JP2928113B2 - Pill box type vacuum window - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pillbox type vacuum window, and more particularly to a pillbox type vacuum window used for an input / output window of a microwave tube.

[0002]

2. Description of the Related Art Microwave power is applied to various applications such as TV broadcasting, line-of-sight communication, line-of-sight communication, satellite communication, space communication, radar, microwave heating, and the like. Wave tubes include traveling wave tubes, klystrons, and magnetrons. Microwave tubes mainly include traveling wave tubes and clastrons.
The optimum one is selected from these microwave tubes according to the level of the microwave power. In the broadcasting and communication fields, traveling wave tubes and klystrons are mainly used as the last-stage amplifier tubes of transmitters. . The demands for higher performance of these microwave tubes are becoming stricter year by year, and there is a tendency for higher frequency, wider band, higher output, smaller size, and more stable operation. In microwave tubes of high frequency and high output, there is an increasing risk of breakage due to abnormal operation due to miniaturization of dimensions due to higher frequency and increase in voltage and current due to higher output.

Next, the structure of a conventional microwave tube will be described with reference to an example of a helix type traveling wave tube having a helix type slow wave circuit which is one of the linear beam microwave tubes.

FIG. 8 is a sectional view showing an example of the configuration of a conventional helix type traveling wave tube. As shown in FIG. 8, the conventional linear beam microwave tube is mainly composed of an electron gun unit 1 that mainly generates an electron beam, and a delay unit that amplifies the input microwave by the interaction between the electron beam emitted from the electron beam unit 1 and an input signal. It comprises a wave circuit section 2 and a collector section 3 which captures the electron beam transmitted through the slow wave circuit section 2 and converts it into thermal energy. A focusing magnetic field device unit which focuses the electron beam emitted from the electron gun unit 1 outside the slow wave circuit unit 2 and generates a magnetic field for passing the electron beam through the slow wave circuit unit 2 with a substantially constant beam diameter. 4 are provided. Further, it comprises a microwave input section 5 for inputting microwave power, a microwave output section 6 for extracting amplified microwave power, and a case 7 for fixing the above members.

FIG. 9 is a sectional view showing an example of the configuration of a microwave output section of a conventional linear beam microwave tube. FIG.
As shown in FIG. 1, the conventional microwave output unit 6 has an antenna 9 welded to the end of a helix 8 that interacts with an electron beam in the slow wave circuit unit 2, and the TEM transmitted from the antenna 9 The high-frequency power of the mode is converted by the coaxial waveguide converter 10 into the TE mode which is the transmission mode of the rectangular waveguide, and reaches the pill box type vacuum window 11 for vacuum sealing the linear beam microwave tube. The high frequency power of the TE mode is transmitted from the rectangular waveguide 13 having the same shape as the rectangular waveguide 12 on the opposite side. Thereafter, the step or the tapered waveguide 14 causes the loss to be low within the operating frequency, that is, it is transmitted to the rectangular waveguide 15 larger than the previous rectangular waveguide 12. And it is connected to the apparatus side via the flange 16.

FIGS. 10A and 10B are a longitudinal sectional view and a transverse sectional view showing an example of the configuration of a conventional pill box type vacuum window. At the center thereof is a dielectric disk 17 made of alumina ceramics or the like, and the dielectric disk 17 is mounted on a circular waveguide 18 having substantially the same inner diameter as the dielectric disk 17 by brazing or the like, The circular waveguide 18
Rectangular waveguides 12, 13 are joined to both ends of the substrate by brazing or the like.

