JPH04245143A - Traveling wave tube - Google Patents

Abstract

PURPOSE:To realize the downsizing of structural dimension of a circuit and obtain a traveling wave tube capable of carrying out stable operation. CONSTITUTION:A traveling wave tube is constituted in such a way that a slow- wave circuit is constituted of a strip line so as to be on dielectric substrate; a cathode 2, an anode 3 and a collector 5 are also formed on the same substrate; its upper part is sealed up airtightly by means of a metallic cap; and all lead wires are taken out from the rear surface of the substrate through holes which are arranged on the dielectric substrate 1 and are capable of being sealed up airtightly.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to traveling wave tubes, and in particular, a slow wave circuit is formed on a dielectric substrate using strip lines, and the cathode, anode, and collector are also formed on the dielectric substrate to achieve miniaturization. Concerning traveling wave tubes.

0002

[Prior Art] As shown in the schematic cross-sectional view of FIG. 3, a conventional helix-type traveling wave tube has a circular heater 21, a cathode 22, an anode 23, and a helix made of tungsten, etc., formed in a cylindrical tube. A slow wave circuit 24, a collector 25, and a magnet (not shown) are arranged around it. With this configuration, electrons are emitted from the cathode 22 and sent through the slow wave circuit 24, and when microwaves are supplied from the input section 26 of the slow wave circuit 24, the microwaves are amplified by interaction with the electron flow and output from the slow wave circuit 24. It is taken out from section 27.

[0003]Recently, with the increasing precision of radars, etc., the microwaves used are required to have higher frequencies.As the frequencies become higher, the wavelengths become shorter, and each circuit structure also needs to be made smaller. There is a demand for compact devices for high frequencies. For this reason, the slow-wave circuits such as helices need to be extremely small, but it has become difficult to accurately manufacture small helices from hard materials like tungsten using conventional machining techniques.

0004

[Problems to be Solved by the Invention] In the traveling wave tube of the conventional structure, the reduction in the structural dimensions of the circuit has reached its limit from the viewpoint of machining technology, and it is no longer possible to increase the operating frequency. There is.

[0005]

[Means for Solving the Problems] The present invention has been made in view of the above circumstances, and consists of a slow wave circuit formed by strip lines on a dielectric substrate, and a cathode, an anode, and a collector also formed on the same dielectric substrate. At the same time, the upper part thereof is hermetically sealed with a metal lid, and each lead wire can be taken out from the back surface of the substrate through a through hole that can be hermetically sealed provided in the dielectric substrate.

[0006]

[Operation] Since the structure is configured so that electrons can travel through the space immediately above the slow wave circuit formed by strip lines on the dielectric substrate, the microwaves supplied to the slow wave circuit are similar to conventional traveling wave tubes. The interaction between the electron flow and the electron flow results in the amplification of microwaves.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a traveling wave tube which is an embodiment of the present invention, and FIG. 2 is a sectional view taken along line AA in FIG. In the figure 1
is a dielectric substrate, and 2, 3, 4, and 5 are dielectric substrates 1, respectively.
A cathode, an anode, a slow wave circuit, and a collector 6 arranged on the surface of the dielectric substrate 1 are covered with a lid part 7 and 8 that surrounds the cathode 2, an anode 3, a slow wave circuit 4, and a collector 5 and hermetically seals them. , 11 are electrode leads that communicate with the cathode 2, anode 3, and collector 5, respectively, and are led out through through holes provided in the dielectric substrate 1. This through hole is hermetically sealed together with the electrode lead by brazing or glass sealing. Reference numerals 9 and 10 are a high frequency input terminal and a high frequency output terminal to the slow wave circuit 4, respectively, which are similarly led out through through holes provided in the dielectric substrate 1, and these through holes are also hermetically sealed. Reference numeral 12 indicates a radio wave absorber attached to the inner surface of the lid portion 6, and reference numeral 13 indicates a metal coating attached to a portion other than the through-hole portion on the back surface of the dielectric substrate.

In this embodiment, a field emission type cathode 2 made of, for example, a semiconductor material is formed on the surface of a dielectric substrate 1 so that electrons can travel over a slow wave circuit 4 formed on the dielectric substrate 1. However, as shown in the figure, the anode 3 is also formed of a hollow thin piece so as not to affect electron travel. The slow wave circuit 4 is formed as a microstrip line in a zigzag shape as shown in the figure on the surface of the dielectric substrate 1, and one end thereof is connected to the high frequency input terminal 9 through a through hole provided in the dielectric substrate 1. The other end is connected to the high frequency output terminal 10.

The collector 5 captures electrons emitted from the cathode 2, and is disposed on the dielectric substrate 1 at a position higher than the electron travel portion, that is, the surface of the dielectric substrate 1 by more than the thickness of the strip line. With this structure, each electrode lead and the lid part 6
A traveling wave tube is constructed by hermetically sealing the tube and evacuating the inside using an exhaust pipe (not shown).

In this state, if an electron focusing magnet or the like is placed around the cathode electrode 2 and an electric potential difference is applied between the cathode electrode 2 and the anode electrode 3, an electron beam is emitted from the cathode electrode 2. The emitted electron beam travels on a slow wave circuit 4 consisting of a pattern. The microwave input from the high-frequency input section 9 interacts with the electron beam traveling on the slow-wave circuit 4 in the slow-wave circuit 4, undergoes density modulation, and is amplified and output from the high-frequency output section 10.

On the other hand, the electron beam passing through the slow wave circuit 4 is captured by the collector 5, and operates in the same manner as a conventional traveling wave tube. Furthermore, if a radio wave absorber 12 such as carbon is attached to the inner surface of the lid part 6, electrons that have strayed from the traveling path can be
It can absorb unnecessary mode radio waves generated in space and maintain normal operation of the traveling wave tube.

0012

[Effects of the Invention] As explained above, according to the present invention,
Even if the operating frequency is increased compared to the conventional structure and the structure is made very small, it can be easily formed with high precision, and a traveling wave tube with good performance can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a traveling wave tube that is an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG. 1;

FIG. 3 is a schematic diagram showing the structure of a conventional traveling wave tube.

[Explanation of symbols]

1 Dielectric substrate 2 Cathode 3 Anode 4 Slow wave circuit 5 Collector 6 Lid part 7, 8, 11 Electrode lead 9 High frequency input terminal 10 High frequency output terminal 12 Radio wave absorber 13 Metal coating

Claims (2)

[Claims] [Claim 1] A cathode disposed on the surface of a dielectric substrate;
an anode disposed on the surface of the dielectric substrate and applying an electric field necessary for electron emission to the cathode; a slow wave circuit formed in a zigzag pattern with strip lines on the surface of the dielectric substrate; A collector for capturing electrons passing over the slow wave circuit, and a collector formed in the dielectric substrate so as to penetrate the cathode, anode, the slow wave circuit, the electrode of the collector or the input/output lead and hermetically seal it. a through-hole portion provided in the dielectric substrate, a metal coating adhered to a portion other than the through-hole portion on the back side of the dielectric substrate, and a metal coating surrounding the cathode, anode, slow wave circuit, and collector on the surface of the dielectric substrate. Consists of a hermetically sealed lid,
A traveling wave tube characterized in that a space surrounded by the lid and the dielectric substrate is evacuated. 2. The traveling wave tube according to claim 1, wherein a radio wave absorber is attached to the inner surface of the lid.