JPH0592945U - Helix type traveling wave tube - Google Patents

Abstract

(57) [Summary] [Structure] In the coaxial structure portion of the high-frequency input / output structure, the coaxial outer conductor 4 has a thick cylindrical step portion 4a, and this step portion includes a pair of pole pieces 10a of the input / output portion. , 10b are in contact with and fixed to the outer peripheral ends. Further, the remaining thin cylindrical portion of the coaxial outer conductor 4 is also fixed to the opposite side surfaces of the pair of pole pieces 10a and 10b. [Effect] Even if a moment force due to the mass from the coaxial waveguide conversion part to the waveguide flange is applied to the coaxial outer conductor part, the fixing strength is sufficient, so the impedance matching of the high frequency input / output part does not change, and stable operation is achieved. A helix type traveling wave tube is obtained.

Description

[Detailed description of the device]

The present invention relates to a helix type traveling wave tube that operates in the millimeter wave region, and particularly to a high frequency input / output circuit structure.

[0002]

[Prior Art]

 Radio waves used in communications and broadcasting have expanded from the microwave region to the millimeter wave region, and the traveling wave tube as an electromagnetic wave source has been increased in frequency and output. In order to obtain a high output in the millimeter wave region, a coupled cavity type traveling wave tube is generally suitable, but the structure is complicated and the shape tends to be large, so that it can be used in satellites, aircrafts, etc. If miniaturization is required, a helix-type traveling wave tube is rather adopted.

When designing a helical traveling-wave tube in the millimeter wave region, one of the important problems to be solved is one of the high-frequency input / output circuit structure that accompanies the miniaturization of the helical slow-wave circuit by increasing the frequency. It is a design. There are two types of input / output structures for traveling-wave tubes: a coaxial-type hermetic window type and a waveguide-type hermetic window type. Generally, a waveguide-type hermetic window is used in the millimeter wave region. The connection method between the helix and the waveguide system is to take the coaxial circuit out of the helix and connect it to the waveguide system via the coaxial waveguide conversion unit (including the matching section), or to directly connect the helix to the waveguide system. There is a method to excite the system, but the latter has a relatively small degree of design freedom and the disturbance of the focusing magnetic field at the input / output section is relatively large, so the former is adopted in the vicinity of the 40 GHz band.

FIG. 3 is a diagram showing the structure of an input / output circuit connected to the coaxial extraction waveguide system. The end of the helix 1 is connected to the coaxial inner conductor 3, and is connected to an external circuit through the coaxial waveguide conversion section 5, the waveguide system hermetic window 6, the connection waveguide 7 and the waveguide flange 8. It has a structure. FIG. 4 is a diagram showing the details of the portion A of FIG. 3 and shows a conventional configuration. The end of the thin cylindrical coaxial outer conductor 4 is brazed to the small hole provided in the pole piece spacer 12c between the pole pieces 10a and 10b constituting the periodic magnetic field device, and the end of the helix 1 is It has a structure in which it is connected to the coaxial inner conductor 3 via the helix tape 2. Note that 11a, 11b and 11c are magnets, and 12a and 12b are pole piece spacers.

[0005]

[Problems to be solved by the device]

 The size of the coaxial output from the helix of the input / output circuit is relatively small due to the design restrictions of the periodic magnetic field device, while the size and weight from the coaxial waveguide converter to the waveguide flange are relatively large. .. Therefore, when used in a severe vibration / shock environment such as a traveling wave tube for satellites or aircraft, the strength of the coaxial outer conductor or the brazed part between the coaxial outer conductor and the pole piece spacer is insufficient. Therefore, there is a problem that impedance matching changes and output fluctuation occurs, and in the worst case, vacuum tightness is impaired.

[0006]

[Means for Solving the Problems]

 The coaxial outer conductor of the coaxial extraction portion of the high-frequency input / output structure of the present invention has a thick cylindrical step portion, which is in contact with the outer peripheral ends of the pair of pole pieces of the input / output portion of the periodic magnetic field device. And the remaining thin cylindrical portion of the coaxial outer conductor is brazed to the opposite side surfaces of the pair of pole pieces.

