Abstract: Disclosed are overvoltage arresters comprising a columnar arrangement of arrester elements, insulating elements and conducting elements. The elements are arranged to provide a current flow in at least one plane extending transversely to the columns. The conducting frame elements connect other elements thereto which elements extend both axially and transversely of the columns. For an arrester including n conducting frame members per plane, n-1 arrester elements are arranged per plane of the columnar structure. The current connection between adjacent plane is made by an arrester element or by a conducting member preferably such that opposite current flows are obtained in adjacent planes. Overvoltage arresters according to the invention are particularly suited for using voltage-dependent resistors of the zinc oxide type alone or in conjunction with spark gaps. The columnar structure may be disposed in a customary insulating gas such as nitrogen or in a gas with particularly high insulating strength such as SF.

Abstract: In a traveling wave tube (TWT) using an interaction circuit of the helix-derived type, the gain of the tube normally varies significantly over the passband. The invention provides a simple method of reducing the gain variation together with a reduction in the noise power density produced at the output of the tube. This is accomplished by affixing a nonresonant terminated transmission line such as a meander line on at least one of the dielectric rods used to support the helix.

Abstract: A supporting system for a delay line of a travelling wave tube wherein a number of clamping rings press dielectric support rods against the delay line. The clamping rings have a natural length along the delay line and a spacing distance such that (N.multidot.w.lambda.)/4=L.sub.1,2, where L.sub.1,2 designates the length of the line resonators, .lambda..sub.w the wave length on the delay line, and N a whole uneven number.

Abstract: A valve arrester comprises a serial arrangement which includes at least one nonlinear resistor and spark gaps implemented as arcing horns which are housed in slit-type arc extinction chambers whose walls are made of an electric insulation material and form a single helical blade. The latter is arranged on a central cylindrical member and adapted to produce a single helical arc which is formed from arcs struck during the arrester breakdown in the spark gaps, said arcs being joined together during their movement.

Abstract: A traveling-wave-tube has a vacuum housing that includes the helix rf circuitry. The helix conductor is intertwined with and hermetically sealed to the insulating material comprising the vacuum housing. Thus, portions of the helix serve for interaction with the electron beam in the center of the vacuum housing while other portions are in contact with the atmosphere, thus cooling the helix and permitting the tube to operate at higher average powers.

Abstract: Capacitance grading is provided within gas insulated lightning arresters containing stacked zinc oxide varistors by means of a grading ring electrically connected to the line terminal or, for arresters of the higher voltage ratings, by means of a plurality of telescoping external electrostatic shields. The shields are arranged so that the degree of overlap between sequential shields decreases from the line end to the ground end of the varistor stacks. The capacitance grading is provided by the degree of overlap between the sequential shields and the ratio of the radii of the overlapping shields.

Abstract: A focusing device for an electron tube is constituted by alternating magnets and pole pieces in the form of washers, which are fixed against one another in such a way as to form a cylinder surrounding the envelope of the tube and being of the same axis as the latter, the electron beam propagating along said axis. The magnetized washers have a central hole and are interrupted over part of their circumference by an opening permitting their fitting between the pole pieces previously fixed to the envelope.

Abstract: In a microwave tube of the type wherein an electron beam emitted by an electron gun is focused and caused to interact with an input high frequency wave at a high frequency circuit unit by magnetic flux generated by a periodic permanent magnet assembly, and the electron beam after the interaction is collected by a collector unit, the portion connected to the output unit of the high frequency circuit unit comprises a column-shaped waveguide member having an end surface comprising a portion of the wall of a cavity at the end of the high frequency circuit unit, the member being bored with a central aperture at the center axis to allow electron beam to pass from the electron gun to the collector unit. A waveguide for guiding the electromagnetic waves from the end surface to the output unit is also provided, and the end surface is shaped like a fan.

