JPS62119836A - Magnetron - Google Patents

Abstract

PURPOSE:To prevent a specific needless radiation wave from being radiated outside from an antenna, by providing a needless-radiation suppressor, which is coaxially fitted to an output antenna conductor and composed of a dielectric resonator and a metal wall covering its surface. CONSTITUTION:An output antenna conductor 9, whose one end is fixed on a vane 3 of an anode cylinder 1 in a magnetron, is arranged extending in an airtight space 8 comprising a sealed metal unit 5, an insulating cylinder 6, and a metal cap 7. Besides, a needless-radiation suppressor 11, which is composed of a columnar dielectric resonator 12 made of ceramics and a metal wall 13 covering its surface in the axial direction, is fixed with the antenna conductor 9 for insertion. Then, it is arranged to be situated in a coaxial propagation path structure composed of the antenna conductor 9 and a sealed metal unit 5 encircling the conductor coaxially. Therefore, needless radiation can be suppressed with good precision, by forming the dielectric resonator 12 in dimensions in which it is resonated with a specific needless-radiation wave.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Application The present invention relates to magnetrons, and is particularly directed to techniques for suppressing unnecessary radiation thereof.

(b) Conventional technology In general, microwaves emitted from a magnetron include many high-level i1IrIIL waves such as second, third, and first waves in addition to the fundamental wave.
8 ri are included, and those are unnecessary radiation.

Recently, unnecessary radiation corresponding to the fifth harmonic wave has become particularly prevalent.

SL4F) It is viewed as a problem because it is similar to the 12GH2 band of 47191 Star Broadcasting.

Conventionally, as an unnecessary four-shot suppression technology for magnetrons, for example, as seen in Japanese Patent Publication No. 57-6781,
It has been proposed to provide a choke cavity in the antenna conductor, but it is difficult to create a choke cavity with accurate dimensions, so there is still room for improvement in achieving good suppression of unwanted radiation. be.

(c) Problems to be Solved by the Invention The present invention provides a technology that allows a more accurate unnecessary radiation suppression effect to be obtained with a simpler structure.

(d) Companion means for solving the problems The magnetron of the present invention includes an output antenna conductor extending in an airtight space, and the above-mentioned airtight space. ! ! Supplement the unnecessary radiation suppressor arranged in all questions, and add a dielectric resonator attached to the output antenna conductor to the unnecessary radiation suppressor and the direction in which the output antenna conductor of the resonator extends. It consists of a metal wall with parallel surfaces.

Unexploded rye VCX-, the unnecessary radiation suppressor is installed in a coaxial structure formed by the Deba antenna conductor and a sealing metal body that axially surrounds the entire Deba antenna conductor to form the airtight space. Furthermore, in the third aspect of the present invention, the dielectric resonator is preferably formed of alumina.

(E) Function According to the present invention, a remarkable band-reflection effect appears due to the combination of the dielectric resonator and its surface tcIk alloy JIA wall, and therefore the resonance dimensions of the dielectric resonator are set appropriately. As a result, it is possible to effectively suppress specific unnecessary radiation waves from being radiated to the outside from the antenna.

(to) Yi power FIG. 1 shows a magnetron according to an embodiment of the present invention.

(IJ is an anode cylindrical body, (2) is a cathode body installed on the central axis of the cylinder, (3) (3J... is an anode cylindrical body (1
) are solidly layered on the inner surface of the cathode body (2), and are arranged radially around the cathode body (2), with the number of ea anode vanes;
Z) It is a pole piece fixed to one open gee.

(5 bar 6) and (7).

The sealing metal body, the insulating cylinder, and the first metal cap, which are stacked and fixed in sequence on the pole piece (4), respectively, form an airtight space (8) that communicates only with the inside of the anode cylinder iII. (9) is fixed at one end to the anode vane (3), extends VF- inside the airtight space (8) after 7, and has the other end fixed to the metal cap (41).
7), the output antenna conductor f+ is fixedly supported on the QG, and the first
Once it is put on the metal cap (7), it becomes a second metal cap. still,
The above configuration itself is well known.

The end is an unnecessary radiation suppressor that exists as a feature of the embodiment of the present invention, and is located in an airtight space (8).

In FIG. 2c, the unnecessary radiation suppressor συ is shown in detail.

tta is the above output antenna conductor +9)ic (111 passed through the cylindrical dielectric resonator made of ceramics, (1
3 is a metal wall whose surface is parallel to the insertion direction.

The best way to fix the conductor (9) is by press-fitting or soldering. The non-resonator u4 has a dimension that resonates with a specific unnecessary radiation wave, and the resonator α4 and the metal wall 04 are connected to the output antenna conductor (9) t-of the microwaves propagating.
A remarkable reflection phenomenon'(i-
% thin.

