New Japan Radio Co., Ltd.

New Japan Radio, Ltd

Hideyuki Obata

Misao Iseki

Naoki Tsuji

Toru Kimura

Hiroyuki Miyamoto

Akinori Umeda

Kiyoshi Kishiki

Yukio Torikai

Kunihiko Takahashi

Toshihiko Yamashita

An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular, a heater to increase the temperature of the cathode, and an anode to apply a positive electric potential relative to the cathode to extract electrons in a predetermined direction is provided. The cathode comprises a through hole at a central portion thereof along a central axis of the cathode, and either the cathode comprises a no-emitting layer at at least one of an opening edge on the electron emitting surface side of the through hole and an inner surface of the through hole, or the opening edge on the electron emitting surface side of the through hole is a chamfered C surface or a chamfered R surface.

Electron gun and manufacturing method therefor

An electron gun comprising a cathode having an electron emitting surface and whose planar shape is circular; a heater; an anode being arranged to oppose the cathode; and a heat resistant member. The anode applies a positive potential relative to the cathode to extract electrons in a predetermined direction. The cathode has, in a central portion thereof, a through hole along a central axis of the cathode. The heat resistant member has a first portion to close the through hole and a second portion being positioned between the cathode and the heater.

Electron gun

The object of the presently disclosed embodiment is to improve heat dissipation and an overall cooling efficiency to raise a peak oscillation output. To achieve the object, there is provided a coaxial magnetron having the following configuration: Around a cathode, vanes and an anode cylinder form an anode resonant cavity, and a cylindrical side body forms an outer cavity. An input side structure having an input part and an upper structure are joined to both ends of the cylindrical side body. One end of the anode cylinder is joined to the input side structure. A groove (or step) for adjusting the distance between the structures and at the both ends is provided, and the groove is joined to the other end of the anode cylinder.

Coaxial magnetron

The switching element is provided in a state of being electromagnetically coupled to the cavity resonator of the high frequency oscillator; the bias voltage applying terminal is connected to one electrode of the switching element; another electrode of the switching element is electrically connected to the cavity resonator (the anode shell in FIG.); the metal plate having a size enough for reflecting an electric wave to be transmitted before and after the switching element in a high-frequency manner is provided at any one end of the switching element; and by applying a bias voltage to the switching element and varying that, a reactance of the switching element is changed and a resonance frequency of the cavity resonator is varied. By this method, an oscillation frequency can be varied greatly relative to a small change in a bias voltage.

Method for varying oscillation frequency of high frequency oscillator

A highly-reliable electronic frequency tuning magnetron comprises an anode for forming a resonant cavity which is segmented into a plurality of spaces in an inner periphery side of a cylindrical anode shell, a cathode provided at the center of the anode shell along its cylindrical axial direction and an exhausted structure having a coaxial central conductor which is connected to the inside of the cavity of the anode shell and is coupled thereto in a high-frequency manner, wherein the coaxial central conductor is externally led through a wall of the exhausted structure via a through-hole and the through-hole is covered by a dielectric portion placed between an external conductor for constituting the coaxial central conductor and the central conductor, wherein a portion of the led coaxial central conductor is conductively connected to a switching element.

Electronic frequency tuning magnetron

A filter including a body on which a waveguide groove, whose one surface is open, is formed in a U-shape and a plurarity of inductive resonant windows are provided along a longitudinal direction of the waveguide groove at a predetermined interval in the waveguide groove; and a cover being provided on a top surface of the body so as to cover the surface being open, wherein the plurality of inductive resonant windows are provided in such a manner that a cavity, which is enclosed by two of the plurality of inductive resonant windows being adjacent, the body and cover, resonates at a predetermined frequency and passes a electromagnetic wave in a predetermined frequency band and wherein one end of the U-shaped waveguide groove is an input terminal and other end is an output terminal, and the input terminal and output terminal are formed on a same surface.

U-shaped microwave and millimeter wave resonator filter

A pulse magnetron includes a cylindrical shell anode, a cathode provided at the center of the anode having a number of vanes mounted radially on an inner wall of the cylindrical anode shell, and a pair of pole pieces provided for applying a magnetic field to an interaction space where the outer side of the cathode is opposed to inner ends of the vanes. The anode and the cathode are arranged to satisfy at least either (i) increasing the radius of the inscribed circle defined by the inner ends of the vanes or (ii) decreasing the radius of the cathode surface as the magnetic flux density along the axial direction of the cathode at both ends of the inner end of the height of the vanes.

Pulse magnetron with different anode and cathode radiuses

The object to the present invention is to provide a magnetron which can reduce spurious oscillation such as the &#x3c0;&#x2212;1 mode which presents a problem particularly in magnetrons and can reduce spurious radiations without placing filters. The magnetron of the present invention includes an anodeformed by plural vanesin such a manner that inner endsare radially extended toward the center of the anode shellfrom the inner wall of a cylindrical anode shell, and a cathodeprovided at the center of the anode. The magnetron of the present invention further includes a pair of pole piecesprovided in such a manner that a magnetic field can be applied on the interaction spacewhere the inner endsof the vanesand the cathodeface with each other. At least one of the pair of pole pieces is provided in such a manner that in a range A at least &#x2153; of the vane length L from the inner endof the vane, the distance B between the side surfacesof the vanes and the surfaceadjacent the inner endof the pole piecesis within 0.015 &#x3bb; wherein &#x3bb; is the oscillation wavelength of the magnetron, and said vane length is a distance from said one end to said inner end.

Magnetron

A cathode for a magnetron having concave/convex portions on a surface of a cylindrical base metal with thermionic emitting materials being fixedly attached to concave portions from among the concave/convex portions. The convex portions of the concave/convex portions are arranged to be inclining. It is enabled to effectively protect thermionic emitting materials from inverse impulse of electrons or ions and from oscillation to thereby restrain consumption and omission of these thermionic emitting materials and to decrease higher harmonics of radiation.

Growing community of inventors

Fujimino, Japan

Hideyuki Obata