Abstract: A series circuit of a gap section and a valve block is connected between a transmission line and the ground. The valve block consists of a plurality of nonlinear resistor elements connected in series. A first impedance circuit consisting of a resistor and a capacitor connected in series is connected in parallel to the gap section. Also, a second impedance circuit consisting of another resistor and another capacitor connected in parallel is connected in parallel to the valve block. The ratio of the voltage applied across the gap section to that applied across the valve block is determined by the ratio of the impedance of the first impedance circuit to that of the second impedance circuit. A pair of discharge electrodes included in the gap section, which are a prescribed distance apart from each other, comprise a narrower gap region at which spark is started.

Abstract: A lightning arrestor comprising at least two stacks of resistor disks juxtaposed within a housing and electrically connected in parallel. The stacks include the same number of disks, at least 35, and preferably 100 or more. Each stack comprises at least two sub-stacks which are aligned end-to-end and electrically connected. Adjacent sub-stacks of parallel stacks are mechanically connected but electrically insulated from each other.

Abstract: A traveling-wave tube protection circuit prevents faults in its associated power source from damaging it. The power source supplied DC voltages to the collector, slow-wave circuit, anode and cathode of the traveling-wave tube. A power source control circuit is provided between the anode electrode and the anode power source circuit and is used for applying a control voltage to the anode electrode. The control voltage stops the operation of the traveling-wave tube during the transient times which occur responsive to the initiation and the termination of the power source circuit operations. On shutdown, the power source control circuit also stops the supply of the control voltage to the anode electrode after the transient response is terminated. The power source control circuit has a high-frequency oscillator driven in response to either the initiation or the termination of the operation of the power supply means.

Abstract: A coupled cavity traveling wave tube (10, 10') is provided having a velocity taper, i.e., gradual velocity reduction, which affords beam-wave resynchronization and thereby enhances efficiency. The required wave velocity reduction is achieved by reducing the resonant frequencies of the individual resonant cavities as a function of the distance from the electron gun (16, 16'), through changes in internal cavity dimensions. The required changes in cavity dimensions can be accomplished for example, by gradually increasing the cavity radius (R.sub.2, R.sub.3, R.sub.4) or decreasing the gap length (l.sub.1, l.sub.2), from cavity to cavity. With this approach the velocity reduction is carried out without an increase in circuit resistive losses and the upper and lower cut off frequencies are reduced in approximately the same manner.

Abstract: A coupled cavity traveling wave tube is disclosed which includes a plurality of pole piece members and hollow spacer members which are alternately arrayed to define a plurality of cavities. The pole piece members each has a central aperture and a coupling slot through which microwave energy is coupled between adjacent cavities. The tube includes a plurality of first loss elements each of which is positioned in both of two respective adjacent cavities, with each of the first loss elements having its first end in contact with the front face of a respective one of the alternate pole piece members, its central portion pass through an aperture in the next intervening pole piece member in which it is coupled to the coupling slot in that pole piece member, and its second end in contact with the rear face of the next alternate pole piece member.

Abstract: An arrester comprises a plurality of blocks connected in parallel between first and second connecting metal plates and each comprised of a plurality of stacked nonlinear resistor elements, at least one block comprised of a plurality of stacked nonlinear resistor elements and connected between the second connecting metal plate and a third connecting metal plate grounded, and a discharge gap connected in parallel with the later-mentioned block and between the second and third connecting metal plates. The discharge gap is provided below one of the blocks connected in parallel between the first and second connecting metal plates.

Abstract: In a traveling wave tube (TWT) with a non-dispersive interaction circuit such as a helix, the length of the circuit in wavelengths, and hence the gain of the tube, varies with the frequency. The variations of gain over a very wide bandwidth can cause oscillation problems. The invention provides an inverse variation with frequency of the physical length over which the circuit interacts with the beam. This is done by resonant attenuators coupling to the interaction circuit over various lengths depending on their resonant frequency, the attenuation being enough to effectively remove the interaction circuit wave. The attenuators are preferably formed of resonant sections of slow-wave circuit deposited on longitudinal ceramic rods such as the helix support rods.

