Abstract: An electromagnetic wave amplifier and an electromagnetic wave generator operate using electron beams in a vacuum environment. The amplifier, arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an amplifying section for amplifying an inputted electromagnetic wave in one direction by utilizing energy received from an electron beam emitted from the electron emitting section and traveling in the vacuum along a dielectric waveguide having a wave-shaped form. The generator, also arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an oscillating section for generating an electromagnetic wave by utilizing electron beams emitted from the electron emitting section and travelling in the vacuum along a dielectric waveguide having a composite wave-shaped form.

Abstract: A system and method for increasing the power density distribution uniformity of a gyrotron radiation beam provides a mirror for reflecting the gyrotron beam onto an object to be irradiated, where the shape of the mirror surface is changed by a plurality of controllable and movable mirror support members in a chaotic or random manner during generation of the gyrotron beam on the mirror surface, and the shape of the mirror surface is changed at a predetermined frequency F according to a predefined algorithm.

Abstract: An ultra bright, low wattage inductively coupled electrodeless aperture lamp is powered by a solid state RF source in the range of several tens to several hundreds of watts at various frequencies in the range of 400 to 900 MHz. Numerous novel lamp circuits and components are disclosed including a wedding ring shaped coil having one axial and one radial lead, a high accuracy capacitor stack, a high thermal conductivity aperture cup and various other aperture bulb configurations, a coaxial capacitor arrangement, and an integrated coil and capacitor assembly. Numerous novel RF circuits are also disclosed including a high power oscillator circuit with reduced complexity resonant pole configuration, parallel RF power FET transistors with soft gate switching, a continuously variable frequency tuning circuit, a six port directional coupler, an impedance switching RF source, and an RF source with controlled frequency-load characteristics.

Abstract: An electron beam tube includes an electron gun included within a vacuum envelope defined partly by a ceramic cylinder. The ceramic cylinder includes straight sided portions and with an intervening conical section between them. The straight sided portions and form part of two r.f. chokes, being metallized on their inner and outer surfaces and forming a connection with a cavity forming part.

Abstract: The present invention is based on a relatively simple mechanism which heretofore has not been tried before. The mechanism depends on modulation of a collimated beam transverse to the beam direction rather than the usual longitudinal modulation. Conversion of the transverse motion into longitudinal bunching in an output cavity is accomplished by means of the difference in path length in a bending magnet. Since the present invention does not depend on longitudinal modulation, it is suitable for pulsed superpower (1 GW) applications, but it can be equally suited for multi-megawatt cw applications. The present invention pertains to an apparatus for bunching relativistic electrons. The apparatus comprises means for imparting a periodic velocity in a first direction in a first region to electrons of an electron beam moving in a second direction.

Abstract: For use in a beam index color cathode ray tube (CRT), a multi-beam group electron gun directs first and second groups of vertically aligned electron beams on respective parallel, horizontally aligned color phosphor stripes on the CRT's display screen. Each group of electron beams includes three beams, one for each of the three primary colors of red, green and blue. The first and second electron beam groups are horizontally offset from one another, with the upper, intermediate and lower electron beams in each group tracing the same horizontal phosphor stripe as the beams scan the display screen and with a time delay provided to synchronize the video information of both electron beam groups. A color video signal is provided either to a respective cathode or to a respective segmented conductive portion containing a beam passing aperture in the electron gun's G1 control grid for individually modulating each beam with color video image information.

Abstract: A capacitor includes a conductive tube, covered by insulating material and a layer of conductive material located at the central part of the tube. The geometry presents a low inherent inductance and a continuous, distributed conductance. The capacitor may be used as a bypass capacitor in an IOT amplifier to reduce stray and leakage high frequency radiation, in one amplifier being located within the inner wall of an annular input cavity.

Abstract: In a field emission cathode emitting an electron beam modulated by any desired high frequency, a cathode tip is formed in one surface of an N type semiconductor substrate constituting a collector region, an insulating layer formed on the one surface of the semiconductor substrate to have an opening which surrounds said cathode tip, a gate electrode is formed on the insulating layer to have an opening which surrounds the cathode tip, a P type base region is formed in the other surface of the semiconductor substrate, a base electrode is formed on the base region, an N type emitter region is formed in the base region, and an emitter electrode is formed on the emitter region. A DC supply source is connected across the gate electrode and the emitter electrode and a high frequency supply source is connected across the base electrode and the emitter electrode.

