JPH0660819A - Millimeter wave band connecting cavity type traveling wave tube - Google Patents

Abstract

PURPOSE:To provide a millimeter wave band connecting cavity type traveling wave tube without either oscillation in a noncontinuous portion in a 2pi mode and a high impedance region from a 2pi mode to an operating frequency, or a characteristic change in the operating frequency. CONSTITUTION:In a millimeter wave band connecting cavity type traveling wave tube, loss members 2, 2', 3, 3' for restraining oscillation in the vicinity of a 2pi mode and a 2pi mode frequency are made of materials having various SiC component ratios inside of a cavity 1. Consequently, it is possible to restrain oscillation of a tubular bulb so as to restrain a loss quantity in an operating band, thus providing a stable millimeter wave band connecting cavity type traveling wave tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a millimeter wave band coupled cavity type traveling wave tube, and more particularly to a cavity structure constituting a high frequency circuit section.

[0002]

2. Description of the Related Art The cavity structure of a high frequency circuit of a conventional millimeter wave band coupled cavity type traveling wave tube has a cavity 1 as shown in the sectional views of FIGS. 2 (a) and 2 (b). In order to suppress the oscillation in the 2π mode, a loss body 2 having microwave absorption characteristics at a frequency in the 2π mode and a loss body 3 for preventing oscillation in a high impedance region between the 2π mode frequency and the operating frequency are provided. Had been placed.

[0003]

The cavity structure of the conventional coupled cavity type traveling wave tube described above has a frequency of 2π mode and a frequency of 2π mode.
2 with absorption characteristics between π mode frequency and operating frequency
Oscillation was suppressed by arranging different types of loss bodies, but in the millimeter-wave region, where demand is increasing in recent years, component dimensions become extremely small, and variations in dimensional accuracy cause loss bodies to absorb a given frequency. However, there is a problem in that the amount of loss increases in the operating band and the predetermined electrical characteristics cannot be obtained.

[0004]

SUMMARY OF THE INVENTION The present invention ends the interaction between an electron gun section that emits and forms an electron beam, a high-frequency circuit section that amplifies a microwave by the interaction with the electron beam, and the microwave. In a millimeter wave band coupled cavity type traveling wave tube having a focusing device section for focusing an electron beam to a constant diameter, a frequency of 2π mode and a high impedance near 2π mode are provided in a cavity forming a high frequency circuit section. Loss bodies having different SiC component ratios are arranged as the loss bodies for suppressing the oscillation caused by the discontinuity of the coupling impedance in the frequency domain.

[0005]

The present invention will be described below with reference to the drawings. 1 (a) and 1 (b) are cross-sectional views showing a cavity structure of a high frequency circuit section according to an embodiment of the present invention. As shown in the figure, a loss body 2 for preventing 2π mode oscillation and a loss body 3 for preventing oscillation in a high impedance region between the 2π mode frequency and the operating frequency are arranged in a cavity 1 forming a high frequency circuit section. The microwave absorbing loss body is made of a material such as MgO-SiC or BeO-SiC having good thermal conductivity, and the SiC component ratio of this loss body is 5 ± 0 depending on the cavity 1 alone. It is changed so as to obtain the absorption characteristic within a predetermined range number within the range of 0.5% and 2 ± 0.3%. For example, the loss body 2 shown in the figure has a SiC component ratio of 5%, and the loss body 2 '
Is 5.1%, the loss body 3 is 2%, and the loss body 3'is 1.9%. This makes it possible to correct a change in absorption characteristics due to variations in the dimensional accuracy of the cavity 1, suppress oscillation, and provide a stable millimeter-wave band coupled cavity traveling wave tube.

[0006]

As described above, according to the present invention, the SiC component ratio of the loss body for suppressing the oscillation generated in the high impedance region between the 2π mode frequency and the 2π mode to the operating frequency is changed, and the cavity size is changed. By correcting the absorption characteristics due to variations in accuracy, it is possible to suppress oscillation and suppress the loss amount in the operating band, and obtain a stable millimeter wave band coupled cavity type traveling wave tube.

[Brief description of drawings]

1A and 1B are cross-sectional views of a cavity according to an embodiment of the present invention.

2 (a) and 2 (b) are cross-sectional views of an example of a cavity of a conventional coupled cavity type traveling wave tube.

[Explanation of symbols]

 1 Cavity 2,2 ', 3,3' Loss body

Claims (1)

[Claims] 1. An electron gun section that emits and forms an electron beam, a high-frequency circuit section that amplifies a microwave by the interaction of the electron beam, and an electron beam that has completed the interaction of the microwave. In a millimeter wave band coupled cavity type traveling wave tube having a collector section and a focusing device for focusing the electron beam to a constant diameter, in a cavity of the high frequency circuit section in a high impedance frequency region near a 2π mode. 2. A millimeter wave band coupled cavity type traveling wave tube, wherein loss bodies having different SiC component ratios are arranged to suppress oscillation caused by the discontinuity of the coupling impedance.