Abstract: In traveling wave tubes with broad bandwidth, such as an octave or more, the gain varies by many dB across the band. One or more lossy circuits inside the tube coupled to the interaction helix-type slow-wave circuit are resonant at frequencies within the operating band. They provide a loss varying with frequency to compensate for the gain variation. The resonant circuits are typically metallized patterns on a dielectric rod which may be a support rod for the interaction circuit. Compared to an external gain equilizer in the drive circuit of the TWT, the internal equalizer is cheaper and provides a better noise figure.

Abstract: A high frequency electromagnetic wave generator is disclosed which comprises an electron gun which directs an electron beam through a region generally adjacent a diffraction grating. The grating cooperates with an opposed reflecting surface to produce a standing electromagnetic wave. The reflector comprises a highly reflective dielectric coated mirror. Supporting means for the diffraction grating may also comprise a reflective dielectric surface.

Abstract: The areas of the walls 1 separating two adjacent cavities that are located on the periphery of the opening 3 for allowing through the electron beam, and whose thermal resistance is greatest, are those comprised between this opening 3 and a cavity coupling opening 2. Owing to the opening 3 for allowing through the electron beam (elliptical, centered on the axis of the line 00', with the large axis of the ellipse merging with the axis of symmetry AA' of the coupling openings 2 intersecting the axis 00'), these areas are the furthest away from the axis of the line 00' along which the electron beam is propagated. The invention is applied to microwave tubes and in particular to travelling-wave tubes.

Abstract: In a traveling wave tube device of the type comprising a helix which causes a microwave power to interact with an electron beam and a periodic permanent magnet assembly for focusing the electron beam, there are provided a plurality of annular permanent magnets and a plurality of pole pieces which are alternately disposed between input and output member of the microwave. The permanent magnets and pole pieces define annular recesses and a plurality of troidal metal spring rings are disposed in each recess in thermal contact with the permanent magnets and a carbonaceous coating coated on a pumped enclosure containing the helix.

Abstract: A traveling wave tube (TWT) has a slow wave structure in the form of a helix for amplifying the forward electromagnetic wave. The TWT is provided with an outer slow wave assembly for attenuating a backward wave to provide stability to the TWT. A set of ceramic rods are uniformly spaced circumferentially around the helix for supporting the outer slow wave assembly which is formed by an electrically conducting wire wound around the supporting rods. The wire is wound in a helical fashion with individual turns of the helix being spaced apart to form the outer slow wave structure. An electrically conducting cylinder surrounds the outer slow wave structure and is in contact therewith only at the sites of the rods. Dielectric slabs, having a slow wave structure such as a meander line disposed thereon, are inserted periodically around the outer slow wave structure in spaces between the winding and the cylinder.

Abstract: A slow wave guiding structure such as a helix delay line for electron intction devices of the traveling wave type having diamond heat sink supports for substantial enhancement of power levels of operation is provided. The diamond supported helix structures are maintained in good thermal contact by pressure only in lieu of the diamonds being bonded to metallic members. The invention is applicable to numerous slow wave structures including ladder, ring-bar, meander, as well as interdigital types.

Abstract: The object of the invention is to provide a depressed collector which captures the spent electrons of a microwave transmitting tube at high efficiency in both high and low power modes of operation.The collector comprises entrance and end electrodes (14 and 18, respectively), electrode (18) having a spike extending toward entrance electrode (14). Intermediate electrodes (15, 16 and 17) and the entrance electrode (14) each have a central aperture and, together, these electrodes capture most high power mode spent electrons. The apertures of the electrodes (14-17) increase in size in a downstream direction.To capture low power mode spent electrons a low power mode electrode (19) is positioned between the last intermediate electrode (17) and the end electrode (18). This electrode (19) has a central aperture preferably smaller but no larger than that of electrode (17).

Abstract: A traveling wave tube has a delay line in the form of a spiral conductor supported within a metallic vacuum shell by a plurality of dielectric support rods. The support rods are covered at least partially with a metalization and soldered together with the delay line and the vacuum shell is shrunk onto the support rods, thus providing a simple structure having good heat dissipating properties.