FIG. 11 shows a 14 GHz by computer simulation of an example of the pill box type vacuum window of FIG.
FIG. 9 is a characteristic diagram showing frequency characteristics of a constant voltage standing wave ratio of a band.
The dimensions of each part are as follows: long side a = 15, 8 m of rectangular waveguide 13
m, short side b = 7.9, inner radius R of cylindrical waveguide 18 = 9 m
m, thickness d of dielectric disk 17 made of alumina ceramics
= 0.6 mm, end face of cylindrical waveguide 18 and dielectric disk 17
Is 3 mm, and a simulation result is obtained when the dielectric constant ε of the alumina ceramic dielectric disk 17 is 9.2. As shown in FIG. 11, in the conventional pill box type vacuum window, 11 to 12 GH
The constant voltage standing wave ratio (hereinafter, VSW) of 1.2 or less in the range of z
R) is obtained.

Next, a conventional pillbox type vacuum window will be described with reference to a cited example.

FIGS. 12 (a) and 12 (b) are a longitudinal sectional view and a transverse sectional view showing the structure of Reference Example 1 of a conventional pillbox type vacuum window. Reference example 1 is a pill box type vacuum window disclosed in Japanese Patent Application Laid-Open No. 4-92341.
As shown in (b), the long sides a and the short sides b of the rectangular waveguides 12 and 13 forming the pill box type vacuum window have the same dimensions, respectively, and the long side a and the inner radius R of the circular waveguide 18. Between R
It is characterized in that the relationship <a / 2 exists. With this configuration, a very wide-band pillbox-type vacuum window can be obtained. By using this pillbox-type vacuum window as an input / output window of a microwave tube, a very wide-band microwave tube can be obtained. Things.

FIGS. 13 (a) and 13 (b) are a longitudinal sectional view and a transverse sectional view, respectively, showing the structure of Reference Example 2 of a conventional pillbox type vacuum window. Reference example 2 is a pill box type vacuum window disclosed in Japanese Patent Application Laid-Open No. 3-145201.
As shown in (a) and (b), a pillbox type vacuum window is formed by connecting the rectangular waveguides 12 and 13 including the matching transformer at both ends of the circular waveguide 18. And With this configuration, it is possible to operate in a wide frequency band without a ghost mode. Also, the mechanical properties are improved and the dimensions are reduced.

[0011]

In the conventional microwave tube using the pill box type vacuum window, a device using the microwave tube usually has a large shape having the lowest loss even within the operating frequency. A rectangular waveguide is used. For this reason, in the conventional pill box type vacuum window, a method of making the shape of the rectangular waveguides at both ends of the circular waveguide the same size as the device, or providing a step or a tapered waveguide on the device side. The shape of the rectangular waveguide was matched. However, due to recent demands for downsizing and cost reduction of devices, it is no longer necessary to provide steps or tapered waveguides on the device side.
Also, in order to reduce the vacuum capacity of the microwave tube, the dimensions of the rectangular waveguide up to the pillbox type vacuum window should be as small as possible within the operating frequency, and the air in the pillbox type vacuum window should be as small as possible. On the device side, there is a tendency to use a tapered waveguide or a stepped waveguide, which is a kind of matching transformer, to expand the device to a desired size. This is because, as shown in the cited reference 1, in the conventional pill box type vacuum window, the rectangular waveguides at both ends of the circular waveguide have the same shape. The reason for the same shape is that the impedance of the rectangular waveguide is the same, the calculation is easy in designing the pillbox type vacuum window, and a good VSWR frequency characteristic is obtained in the frequency band used. It was thought that it would be done. However, the above-mentioned means is complicated in structure, and requires a rectangular waveguide having a length at least half a wavelength of a used frequency in order to provide a matching transformer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pillbox type vacuum window which is small in size and simple in structure without the need for providing a matching transformer and can reduce the length of a rectangular waveguide.

[0013]

According to a first aspect of the present invention, there is provided a pillbox-type vacuum window comprising: a dielectric disk; and a circular shape having substantially the same inner diameter as the diameter of the dielectric disk and having the dielectric disk mounted at the center thereof. In a pillbox-type vacuum window having a waveguide and two rectangular waveguides connected to both ends of the circular waveguide, a length of a long side and a length of a short side of each of the two rectangular waveguides are set. The length of both sides is different. In this pillbox type vacuum window, the inner diameter of the circular waveguide is smaller than the length of the diagonal of the rectangular waveguide connected to one end of the circular waveguide, and the inner diameter of the rectangular waveguide connected to the other end is small. It is configured to be larger than the length of the diagonal line.