Abstract: A Wehnelt electrode and a cold cathode are pressed against and fixed to each other under spring force with a ceramic plate interposed therebetween. Metallized layers connected to a gate electrode and a focusing electrode are disposed on surfaces of the ceramic plate. The gate electrode and the focusing electrode are connected to external power supplies via the metallized layers as feeder path structures. With this arrangement, an electron gun for an electron tube with a cold cathode can be designed with increased degree of freedom, reduced in size, can easily be assembled at the time of manufacture, has high dimensional accuracy, provides high dielectric strength between gate and Wehnelt electrodes, and is highly resistant to vibrations.

Abstract: A signal output assembly for an inductive output amplifier comprises a primary output cavity including a drift tube enclosing a modulated electron beam. The density modulated beam passes across a gap separating portions of the drift tube and induces an amplified RF signal into the primary output cavity. A secondary output cavity comprises a coaxial resonator terminated in an inductive coupling loop, and a waveguide having a ridge. The coaxial resonator and the inductive coupling loop have a combined electrical length approximately equivalent to an odd multiple of one-quarter wavelengths of the input signal (n&lgr;/4), where n is an odd integer. The coaxial resonator is electrically connected perpendicularly to a center of the ridge such that first and second portions of the ridge extend in opposite directions from the connection with the coaxial resonator to respective ends of the waveguide.

Abstract: A linear beam amplification device includes an axially centered electron emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification device comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavity and is in electrical communication with an interaction region defined between the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron.

Abstract: A high power switching apparatus comprises an annular cathode having a surface capable of emitting a hollow electron beam therefrom and an anode cavity spaced from said cathode. The cavity has an annular opening smaller in dimension than a corresponding internal dimension that defines the cavity to provide a Faraday cage collector of the hollow electron beam. A control electrode, disposed between the cathode and the anode cavity in a non-intercepting position relative to the hollow electron beam, provides a controlling electric field region for modulation of the hollow electron beam. Arc suppressing electrodes, at approximately the same potential as the cathode, are disposed between the control electrode and the anode. An intermediate high voltage electrode, disposed between the arc suppressing electrodes and the anode cavity in a non-intercepting position relative to the hollow electron beam, provides a controlling electric field region for channeling of the hollow electron beam.

Abstract: A cold cathode electron gun includes a field emission cathode array type cold cathode for emitting electron beams toward an RF circuit unit of a microwave tube. An annular Wehnelt electrode, a first anode electrode and a second anode electrode are disposed in order from the field emission cathode array type cold cathode side coaxially with the field emission cathode array type cold cathode between the field emission cathode array type cold cathode and the RF circuit unit. The potential Ea1 of the first anode electrode, the potential Ea2 of the second anode electrode and the potential Eb of the RF circuit unit has a relationship of Ea1>Eb>EA2.gtoreq.0 V.

Abstract: In an electron gun, a conductive chamber defines a cavity. A photocathode is disposed in the cavity. Photoelectrons are emitted from the photocathode into the cavity when light is applied to the photocathode. A wave guide mounted on the conductive chamber introduces a micro wave into the cavity. Via an opening formed in the wall of the conductive chamber, the photoelectrons are output to the outside of the cavity. Coolant is flowed through a flow path formed in the wall of the conductive chamber, to suppress a temperature rise of the conductive chamber.

Abstract: A linear-beam microwave tube comprises at least one electron beam directed along an axis crossing a cavity known as an output cavity in which it interacts with a microwave, this cavity having a terminal wall that separates it from a collector, the electron beam penetrating the collector by at least one aperture in the terminal wall. The terminal wall furthermore comprises at least one coupling unit to couple the output cavity with the collector, the microwave having to circulate in the collector before being extracted therefrom. Applications: klystrons and travelling-wave tubes that are easy to mount and inexpensive.

Abstract: A linear electron beam tube such as an IOT includes an input cavity formed from an inner body portion and an outer body portion which are joined together by a ceramic cylinder. The input cavity surrounds an electron gun and permits electrical connection to be made to the cathode and grid via parts of the inner body portion and. Metallization layers in conjunction with the intervening ceramic material of the cylinder define rf chokes. The construction enables high voltage parts of the arrangement to be insulated from the low voltage outer body portion whilst presenting a low leakage path for r.f.

