DE1078696B - Traveling field pipes with a conductive helix as a delay line - Google Patents

Description

GERMAN

The invention relates to a traveling wave tube with a conductive helix as a delay line, an electron gun on the one end of the delay line for creating one within the delay line along the same traversing electron beam and a collecting electrode at the other end of the delay line, at the end of the delay line at the first-mentioned end of the delay line adjacent to the beam generation system a helical conductor merging into the delay line is provided, which is bent relative to the delay line in such a way that the beam generating system is close at the end of the delay line, and that at its other end evenly in goes over a straight ladder.

It is already known to build traveling wave tubes in the manner indicated above, the conductive Helix and the helical conductor are supported in a known manner by suitable means.

On the other hand, it is also known to have the conductive coil at both ends of a traveling wave tube to let go immediately into a coaxial line. However, such a transition is quite large Losses due to mismatching in the input and output, which can also give rise to oscillations.

The invention aims to provide a construction which gives less losses.

In a traveling wave tube of the type mentioned at the outset, according to the invention, at least those are used as a delay line serving helix and the helical conductor in a continuous, tubular Recess of a metal part (jacket), which consists of two metal plates in which trough-shaped Channels are attached in such a way that the tubular recess results when the panels are assembled, arranged and supported by insulating means against the recess wall.

The straight conductor, into which the helical conductor merges, can have a gradually increasing cross section received until the required dimension is reached for connection to the inner conductor of a coaxial line, the outer conductor of which is connected to the wall of the associated channels in the jacket can be that it forms an extension of these channels. When the two ends of the high frequency conductor are designed in this way, the result is a particularly advantageous traveling wave tube, which on both sides, d. H. at the input and output, is adapted to a coaxial line, and the traveling wave tube that is essentially a broadband tube, is thus direct and without further restriction for broadband circuits suitable. When the two ends of the high-frequency conductor move in the same direction

with a conductive coil

as a delay line

Applicant:

NV Philips' Gloeilampenfabrieken,
Eindhoven (Netherlands)

Representative: Dr. rer. nat. P. Roßbach, patent attorney,
Hamburg 1, Mönckebergstr. 7th

Claimed priority:
Great Britain 17 November 1953

Norman Wright Robinson,

Carshalton Beeches, Surrey,

and Harry Guy Flood, West Wickham, Kent

(Great Britain),
have been named as inventors

stretch, all DC and low-frequency cables can to be inserted into the tube on one side, while the radio frequency connections can be made at the other end of the tube.

The collecting electrode can be supported by the jacket, for example by means of an insulator, which is attached to the coat. The jacket can be surrounded by a cylindrical vacuum envelope whose end faces the electrical connections are passed through.

The invention is explained in more detail below using an exemplary embodiment.

Fig. 1 is a plan view of one part and Fig. 2 is a plan view of the other part of FIG two parts of the existing jacket for a traveling wave tube according to the invention;

3 and 4 are the side views of the end faces of the shell when the two parts of FIG and 2 are matched;

Fig. 5 illustrates one stage in the manufacture of the tube in greater detail;

Figure 6 shows a portion of the conductive coil and helical conductor;

909 768/337

Fig. 7 shows a detail of part of the tube, and

Fig. 8 shows a finished tube according to the invention.

The traveling wave tube according to the invention contains two metal plates 1 (Fig. 1) and 2 (Fig. 2). The plates 1 and 2 are pressed from sheet metal, with trough-shaped channels being formed in the pressing pieces 1 and 2 so that when the pressing piece 2 is fitted onto the pressing piece 1 by turning around the upper edge, an uninterrupted, tubular recess of round cross-section is enclosed by the pressings 1 and 2. The pressing piece 1 has a curved edge 4 and the pressing piece 2 has a curved edge 5. The channels 7 and 8 represent a first part of the uninterrupted recess parallel to the edges 4 and 5, the channels 9 and 10 a second part, wherein the channels 9 and 10 are smoothly bent and a connection between the channels 7 and 8 and the Establish channels 11 and 12, the latter forming a third part parallel to the first part. The fluently bent channels 13 and 14 form a fourth part which is initially perpendicular to the third part, and the channels 15 and 16 form a fifth part parallel to the third part. The left ends of the channels 11 and 12 emerge at 11 α and 12 α , and on the other side they open into enlarged channels 17 and 18. The channels 15 and 16 emerge at 15 α and 16 a .

The uninterrupted recess includes and holds the insulating means holding the high-frequency conductor, in this case an insulating coil. In channels 9, 10, 11., 12 and 13, 14, the high-frequency conductor has the shape of a regular helix; in the channels 7, 8 and 15, 16 the pitch of the helix gradually increases until the high-frequency conductor runs in a straight line. The part of the high-frequency conductor arranged in the channels 11, 12 is the "conductive coil" serving as a delay line, the extensions of the high-frequency conductor at the ends of the conductive coil are the "helical conductors". The channels 17 and 18 comprise and hold the device for generating the electron beam and for directing this beam. Grooves 26 and 27 are provided in the pressing pieces to prevent the conductors in the channels 11, 12 and 15, 16 from interfering with one another. The manner in which the insulating coil and the conductive coil and the helical conductors can be made has been described in patent 933,352. The helical parts with a gradually increasing slope can easily be wound simultaneously and from the same conductor as the conductive helix and the subsequent helical conductor.