According to a second aspect of the present invention, there is provided a pillbox type vacuum window including a dielectric disk, and a circular disk having an outer diameter smaller than the diameter of the dielectric disk and having the dielectric disk mounted at the center thereof. In a pillbox-type vacuum window having a waveguide and two rectangular waveguides connected to both ends of the circular waveguide, a length of a long side and a length of a short side of each of the two rectangular waveguides are set. The length of the side and the length of both sides are different. In this pillbox type vacuum window, the inner diameter of the circular waveguide is smaller than the length of the diagonal of the rectangular waveguide connected to one end of the circular waveguide, and the inner diameter of the rectangular waveguide connected to the other end is smaller. It is configured to be larger than the length of the diagonal line.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a microwave output unit of a microwave tube using the first embodiment of the present invention. As shown in FIG. 1, a microwave output unit using the first embodiment of the present invention has an antenna 9 welded to an end of a helix 8 interacting with an electron beam in a slow wave circuit unit 2. The TEM mode high-frequency power transmitted from the antenna 9 is converted by the coaxial waveguide converter 10 into a TE mode which is a rectangular waveguide transmission mode, and the linear beam microwave tube is vacuum-sealed. And a pillbox-type vacuum window 11 for transmitting the high-frequency power in the TE mode from a rectangular waveguide 13 having a larger shape than the rectangular waveguide 12 on the opposite side. After that, it is connected to the device side via the flange 16. In this embodiment, the length of the diagonal of the rectangular waveguide 12 is smaller than the inner diameter of the circular waveguide 18, and the length of the diagonal of the rectangular waveguide 13 is the length of the circular waveguide 18.
Is larger than the inner diameter of

FIGS. 2A and 2B are a longitudinal sectional view and a transverse sectional view of a first embodiment of the present invention. In the first embodiment of the present invention, as shown in FIGS. 2A and 2B, a dielectric disk 17 made of alumina ceramic or the like is provided at the center thereof, and the dielectric disk 17 is substantially formed. The circular waveguide 18 having the same inner diameter as the dielectric disk 17 is mounted by brazing or the like, and rectangular waveguides 12 and 13 having different shapes are joined to both ends of the circular waveguide 18 by brazing or the like. ing. These rectangular waveguides 12, 13 are EI
In the AJ standard, those having overlapping use frequency ranges are used.

FIG. 3 is a characteristic diagram showing a frequency characteristic of a VSWR in a 14 GHz band by computer simulation according to the first embodiment of the present invention. The long side a1 of the one rectangular waveguide 12 = 15.8 mm, the short side b1 = 7.9 mm, the long side a2 of the other rectangular waveguide 13 = 19.05 mm, the short side b2 = 9.525 mm, and the circular waveguide Inner radius R of wave tube 18 = 9
mm, the thickness d of the dielectric band disk 17 made of alumina ceramics d = 0.6 mm, the relative permittivity ε = 9.2, and the circular waveguide 1
8, the distance s = 3 mm between the end face of the substrate 8 and the dielectric disk 17;
The dimensions a1 and b1 in this case are 14 GHz which is the operating frequency.
In the z band, a rectangular waveguide 12 having the smallest possible shape
And the dimensions a2 and b2 are the operating frequencies of 14 GHz.
Large rectangular waveguide 1 with the lowest loss in the band
3. FIG. 3 shows the simulation results obtained at this time. As shown in FIG. 3, the frequency characteristics of the VSWR of the conventional pill box type vacuum window shown in FIG. Was confirmed. That is, the rectangular waveguides 12 whose operating frequencies overlap each other,
In No. 13, it was found that the difference in characteristic impedance was small, and the effect on the pillbox type vacuum window was small and negligible.

