JPH0744008B2 - Microwave tube - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a microwave tube for efficiently extracting a high frequency through a high frequency extraction window provided in a waveguide.

[Prior art]

FIG. 2 is a schematic sectional view showing a conventional microwave tube shown in, for example, US Pat. No. 4,620,70, in which 21 is an electron gun and 22 is a collection of electrons emitted from the electron gun 21. Electron beam, 23 is an anode for accelerating the electron beam 22, 24 is an oscillation cavity through which the electron beam 22 passes and generates microwaves, 25 is a collector for collecting the electron beam after the action, and 26 is an oscillation cavity. It is a high frequency extraction window for extracting the high frequency generated at 24. Further, as the high frequency extraction window 26 of such a microwave tube, for example, as shown in FIG.
-91501, in which, 1 is a waveguide for guiding the high frequency generated in the oscillation cavity 24, 2 is a first dielectric located at the end of the waveguide 1, and 3 is A second dielectric member facing the first dielectric member 4, 4 is a flanged waveguide joined to the first dielectric member 2, and 5 is the first dielectric member 2 and the second dielectric member.
Cooling water inlet for flowing cooling water to and from the dielectric 3 of
Is a cooling water outlet, 7 is an outer cylinder for positioning the first dielectric 2 and the second dielectric 3 and enclosing the cooling water, 11 is the first dielectric 2 and the second dielectric 3 , A dielectric gap formed between P and P, P ₁ is the outlet pressure of the space surrounded by the flanged waveguide 4 and the second dielectric 3, P ₂ is the cooling water pressure, and P ₃ is the waveguide. The pressure inside the sphere in the space surrounded by 1 and the first dielectric 2, T ₁ is the thickness of the first dielectric 2, and T ₂ is the thickness of the second dielectric 3. Next, the operation will be described. The electrons emitted from the electron gun 21 become an electron beam 22, accelerated by the anode 23, and pass through the oscillation cavity 24. At this time, this oscillation cavity 24
When there is an appropriate magnetic field, the microwave of the frequency corresponding to this is excited, the inner wall of the collector 25 acts as a waveguide, the microwave is guided to the high frequency extraction window 26, and further passes through it. It is released to the outside. The high-frequency extraction window 26 has a vacuum on one side and an atmosphere on the other side. The first dielectric 2 is located on the vacuum side and the second dielectric 3 is located on the atmosphere side. The microwave guided by the waveguide 1 passes through the first dielectric 2 and then the dielectric gap 11,
Through the dielectric 3 of, and is guided to the flanged waveguide 4,
Radiated from its end. Here, the two first dielectrics 2
The second dielectric 3 has the same thickness, the cooling water enters through the cooling water inlet 5, passes through the dielectric gap 11 between the first dielectric 2 and the second dielectric 3, and exits the cooling water. It is discharged from 6. Since the cooling water has a pressure loss in the cooling water passage, it circulates at the cooling water pressure P ₂ which is a certain water supply pressure. On the other hand, the space surrounded by the waveguide 1 and the first dielectric 2, that is, the inside of the sphere,
The pressure inside the sphere is P ₃ , and it is a vacuum. In addition, the space surrounded by the waveguide 4 with the flange 4 and the second dielectric 3, that is, the high frequency extraction portion is generally pressurized to a few atmospheres with an insulating gas in order to extract a large high frequency output. For example, cooling water pressure P ₂
Is 5 kg / cm ² · G, the pressure P ₁ on the high frequency extraction side is 2 kg / cm ²
・ G. Further, the pressure applied to the dielectric gap 11 is normally determined by the pressure loss generated at that portion, but when the cooling water outlet 6 is closed, the cooling water pressure P ₂ is applied as it is. Therefore, up to now, the thicknesses of the first and second dielectric bodies 2 and 3 are set to be equal to each other according to the magnitudes of the pressures P ₁ , P ₂ and P ₃ , respectively. Had set.

[Problems to be Solved by the Invention]

Since the conventional microwave tube is configured as described above, the thicknesses of the first dielectric body 2 and the second dielectric body 3 are selected in consideration of the withstand pressure strength, and those having the same thickness. However, as a result, there is a problem in that the high-frequency transmission efficiency of the dielectrics 2 and 3 is significantly reduced. The present invention has been made in order to solve the above-mentioned problems, in which the individual thicknesses of the plurality of dielectrics forming the high-frequency extraction window are set so that the high-frequency passage loss is maximized while the desired withstand voltage performance is obtained. It is an object to obtain a microwave tube that can have a small thickness.

[Means for Solving the Problems]

In the microwave tube according to the present invention, the individual thicknesses of the plurality of dielectrics forming the high frequency extraction window are set to the cooling water pressure, the sphere pressure and the high frequency extraction part pressure supplied to the dielectric gaps. It is configured to have a set thickness with a strength commensurate with.

[Action]

The first dielectric in the present invention has a thickness that provides a relatively sufficient strength according to the internal pressure of the sphere and the cooling water pressure, while the second dielectric has a small difference between the cooling water pressure and the extraction side pressure. As a result, the thickness of the dielectric as a whole can be made sufficiently thin so that the high frequency passage loss can be reduced.

