JPH0224937A - Magnetron device - Google Patents

Abstract

PURPOSE:To have optimum impedance matching of a magnetron of a short output end type with a waveguide pipe in conventional dimensions by specifying the distance of the center axis of the output end from a short plate of waveguide pipe, and arranging an impedance matching stab within waveguide pipe leading from the output end to the load side. CONSTITUTION:The distance of the center axis of an output end 2 from a short plate 3 of a waveguide pipe 4 is set to 0.1-0.2lambda (lambda is fundamental wavelength of oscillated microwave). An impedance matching stab 15 is arranged in the waveguide pipe 4 leading from the output end 3 to the load side. This provides optimum impedance matching owing to reflecting action by the short plate and stab even though a magnetron of short output end type is used in combination with a waveguide pipe is conventional dimensions, and common use of waveguide pipe or interchangeability of magnetron is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a short output end type in which the protrusion length of the output end is set to 0.18λ or less, where λ is the fundamental wavelength of the oscillated microwave. The present invention relates to a magnetron device comprising a magnetron and a prismatic cylindrical waveguide probe-coupled to the output end.

2. Description of the Related Art In general, a magnetron device used in a microwave oven or the like is constructed as shown in FIG. It protrudes into the cylindrical waveguide 4, and thus the magnetron 1 and the waveguide 4 are probe-coupled. A pair of upper and lower permanent magnets 5a and 5b, which are magnetically coupled to the magnetic pole pieces of the magnetron 1, constitute an external magnetic circuit for the magnetron 1 together with a frame-shaped yoke 6, and are attached to the frame-shaped yoke 6. The shield case 7 has a through-type capacitor 8 attached to its side wall. A choke coil (not shown) connected between the cathode terminal of the magnetron 1 and the capacitor 8 constitutes an LC filter circuit together with the capacitor 8.

The protrusion length A of the output end portion 2 is approximately λ/4, or approximately 0.2λ to 0.3λ, where λ is the base water wave wavelength of the oscillated microwave.
The inner dimension W in the width direction and the inner dimension in the height direction of the waveguide 4 are W=0.57λ to 0.78λ,
It is set to h>0.22λ. Further, the distance d from the central axis of the output end 2 to the short plate 3 is d>0.5
It is set to λ.

A magnetron device manufactured based on such design standards can obtain optimal impedance matching between the magnetron 1 and the waveguide 4 probe-coupled to it, so that the radiation from the output end 2 is reduced. We were able to efficiently transmit the microwave energy to the load side.

The output end portion 2 is configured as shown in FIG. 5, and includes a microwave output conductor 9 extending from the resonant cavity.
is in the pinch-off part of the metal exhaust pipe 10, or the exhaust pipe 1
A metal cap-shaped body 11 is fitted to the top. 12 is a ceramic ring, 13 is a metal tube for sealing, and 14 is a gasket made of a braided body of thin metal wires.

Problems to be Solved by the Invention On the other hand, in order to reduce the size of microwave ovens or expand the internal volume of the microwave cooking chamber, there has been a demand for smaller magnetrons, and the protrusion length A of the output end 2 has become smaller than 0. Short and small output end type magnetrons of 18λ or less have appeared. However, when such a magnetron is probe-coupled to a waveguide of conventional dimensions, good impedance matching cannot be obtained between the two, and the microwaves emitted from the output end 2 cannot be efficiently transmitted to the load side.

Therefore, an object of the present invention is to provide a magnetron device that can efficiently and stably supply microwaves to a load side even when a short and small output end type magnetron is probe-coupled to a waveguide of a conventional size type. It's about doing.

Means for Solving the Problems According to the present invention, a magnetron with an output end protruding length of 0.18λ or less and a rectangular cylindrical thick wave tube of conventional dimensions are used. The distance from the short plate to the central axis of the output end is set to 0.1λ to 0.2λ, while a cylindrical or cylindrical impedance matching member is installed in the waveguide leading from the output end to the load side. Make the stub stand up.

Operation With this configuration, while using a short and small output end type magnetron and a waveguide of conventional dimensions, a good reflection effect due to the short plate and stub, that is, a conventional ALiλ/4 Optimum impedance matching can be obtained between the two in the same way as when using a magnetron.