Abstract: A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

Abstract: An electromagnetic wave matching element makes it possible to reduce the cost of a transmission system to a great degree. An electromagnetic wave matching element is adapted to allow electromagnetic wave beams incident from an entrance to be reflected by using plural mirrors to couple these reflected electromagnetic wave beams to an external transmission system through an exit. Mirrors are used that have a shape adapted to receive the plural electromagnetic waves in a beam form and to output electromagnetic wave beams having a predetermined distribution in which the number of the output electromagnetic waves is different from the number of the received electromagnetic waves.

Abstract: The present invention relates to a device for attenuating unwanted waves appearing in an electron tube which includes at least two coaxial cylindrical electrodes (2, 3). The electrodes (2, 3) contribute to forming the walls of a coaxial resonator. The unwanted waves to be attentuated generate surface currents in the walls of the coaxial resonator. The attenuation device includes several electrically conducting resistive elements (10) inserted into at least one wall of the resonator and arranged so as to cut the surface currents.

Abstract: An actuator for rotation of coupling means such as a loop in a high frequency resonant cavity includes a rotatable member to which the loop is fixed and a rod located adjacent it. The member and rod have interengaging teeth such that when the rod is moved inwardly or outwardly by an operator it causes the member, and hence the loop, to rotate. This is a compact assembly having components which are simple and easy to facilitate. In a preferred embodiment, the rod is located in a groove in the cavity wall.

Abstract: A resonant cavity (49) which facilitates coupling to another resonant cavity includes walls (40, 42) and an electrically conducting mast (43). One of the walls (40) has a coupling orifice (41) for coupling the resonant cavity (49) to another resonant cavity. The electrically conducting mast (43) projects from the second wall (42) opposite the first wall (40) and faces the coupling orifice (41). The electrically conducting mast (43) terminates with a hook-shaped portion (44) which contacts an edge of the coupling orifice (41). The resonant cavity (49) is suited for applications requiring secondary output cavities coupled to inductive output tubes.

Abstract: A high power switching apparatus comprises an annular cathode having a surface capable of emitting a hollow electron beam therefrom and an anode cavity spaced from said cathode. The cavity has an annular opening smaller in dimension than a corresponding internal dimension that defines the cavity to provide a Faraday cage collector of the hollow electron beam. A control electrode is disposed between the cathode and the anode cavity in a non-intercepting position relative to the hollow electron beam. The control electrode further comprises a first electrode element disposed outside of the hollow electron beam and a second electrode element disposed inside of the hollow electron beam. A controlling electric field region is provided between the first and second electrode elements for modulation of the hollow electron beam. Arc suppressing electrodes are also disposed between the control electrode and the anode. The arc suppressing electrodes are the same electric potential of the cathode.

Abstract: A gyrotron system comprises an electron gun that produces an electron beam, a magnetic field generating unit comprising a permanent magnet and two electromagnets and capable of generating an axial magnetic field that drives electrons emitted from the electron gun for revolving motion, a cavity resonator that causes cyclotron resonance maser interaction between the revolving electrons and a high-frequency electromagnetic field resonating in a natural mode, a collector for collecting the electron beam traveled through the cavity resonator, and an output window through which a high-frequency wave produced by the cyclotron resonance maser interaction propagates. The gyrotron system can be fabricated at a comparatively low cost, is easy to operate, has a comparatively small size and is capable of operating at a comparatively low running cost.

Abstract: A low-loss magnetic structure that provides an electron beam focusing field that can be accessed without field reversal. More specifically, the structure provides a uniform magnetic field that can be accessed from an adjacent field-free chamber within which an electron beam source of any size can be housed. The field-free chamber is separated from uniform field by a passive ferromagnet having a hole through which the electron beam can pass. The passive ferromagnet is instrumental in preventing the uniform field from entering the field-free chamber.

Abstract: In the gyrotron apparatus of the present invention, the microwave absorbing unit is provided around the insulation cylinder located between the microwave reflecting transmitter and the collector so as to electrically insulate them from each other, and constituting a part of the vacuum chamber. With this structure, the leakage of an unnecessary microwave to the outside through the insulation cylinder, which may occur when the apparatus is operated with a reduced potential of the collector with regard to the transmitter, can be more surely suppressed.

