Magnetron

Abstract

To provide a magnetron capable of reducing noises in a low frequency band of 30 MHz or less without deteriorating the stability of a load depending on phases, and also ensuring the precision of assembly dimensions without increasing the number of components, a coiled filament 3 is arranged between an input-side end hat 61 and an output-side end hat 7 which are supported by a cathode supporting rod 8. A larger-diameter boss 61 a in the end hat 61 extends to the interior of an interaction space, a smaller-diameter boss 61 b and one end 3a of the filament 3 are secured to each other, and the other end 3b is secured to a boss 7a of the end hat 7. Here, the dimension of an axial free length part F which forms an electron emission part which is not secured to the end hats 61 and 7 of the filament 3 is set to 50% or more and 80% or less of the axial dimension H of plate-like vanes 2, and the electron emission part is arranged so as to be displaced to the output side.

Description

technical field [0001] The present invention relates to a magnetron used in a high-frequency device whose noise is intended to be reduced. Background technique [0002] A conventional magnetron will be explained below with reference to the drawings. [0003] Fig. 32 is a longitudinal sectional view showing an interaction space where electrons of a magnetron move in a conventional device. In this magnetron, a plurality of plate blades 2 (only two blades are shown in this figure) are arranged radially inside the anode tube 1, and the plate blades 2 pass through pressure equalizing rings 9, 10, 11 and 12 Connect alternately. By connecting the grading rings 9, 10, 11 and 12 alternately in this way, the magnetron will oscillate stably in the mode. Meanwhile, a cathode 13 constituted by a spiral filament 3 , a pair of end caps 6 and 7 , and a cathode support rod 8 is provided along the central axis of the anode tube 1 . The filament 3 is made of tungsten containing 1-2% thoriu...

AI Technical Summary

Problems solved by technology

[0016] Although the effect of reducing noise below 1 MHz is described in the technology given in Patent Document 2, no attention is paid to the relationship with the peak anode current value

As shown in FIG. 38 , it was also confirmed by experiments conducted by the inventors of the present application on the basis of the technology disclosed in Patent Document 2 that the noise reduction effect was confirmed in the region where the average anode current value was 100 mA or less, while the noise reduction effect was confirmed at 200 mA and The anode current region of 300mA shows little noise reduction effect

It is believed that this is because the amount of electron emission is set so that the peak current can be guaranteed, so electrons become excessive in the small current region

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