Abstract: In a travelling-wave tube (20), a cylindrically-shaped slow-wave circuit cavity-defining member (34) is supported by and is thermomechanically bonded to a tubularly-configured vacuum wall member (32). The bonded joint comprises a pair of arcuate grooves (52) extending lengthwise of the slow-wave circuit and positioned diametrically opposite one another about the axis of the tube. A helical or wavy spring (54, 58) lies in each groove and is resiliently biased in intimate mechanical and thermal contact between the groove and the vacuum wall. The helical spring, in particular, can be used as a conduit for exhaust of gases from the travelling-wave tube during its fabrication.

Abstract: A radio frequency amplifier having a slow wave structure supported adjacent an electron beam by a support structure. The support structure includes at least one structural support member, having a supporting rod, and a dielectric material disposed on an outer surface portion of the supporting rod. The dielectric material is different from the material of the supporting rod. More particularly the dielectric material is electrically insulating having either a resistivity which reduces upon impingement of electrons from the electron beam or a secondary emission ratio that is substantially unity. The supporting rod has high thermal conductivity and is preferably boron nitride. The dielectric material is preferably titania, magnesia or beryllia.

Abstract: The collector in a linear-beam electron tube is insulated from its heat sink so that it can be operated at a depressed potential. The insulation comprises two bands of dielectric sequentially in contact between the collector and heat sink. The intervening space is sealed off and preferably filled with a dielectric fluid to improve heat transfer and inhibit voltage breakdown. Gaps in one band are preferably aligned with solid parts of the other to reduce electric leakage.

Abstract: The invention disclosed herein is a permanent magnet structure which is uul in focusing or guiding charged particle beams, such as those employed in traveling wave tubes, wigglers and undulators. The magnets are annular or planar in shape and have a cross-sectional configuration which is triangular in shape. The cross section forming the triangular magnet sections is that plane which contains the linear beam path and intersects the magnets. The magnetizations of the magnets are oriented perpendicular to the magnetizations of adjacent magnets such that no magnetic poles exist on the outer surface of the permanent magnetic structure.

Abstract: The disclosure concerns microwave tubes and, more particularly, travelling wave tubes wherein the region under vacuum is isolated from the external HF input/output circuits by vacuum-tight windows. The disclosed window consists of a ceramic cylinder, the two ends of which bear metallic flexible rings. This window is brazed to the cylindrical chamber of the part under vacuum by means of a clearance machined in the chamber, so that the chamber and the window are integrated and coaxial. The HF transmission through the window is achieved by means of an antenna formed by a metallic strip mounted, at right angles, on a metallic cylinder that fits the chamber. The device can be applied to power microwave tubes and, notably, to travelling wave tubes.

Abstract: In a travelling wave tube, the delay line of which is coupled to a transmission line of an external microwave circuit by a coupling pin having a coupling surface that faces an end surface of the transmission line, a microwave window extends between the coupling surface of the coupling pin and the end surface of the transmission line. This window is permeable to the microwave energy and impermeable to the gases. It is fixed imperviously to the travelling wave tube.

Abstract: A travelling-wave tube has a cylindrical sleeve containing a delay line and a coupling device between the delay line and an external microwave circuit for removal or injection of microwave energy. This external circuit comprises a transmission line possessing a conductive internal core. A conductive part is placed at one end of the delay line. It has a coupling pin that projects inwards into the sleeve and is brazed to an end of the delay line. The conductive part is brazed to the sleeve. The coupling between the delay line and the external circuit is made between the part and the internal conductive core of the transmission line. This coupling is without contact, a narrow gap being prepared between the external surface of the part located on the side of the coupling pin and the internal conductive core.

Abstract: Slow-wave structures are formed by the method of this invention in the form of a coupled-cavity structure. The coupled-cavity form of waveguide slow-wave structures is formed by wire electric discharge machining of disks from a solid rod of copper. The disks are supported in their desired positions by retained portions of the rod while the disks are brazed inside a cylindrical shell of copper. After brazing, the retained portions may be partially removed to form the completed slow-wave structure.

Abstract: An integral conductively-loaded encasing barrel for a slow-wave structure is formed by electrical discharge machining a plurality of circumferentially spaced longitudinally extending slots in the interior surface of the barrel. The machining discharge is established between a portion of the interior surface of the barrel and an electrode wire which is moved in a longitudinal direction within the barrel while the barrel is moved in a preselected manner in a plane transverse to the direction of movement of the wire. A subassembly comprising a slow-wave structure and a plurality of longitudinally disposed electrically insulating support rods in contact with and circumferentially spaced about the outer surface of the slow-wave structure is secured within the barrel with the support rods disposed within respective machined slots. The radially inwardly projecting portions of the barrel between the slots provide integral conductive loading for the slow-wave structure.

