Abstract: A high-power microwave generator employing a plurality of inexpensive commercial magnetron tubes cross-coupled by means of a secondary coupling path between each magnetron output pair, whereby a portion of the output energy from a first magnetron tube is injected into a second magnetron tube and a portion of the output energy from the second magnetron tube is similarly injected into the first magnetron tube. The resulting cross-injection of microwave energies brings the respective magnetron tube pair into a phase-lock sufficiently stable to permit coherent combination of their outputs for many high-power microwave applications, such as directed energy weapon systems. The magnetron phase-locking system requires no external components other than the secondary coupling paths of this invention.

Abstract: The object to the present invention is to provide a magnetron which can reduce spurious oscillation such as the ??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 anode 1 formed by plural vanes 12 in such a manner that inner ends 12 are radially extended toward the center of the anode shell 11 from the inner wall of a cylindrical anode shell, and a cathode 2 provided at the center of the anode 1. The magnetron of the present invention further includes a pair of pole pieces 4 provided in such a manner that a magnetic field can be applied on the interaction space 2 where the inner ends 12a of the vanes 12 and the cathode 2 face with each other.

Abstract: The object to the present invention is to provide a magnetron which can reduce spurious oscillation such as the &pgr;-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 anode 1 formed by plural vanes 12 in such a manner that inner ends 12 are radially extended toward the center of the anode shell 11 from the inner wall of a cylindrical anode shell, and a cathode 2 provided at the center of the anode 1. The magnetron of the present invention further includes a pair of pole pieces 4 provided in such a manner that a magnetic field can be applied on the interaction space 2 where the inner ends 12a of the vanes 12 and the cathode 2 face with each other.

Abstract: A power supply for a magnetron varies a power output level and prevents moding of the magnetron. To provide a variable power output, a microprocessor senses an anode current and voltage of the magnetron. Based on the sensed signals, the microprocessor adjusts the conduction angle of a thyristor to obtain the desired power level. The microprocessor also monitors the anode voltage for detecting moding of the magnetron. If moding is detected, the microprocessor adjusts the conduction angle of another thyristor to change the current supplied to the filament. By changing the filament current, the microprocessor effectively prevents the moding of the magnetron.

Abstract: An improved low power pulsed anode magnetron is provided having a cylindrical cathode centrally disposed within a plurality of radial anode vanes. An interaction region is provided between the surface of the cathode and the anode vane tips. A ratio of the anode-to-cathode space over the center-to-center distance between adjacent vane tips is within a range between 0.95 and 1.05. The cathode is joined to a magnetic polepiece assembly which channels magnetic flux to the interaction region. Both the cathode and the polepiece are mechanically adjustable from external to the magnetron to reposition the cathode and polepiece with respect to the anode vanes. The cathode surface is formed from an active nickel alloy which is cleaned by a chemical process followed by a high temperature and vacuum firing. An emissive surface is applied over the cleaned cathode surface.

Abstract: An electron beam microwave device having an evacuated interaction chamber to which are coupled a resonant cavity which has an opening between the resonant cavity and the evacuated interaction chamber and an electron gun which causes a narrow beam of electrons to traverse the evacuated interaction chamber. The device also contains a mechanism for feeding back a microwave electromagnetic field from the resonant cavity to the evacuated interaction chamber in such a way as to modulate the direction of propagation of the electron beam, thereby further amplifying the microwave electromagnetic field. Furthermore, provision is made for coupling the electromagnetic field out of the electron beam microwave device.

Abstract: A magnetron choke for microwave ovens has a tube member having its wall divided into two side walls of different heights respectively on each side of slots in the tube wall to provide two resonant points for suppressing harmonics in a wider range of frequency bands. Another tube member arranged on the bottom of the former can suppress frequency further in a wider range.

Abstract: A gyroklystron device includes an electron beam source, a plurality of bunching cavities and an output cavity. A first bunching cavity has an input coupling aperture for receiving an rf signal from an rf signal injecting source. Each of the bunching cavities has a first pair of substantially uniform-angle slots of a preselected angle, which are diametrically opposed, and extend axially, parallel to the direction of the electron beam and extend into drift regions on both sides of the cavities. The first pair of slots control the Q of a desired mode and higher order modes. A second and third pair of slots are diametrically opposed and extend axially, parallel to the direction of the first pair of slots, but are rotated 90 degrees circumferentially from the first pair of slots. These slots control the axial profile of any mode that leaks out beyond the desired mode and control the length of field interaction with the electron beam.

Abstract: In a gyrotron cavity resonator, generated energy is extracted into a symmetric set of fundamental-mode waveguides by ports disposed to couple energy in phase from the operating electromagnetic mode but in anti-phase with respect to an unwanted mode of lower cutoff frequency than the operating mode, thereby neutralizing coupling to the unwanted mode. A second set of interspersed ports may be disposed to load degenerate, orthogonal modes.

Abstract: A gyrotron interaction resonator 29 operating in a TE.sub.n1 cavity mode has an array of longitudinal slots 32 in the conductive wall 30. The slots 32 are spaced to couple to the unwanted TE.sub.n1 modes and to other modes of differing n and not to the desired mode. Wave-absorptive material 34 spaced from the inner cavity wall 28 and coupled to slots 32 absorbs the unwanted modes.