Fig. 5 shows how the insulating coil is so bent can be that its longitudinal axis is bent at an angle of 90 °. The insulating coil 22 becomes heated for this purpose at the bend 20, so that the right part of the helix bends in the direction of the arrow. The conductive coil and the helical conductor can be introduced into the insulating coil by the high-frequency conductor and the insulating coil are carefully rotated against each other, so that the High-frequency conductor slides within the turns of the insulating coil to its intended location.

Fig. 6 shows the transition between the conductive coil 21 and a helical conductor 23 and the way in which the high frequency conductor in this section is preferentially bent to avoid the path not to block the electron beam. The helical conductors can with the conductive coil a Form a unit, but they can also be manufactured separately and attached to the conductive coil. Figures 3 and 4 are side views from opposite end faces of the shell formed from the parts 1 and 2 consists.

Fig. 7 shows the channel 15 with the helical part 24 with gradually increasing slope, which the Transition from the helical conductor 23 to the

ίο straight ladder part 25 forms. The diameter of the straight conductor part 25 is gradually enlarged, for example by electroplating, until the end 31 has the desired dimension, around the inner conductor of a, for example, 75-ohmic coaxial. management to form or to pass into the inner conductor of such a line.

When the high frequency conductor and its insulating support have been correctly positioned in the pressing piece 1 and the electron gun in the channel 17 is precisely directed to deliver an electron beam passing through the center of the conductive coil, the pressing piece 2 is placed on the pressing piece 1 and attached to it attached, for example by soldering or by changing the shape of the edges 4 and 5 of the plates. The free ends 31 of the high-frequency conductor are then soldered to the inner conductors of two coaxial lines, while the outer conductors of the coaxial lines are connected to the extensions 7, 8 and 15 a, 16 α .

In Fig. 8 is a complete tube according to the invention with a vacuum-tight outer shell 28 and the locking pieces 29 and 30 shown. The collecting electrode is designated by 32. The cathode 33 is held in a ceramic plate 36. The acceleration electrode is designated by 34.

The edges 4 and 5 are attached to the part 28 to prevent rotation or other movement.

In one embodiment of the tube described with reference to the drawings, there was an insulating coil made of glass with a diameter of 1 mm. The conductive coil and helical conductor were made of copper wire with a diameter of 0.1 mm, and there were 92 turns per 2.5 cm on a mandrel wound with a diameter of 1 mm. The transition from the helical conductor to the straight one Conductor part was made in 46 turns over an area of 25 mm in channels 15 and 16 and likewise in 46 turns over an area of 25 mm in channels 7 and 8. The outer dimension h of the tube were: diameter 2.5 cm, length 22.5 cm, and the tube was suitable for use at a wavelength of about 3 cm. The losses due to the right-angled bend in the. Transitions from the conductive helix to the helical conductors were about 2 db each.

Preferably the connections to the electron gun, the collecting electrode and the getter on the side of the electron gun, while the connections with the High-frequency conductors are led out on the side of the collecting electrode. The entrance will preferably connected to the high-frequency conductor in channels 15 and 16, because at the entrance (da there the signal is relatively weak) reflections are particularly disturbing, so that a slow, gradual transition is desirable.

The type described with reference to the drawing is compact, and it is characterized in that a broadband traveling wave tube on both the input side and the output side in one

for broadband transmission suitable way adapts to the broadband coaxial lines.

It can be seen that the regularity of the conductive coil must be maintained in order to influence the phase shift of the electron beam, but the regularity of the helical conductors is not so important.

Claims (5)

Patent claims: 1. Traveling wave tube with a conductive helix as a delay line, an electron gun at one end of the delay line for generating one running along the delay line within the delay line Electron beam and a collecting electrode at the other end of the delay line, at the the first-mentioned end of the delay line adjacent to the beam generation system helical conductor passing over into the delay line is provided, which opposite the delay line is bent so that the beam generating system is near the end of the Delay line can be arranged, and the one at its other end evenly into one straight conductor passes over, characterized in that at least as a delay line serving helix and the helical conductor in a continuous, tubular recess a metal part (jacket), which consists of two metal plates in which trough-shaped Channels are attached so that when the plates are assembled, the tubular recess results, are arranged and supported by insulating means against the recess wall are. 2. Traveling wave tube according to claim 1, characterized in that further in the metal plates Trough-shaped channels are provided for receiving the electron gun. 3. Traveling wave tube according to claim 1 or 2, characterized in that the helical Head gradually bends in the direction of the axis of the helix serving as the delay line. 4. Traveling wave tube according to claim 1, 2 or 3, characterized in that on which the collecting electrode adjacent end of the delay line in the same way a helical conductor is provided. 5. traveling wave tube according to claim 1, 2, 3 or 4, characterized in that the supply and Dissipation of the high-frequency energy takes place at the same end of the tube. Considered publications:
U.S. Patent Nos. 2,516,944, 2,578,434. 1 sheet of drawings 909 · 768/33? 3.60