Abstract: A traveling-wave tube (10) has a confined-flow periodic permanent magnet focusing arrangement (26) in which either the first magnet (60f) or the third magnet (60t) from the electron gun (12) has an extent or axial thickness along the electron stream path which is one-half that of the remaining magnets in the arrangement, thereby providing a scalar magnetic potential of essentially zero on the electron gun pole piece (46), thereby eliminating the field reversal at the cathode (14). This enables a magnetic field to be provided in the region of the electron gun between the gun pole piece (46) and a location behind the cathode due solely to the magnetic field leaking through the gun pole piece aperture (50). The axial magnetic field within the electron gun (12) may be tailored or fine tuned, by varying the size of the aperture (50) in the gun pole piece (46).

Abstract: The plasma produced by means of microwaves in the presence of a magnetic field and a gas serves to coat a substrate which is situated in a chamber having metal walls. The microwaves are repeatedly reflected at the metal walls, so that the chamber has numerous microwave modes. By means of permanent magnets, which are placed either inside the chamber or outside the chamber in the vicinity of the substrate that is to be coated, it is possible to produce within this chamber an electron-cyclotron resonance which permits a locally controlled ignition of the plasma.

Abstract: A coupled-cavity circuit for a microwave electron tube is shown having one or more cavities whose cross-sections are polygonally shaped, such as rectangles. Located in one or more corners of the polygonally shaped cavities are irises which have a higher resonant frequency. These irises are generally triangularly shaped with rounded corners and one leg of the triangle rounded about the drift tube of the microwave electron tube.

Abstract: A high-power microwave/mm-wave oscillator is filled with an ionizable gas at a pressure of about 1-20 mTorr, into which an electron beam is injected at a high current density of at least about 1 amp/cm.sup.2, but typically 50-100 A/cm.sup.2. A plasma is formed which inhibits space-charge blowup of the beam, thereby eliminating the prior requirement of a magnet system to control the beam. The system functions as a slow-wave tube to produce narrow-band microwaves for a gas pressure of about 1-5 mTorr, and as a plasma wave tube to produce broadband microwave/mm-wave radiation for a gas pressure of about 10-20 mTorr.

Abstract: A coaxial TWT comprises a hollow beam gun which injects a thin annular beam between multifilar helices independently supported by thin-walled dielectric sleeves. The beam is focussed by a balanced, coaxial PPM focussing assembly, causing a stable hollow beam flow. The input and output coupling helixes, and the interaction helices which form the slow-wave structure on the exterior and the interior of the hollow beam, respectively, are preferably counterwound with respect to each other to provide greater frequency bandwidth than when similarly wound. Input and output helix coupling to either the inner or the outer helix is possible.

Abstract: Switching power supply for generating a voltage for a pulsating load (2), in particular for generating a helix voltage for a TWT. The switching power supply is provided with a dc voltage source (1), a buffer (12) from which the load (2) is powered, and switches (3) and a control circuit (5) for regulating the charging of the buffer from the dc voltage source (1), whereby the power supply is provided with a circuit coupled to the dc voltage source (1), which circuit consists of a current source (6), the above-mentioned switches (3) and a primary (9) of a converter (7). The buffer (12) is powered from the secondary (11) of the said converter (7). The control circuit (5) controls the switches (3) by means of a signal which is a function of the rhythm of the pulsating load and the voltage across the buffer.

Abstract: A coupled-cavity delay line for a traveling-wave tube which includes a device for focusing an electron beam along the axis of the delay line for interaction between the electron beam and an electromagnetic wave propagating along the delay line. The focusing device includes an alternate series of permanent magnets and pole pieces which confine resonant cavities on each side. Each of the pole pieces is common to a pair of adjacent cavities and is provided with a drift tube which is positioned at a center thereof and which has a central aperture for passage of the electron beam. Each of the pole pieces is also pierced by at least one intercavity coupling aperture. The delay line also comprises a heat transfer member provided in at least one of the pole pieces to extend from the drift tube to the outside of the pole piece. This heat transfer member is made of a material such as copper having a heat conductivity higher than that of a pole piece.

