Energy transmission structure of high-power spiral pulse traveling wave tubeTechnical Field
The invention belongs to the technical field of electric vacuum devices, and particularly relates to an energy transmission structure of a high-power spiral pulse traveling wave tube.
Background
The spiral traveling wave tube is widely applied to the fields of radars, electronic countermeasure, communication and the like with the advantages of high power, wide frequency band, high efficiency, high gain and the like, and along with the rapid development of weaponry, the long-distance detection requirement of the radars brings out higher requirements on the output power of the spiral traveling wave tube, and the output power under the requirement of a large duty ratio can comprehensively test the performance and reliability of products.
When the energy transmission structure is designed, the voltage standing wave ratio is required to be as small as possible within the frequency band range, so that the damage of electromagnetic reflection to a traveling wave tube slow wave circuit and an energy transmission device is reduced, and meanwhile, the coupling structure also needs to be low in loss and has the structural characteristics of high reliability, so that the requirements of traveling wave tube use and reliability assessment projects can be met. Therefore, it is desirable to provide a new high reliability power delivery structure for high power helical traveling wave tubes.
Disclosure of Invention
The invention aims to solve the problems of the power tolerance capacity and the reliability of a high-power output coupling structure of a spiral traveling wave tube, realize electromagnetic reflection as small as possible in a frequency band, ensure low-loss transmission, and provide a reliable structure capable of meeting various test requirements, so that the transmission characteristic of the reliable structure meets the use requirement of a high-power pulse traveling wave tube.
The invention provides a traveling wave tube energy transmission structure with reasonable structural design, high power and high reliability, which is a measure applicable to the design of the high average power spiral traveling wave tube energy transmission structure, and is specifically achieved by the following specific technical means:
The energy transmission structure of the high-power spiral line pulse traveling wave tube comprises an energy transmission structure, wherein the energy transmission structure consists of a waveguide structure, an impedance converter, a connecting piece, a conical coaxial window structure and an outer conductor;
The impedance transformer is arranged in the waveguide structure, one end of the impedance transformer is provided with a mounting hole, the connecting piece is arranged in the mounting hole, the outer conductor is connected to one side of the waveguide structure, one end of the connecting piece is arranged in the outer conductor, the conical coaxial window structure is sleeved on the outer side of the connecting piece, and the conical coaxial window structure is sleeved and sealed in the outer conductor.
Further, the impedance transformer is a three-stage chebyshev impedance transformer.
Further, the outer conductor is provided with a waveguide connection transition zone near the connection position with the waveguide structure, and the ratio of the inner diameters of the waveguide connection transition zone is 1.2:1.
Further, a conductor gradual change region is arranged in the middle section of the connecting piece, and the ratio of the size head diameter of the conductor gradual change region is 1.39:1.
Furthermore, the connecting piece is divided into a sleeve and an inner conductor, and the inner and outer matching surfaces of the sleeve and the inner conductor are conical.
Further, the sleeve is welded with the impedance converter into a whole by adopting a copper-silver welding mode through a hydrogen furnace.
Further, the fitting taper angle of the sleeve and the inner conductor is 4++5', the small head diameter of the sleeve is 6.1mm, and the large head diameter of the inner conductor is 8.3mm.
Compared with the prior art, the invention has the following beneficial effects:
1. the waveguide of the coaxial-to-three-stage chebyshev impedance converter is adopted, so that the power resistance capacity of the energy transmission structure of the spiral traveling wave tube is increased;
2. The three-dimensional simulation technology is adopted to further optimize the design to obtain a smaller standing wave ratio, so that the loss of the transmission line to microwave power is obviously reduced, and the influence of high-frequency reflection to the traveling wave tube is reduced;
3. The connecting piece structure between the coaxial and the waveguide adopts taper fit design, the process structure has novel application mode, high connection reliability, convenient assembly, capability of ensuring constant repeated assembly precision, easy ensuring of coaxiality requirement after assembly of parts, good elimination of fit clearance, good self-locking property and sealing property, improvement of transmission performance and ensuring of reliability of the high average power traveling wave tube energy transmission structure.
Drawings
FIG. 1 is a schematic diagram of the energy delivery structure of the present invention.
FIG. 2 is a graph of the analysis results of the three-dimensional simulation technique of the present invention.
Fig. 3 is a schematic structural diagram of the connector between the coaxial window and the waveguide after the reliability structure is optimized.
In the figure, the correspondence between the component names and the drawing numbers is:
1. waveguide structure, 2, impedance converter, 3, connector, 301, inner conductor, 302, sleeve, 4, conical coaxial window structure, 5, outer conductor.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings and examples. The following examples are illustrative of the invention but are not intended to limit the scope of the invention.
