JPH0477414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a magnetron, and particularly to a miniaturized pulsed magnetron for laser use.

(Prior art) For example, pulsed magnetrons used in small ship radars, etc., have recently used cylindrical permanent magnets instead of conventional horseshoe-shaped permanent magnets and are constructed with internal magnetic circuits, making the entire magnetron smaller. It is possible to do so. An example of this is, for example,
Publication No. 79956 is shown.

(Problems to be Solved by the Invention) Although the magnetron disclosed in the above publication can be made relatively compact, the structure is still complex.
There is also room for further miniaturization. In particular, it is necessary to simplify the structure of the output section.

The present invention has been made in view of the above-mentioned circumstances, and in particular provides a magnetron that can simplify the structure of the output section and further downsize.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an output antenna of a rectangular waveguide in which the tips of the output antenna of the oscillation part main body are layered to form a coaxial waveguide conversion part. This is a magnetron in which a through hole is formed in the waveguide wall whose tip ends face each other, and a ferromagnetic yoke plate is closely attached to cover the waveguide from the outside and close the through hole.

(Function) According to the present invention, the through hole formed in the waveguide wall facing the output antenna tip becomes substantially a cavity in the waveguide, and the distance between the output antenna tip and the waveguide wall is set at a high frequency. A distance sufficient to prevent discharge can be secured, and the dimensions of the output portion in the antenna axis direction can be reduced accordingly. Therefore, a small magnetron can be obtained with a relatively simple structure.

(Example) An example will be described below with reference to the drawings. Note that the same parts are represented by the same symbols.

A radar pulse magnetron to which this invention is applied has a structure shown in FIGS. 1 to 4. In the figure, reference numeral 11 represents the oscillating unit main body, which has a pair of cup-shaped pole pieces 13, 13 made of ferromagnetic material fixed to both open ends of the outer anode cylinder 12, and further inside thereof. An electron emitting cathode and a plurality of anode vanes forming a resonant cavity are arranged. The oscillating unit main body 11 has a cathode input section 14 at one end, a metal exhaust pipe 15 at the other end, and a coaxial output antenna 16 connected to a part of the side wall of the anode cylinder. This coaxial output antenna 16 is
A waveguide connecting ring 17 is fixed to the tip of the outer conductor, and an output dielectric 18 made of a ceramic cylinder is hermetically sealed to the tip. Further, the tip of the center conductor 19 is hermetically sealed to the outer end surface of the output dielectric 18 via the conductor disk 20. A rectangular waveguide 21 is arranged so that the tip of the antenna is inserted into the rectangular waveguide 21. This waveguide 21 is integrally formed with a flat base 22 made of aluminum by die casting. Moreover, this waveguide 21 has a short-circuiting surface 23, and the waveguide internal cavity is continuous to the front surface of the flat base 22 and continues to the opening 24, and an antenna insertion hole formed at the bottom of the waveguide 21 is connected to the opening 24. A connecting ring 17 is electrically short-circuited to the hole 25 .

Therefore, a through hole 26 having a diameter larger than the diameter of the antenna tip is bored in the waveguide wall of the waveguide 21 at a position opposite to the antenna tip.

The inner magnetic poles of a pair of cylindrical permanent magnets 27, 27 are magnetically connected to the pole piece 13 of the oscillating unit main body 11 via ferromagnetic shim plates 28, 28. Opposing end surfaces of a U-shaped ferromagnetic yoke plate 29 are magnetically connected to the outer magnetic poles of the magnets 27 , 27 . This yoke plate 29 is also electrically short-circuited via a conductive gasket 31 having a spring property so that its central portion 30 covers and closes the outer surface of the waveguide 21, that is, the through hole 26. There is. This closes the internal cavity of the waveguide. An alignment screw 32 is screwed into the center portion 30 of the yoke plate from the outside so as to protrude into the center of the through hole 26 of the waveguide. In this way, the oscillating unit main body 11, the permanent magnet 27, and the yoke plate 29 are mechanically fixed to the flat base 22 and the waveguide 21, which are integrally formed.

In addition, the reference numeral 33 in the figure represents a fixing hole formed in the flat base, and the reference numeral 34 represents an insulating bushing. Protruding length. At this time, the through hole formed in the waveguide wall increases the distance between the antenna tip and the inner surface of the yoke plate, which becomes substantially a part of the waveguide, making it difficult for high-frequency discharge to occur. Therefore, the axial dimension of the antenna can be reduced accordingly. Note that the high frequency matching between the antenna tip and the rectangular waveguide that constitute the coaxial waveguide converter can be finely adjusted using the screw 32, and in that case, the screw must be screwed into the yoke plate located on the outside. Therefore, the configuration of this output section can be simplified.

[Effects of the Invention] As explained above, according to the present invention, the through hole bored in the waveguide wall facing the output antenna tip and the yoke plate surface covering the through hole are substantially formed in the cavity in the waveguide. , the distance between the inner walls of the waveguide in the direction along the axis increases. This means that the distance between the output antenna tip and the waveguide wall is sufficient to prevent high-frequency discharge, and as a result, the output antenna tip can be inserted deeply into the waveguide. Therefore, the dimension of the output section in the antenna axis direction can be reduced accordingly. Therefore, a small magnetron can be obtained with a relatively simple structure.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part showing an embodiment of the present invention, FIG. 2 is a top view thereof, and FIG. 3 is a rear view thereof.
FIG. 4 is a perspective view of the main part. DESCRIPTION OF SYMBOLS 11... Oscillator main body, 16... Output antenna part, 21... Rectangular waveguide, 22... Flat base,
26...Through hole, 27...Permanent magnet, 29...Yoke plate.

Claims (1)

[Claims] 1. An oscillating unit main body that includes a cathode, a radial vane, and a pair of pole pieces, and has a coaxial output antenna protruding from the side wall of an anode cylinder, and a tip of the output antenna of the oscillating unit main body. a rectangular waveguide that is inserted to form a coaxial waveguide converter; a pair of cylindrical permanent magnets that are magnetically connected to the pole piece; A magnetron comprising a ferromagnetic yoke plate disposed surrounding the outside and fixed in mechanical contact with a part of the waveguide, wherein the output antenna tips of the waveguide face each other. A magnetron characterized in that a through hole is formed in a waveguide wall, and the yoke plate is closely attached to cover the waveguide from the outside and close the through hole.