Abstract: It is an object of the invention to provide a miniature traveling wave tube which will have most of the advantages of solid state circuitry but with higher efficiency and without being highly sensitive to temperature and various types of electromagnetic radiation and subatomic particles as are solid state devices.The traveling wave tube which is about 2.5 cm in length includes a slow wave circuit (SWS) comprising apertured fins with a top cover which is insulated from the fins by strips or rungs of electrically insulating, dielectric material.Another object of the invention is to construct a SWS of extremely small size by employing various grooving or etching methods and by providing insulating strips or rungs by various deposition and masking techniques.

Abstract: A wide band device is provided for coupling between the delay line of a travelling wave tube and the external circuit transmitting the energy of the tube, comprising a coupling wave guide having a single ridge, connected on one side to the delay line and on the other being extended by one of the two ridges of the output guide, the section of the coupling guide increasing progressively, with constant impedance from the line to the output guide whereas this latter has an impedance transformer providing impedance matching between its standard guide part and the coupling guide.

Abstract: A slow-wave circuit for a TWT has periodic transverse plates extending across the axial by extending vacuum envelope. An opposed pair of apertures 24, 26 in each plate 20 couple adjacent cavities 28 between plates 20. Coupling apertures 24 in alternate plates 20 are rotated transverse to apertures 26 in the other plates to provide coupling only between adjacent cavities 28. Each plate 20 has transverse ridges 30 enclosing its axial beam aperture 22. The ridges 30 are orthogonal to the coupling apertures 24, 26 to increase beam coupling and decrease capacitance for wider bandwidth and higher impedance.

Abstract: A power supply for helix and collector electrodes of a traveling wave tube is driven by an AC power source having a frequency of at least 500 KHz. The helix supply includes plural, stacked voltage double AC to DC modules responsive to the 500 KHz source. The collector supply includes plural AC to DC modules, each having a diode full wave rectifier bridge, connected in stacked relation. Each of the modules includes a transformer with a ferrite, toroidal core dimensioned so that it is not driven into saturation by the 500 KHz source. Each module also includes inexpensive, signal switching diodes having a recovery time of approximately 4 nanoseconds. The ratio of the collector to helix DC voltages is maintained constant by threading a common lead through the apertures of the toroidal cores of the helix and collector modules. A separate common lead threaded through the apertures of the toroidal cores in the collector modules is connected directly to the 500 KHz power source.

Abstract: A traveling-wave tube has coupled cells in a periodic arrangement defined between apertured irises separated by respective spacers. The spacers have dielectric waveguides terminating in lossly loads to attenuate RF frequencies above the upper limit of the frequency to be amplified by the tube.

Abstract: A helix slow-wave circuit for use in a linear-beam microwave tube device, comprises a first helix formed by a first wire-like member wound in a first sense at a plurality of turns, and a second helix formed by a second wire-like member wound at a plurality of turns in a second sense opposite to the first sense so as to coaxially surround and superpose on the first helix so that the first and second helixes intersect each other at suitable intervals along an axial direction of the helixes. The first helix is fixed to the second helix in at least some of intersecting points between the first and second helixes.

Abstract: Slow-wave structures are formed by the method of this invention in the form of helical or coupled-cavity structures. A helical waveguide form of slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then totally eroded away to form a slow wave structure having a helical radially-extending portion, or if only partially eroded with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The helix is extended into a rectangular waveguide for coupling the slow-wave structure to the source and to the load. The coupled-cavity forms of waveguide slow-wave structures are formed by machining disks from a solid rod of copper.

Abstract: An electron beam catcher for velocity modulated electron tubes which is formed as a two multi-stage collector comprising a plurality of catcher electrodes 1 and 2 surrounding the electron beam and mounted so that one follows the other in the direction of the electron beam axis and the catcher electrodes are electrically insulated from each other and are surrounded by a metallic outer envelope 3. A plurality of semicylindrical insulating parts 4 and 4' extended in the axial direction and are mounted between the catcher electrodes 1 and 2 and the outer metallic cover or vacuum envelope 3 which is heated to cause it to expand and is then shrunk onto the insulator parts 4 and 4' such that the oblong insulator parts 4 and 4' are pressed against the catcher electrodes 1 and 2 and are tightly held by the metallic outer vacuum envelope 3. The electron catcher 15 particularly useful in high powered travelling wave tubes.