Abstract: The present invention comprises a microwave mode convert having a cylindrical waveguide input. Attached to the waveguide input is a transition section which gradually changes from the elliptical or cylindrical waveguide input. The output section is also an elliptical waveguide. The output section may also have an elliptical or cylindrical waveguide attached to it. The mode converter of the present invention has input a TM.sub.01 mode microwave energy from a cylindrical waveguide and outputs TE.sub.11 or TEM mode microwave energy which is an elliptical or circular pencil beam of radiation with high directivity.

Abstract: The invention relates to a cathode ray tube having an input resonator cavity which includes a first metal wall (2) and, spaced apart therefrom, a second metal wall (3) each conveying a low electric potential and constituting coupling areas (6, 7) at axially spaced locations, in which areas metal elements (10, 12) conveying a high electric potential are located opposite surface sections (8, 9 and 14, 15) which are electrically connected to the metal walls (2, 3) via insulating dielectrics (11, 13), the coupling areas (6, 7) being separated by a spacing dielectric. A high-voltage stable arrangement which is resistant to temperature fluctuations is obtained in that the spacing dielectric consists of a different material than the insulating dielectrics (6, 7) and has a lower value of the product of loss factor and dielectric constant (tg.delta..times..epsilon.) at a high frequency.

Abstract: An electron beam generated by an electron gun is oscillated in a cavity resonator and output as a millimeter electromagnetic wave. The output electromagnetic wave is transmitted to a cylindrical mode converter. The inner wall surface of this mode converter has a plurality of sets of ridges and grooves spirally formed at equal pitches so as to gradually change the degree of corrugation in the transmission direction of the electromagnetic wave. The mode converter separates the input electromagnetic wave from the cavity resonator into a plurality of electromagnetic waves having the same power distribution. The output electromagnetic waves from the mode converter are transformed into wave beams by mirror systems and output to the outside of a gyrotron from output windows provided in a one-to-one correspondence with these electromagnetic waves.

Abstract: A discrete monotron oscillator for use in a high power microwave device is formed with a microwave oscillator having a half-wavelength resonant coaxial microwave cavity operating in fundamental TEM mode for microwave oscillation with an inner conductor defining a drift tube for propagating an electron beam and an outer conductor coaxial with the inner conductor. The inner conductor defines a modulating gap and an extraction gap downstream of the modulating gap. The modulating gap and the extraction gap connect the coaxial microwave cavity with the drift tube so that energy for the microwave oscillation is extracted from the electron beam at the extraction gap and modulates the electron beam at the modulating gap. For high power operation, an annular electron beam is used.

Abstract: An r.f. radiation absorbing material able to hold off a 30 to 40 kV voltage difference is described as formed by a silicon rubber loaded with ferrite particles. The material is used to reduce self-oscillation in amplifiers.

Abstract: Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.

Abstract: A new charged particle accelerator with radio frequency quadrupole accelerating cavities is presented in this invention. Some focussing coils are mounted outside or inside several cavities of them. The accelerator emits charged particle whose kinetic energy can be varied as occasion demands.

Abstract: A microwave coupler with improved efficiency receives microwave energy in a principal mode TEm,n (m and n being whole numbers and n being not zero) and gives a quasi-optical energy beam. It comprises a mode converter that receives energy in the principal mode and converts a part of it into an auxiliary mode TEp,q (with p and q being whole numbers, q close to one and not zero, p greater than q). The energy in the principal mode and in the auxiliary mode get propagated in a radiator and emerge in the form of the quasi-optical beam by an aperture that coincides with a minimum electrical field resulting from the electrical field of the principal mode and the electrical field of the auxiliary mode. The disclosure has applications notably to the field of gyrotubes.

Abstract: In an electron beam tube, such as an IOT, ferrite loaded silicone rubber or some other ferrite loaded dielectric material, is carried by a wall of an input cavity. The material absorbs r.f. energy, reducing coupling between different parts of the tube which could otherwise result in undesirable oscillation. Furthermore, its provision on part of the input cavity wall enables easy access to be made for replacement and servicing requirements.

Abstract: A harmonic gyro-TWT is provided that has only one possible mode of operation. The harmonic gyro-TWT comprises a waveguide and an electron beam projected through the waveguide and encircling an axis of the waveguide. A plurality of evenly spaced electrical conductors are disposed within the waveguide parallel to the axis and spaced a fixed distance from an inner wall of the waveguide. The electrical conductors are connected together at an end of the waveguide. The electrical conductors are excited in phase with an AC signal connected between the electrical conductors and the inner wall of the waveguide. As a result, a multipole field having an order equal to twice the number of electrical conductors is defined within the waveguide. A plurality of support rails couple the inside surface of the waveguide to each respective one of the plurality of electrical conductors.

