outer conductor of the coaxial energy transmission window. Since the nut 23 is located at the end of the slender RF coaxial cable 10, the operating space for tightening the nut is no longer restricted, so that it can be easily and conveniently connected to the inner and outer conductors of the coaxial energy transmission window.

[0030] Furthermore, the nut 23 is configured as a barrel, with the inner conductor 21 and outer conductor 22 located within the nut 23. A through-hole is provided on the top surface of the nut 23, through which one end of the coaxial RF cable 10 passes to connect to the inner conductor 21 and outer conductor 22. Preferably, the height of the nut 23 is set to 5.8 mm, which is 64% smaller than the 16 mm height of a standard male connector.

[0031] The adapter device of the present invention not only solves the problem of limited operating space and inconvenience in tightening nuts, but also reduces the overall height of the energy transmission coupler. This allows the connection from the coaxial energy transmission window to the coaxial cable, which originally required three parts (inner adapter, outer adapter, and standard male connector), to be achieved with only a non-standard coaxial connector. As a result, the size of the energy transmission coupler has been compacted, with the height reduced from the original 30.3mm to 15.15mm, reducing the size by half. After testing the product, the voltage standing wave ratio in the 37GHz to 42GHz frequency band reached below 1.2, indicating that the improved coaxial coupler has a good impedance matching level.

[0032] like Figure 2 and Figure 3 As shown, the outer conductor 22 is set to be cylindrical, and the top surface of the cylinder extends radially outward to form an annular boss 24. The top surface of the nut 23 abuts against the annular boss 24 to crimp the outer conductor 22 to the coaxial energy transmission window outer conductor 41.

[0033] The annular boss 24 increases the contact area between the outer conductor 22 and the nut 23 , thereby increasing the pressing force of the nut 23 on the outer conductor 22 and ensuring close contact between the outer conductor 22 and the coaxial energy transmission window outer conductor 41 .

[0034] Furthermore, the inner conductor 21 is a nickel tube, which can improve the oxidation resistance and corrosion resistance of the inner conductor 21. The nickel tube and the coaxial energy transmission window inner conductor 42 are detachable movable parts assembled by tight size fit. After the inner conductor 21 is plugged in multiple times and aged, it can be directly replaced with a new one. When connected, it can be matched and installed with the coaxial energy transmission window inner conductor 42, which does not affect the effective use of the traveling wave tube, and avoids the situation in conventional structures where the effective use of the traveling wave tube is affected or even scrapped due to the aging of the metal tube due to multiple plugging.

[0035] The coaxial energy transmission window in this embodiment is used in the same manner as a conventional coaxial coupler: The coaxial energy transmission window is welded to the end of the slow-wave structure's helix, ensuring that the bottom of the window pin (i.e., the bottom of the coaxial energy transmission window's inner conductor 42) is welded to the helix. The adapter 20 is then threaded onto the coaxial energy transmission window to establish connection to the external system. This coaxial energy transmission coupler boasts a compact size and high reliability, making it suitable for a variety of helix traveling wave tubes requiring miniaturization and seeking to reduce lateral dimensions by shortening the coaxial coupler's height.

[0036] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A switching device for a traveling wave tube coaxial energy transmission window, characterized in that: include: A radio frequency coaxial cable and an adapter and a standard radio frequency coaxial connector respectively connected to both ends of the radio frequency coaxial cable. The adapter includes an inner conductor and an outer conductor respectively connected to the radio frequency coaxial cable, and a nut rotatably sleeved on the outer conductor. The inner conductor is in the shape of a circular tube and is used to be plugged into the inner conductor of the coaxial energy transmission window of a traveling wave tube. The nut is used to be threaded with the coaxial energy transmission window of the traveling wave tube. The height of the nut is less than the height of the nut of the standard radio frequency coaxial connector. The outer conductor is set to be cylindrical, and the top surface of the cylinder extends radially outward to form an annular boss. The top surface of the nut abuts against the annular boss to press the outer conductor onto the outer conductor of the coaxial energy transmission window.

2. The switching device according to claim 1, characterized in that: The nut is configured to be barrel-shaped, and the inner conductor and the outer conductor are both located inside the nut.

3. The switching device according to claim 1, characterized in that: The height of the nut is 5.8 mm.

4. The switching device according to claim 1, characterized in that: The standard radio frequency coaxial connector is a male connector.

5. The switching device according to claim 1, characterized in that: The inner conductor is a nickel tube.

6. The switching device according to claim 5, characterized in that: There is interference fit between the nickel tube and the inner conductor of the coaxial energy transmission window.

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