Abstract: Microwave oscillators and amplifiers which utilize a superconducting slow-wave circuit. The slow circuit is made from materials which exhibit superconductivity at relatively high critical temperatures. The slow wave circuit is integral with the device's vacuum housing. Coolant exterior to the vacuum housing maintains the circuit in the superconducting state. The slow-wave circuit, which protrudes into the vacuum housing provides modulation of an electron beam which traverses the interior of the vacuum housing. Output power is ultimately extracted from the slow wave circuit.

Abstract: A traveling wave tube has a cylindrical vacuum envelope surrounding a delay line. The vacuum envelope is tightly surrounded by a permanent magnet system of ring-shaped pole discs and of magnetic rings respectively arranged between the pole discs and oppositely polarized in alternating fashion in an axial direction. The permanent magnet system is inserted into an outer envelope in form-fit fashion. An attitude and position retention for the focusing elements which is resistant to temperature shock is provided in the traveling wave tube. For this purpose the permanent magnet system is glued at its outside generated surface and the glue is formed of a mixture of an epoxy resin having adhesive properties and of glass fibers provided therein in an undirected attitude. This traveling wave tube is useful given extreme temperature fluctuations, such as in a range from -60.degree. C. through +95.degree. C.

Abstract: Slow-wave structures are formed by the method of this invention in the form of helical or coupled-cavity structures. A helical waveguide form of slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then totally eroded away to form a slow wave structure having a helical radially-extending portion, or if only partially eroded with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The coupled-cavity forms of waveguide slow-wave structures are formed by machining disks from a solid rod of copper. The disks are supported in their desired positions by an axial retained portion of the rod until the disks are brazed inside a cylindrical shell of copper.

Abstract: A power supply for helix and collector electrodes of a traveling wave tube is driven by an AC power source having a frequency of at least 500 KHz. The helix supply includes plural, stacked voltage doubler AC to DC modules responsive to the 500 KHz source. The collector supply includes plural AC to DC modules, each having a diode full wave rectifier bridge, connected in stacked relation. Each of the modules includes a transformer with a ferrite, toroidal core dimensioned so that it is not driven into saturation by the 500 KHz source. Each module also includes inexpensive, signal switching diodes having a recovery time of approximately 4 nanoseconds. The ratio of the collector to helix DC voltages is maintained constant by threading a common lead through the apertures of the toroidal cores of the helix and collector modules. A separate common lead threaded through the apertures of the toroidal cores in the collector modules is connected directly to the 500 KHz power source.

Abstract: A waveguide helical slow-wave structure is formed of a solid rod of copper machined with a deep, narrow helical groove. A copper sleeve is brazed to the periphery of the resulting helical thread to form a helically spiraling pathway about a solid axially centered and axially extending center portion. The center portion is then partially eroded away to form a slow wave structure having a helical radially-extending portion with an inner helical axially-extending ridge to provide a helical axially-centered gap between adjacent ridges. The slow wave structure contains the microwave energy which follows the spiral path of the structure and produces RF voltage across the gap of adjacent portions of the ridges to thereby form a gapped-wall surrounding an axially-extending hole for gap electric field interaction with the axial electron beam of a traveling wave tube of which the slow wave structure is a part.

Abstract: A coupled cavity travelling wave tube has a coupling wall/ferro-magnetic pole piece formed as an iron-copper-iron sandwich with a coolant channel therein defined at least in part by the inner copper member of the sandwich. Where the coolant channel is defined also in part by a surface of an outer ferromagnetic member, at least that surface is electroplated.

Abstract: An electron gun for a vacuum tube employs a mounting element having an inner annular section with a defined thickness made to predetermined dimensional tolerances. The cathode subassembly is positioned on one surface of the annular section and a grid electrode is located on the opposing surface. When the mounting element is set within the vacuum tube facing the anode electrode, the location of the cathode subassembly and grid electrode in the mounting element establishes a precise cathode-to-anode spacing and the electrodes are properly aligned and concentric to a central axis along which the electron beam travels.

Abstract: A coupled cavity TWT comprises a hollow copper tube having a plurality of tranverse walls of iron which define cavities. The walls each include an aperture on the longitudinal axis of the tube through which an electron beam passes during operation of the TWT. Any energy dissipated by electrons colliding with the surfaces of the apertures is conducted as heat away from the walls along thermal conduction paths which include copper elongate members.

Abstract: A high-power switch tube is shown constructed from a plurality of electron guns each gun having a cathode and an anode. Between the cathode and anode is mounted a shadow grid closest to the cathode beyond which is mounted a control grid, a screen grid, and, in some applications, by a suppressor grid. Each anode is formed with an anode cavity having an opening that is smaller in dimension than the largest dimension of the cavity thus forming a Faraday cage collector which prevents secondary emission problems.