In the description of the present invention, unless otherwise indicated, the meaning of "plurality" is two or more, and the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus are not to be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, unless explicitly stated and limited otherwise, the terms "connected" and "connected" are to be construed broadly, and for example, they may be fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1
As shown in fig. 1:
The invention provides an energy transmission structure of a high-power spiral line pulse traveling wave tube, which comprises an energy transmission structure, wherein the energy transmission structure consists of a waveguide structure 1, an impedance converter 2, a connecting piece 3, a conical coaxial window structure 4 and an outer conductor 5, the impedance converter 2 is arranged in the waveguide structure 1, one end of the impedance converter 2 is provided with a mounting hole, the connecting piece 3 is arranged in the mounting hole, the outer conductor 5 is connected to one side of the waveguide structure 1, one end of the connecting piece 3 is arranged in the outer conductor 5, the conical coaxial window structure 4 is sleeved outside the connecting piece 3, and the conical coaxial window structure 4 is sleeved and sealed in the outer conductor 5;
Wherein the impedance transformer 2 is a three-stage chebyshev impedance transformer.
Wherein the outer conductor 5 is provided with a waveguide connection transition zone near the connection with the waveguide structure 1, and the ratio a/b of the inner diameter of the waveguide connection transition zone is 1.2:1.
Wherein, the middle section of the connecting piece 3 is provided with a conductor gradual change region, and the ratio c:d of the diameters of the big end and the small end of the conductor gradual change region is 1.39:1.
The coaxial line with the optimal size and the impedance transformer are selected, the impedance matching of the transmission line is completed through the optimization of three-dimensional electromagnetic simulation software, the three-dimensional electromagnetic simulation calculation and analysis results are shown in the figure 2, the standing wave ratio in the frequency band range is about 1.25, the actual tubing test is about 1.35, and the anastomosis degree is high.
Example 2
As shown in fig. 3, the connecting piece 3 is divided into a sleeve 301 and an inner conductor 302, the inner and outer matching surfaces of the sleeve and the inner conductor are conical, and the inner conductor 302 is fastened by a nut by utilizing the characteristic that the matching surfaces are conical, so that the matching of the two parts is tighter and tighter, and the matching gap is completely eliminated.
The sleeve 301 is fixed on the impedance converter 2 by a die, welded with the impedance converter 2 into a whole by a hydrogen furnace in a copper-silver welding mode, and then the inner conductor 302 is inserted into the sleeve 301 along the taper for assembly, so that the fitting degree can be judged according to the height position of the inner conductor 302 in the sleeve 301.
Wherein, the fitting cone angle of the sleeve 301 and the inner conductor 302 is 4 DEG + -5', the small head diameter of the sleeve 301 is 6.1mm, and the large head diameter of the inner conductor 302 is 8.3mm.
In conclusion, the invention carries out structural design according to engineering calculation and three-dimensional simulation software, and the following technical progress is obtained:
1. The power capacity of the energy transmission structure is improved by adopting the energy transmission structure of the coaxial window output transfer waveguide, the lower voltage standing wave ratio is realized by the three-dimensional simulation software optimization design, the negative influence of high-frequency reflection on the traveling wave tube is reduced, and the energy transmission requirement of the spiral traveling wave tube under the working ratio of 10% is met.
2. By adopting the conical matched energy transmission structure, the high-reliability transmission characteristic of the high-power helix traveling wave tube under the condition of large work ratio is realized by a reliable connection mode.
3. The energy transmission device with reasonable design structure, high power and high reliability meets the reliability assessment index in the S-band high-power spiral traveling wave tube development project, the traveling wave tube is tested by various severe environment tests (-40 ℃ low-temperature work, 55 ℃ high-temperature work, -55 ℃ low-temperature storage test and 70 ℃ high-temperature storage test) in the identification link at present, the non-working state a=20g, tau=11 ms, the impact vibration resistant test, the temperature cycle test, the low-pressure test, the long mold test, the salt spray test and the like of 18 times of impact in six directions of +/-X, +/-Y and +/-Z axes are carried out, the service life test of 800 hours (10% of the service life is guaranteed) is successfully completed in the identification, the traveling wave tube performance is normal during the test, the work is stable, and the design goal of long service life and high reliability is achieved by the energy transmission structure is demonstrated.
The invention is suitable for the helical traveling wave tube which has the advantages of realizing the 10% working ratio, 12kW pulse output power and guaranteeing the service life of 8000 hours in the S-band frequency range, and the indexes of long service life and high output power (more than 1.2 kW) in the project have higher requirements on the output coupling structure. The service life and average output power of the same-band similar helix traveling wave tube are mostly within 3000 hours and 350w, and the small power capacity determines that the coaxial output structure is mostly adopted. The energy transmission structure of the invention has greatly improved power capacity and use reliability compared with the prior products of the same type.
The embodiments of the invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.