JPS6252420B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in straight beam type microwave tube devices, such as klystrons and traveling wave tubes, and particularly in high power microwave tube devices.

It is well known that straight beam type microwave tube devices such as klystrons and traveling wave tubes are generally used for high power amplification of microwaves in television transmitters and the like. Recently, however, there has been an increasing demand for microwave tube devices that can provide high-power microwave output, such as in nuclear fusion devices, where high-frequency heating devices using high-power klystrons are used to inject electromagnetic energy into plasma. ing. For example, in one example of the above-mentioned high-frequency heating device for a nuclear fusion device, the maximum value of the high-frequency output is said to be 200 kW at two frequencies of 650 MHz and 750 MHz.

An example of such a high-power microwave tube device is a multi-cavity klystron. As shown in the schematic diagram of its structure in Figure 1, this multi-cavity klystron includes an electron gun section 1 that generates an electron beam, a microwave input section 2, and a microwave output section 3. An input cavity resonator 4, an intermediate cavity resonator 5, and an output cavity resonator 6 are arranged to amplify microwaves (although only three cavities are shown here, there are actually four cavity resonators). (often more than one) and a collector electrode 7 for collecting the electron beam are successively connected using a drift tube 8.

The electron beam emitted from the electron gun section 1 undergoes velocity modulation within the input cavity resonator 4 by the microwave signal applied from the microwave input section 2, and further passes through the drift tube 8 and the intermediate cavity resonator 5. It is converted into density modulation while passing through. This density-modulated electron beam generates an amplified microwave signal output in the output cavity resonator 6, which is extracted from the microwave output section 3 to an external load, and then collected by the collector electrode 7. Ru.

In such a microwave tube device, the structure of the microwave output section 3 is the most problematic when obtaining high-power microwave output as described above.

FIG. 2 shows a cross-sectional view of an output cavity resonator including a microwave output section according to an example of the prior art that is devised to obtain this high-power microwave output. In the figure, 6 is an output cavity resonator, 8 is a drift tube, 9 is a dielectric output window with a vacuum-sealed structure for extracting microwave output to an external load, 1
0 is an output waveguide, 11 is a coupling window, and 12 is a tuner.

The microwave signal power in the output cavity resonator 6 is
Two coupling windows 11 provided in the output cavity resonator 6
into the respective output waveguides 10 through
The signal is taken out to an external load through an output window 9 which is provided at the end of the output waveguide 10 and has a vacuum-sealed structure made of a dielectric material such as aluminum oxide (Al ₂ O ₃ ). The tuner 12 shown in the figure is attached to the cavity resonator via a bellows, and is used to tune the resonant frequency of the output cavity resonator 6 to the microwave signal.

Here, the important problem in extracting high-power microwave output is that the output window is heated due to dielectric loss and there is a limit to the electric field strength against high-frequency power, so there is a limit to the microwave power that can be extracted from the output window 9. This means that there is. Therefore, in one conventional example, as shown in FIG. 2, two output windows are individually provided so that high-power microwave output can be taken out.

However, although the conventional technique shown in FIG. 2 achieves the objective of extracting large amounts of power to an external load, it does have some drawbacks due to its structure.

First, the first drawback is that, as shown in FIG. This means that the space utilization rate) will deteriorate. For example, if one more output window is provided, it would be difficult to add more, and in an actual microwave tube device, a focusing device (not shown) is used to focus the electron beam in the axial direction of the entire cavity. However, if a number of output waveguides extend outside the output cavity resonator in this way, difficulties arise such as the structure becoming complicated.

Next, as a second drawback, according to the structure shown in FIG. 2, the tuner 12 and the coupling window 11 are
corresponds to 90 degrees with respect to the center point of the output cavity resonator 6. In this way, when the tuner and the coupling window are close, the external Q (Q _E ) of the cavity resonator 6
There are concerns about deterioration of characteristics due to sudden changes in frequency and adverse effects due to generation of unnecessary resonance modes.

An object of the present invention is to provide a high-power microwave device that eliminates the drawbacks shown in the above-mentioned conventional example by having a structure in which one output waveguide has a plurality of output windows. .

The microwave tube device of the present invention includes an electron gun section that generates an electron beam, a microwave input section, a microwave output section, and a plurality of cavity resonators arranged so as to amplify the microwave by the action of the electron beam. and a collector electrode for collecting the electron beam, the microwave output section including an output waveguide having a plurality of dielectric output windows having a vacuum-sealed structure. It is characterized by being configured.

