JPS63213242A - Multistage potential decreasing collector for microwave tube - Google Patents

Abstract

PURPOSE:To prevent retrogression of return electrons and secondary electrons into a high frequency circuit part by specifying the distance from a bottom plate part to the tip of a spike which is provided in the center of the bottom plate of the last stage collector electrode. CONSTITUTION:In multistage potential decreasing collectors, whose potentials are kept decreasing in order, the last stage collector electrode 5 has a conical shaped part 5a with an electron passing aperture with a radius of r, a disc shaped bottom plate part 5b and a cylindrical part 5c which connects the conical shaped part 5a and the disc shaped bottom plate part 5b. A spike 9 is provided in the center of the bottom plate 5b standing along the vertical axis passing through the center. The distance Z, from the tip of the spike 9 to the bottom plate 5b, is in the range of z0-r<=Z<=Z0+r where Z0 is the point on the conical shaped electron beam passing aperture 8 through which the vertical axis passes. Thus a divergent electric field is formed in the vicinity of the center axis 7, thereby the retrogression of return electrons and the secondary electrons into the high frequency circuit part can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a multistage potential drop collector for microwave tubes.

BACKGROUND OF THE INVENTION It is well known that one method for improving the overall efficiency of microwave tubes such as helical traveling wave is to reduce the collector potential. Particularly in recent years, there has been a strong demand for improvements in the overall efficiency of traveling wave tubes mounted on satellites in order to make the satellite bodies smaller and lighter. For this reason, a multi-stage potential drop collector is adopted to capture the velocity-modulated electron beam that passes through a high-frequency circuit section such as a helix where the interaction between the electron beam and the high frequency occurs, improving the overall efficiency by more than 50%. I was able to do that.

A schematic cross-sectional view of a four-stage potential drop collector of this technology is shown in the second figure.
As shown in the figure. A first collector electrode 2, a second collector electrode 3, and a third collector electrode are placed at predetermined positions along the central axis 7 of the collector.
A collector electrode 4 and a fourth collector electrode 5 are arranged. The first to third collector electrodes each have a conical shape with an electron passage hole. The fourth collector electrode 5 includes a conical portion 5a and a bottom plate portion 5b, and a conical portion 5a and a bottom plate portion 5.
It consists of a cylindrical part 5C that connects b. Further, the conical portion 5a of the fourth collector electrode 5 has an electron passing hole 8.
is provided. First to fourth collector electrodes 2.3
．． 4.5 respectively VC1>V C2>V C3>
Voltage related to V o4 ■. 8, VC2, VC3,
VC< is applied to each.

In such a configuration, the electron beam that has completed the interaction with the high frequency in the high frequency circuit section (not shown) has various velocity components that are velocity modulated, and depending on these velocities, the entire collector is The heat is distributed to the first to fourth collector electrodes 2.3.4.5 and captured so as to minimize heat loss. Their tracks are shown in FIG. Note that the primary electrons that reach each electrode collide and emit secondary electrons from the electrodes. Further, negative electrons that cannot reach the electrode become return electrons 6 that go back in the original direction.

The basic requirements for a multi-stage potential drop collector are to capture these secondary electrons and return electrons 6 in the entire collector without returning them to the high-frequency circuit, and to minimize the heat loss generated in the collector section so that the collector has a high height. It's about gaining efficiency. As the collector efficiency increases, the overall efficiency of the microwave tube also increases.

Problems to be Solved by the Invention In the conventional multi-stage potential drop collector as shown in FIG. 2, the first to fourth collector electrodes 2.
The electric field between the electrodes formed by 3.4.5 is not a divergent electric field, and the electrons near the central axis 7 do not enter each collector electrode, but instead go back and become electrons 6 and return to the high-frequency circuit section. As a microwave tube, there was a problem in that it had a large negative effect on high frequency characteristics. Also, this return electron 6
■The voltage of each electrode in order to remove the influence on the high frequency characteristics by. , ~V C4, the collector efficiency will deteriorate and the velocity of the electron beam captured by the fourth collector electrode 5 will increase in the DC operating state where there is no interaction with the high frequency. Secondary electrons are generated, and these secondary electrons return to the high frequency circuit section, causing problems such as oscillation.

As a means of suppressing the return of the secondary electrons and return electrons from the collector section to the high-frequency circuit section, there is a method of providing a negative potential spike on the central axis of the final stage collector (IEEE Transmission ET 7).
ans,) ED-24, No, IP, 43. Ja
n, 1977) was proposed. However, this method has drawbacks such as the need for a special negative potential electrode for spiking and the heat capacity of the final stage collector being too small for high power microwave tubes.

The present invention has been made in view of the problems of the prior art, and provides a sufficiently low collector potential, prevents return electrons and secondary electrons from moving backward from the collector section to the high frequency circuit section, and maintains high collector efficiency. It is an object of the present invention to provide a multi-stage potential drop collector for a microwave tube.

Means for Solving the Problems A multi-stage potential drop collector for a microwave tube according to the present invention that achieves the above object has the following configuration.