Embodiments Next, the present invention will be explained along with embodiments shown in the drawings.

The magnetron 1 in the device shown in FIG.
The probe is coupled to the rectangular cylindrical waveguide 4 at the output end 2 where the angle is 211 (ξ0.17λ). Fundamental wave wavelength λ
The inner dimension W in the width direction of the waveguide 4, which transmits the output microwave of approximately 122 mm to the load side, is 95.3 M (approximately 0.78 λ
), the internal dimension in the height direction is 54. ．． 6n+m (approximately 0.4
5λ).

Then, the distance d from the central axis of the output end 2 to the seat plate 3 is set to 18.6RIl (approximately 0.15λ),
A cylindrical or cylindrical impedance matching stub 15 made of metal or other conductive material is erected in the waveguide 4 leading from the output end 2 to the load side.

In such a configuration, when the impedance matching condition was measured by varying the height H and installation position of the stub 15 (distance iI to L from the center of the output end), the results were as shown in the chart in FIG. , H=22mm (horizontal axis), L=68r
rtm (vertical axis), it matches the perfect matching point in the center of the figure. In other words, even if the protrusion length A is 0.18λ or less, it is possible to obtain the best transmission efficiency, which is exactly the same as when using a magnetron with AL: rλ/4. Furthermore, it can be seen that as long as H and L are close to the above values, there is no significant deviation from the perfectly matched state. In addition, in the graph of FIG. 2, the rotation direction scale indicates the phase of the microwave in the waveguide, and the radiation direction scale indicates the standing wave voltage ratio.

The above-mentioned impedance matching using a short and small output type magnetron is W=0.57λ~0.78λ,
Similar results were obtained when h=0.4λ to 0.5λ and d=0.1λ to 0.2λ.

Figure 3 shows a short and small output section type magnetron with A'' = 0.17λ compared to a conventional magnetron with W = 95.3w* (approximately 0.78λ).
, shows the impedance matching state when the probe is coupled to a rectangular cylindrical waveguide with h = 54.6 m (approximately 0.45 λ) under the condition of d = 18.6 m + * (0,15 λ) (no stub). Since the operating point P greatly deviates from the perfect matching point in the center of the figure, good impedance matching cannot be obtained and the excitation efficiency is significantly reduced.

Effects of the Invention As described above, (1) According to the present invention, a magnetron with a short and small output section can be constructed by simply providing a stub at a predetermined position within a waveguide having conventional internal dimensions and adjusting the position occupied by the short plate appropriately. Therefore, it is possible to satisfy the condition of perfect matching by using the waveguide, and it is possible to obtain the commonality of the waveguide or the compatibility of the magnetron.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of a magnetron device embodying the present invention, Fig. 2 is a diagram showing the impedance matching state of the same device, and Fig. 3 is a probe of a short-output type magnetron in a conventional waveguide. FIG. 4 is a partially cutaway perspective view of a conventional magnetron device, and FIG. 5 is a side sectional view of the vicinity of the output end of the device. 1... Magnetron, 2... Output end, 3... Short plate, 4... Waveguide,
15...Invida agent 26 Masu filler Kano Futaka and 1 other person (7 games))D2--1 Output Contents of amendment to Figure 2 procedural amendment 1986 November 16th (1> rd > 0.5λ on page 3, line 6 of the specification) >
Corrected to 0.15λ. Display of the case 1986 Patent No. 175724 Name of the invention Person who corrects magnetron device Relationship to the case 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture Representative of Matsushita Electronics Co., Ltd. 23rd son 1006 Oaza Kadoma, Kadoma City, Osaka Prefecture 571 [Contact number (Tokyo) 434 Tokyo Patent Branch] Subject of amendment

Claims (1)

[Claims] The protrusion length of the output end of the magnetron is 0.18λ or less (where λ is the fundamental wave wavelength of the oscillated microwave), and the prismatic cylindrical waveguide probe-coupled to this part has a width of 0.57λ to 0.7
In a magnetron device whose internal dimensions are set to 8λ and a height of 0.4λ to 0.5λ, the distance from the short plate that closes one opening of the waveguide to the central axis of the output end is 0. .1 to 0.2λ, and a cylindrical or cylindrical impedance matching stub is erected in a waveguide leading from the output end to the load side.