Abstract: A traveling wave tube has a helix or ring-bridge delay line arranged within a vacuum envelope and a plurality of dielectric holding rods parallel to each other for supporting the delay line. The vacuum envelope has an axial longitudinal groove intermediate between two holding rods, and a pressure element located within the groove presses, by way of a tension plate, the holding rods against receiving surfaces provided in the interior of the vacuum envelope, whereby the holding rods are in good mechanical and heat-conducting relationship with the envelope.

Abstract: A traveling wave device, or the like, having an internal metallic helical core element which has a plurality of particulate deposition deposited dielectric segments to form an unific slow wave structure having an improved balance between the heat conductive and electrical requirements of said slow wave structure; and methods for forming said balanced slow wave structure.

Abstract: A helix type traveling-wave tube comprises a conductive tubular envelope wherein a coaxial helix interaction structure is provided, the function of which is to shield the electromagnetic wave of the signal. By a proper arrangement of metallic conductive elements suitably applied upon dielectric support rods firmly inserted between the inner conductive surface of said tubular envelope and outer perimetrical surface of said helix, a selective shielding may be attained in order that the helix dispersions are almost null or even negative and the operative frequency band is remarkably extended with a substantially constant velocity of phase.

Abstract: The present invention relates to a backward wave mode oscillator tube, the delay line of which is in two sections of dissimilar length both operating in the backward wave mode, aligned in the direction of propagation of the electrons of the beam, the second being substantially shorter than the first and exhibiting a structure homothetic with the first in the ratio 1/n, n being an integer, with a load arranged at the end of this second section which is adjacent the electron-gun, in which load is picked-up electromagnetic energy on the n.sup.th harmonic of the predominant component of the wave in the first section.

Abstract: A coupled cavity type traveling wave tube wherein selected matching and main cavities in the tube are provided with a layer of high resistance metal to minimize generation of reflected waves and thereby to achieve stable operation with high efficiency.

Abstract: A delay line for a high frequency tube that is cooled by circulating fluid.The cooling fluid circulates in a duct (FIG. 3, 10), formed in the space between two sleeves (8 and 9). The sleeves are of non-magnetic material, impervious to the cooling fluid, and have an axis parallel to the axis of the delay line. The first sleeve (8), is vacuum tight, brazed or hard soldered to dielectric supports (2) and, in cross section connects two adjacent supports in a straight line. The second sleeve (9), is cylindrical, and contains the first sleeve to which it is brazed at several points. A focusing device made of permanent magnets is mounted on the second sleeve.The invention will find use in high frequency tubes.

Abstract: The external outline of the transverse section of the walls externally bounding the cavities (4) is circular, but the thickness of these walls is not constant, being smaller in the zones of these walls which are not traversed by the cooling ducts (5) than in the other zones. Application to travelling-wave tubes carried in aircraft.

Abstract: A surge arrester of compact construction includes a housing formed preferably of elastomeric material through which a pair of spaced terminals protrude and between which a stack of metal oxide varistor discs is disposed and connected in series therewith. Disposed below the lower one of the discs and in contact therewith is a conductive base plate and an electrode is spaced somewhat from the lower surface of the base plate to form a gap and is provided with shunt means connecting the electrode with the upper surface of the lower disc so that an overvoltage surge condition and the resulting arc across the gap establishes a shunt circuit around the lower disc.

Abstract: In a travelling-wave tube for very high frequencies the slow-wave circuit is formed of four metal combs having teeth pointed toward the electron beam. The combs are arranged in two pairs. The teeth of the two combs in each pair extend inward from opposite sides of the beam and are axially aligned to form the electrical equivalent of a half-wave bar or ladder structure. They may or may not be joined at the tips because those are low-current points. The teeth of one pair are at right angles to those of the other pair and are displaced axially to interleave with them. Each comb is preferably made from a single piece of copper to provide better dimensional precision, low circuit loss, mechanical durability and high thermal capability.