That is, in a multi-stage potential reduction collector for a microwave tube that is successively kept at a low potential, the final stage collector electrode includes a conical portion having an electron passage hole with a radius r, a disk-shaped bottom plate portion, and the conical portion. and a cylindrical portion connecting the disc-shaped bottom plate portion, a spike is provided at the center of the bottom plate portion of the final stage collector electrode and erected on a vertical axis passing therethrough, and the tip position of the spike is The distance Z from the bottom plate is in the range Zo-r≦Z≦Zo+r, where Zo is the position of the conical electron beam passage hole on the vertical axis.

A spike is provided on the bottom plate of the final stage collector electrode, and the tip position of the spike is Z. By satisfying the relationship -r≦Z≦z0+r, a diverging electric field is formed near the central axis (Z-axis), and return electrons and secondary electrons near the central axis are prevented from moving back toward the high-frequency circuit section. Ru.

Embodiment An embodiment of a multi-stage potential drop collector for a microwave tube according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a multi-stage potential drop collector for a microwave tube, which is an embodiment of the present invention. In the embodiment shown in FIG. 1, parts similar to those in the conventional example shown in FIG. 2 are given the same reference numerals.

In the multi-stage potential reduction collector for a microwave tube according to the present invention shown in FIG.
, a second collector electrode 3, a third collector electrode 4, and a fourth collector electrode 5 are arranged. Each of the first to third collector electrodes 2.3.4 is formed of a conical conductor plate. The fourth collector electrode 5 includes a conical portion 5a having an electron passing hole 8 with a radius r and a disk-shaped bottom plate portion 5.
and a cylindrical portion 5c connecting the two. Further, the bottom plate portion 5 of the fourth collector electrode 5 is provided with a spike 9 that protrudes along the central axis 7 toward the electron passing hole 8 of the conical portion 5a, and the tip of the spike 9 is centered on the bottom plate portion. Assuming that there is an origin of the axis Z axis, spike 9
The tip position Z is as follows: Zo−r≦Z≦Zo−r where Zo is the position r of the electron passing hole 6 and is within the radius of the electron passing hole 6.

Also, the potential ■ of the first to fourth collectors. I, VO2, ■
. 3. VO2 is maintained in the relationship of Vc+ > VO2 > VO3 > Va4.

In such a configuration, in the high frequency circuit section (not shown),
When the velocity-modulated electron beam 1 finishes interacting with the high frequency and enters the collector section from the left side of the figure along the central axis 7 of the collector section, the electron beam 1 Beam 1 is connected to each collector electrode 2.3.4.5 so as to minimize heat loss in the collector.
captured and distributed over In this embodiment, a spike 9 protrudes from the center of the bottom plate portion 5 of the fourth collector electrode 5.
The tip position Z of the spike 9 is in the range given by the inequality Z, -r≦Z≦Zo+r. For this reason spike 9
Since a diverging electric field is formed between the electron beam 10 and the first to third electrodes, a radial force is applied to the paraxial electron beam 10 and the secondary electrons or return electrons, causing them to travel back toward the high-frequency circuit section. The particles are effectively captured by the first to fourth collector electrodes without being trapped. In addition, even in the DC operating state, not only the paraxial electron beam 10 but also many egg beams are subjected to a force that greatly expands them near the electron passage hole 8 of the fourth collector electrode 5, so even if secondary electrons are generated, many of them are is captured by the fourth collector electrode 5.

Effects of the Invention According to the multi-stage current drop collector for microwave tubes according to the present invention, the final stage collector electrode is composed of a conical part having an electron beam passing hole, a cylindrical part, a bottom plate part, and a spike erected at the center of the bottom plate part. By locating the tip of the spike near the electron passage hole of the final stage collector, a divergent electric field that is effective even for the paraxial electron beam is formed, and the return electrons and secondary electrons are also transmitted to the high-frequency circuit section. We were able to prevent it from moving backwards. Furthermore, even in the DC operating state, the paths of many electrons are expanded by the divergent electric field, which prevents secondary electrons from moving backwards, and because the electrons are captured on the surface of the final stage collector electrode, it has a large heat capacity. Effective as a multistage potential drop collector for power microwave tubes. Further, as a result of detailed computer simulation, it was confirmed that the device according to the present invention improved the overall efficiency by 4% or more compared to the conventional example.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a multi-stage potential drop collector for a microwave tube according to the present invention, and FIG. 2 is a sectional view of a conventional multi-stage potential drop collector for a microwave tube. (Main reference numbers) ■... Electron beam, 2... First collector electrode, 3...
2nd collector electrode, 4...3rd collector electrode, 5...4th collector electrode,

Claims (1)

[Claims] In a multi-stage potential reduction collector for a microwave tube that is successively maintained at a low potential, the final stage collector electrode includes a conical portion having an electron passage hole with a radius r, a disc-shaped bottom plate portion,
a cylindrical portion connecting the conical portion and the disc-shaped bottom plate portion, a spike is provided at the center of the bottom plate portion of the final stage collector electrode and erected on a vertical axis passing therethrough; The distance Z of the tip of the spike from the bottom plate is in the range Z_0-r≦Z≦Z_0+r, where Z_0 is the position on the vertical axis of the conical electron beam passage hole. Multistage potential drop collector for microwave tubes.