FIG. 4 is a sectional view showing the configuration of a straight-beam microwave tube using the first embodiment of the present invention. The overall structure of the linear beam microwave tube of the first embodiment is shown in FIG.
As shown in FIG. 1, an electron gun unit 1 for generating an electron beam, a slow wave circuit unit 2 for amplifying an input microwave by an interaction between an electron beam emitted from the electron beam and an input signal, and a slow wave circuit unit 2 And a collector unit 3 for assisting the electron beam transmitted through and converting the energy into thermal energy. A focusing magnetic field device unit which focuses the electron beam emitted from the electron gun unit 1 outside the slow wave circuit unit 2 and generates a magnetic field for passing the electron beam through the slow wave circuit unit 2 with a substantially constant beam diameter. 4 are provided. The linear beam microwave tube further includes a microwave input unit 5 for inputting microwave power, a microwave output unit 6 for extracting amplified microwave power, and a case 7 for fixing the above members. It is configured to operate as. In the present embodiment, an example of the structure of a helical traveling wave tube is given as one of the microwave tubes, but the present invention can be applied to other microwave tubes such as a coupled cavity traveling wave tube and a klystron.

FIGS. 5A and 5B are a longitudinal sectional view and a transverse sectional view showing the structure of a second embodiment of the present invention. In the second embodiment of the present invention, as shown in FIGS.
A dielectric disk 17 made of alumina ceramics or the like is included. The dielectric disk 17 is sandwiched by a circular waveguide 18 having an outer diameter smaller than the diameter of the dielectric disk 17, and the rectangular waveguides 12 at both ends are formed.
The length of at least one of the long side or the short side of 13 is different. In this structure, since the disk surface of the dielectric disk 17 is sealed, a large sealing area can be obtained.
There is an advantage that the strength can be made firmer than that of the embodiment.
That is, this structure is usually employed in a pillbox type vacuum window used at a frequency of 14 GHz or higher.

FIGS. 6A and 6B are a longitudinal sectional view and a transverse sectional view showing the structure of a third embodiment of the present invention. The third embodiment of the present invention, as shown in FIGS.
At the center thereof is a dielectric disk 17 made of alumina ceramics or the like, and the dielectric disk 17 is mounted on a circular waveguide 18 having substantially the same inner diameter as the dielectric disk 17 by brazing or the like, Rectangular waveguides 12 and 13 having different shapes are joined to both ends of the circular waveguide 18 by brazing or the like. At this time, the rectangular waveguide on the vacuum side is E
It has a small shape outside the IAJ standard, and the outside of the vacuum is a rectangular waveguide having a large shape in consideration of the improvement in RF voltage resistance.

FIG. 7 is a characteristic diagram showing the frequency characteristics of the VSWR by computer simulation according to the third embodiment of the present invention. The VSWR frequency characteristic in this case is shown in FIG.
As shown in the figure, although the portion of the VSWR having a good frequency characteristic is narrowed, the pill box type vacuum window of the present embodiment can be applied to a high-power microwave tube for energy whose working frequency is fixed. There is an advantage that a microwave tube having a high voltage can be miniaturized.

[0023]

As described above, the present invention includes a dielectric disk made of alumina ceramic or the like at the center thereof, and the dielectric disk has an outer diameter substantially equal to or smaller than the diameter of the dielectric disk. is bonded by brazing or the like to the circular waveguide diameter, long side and a short side of the both ends of the circular waveguide
By joining two rectangular waveguides having different lengths by brazing or the like, there is no need to provide a matching transformer, and the length of each rectangular waveguide can be shortened. There is an effect that a mold vacuum window can be provided.

Further, by removing the matching transformer of the rectangular waveguide which has affected the frequency characteristics of the VSWR, complicated design is facilitated, and there is an effect that the miniaturization of the microwave tube is facilitated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a microwave output unit of a microwave tube using a first embodiment of the present invention.