Examples of the invention

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 1 is a waveguide, 2 is a first dielectric attached to the end of the waveguide 1, 3 is a second dielectric facing the first dielectric 2, and 4 is a second dielectric. A flanged waveguide 5 joined to the body 3 is a first dielectric 2 and a second dielectric 3.
A cooling water inlet for cooling the cooling water, 6 a cooling water outlet, 8 an outer cylinder with a bellows for sealing the cooling water, 9 a drawing screw used to connect the waveguide 1 and the flanged waveguide 4 with each other, 10 is a push screw attached to a part of the waveguide 4 with a flange,
11 is a dielectric gap formed by the first dielectric 2 and the second dielectric 3, and serves as a cooling water passage, and P ₁ is an extraction surrounded by the flanged waveguide 4 and the second dielectric 3. Side pressure, P ₂ is cooling water pressure, P ₃ is pressure inside the sphere surrounded by the waveguide 1 and the first dielectric 2, T ₁ is the thickness of the first dielectric 2, and T ₂ is the second Is the thickness of the dielectric 3. Next, the operation will be described. The electrons emitted from the electron gun 21 become an electron beam 21, accelerated by the anode 23, and pass through the oscillation cavity 24. At this time, when an appropriate magnetic field is present in the oscillation cavity 24, microwaves of a certain fixed frequency are excited, the inner wall of the collector 25 acts as a waveguide, and the microwaves are guided to the high frequency extraction window 26. , Passes through it and is released to the outside. The high-frequency extraction window 26 has a vacuum on one side and an atmosphere on the other side, and the first dielectric body 2 is located on the vacuum side and the second dielectric body 3 is located on the atmosphere side. The microwave guided by the waveguide 1 passes through the first dielectric 2 and then through the dielectric gap 11 and the second dielectric 3, is guided to the flanged waveguide 4, and its end Emitted from the department. Then, when the microwave passes through the dielectrics 2 and 3, a loss corresponding to the thickness thereof occurs. Specifically, the dielectrics 2 and 3 generate heat at the passing portion. At this time, the cooling water enters through the cooling water inlet 5, passes through the dielectric gap 11 between the first dielectric 2 and the second dielectric 3, and is discharged through the cooling water outlet 6. Since the cooling water has a pressure loss in the cooling water passage, it circulates at a certain cooling water pressure P ₂ . on the other hand,
The space surrounded by the waveguide 1 and the first dielectric 2, that is, the inside of the sphere, is at a pressure P ₃ inside the sphere and is in vacuum. The space surrounded by the flanged waveguide 4 and the second dielectric 3, that is, the high-frequency extraction portion is generally pressurized with an insulating gas of several atmospheres in order to extract a large high-frequency output. That is, the conventional case similarly to the cooling water pressure ^{_{P 2 5kg / cm 2 · G}} , if the pressure P ₁ of the high-frequency extraction side and 2 kg / cm ² · G, the first dielectric 2
The cooling water pressure-internal pressure and the cooling water pressure-extraction side pressure are applied to the second dielectric 3 and the second dielectric 3 at maximum, respectively. That is, in the above embodiment, the pressure applied to the first dielectric 2 is 5 kg / cm ² G − (− 1 kg / cm ² G) = 6 kg / cm ² G,
The pressure applied to the second dielectric 3 is 5 kg / cm ² G−2 kg / cm ² G =
It becomes 3kg / cm ² G. When air pressure, water pressure, etc. are evenly distributed over the entire surface of the disk, the thickness t of the disk is generally Here, P is the pressure applied to the disc, a is a constant that changes under the indicated conditions, σ is a constant that changes depending on the material, and α is a shape constant. Therefore, if the thickness of the first dielectric 2 is t ₁ , the thickness t ₂ of the second dielectric 3 is From this, in the above embodiment, if the thicknesses of the first and second dielectrics 2 and 3 are selected so that t ₂ ≈0.707t ₁ , the cooling water pressure and the high-frequency extraction side pressure can be determined. It is possible to pass the high frequency with minimum loss while enduring.

【The invention's effect】

As described above, according to the present invention, the thicknesses of the first and second dielectrics can withstand the pressures of the cooling water supplied to the dielectric gaps, the pressure inside the sphere, and the pressure at the high frequency extraction part. Since the thickness of the second dielectric is smaller than that of the first dielectric, the entire dielectric can be made sufficiently thin with a minimum high-frequency transmission loss, Further, by making the entire dielectric thin, it is possible to reduce the consumption of materials, and thus it is possible to obtain the one in which the cost of the dielectric used can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a microwave tube according to an embodiment of the present invention, FIG. 2 is an overall sectional view showing a conventional microwave tube, and FIG. 3 is a part of a conventional microwave tube. It is sectional drawing which expands and shows. 2, 3 is a dielectric, 2 is a first dielectric, 3 is a second dielectric, 1
1 is a dielectric gap, 21 is an electron gun, 22 is an electron beam, 23 is an anode, 24 is an oscillation cavity, and 26 is a high frequency extraction window. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-56-91501 (JP, A) JP-A-63-34838 (JP, A) JP-A-2-86031 (JP, A) Actual development Sho-58- 182349 (JP, U)

Claims (1)

[Claims] 1. An anode for accelerating electrons emitted from an electron gun, an oscillation cavity for passing a beam of electrons accelerated by the anode to generate microwaves, and a high frequency generated by the oscillation cavity. In a microwave tube provided with a first dielectric provided inside the sphere and a high frequency extraction window formed of a second dielectric provided on the high frequency extraction part side. The thickness is set to a thickness that can withstand each pressure of the cooling water supplied to the dielectric gap, the internal pressure of the sphere and the pressure of the high frequency extraction part, and the thickness of the second dielectric is the thickness of the first dielectric. A microwave tube characterized by being made thinner.