JPH0256829A - Microwave tube - Google Patents

Abstract

PURPOSE:To make it possible to realize a stable dual mode operation by providing a beam forming electrode potential control circuit to control the potential of an electrode to form electron beams responding to the variation of a grid potential. CONSTITUTION:A beam forming electrode 3 controls the form of electron beams passing through a grid electrode 2 to inject to an anode 4 hole, and the anode 4 accelerates the electron beams and leads them to a high-frequency wave circuit 7. And a beam forming electrode potential control circuit 6 to control the potential of the beam forming electrode 3 responding to the potential of the grid electrode 2 is provided. The beam forming electrode potential control circuit 6 has a circuit to determine the potential of the beam forming electrode 3 to make the beam permeation to the potential of the grid electrode 2 obtained from a trial production and an experiment from the breaking of electron beams to the operation mode to make the beam current at the maximum, at an optimum value. Consequently, without providing a complex structure for a shielding grid or a water cooling, a stable electron beams suitable for the dual mode operation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a microwave tube, and more particularly to a microwave tube equipped with a drive circuit for grid potential and beam-forming electrode potential.

[Conventional technology]

A microwave tube consists of an electron gun section that injects and forms an electron beam, a high-frequency circuit section that interacts with the electron beam and amplifies high-frequency power, a collector section that captures the electron beam after interaction, and a collector section that keeps the electron beam focused. The main component is a focusing device.

In order to operate the microwave tube in pulses or perform two types of output operation (dual mode), a grid electrode 2 is usually installed in front of the cathode 1 as shown in FIG.
A method is adopted to control the radiation current emitted from the

In recent years, microwave tubes have been required to obtain high frequency power with high output and high efficiency.

For this reason, an electron beam with high current density is required, and dual mode operation is no exception.

Dual-mode electron gun electrode structures are typically designed for high-power operation. Therefore, under potential conditions other than the high output operating point, the trajectory of the electron beam from the cathode 1 will be greatly disturbed. If this turbulent electron beam directly enters the high frequency circuit 7, it will cause thermal problems and also affect the stability of the tube. To prevent this, a beam shaping electrode 5 is provided at the entrance of the high frequency circuit 7 to capture the disturbed electrons. The axial length of the beam shaping electrode 5 must be determined depending on the degree of beam disturbance. Further, depending on the magnitude of the current impinging on the beam shaping electrode 5, heat loss becomes a serious problem, and a cooling method such as water cooling may sometimes be required. This beam shaping electrode 5 causes the total length of the microwave tube to be increased, and cooling such as water cooling complicates the structure of the entire tube.

[Problem to be solved by the invention]

The design of a dual-mode microwave tube grid-equipped electron gun involves determining operating conditions such as beam acceleration voltage, beam current, and grid voltage based on high-power operation, and then determining the shape of each electrode. It's normal. Normal dual mode operation is realized by changing the potential between the cathode and the grid electrode and changing the current from the cathode.

Therefore, in operating conditions other than the operating point set as a reference at the time of design, electron trajectories are disturbed by the electrostatic lens formed between the cathode and the grid electrode. This disturbance in the electron trajectory causes a thermal problem when it collides with the body electrode near the entrance of the high-frequency circuit and the high-frequency circuit, and furthermore, it has the drawback of greatly affecting the stability of the tube.

An object of the present invention is to provide a microwave tube that can realize stable dual-mode operation.

[Means to solve the problem]

The present invention provides a microwave tube including a grid-equipped electron gun, a high-frequency circuit, a collector, and an electron beam focusing device, in which electrodes are used to form an electron beam in response to changes in grid potential. It is configured to include a beam forming electrode potential control circuit that controls the potential.

〔Example〕

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

FIG. 1 is a sectional view of a first embodiment of the invention.

In the first embodiment, as shown in FIG. 1, the cathode 1 is
Electrons are emitted due to the potential difference with the grid electrode 2. The grid electrode 2 controls the amount of electron emission from the cathode 1 by its potential. The beam forming electrode 3 controls the shape of the electron beam that has passed through the grid electrode 2 so that it is incident on the aperture of the anode 4 . The anode 4 accelerates the electron beam and introduces it into the high frequency circuit 7. Then, depending on the potential of the grid electrode 2, beam formation and electric '! It has a beam forming electrode potential control circuit 6 that controls the potential of fA,3.

Beam-forming electrode potential control (beam forming electrode potential control)
It has a circuit that determines the potential of the beam forming electrode 3 at which beam transmission is optimal with respect to the potential of the grid electrode 2 obtained from experiments and the like.

According to this method, there is provided an electron gun with a grid that can prevent large disturbances in electron trajectories between the potentials from cutting off the electron beam from the cathode 1 to the operating point and obtain a stable electron beam even during dual mode operation. can.

In the second embodiment, a programmable device such as a microcomputer is used as the beam forming electrode potential control circuit 6 that controls the potential of the beam forming electrode 3. The beam forming electrode potential control circuit 6 has a program for controlling the potential of the beam forming electrode 3 so as to minimize the body current while monitoring the body current caused by the disturbed electrons.

This embodiment has the advantage that it can be used in common with a microwave tube equipped with a grating electron gun having similar specifications, since the built-in program allows fine adjustment of the beam shape, beam diameter, and beam current.

〔Effect of the invention〕

As explained above, the present invention has a beam-forming electrode potential control circuit that changes the potential of the beam-forming electrode according to changes in the grid electrode potential, thereby reducing the complicated structure for flexible grids and water cooling. This has the effect of making it possible to obtain a stable electron beam suitable for dual-mode operation without having to hold the electron beam.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electron gun with a grid for a microwave tube according to a first embodiment of the present invention, and FIG. 2 is a sectional view of an example of a conventional electron gun with a grid for a microwave tube. DESCRIPTION OF SYMBOLS 1... Cathode, 2... Grid electrode, 3... Beam forming electrode, 4... Anode, 5... Beam shaping electrode, 6... Beam forming electrode potential control circuit, 7... High frequency circuit.

Claims (1)

[Claims] In a microwave tube configured with an electron gun with a grid, a high-frequency circuit, a collector, and an electron beam focusing device, the potential of an electrode for forming an electron beam is controlled in response to changes in the grid potential. A microwave tube comprising a beam forming electrode potential control circuit.