Abstract: An electron beam tube arrangement in an inductive output tetrode. The arrangement comprises a resonant cavity circuit having two cavities, and includes an element for coupling high frequency energy between the two cavities. The coupling element includes a coupling dome projecting into one of the two cavities from a wall thereof. The coupling dome has a base portion which is adapted to be connected to a dome completion member selected from a set comprising at least one dome completion member for adjusting a coupling level between the two cavities.

Abstract: A system which integrates "intelligent" electronic feedback into the structure of vacuum electronic devices whose subcomponents are electronically and/or electro-mechanically adaptive. By "vacuum electronic device," is meant any source of microwave (or millimeter-wave) power generation which is driven by electron beams. Such a device is divided into the following main subsections: an electron emitter, an electron beam shaping & acceleration region, an rf signal input coupler (for amplifiers), an electron-beam drift region, at least one rf/beam interaction region where beam energy is converted to an rf signal, a beam-dump region, and the rf signal output coupler. Some of those subsections are instrumented with electronic sensors. The data collected by those sensors will feed into an "on-board" microcomputer (logic unit subsection 8) which will compare it to "ideal" set of values for those parameters.

Abstract: An inductive output tetrode includes a cylindrical ceramic envelope within which is located an electron gun including a cathode and grid. An annular resonant input cavity into which a high frequency signal is coupled surrounds the envelope and is located adjacent the electron gun so as to provide a modulating electric field in the cathode-grid region to density modulate the electron beam. The input cavity is connected to two metal cylinders arranged immediately adjacent to the outside of the envelope. Metallic portions located within the envelope are co-extensive with cylinders with the material of the envelope 1 being located between them. These structures act as r.f. chokes to reduce high frequency losses from the input cavity. Tuning of the resonant cavity may be achieved by adjusting a tuning member which is at distance of quarter of a wavelength at the resonant frequency from the cathode-grid region.

Abstract: Disclosed is a method and apparatus for generating a very fast electron pulse (30) in a vacuum. The electron source comprises a pulse-forming line (12), a solid-state switch (14), a cold field-emitting cathode (16), and an anode grid (18). The anode grid forms a portion of a side of an evacuated circuit (20) that may be used to produce an oscillating output signal or that may be a portion of a waveguide carrying an rf signal to be amplified. In operation, the pulse-forming line is charged to a desirable voltage. The solid-state switch is then closed, coupling the pulse-forming line to the cathode. An electric field develops between the cathode and anode grid. Under the influence of the electric field, the cathode emits an electron current pulse that is attracted by the anode grid. The current pulse enters the region between the anode and closure grids, and interacts with the electromagnetic field in the cavity at the appropriate time to add its energy to the electromagnetic field of the cavity.

Abstract: The present invention is based on a relatively simple mechanism which heretofore has not been tried before. The mechanism depends on modulation of a collimated beam transverse to the beam direction rather than the usual longitudinal modulation. Conversion of the transverse motion into longitudinal bunching in an output cavity is accomplished by means of the difference in path length in a bending magnet. Since the present invention does not depend on longitudinal modulation, it is suitable for pulsed superpower (1 GW) applications, but it can be equally suited for multi-megawatt cw applications. The present invention pertains to an apparatus for bunching relativistic electrons. The apparatus comprises means for imparting a periodic velocity in a first direction in a first region to electrons of an electron beam moving in a second direction.

Abstract: A folded waveguide gyrotron-traveling-wave-amplifier comprises: an electron gun for transmitting an axis-encircling beam of electrons with large transverse energy along a first path having an axis; an RF source for producing and applying in a second path an RF input millimeter wave signal having a bandwidth in a preselected frequency domain and having a transverse electric field; a source for generating a solenoid magnetic field parallel to the axis along the first path; a beam collector; and an interaction circuit such as an H-plane bend serpentine waveguide positioned within the solenoid magnetic field and having a narrow wall containing a beam tunnel hole for passing the axis-encircling beam of electrons therethrough to the beam collector, an output end, and an input end for receiving and passing the RF input millimeter wave signal through the H-plane bend serpentine waveguide to the output end to modulate the axis-encircling electron beam, the modulated axis-encircling electron beam amplifying the RF inpu

