Abstract: A pulse generator includes a microwave source that delivers a pulsed signal into a resonant compression cavity equipped with a switching device for opening or closing the resonant compression cavity. The pulsed signal is stored in the resonant compression cavity when closed to be compressed therein before being delivered with a greater amplitude and a smaller width when the resonant compression cavity is open. The microwave source is of the amplifier type with an instantaneous bandwidth including the resonant frequency of the resonant compression cavity. The microwave source receives, at an input, an input signal to be amplified that is taken from the resonant compression cavity. Such a pulse generator can find particular application in high-power pulse generators.

Abstract: A microwave modulable field-effect cathode which includes at least one array of emissive tips. A microwave modulation signal is produced by a device including a microwave-controllable semiconductor modulation element which is close to the tip array, and a short microline for conveying the modulation signal to the tip array. The microline provides impedance matching between the tip array and the semiconductor modulation element. Such a device can find application as a compact field-effect cathode, as one example.

Abstract: A pulse generator comprising a microwave source (T, 60) which delivers a pulsed signal into a resonant compression cavity (15) equipped with a switching device (21) for opening it or closing it. The pulsed signal being stored in the resonant compression cavity (15) when closed in order to be compressed therein before being delivered with a greater amplitude and a smaller width when the resonant compression cavity (15) is open. The microwave source (T) is of the amplifier type with an instantaneous bandwidth including the resonant frequency of the resonant compression cavity. It receives at the input (C1) an input signal to be amplified which is taken from the resonant compression cavity (15).

Abstract: A multibeam electron tube with several approximately parallel electron beams passing through a body. Among the beams, at least some define an interbeam volume, each beam defining the interbeam volume being subjected to a perturbing azimuthal magnetic field induced by all the other beams. The tube includes an element allowing, in at least one conducting element located in the interbeam volume, flow of a reverse current in the opposite direction to that of the current of the beams, this reverse current generating, in the beams defining the interbeam space, a magnetic correction field whose purpose is to oppose the perturbing magnetic field. Exemplary embodiments of the present invention especially apply to the multibeam klystrons or traveling wave tubes.

Abstract: The disclosure relates to electron guns comprising several electrodes, including a plurality of cathodes designed for the production, from an emissive face, of an electron beam each. Each of the cathodes is surrounded by a pole piece. This pole piece is designed to convey a magnetic flux close to the emissive face of the cathode. Application to longitudinal-interaction multibeam electron tubes.

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: Disclosed is an multiple-beam electron tube built around an axis (Z). These electron beams go through at least one resonant cavity (10) coaxial with this axis (Z). The beams are contained on both sides of the cavity in drift tubes (3) that end in the cavity in lips (5'), facing each other in the cavity. The spacing between two facing lips is not constant. Application especially to multiple-beam klystrons with improved output.

Abstract: A klystron with widened instantaneous passband comprises a succession of cavities separated by drift tubes, divided into three blocks. The first block comprises all that is upline from a first central cavity, the third block comprises all that is downline from a second central cavity and the second block comprises the central cavities. In each block, the sum of the lengths of the drift tubes is equal to: H+(T.times.180.degree.). H is a quantity ranging from 45 to 135 plasma degrees and T is an integer greater than or equal to zero. In at least one of the blocks, T is greater than or equal to one and the length of at least one tube of this block is greater than or equal to 135 plasma degrees. The disclosed device can be applied to wideband klystrons.

Abstract: This disclosure concerns electron guns comprising several electrodes, including a cathode. The gun has a device producing a magnetic field, adjustable if necessary, in the vicinity of the cathode. This device works together with one of the electrodes other than the cathode. It cooperates notably with the anode or the wehnelt. This device is either a solenoid or one or more permanent magnets. This device is placed either inside or outside the gun. It can be applied to high-power, "O" type electron tubes.

Abstract: The device according to the invention comprises a photocathode (1) illuminated by a luminous source (11) modulated at a high frequency F by an optical device (15) controlled at the frequency F, the optical device (15) being interposed between the luminous source and the photocathode. According to one aspect of the invention, the optical modulator (15) is controlled by a surrounding electromagnetic field at a high frequency F, in which the modulator is immersed. The electron gun device according to another aspect of the invention can be associated to a microwave circuit to obtain microwave oscillator or amplifier tubes. According to another aspect of the invention, the device supplies a pulsed electron beam for injection into particle accelerators.

Abstract: According to the invention, the conducting collector wall (23) on which the electrons are collected is surrounded by a coil winding (36) which is supplied with a periodically varying current, creating a slightly divergent axial magnetic field whose amplitude is periodically variable with time. The electron trajectories strike the collector wall at a grazing, nearly tangential angle, broadening the zone of impact, and the zone of impact is swept back and forth along the length of the collector, further spreading the power to be dissipated on a greater surface of the collector. Application to realization of very high power tubes or moderate power tubes with reduced collector dimensions.

Abstract: The output circuit according to the invention comprises a ring-shaped cavity formed by a waveguide with a section in the shape of an H that is turned back on itself. The output circuit comprises holes for coupling with the output cavity, these holes being evenly arranged on its internal cylindrical wall, and the said output circuit has at least one hole for coupling with a using circuit, set on its external cylindrical wall.

Abstract: The invention relates to multiple beam lasertrons. The n (n: integer greater than 1) electron beams of the lasertron are obtained from the same laser beam from which n secondary laser beams are extracted, by occultation, which are deflected respectively towards the n photocathodes of the lasertron.

Abstract: The dimensions of the resonant cavities of the multiple-beam klystron are determined in such a way as to enable functioning in the TM.sub.0n mode (n=a whole number greater than 1) and drift tubes relative to the beams go through the klystron cavities at places where the electrical field, in the cavities, is at its maximum value. This embodiment results in high-powered klystrons capable at working at high frequencies.

Abstract: A klystron is provided for supplying power with optimum efficiency across a variable impedance load. To attain this result, the field in the output cavity of a klystron is detected by a probe. This field supplies the image of the voltage at the terminals of the interaction gap. The signal supplied by the probe is used for adjusting the amplitude of the ultra-high frequency voltage applied to the input cavity so that the voltage of the terminals of the interaction gap remains less than the tolerable maximum whatever the ratio of standing waves reflected back by the output device.

Abstract: A microwave apparatus comprising n aligned cavities 1 in each of which one of the walls is formed by a plunger 2 integral with a shaft 3. The n shafts 3 bear against n aligned stops 5. Several lines of n stops 5, against which the shafts 3 successively bear, are carried by a support 10 which in one illustrative embodiment comprises a cylinder of revolution the axis of rotation 00' of which is orthogonal to the shafts 3 of the plungers 2, the degree of penetration of each stop 5 with the support 10 being adjustable to adjust the resonance frequencies of the cavities.

Abstract: A coupling device for a microwave tube including a first length of waveguide and a second length of waveguide of rectangular cross-section. The two lengths of waveguide are connected together and have their free ends coupled when operating to a load and to the tube respectively. The large side of the cross-section of the second length of waveguide is equal and parallel to the corresponding side of the first length of waveguide. The small side of the cross-section of the second waveguide is several times smaller than the corresponding side of the first waveguide. Two connected lengths of waveguide form a transition. The first waveguide contains an iris and the coupling device forms an assembly of matched impedance.