Abstract: A lightning arrester enclosed in a grounded metal enclosure filled with SF.sub.6 includes six nonlinear resistors of sintered ZnO serially interconnected in superposed relationship between a high voltage conductor and the enclosure through a cylindrical high voltage conductor. The resistors are divided into three equal units and two shield discs are interposed between the adjacent units and connected to respective hollow cylindrical conductors coaxially disposed in radially spaced relationship around the cylindrical high voltage conductor.

Abstract: A series string of ignitrons for switching a large current at high voltage to ground. Switching is initiated by means of a negative trigger pulse applied to the cathode of the lowest voltage level ignitron next to ground to draw ground current through diodes in the ignitor circuit. The trigger pulse is applied thereby to the next higher ignitron cathode and sequentially to the remainder of the ignitrons in the string through diodes in respective ignitor circuits. Full line voltage is held off of nonconducting diodes and ignitrons by means of varistors.

Abstract: A traveling wave tube arrangement for use in satellite communications systems is disclosed wherein a plurality of traveling wave tube delay structures and an electron gun are contained in a single envelope with beam deflection apparatus. The electron beam deflection apparatus is disposed between the electron gun and the plural traveling wave tube delay structures to selectively deflect the electron beam to the individual delay structures on a time division basis. In one embodiment, electron beam deflection apparatus is simplified by arranging the individual delay structures radially from a point in the path of the electron stream where the stream is deflected by the beam deflection apparatus.

Abstract: A high power hyperfrequency emission tube which comprises, in a vacuum envelope:means for generating and focussing an electron beam;a plurality of energy collecting means;a plurality of means for accelerating the electrons of the beam, formed by hyperfrequency circuits.The collecting means and the accelerating means are distributed along the path of the electron beam and in its direction of propagation, with a spatial period D.sub.c and D.sub.a which is inherent in them, the accelerating means restoring to the electron beam the energy lost at the level of the collecting means.

Abstract: Helical slow-wave structure assemblies including a helical dielectric supporting member are disclosed along with methods for fabricating such assemblies. After the slow-wave structure helix is wound on a mandrel, a masking helix is coaxially wound about the slow-wave structure helix in the same sense as the slow-wave structure helix over the helical space between turns of the slow-wave structure helix and in overlapping relationship with portions of adjacent turns of the slow-wave structure helix. The supporting helix is formed by plasma spraying dielectric material into the helical space between turns of the masking helix. The dielectric material is ground to a predetermined radial dimension, and the mandrel and the masking helix are removed. By utilizing a masking helix of tapered width, a dielectric supporting helix of tapered width may be fabricated to provide a slow-wave structure assembly with a tapered phase velocity.

Abstract: An overvoltage arrester wherein the arrester comprises an insulating housing which encloses a body of cast resin in which is embedded a voltage dependent resistor and a first connecting device, a portion of which protrudes from the resin body and extends out of the housing. The arrester is further provided with a spark gap formed as a separate unit and a second connecting device anchored to the spark gap, both of the latter elements also being disposed in the housing.

Abstract: A gapless surge arrester is disclosed herein and includes a porcelain outer casing and a stack of zinc oxide discs located within the casing for passing surge currents therethrough. Silicon dioxide, preferably sand, is provided between this stack in the casing for transferring heat from the discs to the porcelain outer casing as a result of the surge current and for absorbing fault energy where necessary by changing states.

Abstract: Oscillations due to backward waves in a high-power traveling-wave tube (TWT) are inhibited by a non-reciprocal attenuating device which essentially absorbs only backward waves. A directional coupler mediates the exchange of energy between the TWT interaction circuit and an external circuit containing a non-reciprocal loss element such as a ferrite isolator. In such embodiments the high-frequency power handled by the isolator is much less than the power in the TWT interaction circuit. The frequency band handled by the isolator is much narrower than that handled by the TWT. Coupling to the loss element is through one or more resonant circuit elements such that a "notch" of attenuation is obtained for a backward wave only, at a certain frequency where oscillations are prone, such as the frequency associated with 2.pi. phase shift per cavity in a coalesced-mode coupled-cavity TWT.