Abstract: The mode convertor employs two intermediate modes, a coaxial TEM and a rectangular waveguide TE.sub.10 mode, in the transition between the TM.sub.01 and TE.sub.11 circular waveguide modes. The coaxial line provides isolation while acting as a mode filter between the device input and output ports. The rectangular waveguide provides a wide mode separation ratio between the TE.sub.10 and TM.sub.11 modes. The TE.sub.10 mode then transitions into the TE.sub.11 in the circular output waveguide. The coaxial section keeps the output TE.sub.11 mode from scattering back to the input, and the rectangular section keeps the TM.sub.01 from being excited in the output.

Abstract: A modulated bunched electron beam incident on the inner conductor 16 of a coaxial structure launches TEM waves that are distributed to multiple radial waveguides 22 around the outer conductor 14 of the coaxial structure. A tuning piston 32 may be moved axially within the outer conductor for matching the impedance of the coaxial structure to the waveguide array.

Abstract: In a gyrotron apparatus, an oscillator tube unit and a collector are coupled by a bellows. The collector is received in an evaporation boiler jacket. The oscillator tube is supported on a stand and the collector and the boiler jacket is supported on the other stand.

Abstract: A free electron laser with an advanced wiggler. The wiggler is suitable for creating a transverse magnetic field with two periodicities (P1, P2). This thereby results in the emission spectrum being significantly reduced.

Abstract: An electromagnetic radiation amplification device comprising an electron gun for introducing a stream of electrons into an electron drift tube/wavequide in which an axial magnetic field and a wiggler magnetic field have been induced to impart a helical gyration to the electrons as they travel parallel to the tube. The axial, or guide, magnetic field is directed in the direction opposite to the direction of propagation of the electrons if the electrons have a right handed helical gyration and is directed in the direction of propagation of the electrons if the electrons have a left handed helical gyration.

Abstract: The invention is a mode converter and power splitter device for electron tubes, particularly gyrotrons and tubes of similar categories. These tubes have an output cavity 2, which is a circular form about a centerline, and a hollow electron beam 1 which propagates along the same centerline. The device complying with the invention is a structure which comprises secondary wave guides 6, symmetrical in azimuth around the same centerline as the outlet cavity, each guide 6 containing coupling apertures 7 on its outer wall (that furthest from the centerline), these apertures 7 being arranged to excite a given mode in the guide. One important embodiment of the invention is that the electron tube operates in a TE.sub.m,n mode with a high azimuth index m and the number of secondary guides 1=m. Another important embodiment of the invention is that secondary guides 6 are trapezoidal in section. Another important embodiment of the invention is that secondary guides 6 are excited in the fundamental mode.

Abstract: There is provided a gyrotron including a quasi-optical mode converter wherein a solid dielectric layer such as silicon carbide for absorbing unnecessary millimeter waves generated by diffraction of the quasi-optical mode converter is arranged in annular shape in the periphery of the quasi-optical mode converter, and millimeter absorption fluid can be supplied to the periphery of the mode converter in a predetermined direction through vacuum barrier walls formed by a dielectric member, thereby efficiently absorbing the diffracted millimeter wave which is the cause of generating heat.

Abstract: An electron beam tube arrangement has an output cavity resonator circuit which includes a first output cavity, a second output cavity being coupled thereto by means of a coupling loop. The coupling loop is located in the first cavity and connected to said second cavity. In one embodiment of the invention, the second cavity also contains a coupling loop which is electrically connected to that in the first output cavity.

Abstract: The present invention is a coupled cavity gyrotron-traveling-wave-tube amplifier which produces highly efficient, broad band millimeter wave radiation. The present invention comprises an electron gun, a double ridged coupled cavity interaction circuit and a beam collector. In operation the gun injects a gyrating electron beam through a beam tunnel of a side wall of the coupled cavity. When the electron beam phase is synchronized with the rf phase of the transverse electric mode in the coupled cavity circuit, the electron beam is modulated and amplifies the rf input signal through the negative mass instability called electron cyclontron instability. The coupled cavity design of the interaction circuit effctively slows the rf-wave velocity, allowing amplification of the rf- wave over a broad band. This t ype of broad band microwave energy is highly useful in radar, communications and jamming technology.