Abstract: The present invention provides a vircator with improved efficiency. An elongated anode is aligned with an elongated cathode so as to produce an elongated virtual cathode when a direct current voltage source is electrically connected to the elongated cathode. A surface wave having a velocity near the velocity of light will be produced on the virtual cathode. Waveguide means enclosing the virtual cathode is disposed so as to propagate microwave radiation in a direction parallel to the direction of elongation of the cathode, anode and virtual cathode. The waveguide is designed to match the phase velocity of the microwave to the velocity of the virtual cathode surface wave.

Abstract: A magnetic sensor for measuring the helix current of a traveling wave tube (TWT). The sensor includes a helix current sense inductor and a reference inductor. The sense inductor includes windings for receiving the cathode and collector currents of the TWT and for receiving a bias current, and also a sense winding. The cathode and collector currents cause permeability of the core to vary in proportion to the difference between those currents, which is equal to the helix current. The bias current is supplied to the bias winding to compensate the sense inductor for temperature-related permeability variations. The bias current is supplied by the reference inductor which is selected to have magnetic properties which match those of the sense inductor. A plurality of sense inductors in conjunction with one common reference inductor may be used for sensing the respective helix currents in the TWTs in a multi-TWT array.

Abstract: A resonant cavity arranged for an electron beam to pass therethrough, is made of two spaced apart parallel substantially planar members movable with respect to each other in a direction perpendicular to their major surfaces, at least one of said members having a delay line structure on its inner face within the gap between said two members. Means are arranged for moving the members relative to each other so as to vary the spacing between said members, whereby the oscillation frequency is tuned easily. The resonant cavity can be used to realize wide-band extended interaction oscillators and klystron amplifiers.

Abstract: An improved grid arrangement is shown for a gridded electron gun wherein the control grid and/or shadow grid is provided with tapering grid vanes which reduce the amount of voltage required to cut off the electron beam. Alternately, a fewer number of grid vanes may be utilized to accomplish the same cutoff of the electron beam thus reducing the loading on the cathode and improving the transmission of the electron beam.

Abstract: A plurality of longitudinally disposed dielectric support rods are attached to the outer circumferential surface of a helical slow-wave structure to form a subassembly. The subassembly is mounted in a light press-fit relationship within an enveloping structure comprising a plurality of annular nonmagnetic spacer elements repectively interposed between and abutting a plurality of annular ferromagnetic pole pieces. Plastically deforming force is applied by means of a pair of dies to the outer surface of the spacer elements to crimp the spacer elements onto the support rods and thereby firmly hold the slow-wave structure-rod subassembly within the enveloping structure.

Abstract: A coupled cavity travelling wave tube of the space harmonic type is provided wherein the interaction gaps in successive cavities are alternately offset towards the input end of the slow wave structure and towards the output of the slow wave structure, whereby beam electrons which are synchronous at band edge frequencies tend to experience a phase reversal in the electro-magnetic wave propagating in the slow wave structure, at each successive interaction gap.

Abstract: A waveguide filter (43) comprising a series of resonant cavities (45) separated by walls (47) each formed with an iris opening (49) is assembled from two complementary box-like bodies (25) each having an open side (31) and internal partitions forming portions of the walls (47) between the cavities. Each box-like body is manufactured by impact extrusion using an open-topped box-like die (1) in which a slug of material (5) is placed, and a punch (7) which has smaller dimensions than the die and slots (11) for forming the respective partitions. The punch is driven into the die with a force such that the material of the slug is displaced into the slots in the punch and into the space between the punch and the die.

Abstract: A traveling wave tube made in accordance with this invention wherein the folded waveguide interaction circuit and the input/output transitions to standard waveguides are made of a single piece of metal such as oxygen-free, high conductivity copper. By manufacturing the folded waveguide circuit and the input/output circuit-to-standard waveguide transition out of one piece of material, VSWR on the order of 1.1:1 is expected for traveling wave tubes intended to operate at 94 GHz. Furthermore, this invention minimizes expensive tooling and labor while providing a higher yield of traveling wave tubes.

Abstract: A digital cathode current control circuit for controlling the cathode current of a traveling wave tube (TWT) amplifier is disclosed. The cathode current control circuit includes circuitry for providing a comparison signal indicative of the occurrence and amplitude of TWT cathode current pulses; clocking circuitry responsive to the comparison signal for providing a clock signal delayed relative the occurrence of a cathode current pulse; comparison circuitry for comparing the comparison signal with predetermined reference signals indicative of a predetermined cathode current level, and for providing adjustment signals indicative of the adjustment of the TWT cathode current necessary to tend to achieve the predetermined cathode current; and counter circuitry clocked by the delayed clock signal for providing an output count in response to the adjustment signals.