Abstract: An electron beam deflection structure for a high frequency cathode-ray tube incorporates a meanderline slow wave circuit that is supported directly by the same glass rods used to support other portions of the CRT's beam forming and deflection system. To accomplish this, elongate loops that serially interconnect a plurality of deflection plate segments are bent away from the plane of the segments (and the beam axis) and joined by integral support strips to the rods. The elimination of a separate support structure for the deflectors greatly reduces manufacturing costs.

Abstract: A generator for variable frequency submillimeter waves launches surface astic waves in piezoelectric material for generation of an associated acousto-electrical field. An electron beam is acted upon by the acousto-electrical field in a manner simulating the effect of an etched grating, resulting in an output frequency which may be varied by the variation of the acoustic wave frequency, or the velocity of the electron beam.

Abstract: An applique or attachment for a station protector spark gap device includes an insulated enclosure housing a gas tube spark gap device together with fail safe shorting means located circumferentially therearound. Auxiliary gaps in parallel with the gas tube spark gap device are provided as back up should the gas tube vent. Wire leads welded to end plates within the enclosure make connection with the ends of the gas tube spark gap device, the fail safe shorting mechanism and the auxiliary gaps.

Abstract: A traveling wave tube having a helix continuously supported within a dielectric barrel provides efficient operation at high power levels. The wire forming the helix has a greater width along its inner surface adjacent the interaction space of the traveling wave tube than along its outer surface which is continuously secured to the dielectric barrel. The wire confines the electromagnetic field to an area adjacent the interaction space for low dielectric loading thereby assuring a good coupling impedance into and out of the traveling wave tube and a wide bandwidth. Improved thermal conductivity for heat from the helix is provided as a result of the helix being continuously supported and in contact with the dielectric barrel. The tube is low in cost, which makes it attractive for expendable use.

Abstract: An helical type line for travelling wave tube, with a variable diamter. The line is made on a skew surface constituted by a revolution surface on which flat surfaces have been made. The variation of the line diameter may be carried out by a variation of the revolution surface diameter, the flat surfaces being parallel to the axis of the revolution surface. That variation may be also carried out by a variation of the angle made by the flat surfaces in relation to the helix axis, the revolution surface being cylindrical.

Abstract: Voltage surge arrester devices having predetermined shunt gap sparkover voltages are provided by the series combination of high- and low-exponent varistors. In one embodiment the high-exponent varistor comprises zinc oxide and the low-exponent varistor comprises silicon carbide.

Abstract: A high intensity light source having high repetition rate and narrow pulse-width. The light source comprises a metal casing having coaxially mounted arcing electrodes therein which utilize the capacitance of the coaxial system to charge up to the arcing potential. One electrode is electrically connected to the end wall of the casing to provide a reflected wavefront from the end wall after an arc has been struck, such wavefront serving to extinguish the arc and thus provide a sharp pulse. The lamp may be used for such areas as photochemical and photobiological research, in place of much costlier nanosecond lasers.

Abstract: To suppress spurious oscillations in a helix-type traveling wave tube (TWT), frequency-sensitive loading is produced by a lossy resonant circuit attached to a dielectric support and coupled to the fields of the interaction circuit. The lossy circuit is resonant near the band-edge frequency. It may be a section of delay line with reflective terminations. In one embodiment, it is a metallized pattern on a dielectric rod used to support the helix.

Abstract: A surge diverter connected between a conductor and ground comprising several spark-quenching gaps, voltage-controlled shunting resistors connected in series with these gaps and voltage controlled control-resistors, each connected in parallel either to a gap alone or to a unit formed by a gap and a shunting resistor in series with the latter. The voltage-controlled control-resistors have current-voltage characteristics with substantially the same steepness, while the resistance value of these control-resistors at the rated voltage increases sequentially from the conductor to grand.

Abstract: A delay line for transit time amplifier tubes which has a filter characteristic with a negative dispersion in the fundamental wave of the longest pass band, i.e.