An embodiment of the present invention will be described in detail below using the drawings.

FIG. 3 is a sectional view of an output cavity resonator including a microwave output section of a multi-cavity klystron which is an embodiment of the microwave tube device of the present invention. In the figure, 1 to 12 are the same as the conventional example,
13 is an alignment post.

The multi-cavity klystron, which is an embodiment of the present invention, is similar to the conventional example shown in FIG. An input cavity resonator 4, an intermediate cavity resonator 5, and an output cavity resonator 6 are arranged to amplify microwaves by the action of It has a structure in which collector electrodes 7 for collecting electron beams are sequentially connected using a drift tube 8.

The key point of the invention lies in the structure of the output cavity resonator including the microwave output section shown in FIG. That is, an H-plane T-branch type output waveguide 10 having two vacuum-sealed dielectric output windows 9 and a matching post 13 is connected to the output waveguide 10 through a coupling window 11 disposed at a position facing the tuner 12. and is coupled to the output cavity resonator 6.

The matching post 13 is the H-plane T-branched output waveguide 1
The microwave output extracted from the output cavity resonator 6 into the output waveguide 11 via the coupling window 11 is output from the two output windows 9. A matching element made of a small rod of oxygen-free copper, for example, is used for matching so that it can be taken out evenly to an external load. As the matching element, an inductive window may be used instead of the matching post.

The method for manufacturing the multi-cavity klystron, which is an embodiment of the present invention, is the same as the well-known prior art.

According to the embodiment of the present invention described above, one output waveguide 10 having two output windows 9 is used to extract the microwave output through one coupling window 11, so that the same Compared to the case where one output waveguide 10 having one output window 9 was individually taken out via two coupling windows 11 to extract the microwave output, the coupling window 11 and the output waveguide What used to be necessary to address two wave tubes 10 now only needs to be addressed to one. This prevents the space factor around the outer periphery of the output cavity resonator 6 from becoming worse, which has been a problem in the past.

Furthermore, in one embodiment of the present invention, the output waveguide 1
Since the coupling window 11 for coupling 0 is provided on the surface facing the tuner 12, that is, at a position corresponding to 180 degrees with respect to the center point of the cavity resonator 6, as previously described, it corresponds to 90 degrees. The distance between the tuner 12 and the coupling window 11 is maintained at a sufficient length compared to the case where the tuner 12 and the coupling window 11 are provided at This also prevents concerns such as deterioration of characteristics due to sudden changes in _E ) with respect to frequency and adverse effects due to generation of unnecessary resonance modes.

Although the above-mentioned embodiment has been explained in the case of a multi-cavity type klystron, it goes without saying that the present invention can also be applied to a straight beam type microwave tube device such as a microwave traveling wave tube.

As detailed above, the microwave tube device of the present invention has a structure in which one output waveguide has a plurality of output windows, which solves the problems conventionally associated with high-power microwave tube devices. This has the effect of preventing a decrease in the space factor around the outer circumference of the output cavity resonator, deterioration of characteristics due to sudden changes in the frequency of the external Q (Q _E ), and adverse effects due to the generation of unnecessary resonance modes.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the structure of a multi-cavity klystron, and FIGS. 2 and 3 are cross-sectional views of an output cavity resonator including a microwave output section of a conventional example and an embodiment of the present invention, respectively. . 1...Electron gun section, 2...Microwave input section, 3
...Microwave output section, 4...Input cavity resonator,
5... intermediate cavity resonator, 6... output cavity resonator,
7... Collector electrode, 8... Drift tube, 9...
Output window, 10... Output waveguide, 11... Coupling window,
12... Chuyuna, 13... Alignment post.

Claims (1)

[Claims] 1. An electron gun section 1 that generates an electron beam, and a plurality of cavity resonators 4 and 5 that include a microwave input section 2 and a microwave output section 3 and are arranged so as to amplify microwaves by the action of the electron beam. ,6
and a collector electrode 7 that collects the electron beam,
The microwave output section 3 includes one coupling window 11 provided in the output cavity resonator 6, and a coupling window 11 provided in the output cavity resonator 6.
an output waveguide 10 that guides microwaves emitted from the microwave, and the output waveguide 10 is equipped with a plurality of dielectric output windows 9 having a vacuum-sealed structure. .