JPH0538524Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a magnetron output circuit which couples microwaves generated by a magnetron to a waveguide by the output antenna of the magnetron and transmits them through the waveguide, and in particular to a filter which suppresses the output of unnecessary frequency components of the microwaves generated by the magnetron in said circuit.

[Conventional technology]

Two types of filters have been used in conventional magnetron output circuits.

One is a type called a band pass filter as shown in FIG. 3, and the other is a type called a band rejection filter as shown in FIG.

1 is a waveguide, 2 is an output antenna of the magnetron, and the one shown in Fig. 3 selects the diameters of metal rods 5 and 6 and the spacing between them to allow only the radio waves of the necessary frequency to pass through, and to pass the other radio waves. It is designed to block frequency components.

In the device shown in FIG. 4, the spacing between the stubs 7 is selected to block only radio waves of a specific frequency while allowing other frequency components to pass.

[The problem that the idea aims to solve]

In recent years, there has been a strong demand for smaller devices and higher output power in radars and other equipment, but conventional filters with the structure shown in Figure 3 have long waveguides, making it difficult to miniaturize. However, the filter having the structure shown in FIG. 4 has a problem in that it has a low power resistance and is disadvantageous in achieving high output.

The present invention was made to solve the above problems, and aims to provide a filter having a structure that has good power durability and is advantageous for downsizing.

[Means to solve the problem]

In the magnetron output circuit of the present invention, the filter is provided with a cavity near the output antenna in a waveguide to which microwaves oscillated by the magnetron are coupled by the output antenna, and the magnetron oscillates within the cavity. It is constructed by attaching a metal screw with a length that is approximately 1/4 of the wavelength of the frequency component of the microwave whose output is to be suppressed.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 and 2 indicate the same or equivalent parts as the same reference numerals in FIGS. 3 and 4, 3 is a cylindrical cavity, and 4 is a metal screw installed in the cavity 3.

The length l of the metal screw 4 is approximately 1/4 of the wavelength λ of the frequency component whose output is to be suppressed.

By changing the length l of this metal screw 4, it is possible to select the frequency component whose output is to be suppressed.

FIG. 2 shows another embodiment of the invention.

In this example, the metal screw 4 is installed perpendicularly to the center axis of the cylindrical cavity 3, and the installation direction of the metal screw 4 is the first direction.
The present invention is not limited to the examples shown in FIGS.

Furthermore, the number of metal screws 4 is not limited to one, and multiple metal screws 4 may be installed. By installing multiple metal screws 4 with different lengths l, the output of multiple components with different frequencies can be suppressed. You can also do that.

The main frequency component of the microwave oscillated by the magnetron is coupled to the waveguide 1 by the output antenna 2 and output through the waveguide 1. However, in the present invention, a cavity 3 is provided in the waveguide 1. By installing a metal screw 4 in this cavity 3, the distance between the output antenna 2 and the metal screw 4 is made equal to or wider than the distance between the output antenna 2 and the wall of the waveguide 1, so that the microwave electric field is It does not become particularly strong, and no microwave discharge occurs in this part.

Further, with the above structure, the metal screw 4 can be attached near the output antenna 2, and there is no need to lengthen the waveguide 1, which is advantageous for miniaturization.

[Effect of idea]

As explained above, according to the present invention, it is possible to obtain an output circuit that has good power durability and has the effect of suppressing the output of unnecessary frequency components with a short coupling waveguide. This has a large effect in contributing to miniaturization.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figures are explanatory diagrams showing other embodiments of the present invention, FIG.
FIG. 4 is an explanatory diagram showing an example of the structure of a filter in a conventional magnetron output circuit. 1...Waveguide, 2...Output antenna, 3...Cavity, 4...Metal screw, 5...Metal rod, 6...Metal rod, 7...Stub. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a magnetron output circuit that couples microwaves oscillated by a magnetron to a waveguide by an output antenna of the magnetron and outputs the waves through the waveguide, a cavity is provided in the waveguide near the output antenna of the magnetron. , characterized by comprising a band rejection filter configured by installing a metal screw having a length of about 1/4 of the wavelength of the frequency component whose output is to be suppressed in the microwave oscillated by the magnetron in the cavity. magnetron output circuit.