FIGS. 2A and 2B are a longitudinal sectional view and a transverse sectional view showing the configuration of a first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing frequency characteristics of a 14 GHz band VSWR by computer simulation according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a configuration of a straight-beam microwave tube using the first embodiment of the present invention.

FIGS. 5A and 5B are a longitudinal sectional view and a transverse sectional view showing the configuration of a second embodiment of the present invention.

FIGS. 6A and 6B are a longitudinal sectional view and a transverse sectional view showing a configuration of a third embodiment of the present invention.

FIG. 7 is a characteristic diagram showing frequency characteristics of a VSWR by computer simulation according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view showing an example of a configuration of a conventional helical traveling wave tube.

FIG. 9 is a cross-sectional view showing an example of a configuration of a microwave output unit of a conventional linear beam microwave tube.

10A and 10B are a longitudinal sectional view and a transverse sectional view showing an example of the configuration of a conventional pill box type vacuum window.

11 is a characteristic diagram showing a frequency characteristic of a constant voltage standing wave ratio in a 14 GHz band by computer simulation of an example of the pill box type vacuum window of FIG. 10;

FIGS. 12A and 12B are a longitudinal sectional view and a transverse sectional view showing the configuration of Reference Example 1 of a conventional pillbox type vacuum window.

13 (a) and 13 (b) are a longitudinal sectional view and a transverse sectional view showing the configuration of Reference Example 2 of a conventional pillbox type vacuum window.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun part 2 Slow wave circuit part 3 Collector part 4 Focusing magnetic field device part 5 Microwave input part 6 Microwave output part 7 Case 8 Helix 9 Antenna 10 Coaxial waveguide converter 11 Pill box type vacuum window 12 Rectangular point Waveguide 13 Rectangular waveguide 14 Step or tapered waveguide 15 Large rectangular waveguide 16 Flange 17 Dielectric disk 18 Circular waveguide

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01P 1/08 H01J 23/00-25/78

Claims (4)

(57) [Claims] 1. A dielectric disk, a circular waveguide including the dielectric disk, and having the inner diameter substantially equal to the diameter of the dielectric disk and having the dielectric disk mounted at the center thereof, and the circular waveguide Pill box type vacuum window having two rectangular waveguides connected to both ends of the rectangular waveguide, the length of both long sides of the two rectangular waveguides and the length of each short side thereof And the two rectangular waveguides are aligned.
Connected directly to the circular waveguide without using a transformer
Pillbox vacuum window, characterized in that that. 2. A dielectric disk, including the dielectric disk.
At the center with an inner diameter substantially the same as the diameter of the dielectric disk of
A circular waveguide on which a dielectric disk is mounted, and the circular waveguide
Pill bob with two rectangular waveguides connected at both ends
In the box type vacuum window, each of the two rectangular waveguides
Of both long sides and the length of each short side
A rectangular waveguide having a different length and an inner diameter of a circular waveguide smaller than a diagonal length of a rectangular waveguide connected to one end of the circular waveguide and connected to the other end; A pillbox-type vacuum window, which is longer than the length of the diagonal line. 3. A dielectric disk, a circular waveguide including the dielectric disk, having an outer diameter smaller than the diameter of the dielectric disk, and mounting the dielectric disk at the center, and a circular waveguide. In a pillbox-type vacuum window having two rectangular waveguides connected to both ends, the length of both long sides and the length of each short side of the two rectangular waveguides And the two rectangular waveguides
A pillbox type vacuum window, which is directly connected to the circular waveguide without using a mixer . 4. The pillbox type vacuum window according to claim 1, wherein an inner diameter of the circular waveguide is smaller than a diagonal length of a rectangular waveguide connected to one end of the circular waveguide, and A pillbox-type vacuum window having a length larger than a diagonal length of a rectangular waveguide connected to the other end.