To explain this reflection phenomenon, the unnecessary radiation suppressor (11
is a coaxial propagation path structure product VC made by a Deba antenna conductor (9) and a sealing metal body (5) that axially surrounds this conductor.
Three types of coaxial propagation paths were prepared as equivalent experimental structures as shown in FIG. 6A, B, and C. In each propagation path, (9a) is the center! Rhinoceros, (!l
) is a cylindrical external conductor provided coaxially with this central conductor, (12a) is inserted into the central conductor (9a) and is a columnar m electric resonator, (13a) rl, resonator (12al),
It is a metal wall whose surface parallel to its extension direction is metallized. Due to the difference in each propagation path, as is clear from the cause, the inner diameter of the outer conductor (5a) 'tD i 1m11L
If the outer diameter of the kx device (12&) is 2di, then in the case of Fig. 3A, dl<L)t, and in the case of Fig. 6B, dz=Dz.

In the case of FIG. 3C, the point is dl (D3) and the metal wall (16a) is present.

Now %D1=, Dz-Da=17sw, dt=sd3-6
1, and Jt body resonance 6 (125L) i 5th harmonic rBL
(12,25GHz) Resonator, resonator (121
L) t-alumina ceramics (AI!203.εr
long) t 4.1 layer and next. Since the resonator (1211) is formed from a ceramic mold, its dimensional accuracy is important.

That is, the resonant frequency and ff screen can be easily increased.

M4 Diagrams A and B%C show the transmission characteristics of each propagation path in Figure 3 A%B and C, and from this figure, it can be seen that the Co propagation path in Figure 3 has the fifth harmonic (12 25 GHz).

Now,! When the coaxial propagation path structure including the unnecessary radiation suppressor αυ in Fig. 1 vc is set to the same conditions as the propagation path in Fig. 3 C, magnet) ont* is incorporated into the child microwave oven.

The results of measurement of unnecessary radiation emitted from such a microwave oven based on the @Cl5PR standard are shown in concentrated lines in FIG. In Figure K5, the dashed line indicates unnecessary radiation suppression 1f shown in Figure 1.
A magnetron with only 1J% 1M removed and all other conditions the same as in the $1 diagram was installed in the same microwave oven as above, and the same side legs were used to show the following results. #I5 shows the effect of suppressing unnecessary four shots in the magnetron VC of this embodiment. still.

In the magnetron of this example, a t suppression effect appears for the Takaku high 11 & above the 5th high vIA wave.The reason for this is not clear, but based on the characteristics shown in Fig. 4C, the t suppression effect appears. This seems to be related to the phenomenon in which a considerable reflection effect appears even in the frequency range of the fifth harmonic or higher.

FIG. 6 shows an example of a modification of the unnecessary radiation suppressing fllJ body μυ.

In this case, gold I made of metal cylinder instead of metallization
! A dielectric resonance 611'4 is press-fitted into the fourth wall 0.

If both ends of the metal wall u3 are slightly protruded from both ends of the resonance 4α4 as shown in the figure t1, radiation from both ends of the resonance aUa can be prevented.

Figure 7 rc, i$611! A further modified example of g is shown. In this case, # area body resonators (120) (121) having different resonance frequencies are press-fitted into the metal cylindrical wall tta+, thereby suppressing the plurality of high iI4 waves. It has gained.

In the embodiment shown in Fig. 1 as well, individual dielectric components having different resonance frequencies are prepared, and each of these dielectric components is attached with a metal MV attached to the output antenna conductor (9). As a result, the effect of suppressing a plurality of high frequency tlLVc can be obtained.

In each of the above embodiments, as the material for the dielectric resonator, other materials such as barium titanate can be used in addition to alumina.
Alumina is the most suitable material for creating a resonator @t% that can be accommodated with sufficient margin.

In the example 5A above, the unnecessary radiation suppressor αD is a sealing metal (5J and output antenna conductor (9), J coaxial #!a
However, even if the output antenna is installed in an airtight space (other areas of 8J), it will still significantly suppress unnecessary radiation (9).
J-Kara occurs.

(G) Effects of the Invention According to the magnetron of the present invention, effective suppression of unnecessary radiation is achieved by the combination of a dielectric resonator and a metal wall with a ridge on its surface. Each member refines its dimensions, and the resonant device is enhanced, so that it can be used once.
Add unnecessary radiation suppression t%.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a perspective view of the same part, and FIG. 6 is a sectional view showing the Fuken II structure. ! Figure 4: Characteristic curve diagram showing the measurement results of μ-oriented real mirror; Figure 5: σ
FIG. 6 and FIG. 7 are cross-sectional views of main parts showing different embodiments of the present invention. (5)...Sealing metal body, (8)...Airtight space, (
9) -...4 output antennas, liυ...unwanted radiation suppressor, α4...dielectric resonator, tlal...metal wall. Defu Sanyo Electric Co., Ltd.

Claims (3)

[Claims] (1) An output antenna conductor extending in an airtight space and an unnecessary radiation suppressor disposed in the airtight space, the unnecessary radiation suppressor including a dielectric resonator attached to the output antenna conductor. A magnetron comprising: a metal wall covering a surface of the resonator parallel to the extending direction of the output antenna conductor. (2) In claim 1, the unnecessary radiation is suppressed in a coaxial structure formed by the output antenna conductor and a sealing metal body that coaxially surrounds the output antenna conductor to form the airtight space. A magnetron characterized by having a body. (3) The magnetron according to claim 1 or 2, wherein the dielectric resonator is made of alumina.