[0007]

【Example】

 Next, the present invention will be described with reference to the drawings. FIG. 1 is a detailed cross-sectional view of a coaxial take-out portion of a high frequency input / output structure according to a first embodiment of the present invention, which is provided on a pole piece spacer 12c between pole pieces 10a and 10b constituting a periodic magnetic field device. The coaxial inner conductor 3 is connected to the end of the helix 1 through the helix tape 2 through the small hole. The coaxial outer conductor 4 brazed to the small holes of the pole piece spacer 12c has a thick-walled cylindrical step portion 4a. The step portion 4a is in contact with the outer peripheral ends of the pole pieces 10a, 10b, It is brazed and fixed by 20. Furthermore, the remaining thin-walled cylindrical portion of the coaxial outer conductor 4 is brazed and fixed by brazing material 20 to each side surface of the pole pieces 10a, 10b.

As described above, in this embodiment, since the coaxial outer conductor 4 of the coaxial take-out portion is fixed to the pole pieces 10a, 10b by the brazing material, impedance matching is achieved even if vibration or moment force is applied to the high frequency input / output portion. It does not change and cause output fluctuations, or the vacuum tightness is not impaired.

FIG. 2 is a detailed sectional view of the coaxial take-out portion of the high frequency input structure according to the second embodiment of the present invention. The structure is similar to that of the first embodiment, but the coaxial outer conductor is fixed to the pole piece (including part of the magnet outer peripheral portion) with an adhesive 21 instead of the brazing material. This embodiment also has the same effect as that of the first embodiment.

[0010]

[Effect of the device]

 As described above, according to the present invention, the coaxial outer conductor is provided with the step portion of the thick-walled cylinder, and the end face and the remaining thin-walled cylindrical portion are brazed and fixed to the pair of pole pieces of the periodic magnetic field device. It has sufficient strength even if the moment force due to the mass from the waveguide conversion section to the waveguide flange is applied to the coaxial outer conductor section. It was confirmed that the traveling wave tube onboard the satellite adopting this structure does not change the matching of the high-frequency input / output section at all even after the random vibration test of about 20 Grms and performed it stably.

[Brief description of drawings]

FIG. 1 is a detailed cross-sectional view of a coaxial take-out portion of a high frequency input / output structure according to a first embodiment of the present invention.

FIG. 2 is a detailed cross-sectional view of the coaxial take-out portion of the high frequency input / output structure according to the second embodiment of the present invention.

FIG. 3 is a diagram showing an entire high frequency input / output structure of a conventional traveling wave tube.

FIG. 4 is a detailed cross-sectional view of part A (coaxial extraction part) of FIG.

[Explanation of symbols]

 1 Helix 2 Helix Tape 3 Coaxial Inner Conductor 4 Coaxial Outer Conductor 5 Coaxial Waveguide Converter 6 Waveguide System Airtight Window 7 Connection Waveguide 8 Waveguide Flange 10a, 10b Pole Piece 11a, 11b, 11c Magnet 12a, 12b, 12c Pole piece spacer 20 Brazing material 21 Adhesive

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Sugawara 2-12-5 Iwamoto-cho, Chiyoda-ku, Tokyo Inside the Space Communication Basic Technology Research Institute, Inc.

Claims (1)

[Scope of utility model registration request] 1. A helix-type slow-wave circuit structure, a periodic magnetic field device, and high-frequency coupling with a coaxial structure at the end of the helix, which is connected to a hermetic window of a waveguide system via a coaxial waveguide conversion unit to form an external waveguide. In a helix type traveling wave tube having at least a high frequency input / output structure connected to a system, the coaxial outer conductor of the coaxial structure portion has a thick cylindrical step portion, and the step portion is an input / output of the periodic magnetic field device. Of the pair of pole pieces are fixed in contact with the outer peripheral ends of the pair of pole pieces, and the remaining thin cylindrical portions of the coaxial outer conductor are fixed to opposite side surfaces of the pair of pole pieces. Helix type traveling wave tube.