Abstract: A magnetron comprises an anode cylinder, vanes extending radially and inwardly from the anode cylinder, an output-side-sealing metal cylinder sealed to the end of the anode cylinder, an antenna lead connected to one of said vanes and a plurality of flanged metal cylinders enclosing the antenna lead and disposed inside the output-side-sealing metal cylinder along the direction of a magnetron tube axis.

Abstract: A coaxial magnetron has a high-Q resonant cavity surrounding a multiple-resonator anode circuit and coupled by slots to alternate anode resonators. The cavity is resonant in the TE.sub.111 mode, having two zero points of electric field on its periphery. The anode circuit is correspondingly resonant in its N/2-1 mode.Mode suppression means damp out the degenerate TE.sub.111 mode which is not coupled to the output iris.The size and weight of the magnetron are much less than conventional tubes using a cavity resonant in the TE.sub.011 mode with circular electric field.

Abstract: A mode detector for microwave oven magnetrons is disclosed including means for sensing interruption of anode current and providing a discrete indication thereof. An alternative embodiment discloses means to count the number of such interruptions. A method of detecting incipient failure of the magnetron is disclosed wherein the discrete output of a mode detector is observed and a determination is made that an incipient failure exists when the mode detector output frequency exceeds a predetermined limit.

Abstract: Disclosed is a magnetron for a microwave oven which has a drain electrode (60) near a cathode (25) and in a position where an electron beam path is not interfered with. The cathode and the drain electrode are formed in spiral shapes. Turns of the cathode are alternately arranged with those of the drain electrode. When the magnetron is operated, the drain electrode is kept at the same potential as the cathode or is kept at a negative potential relative to that of the cathode. Therefore, positive ions in the vicinity of the cathode are collected at the drain electrode, thus decreasing high frequency noise.

Abstract: The cathode of a coaxial magnetron has a cylindrical electron emitter with a radially extending projection which is asymmetrical with respect to the axis of the emitter. The projection suppresses starting of the magnetron in the TE.sub.121 mode and reduces starting jitter. In a preferred embodiment, the projection is in the form of a circumferential ridge extending around approximately one-half the circumference of the cylindrical surface and is centrally located thereon. The projection is oriented at 45 degrees with respect to the output of the magnetron. The power output of the magnetron is not substantially reduced.

Abstract: A magnetron of simplified mechanical construction and including choke structures for harmonic suppression. The structure includes an anode cylinder having a plurality of vanes therein and upper and lower open ends; a cathode within said anode cylinder; a cathode stem air-tightly coupled with the second open end of the anode cylinder for supporting the cathode; and an output section. The output section includes an insulated cylinder having a first end and air-tightly coupled with the first open end of the anode cylinder and a second open end; an electrically conductive annular member coaxial with the insulated cylinder; an electrically conductive metal cap coaxial with the annular member; and an output conductor for conducting microwave energy from the anode cylinder to the cap, the cap and output conductor defining a first choke structure for suppressing second harmonic energy and the annular member defining a second choke structure for suppressing a fourth harmonic component of microwave energy.

Abstract: A simple but effective filter attenuating one or more frequencies other than the fundamental frequency of a magnetron is provided in the magnetron. The filter comprises one or more stubs each of which extends along one side of an output probe connected to an anode vane of the magnetron. Each stub forms a slot which has an effective electrical length of a quarter wavelength at the frequency to be attenuated by the filter. The probe may be a metal strip and the stub, may be a lug formed by cutting in the strip a mainly longitudinal slot which opens into a side edge of the strip.

Abstract: A standard demountable coaxial magnetron has a cathode and a surrounding de shell formed with slots through which electromagnetic energy is coupled into an external resonant stabilizing cavity. The anode and its associated components are contained in a vacuum-sealed interaction cavity envelope separably mounted in the sleeve-like body of the stabilizing cavity. A ceramic window sealably covers the slots and has its axial ends coupled to the axial ends of the anode shell by kovar strips. Since various unwanted modes of oscillation, such as the TE.sub.121 mode, occur in the external resonant cavity, standard mode-suppression TE.sub.121 chokes are used. Such a choke includes a high rf loss absorber carried in a choke cavity formed between the cavity and the anode. However, the kovar strips also extend through this choke cavity and, in many cases, seriously interfere with mode suppression.

Abstract: Disclosed is a magnetron with a folded 1/4.lambda. choke for suppression of higher harmonics formed by three coaxial conductors, the inner one of which is connected to the output probe of the magnetron.

Abstract: In a coaxial magnetron the resonant circuit interacting with the electrons is coupled to a stabilizing resonator operating in a mode with circular electric field. The coupling is thru a set of slots in the intervening wall. Undesirable resonances localized in the slots are damped by lossy material at the ends of the slots. Undesirable damping of the cavity mode is prevented by a conducting shield covering exposed area of the lossy material and spaced into the cavity away from the slots.

Abstract: A harmonic frequency suppressor is disclosed for microwave magnetrons having an output antenna probe member. A coaxial cylindrical member is disposed within the vacuum envelope to provide in combination with the antenna probe member a line filter for suppressing harmonic frequencies of the generated output signal frequency. The length of the coaxial member is dimensioned to suppress the desired harmonic frequency.