Abstract: A travelling wave tube comprising a tube and a helix mounted in the tube, the helix being made of diamond and being coated at least partially with an electrically conductive material.

Abstract: A helix type traveling wave tube comprises an evacuated envelope containing an electron gun assembly at one end thereof for forming and projecting a beam of electrons over an elongated beam path to an electron collector electrode at the opposite end of the envelope. A helix slow-wave circuit is arranged along the beam path intermediate the electron gun and the beam collector for electromagnetic interaction with the beam. In order to extract an amplified signal from the downstream end of the slow wave circuit, there is provided an coaxial line including an outer conductor air-tightly fixed at one end thereof to the evacuated envelope and an inner conductor having one end connected to an output end of the slow wave circuit. An output waveguide is air-tightly fixed to the other end of the coaxial line outer conductor in such a manner the other end of the coaxial line inner conductor extending into the output waveguide.

Abstract: An improved pole piece structure for periodic-permanent-magnet focused traveling wave tubes is disclosed. In one embodiment, the pole pieces have two fold symmetry and the magnets are arranged about the tube axis in a pattern with two-fold symmetry. This structure accommodates the input or output waveguides while maintaining the symmetry of the magnet placement. This allows the electron beam to remain centered on the tube axis and, therefore, minimizes beam interception. Circuit heating is reduced and the power handling margin of the tube is increased in comparison to conventional TWT structures. In another embodiment, a triangular pole piece configuration is employed, eliminating displacement of the magnets at the coupler and sever cavities and providing a third cooling channel.

Abstract: Free-electron lasers and masers are modified by eliminating the resonator cavity as such. The feedback mechanism, essential to oscillation, is distributed through and integrated with the transmission line which guides the electromagnetic wave at the active region where interaction with the electron beam takes place. The feedback structure is created by perturbations in the transmission line along the length thereof at the locations of the zero electric field lines of a desired oscillatory standing wave mode. The perturbations may take the form of axial, helical, and azimuthal deformation of the transmission line.

Abstract: A traveling-wave tube, including a delay line having two end surfaces, a spatially periodic permanent magnet system surrounding the delay line for the bunched guidance of an electron beam, the delay line having line cells disposed in tandem, each of the cells having an electron beam passage opening formed therein and adjacent partitions separating the cells with a given mutual spacing, each of the partitions having at least one coupling opening formed therein extended substantially in circumferential direction, a ridgeless rectangular waveguide coupled to at least one of the end surfaces of the delay line and protruding away from the delay line substantially at right angles to the axis of the delay line, the waveguide having a location of smallest reflection, a wide side facing away from the delay line extended substantially perpendicular to the longitudinal axis of the delay line and at least one narrow side being steadily tapered toward the delay line down to substantially the given spacing of the adjacent

Abstract: The invention provides a travelling wave tube having a directly heated cathode. Cathode material is applied in a depression in one U-shaped member of a high resistance alloy material and the return path for heater current is provided by another U-shaped strip member beneath the first. The configurations of the two strip members are similar so that stray magnetic fields generated by the equal but opposite currents flowing therein, tend to neutralize one another. In another embodiment the two strip members are replaced by generally cylindrical members, one member being within the other. The surface of the member providing the return path for heater current is polished where it faces the member carrying the cathode material so as to reflect back heat radiated by the last-mentioned member.

Abstract: A travelling-wave tube comprising a delay line in the form of a helix line which is disposed inside of a solid metal vacuum envelope. A high-performance travelling-wave tube whose delay line is distinguished by very good dissipation of the stray heat. A large bandwidth results by providing the delay line with a core of insulator material which has a metal layer at its inside and outside generated surfaces.

Abstract: A beam generating system for electron tubes, particularly travelling wave tubes, is formed of a beam shaping electrode and a dispenser cathode supported therein having an emission disk at its end face. A positional change of the dispenser cathode in the beam shaping electrode at different ambient temperatures is suppressed with the beam generating system, and thus a beam defocussing is avoided. According to the invention, the dispenser cathode is directly connected to the beam shaping electron and is connected below the emission disk by means of a radial cathode support. The beam generating system of this type is particularly employed in travelling wave tubes.