US2803778A - Device for generating electrical oscillations - Google Patents

Device for generating electrical oscillations Download PDF

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Publication number
US2803778A
US2803778A US430964A US43096454A US2803778A US 2803778 A US2803778 A US 2803778A US 430964 A US430964 A US 430964A US 43096454 A US43096454 A US 43096454A US 2803778 A US2803778 A US 2803778A
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United States
Prior art keywords
anode
electrode
aperture
tube
angle
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Expired - Lifetime
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US430964A
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English (en)
Inventor
Diemer Gesinus
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US Philips Corp
North American Philips Co Inc
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US Philips Corp
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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/18—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance
    • H03B5/1817—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a cavity resonator
    • H03B5/1835—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising distributed inductance and capacitance the frequency-determining element being a cavity resonator the active element in the amplifier being a vacuum tube
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/02—Systems using reflection of radio waves, e.g. primary radar systems; Analogous systems
    • G01S13/06—Systems determining position data of a target
    • G01S13/08—Systems for measuring distance only
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/76—Dynamic electron-multiplier tubes, e.g. Farnsworth multiplier tube, multipactor

Definitions

  • the invention relates to devices for generating electrical oscillations of a wavelength of a few centimetres by means of an electric discharge tube, wherein the electrons emanating from the cathode are projected through one or more apertures in an anode on a secondary-emission electrode arranged so as to be parallel to the anode and to discharge tubes for use in such devices.
  • the highest frequency at which such a tube can oscillate as a dyratron, i. e. on the negative internal resistance of the secondary-emission electrode, is determined by the path to be covered by the secondary electrons between the secondary-emission electrode and the anode and by the voltage difference between the two electrodes, it being assumed that the electrons do not oscillate about the parts of the anode but are collected directly.
  • the transit time of the secondary electrons must be small compared with the period of the alternating voltages to be produced.
  • the frequercy cannot exceed approximately 2000 mes. (wavelength 15 Cms). This occurs with an anode-secondary-cmisson electrode spacing of 1 mm. and with a voltage difference of 1000 V. between the two electrodes. By raising the voltage and reducing the spacing the wavelength limit may be slightly lowered but in this case the technical difficulties (flashover) are so great and the efficiency is so low that in the wavelength range below 10 cns. no satisfactory results can be obtained.
  • the negative internal resistance is determined by the variation of the secondary-emission coeicient with the voltage on the secondcry-emission electrode At a voltage of some hundreds of volts at the most this Variation is still suflicient for the most usual substances (the variation is greatest at a voltage of 0 v.).
  • the invention has for its object to obviate the disadvantages of the known devices, among others the high field strength between the anode and the secondary-emission electrode and the low efciency.
  • a device for producing electrical oscillations of a wavelength of a few centimetres in which the electrons emitted from the cathode are projected through one or more apertures in an anode on a secondary-emission electrode parallel to the anode, these electrons are concentrated into one or more beams which have small aperture angles and the axes of which are at an angle of about 45 with the plane of the anode, the voltages on the anode and the secondary-emission electrode and their relative spacing being so chosen that, in the absence of alternating voltages on the electrodes, the primary electrons still just fall upon the sccondaryemission electrode and the transit time of the secondary electrons to the anode is approximately a full period of the oscillations to be produced.
  • the negative internal resistance of the secondary-emssion electrode is determined by the variation of the primary current to the sccondaryemission electrode with the voltage on the latter, whereas, as long as the primary current does not become excessively high, the variation of the sccondary-emission coeicient with voltage hardly has any influence.
  • the value of the negative internal resistance is also determined by the aperture angles of the electron beams.
  • the voltage path of the secondary-emission electrode in which the whole of the primary current is taken over from the anode is approximately of the voltage dillerence between the anode and the secondary-emission electrode.
  • the voltage may be chosen to be such that the secondary-emission coeflicient has approximately its maximum value.
  • the ratio between the voltage on the secondary-emission electrode and that on the anode is chosen to be substantialiy equal to the square of the Sine of the angle which the electron beam makes With the anode plane, whilst the spacing between the two electrodes is determined in this case by the desired transit time.
  • the axis of the electron beam is at an angie of 45 with respect to the plane of the anode.
  • this angle may also be comprised between Zt) and '/0.
  • the aperture angle of the electron beam is determined by the size of the cathode and the distance from an anode and by the diverging eifect of the intervening space between the anode and the secondary-emission electrode. A value of 15 to 20 of the apex of the conical beam directed towards the anode yields excellent results.
  • the transit time of the secondary electrons may, in general, vary between a half and one and a half periods of the oscillations to be produced, with which the tube still continues to oscillate. It is thus possible to tune over a large wavelength range without modifying the voltage.
  • the simplest Construction or' a tube for use in a device according to the invention is that in which only one primary electron beam is used.
  • the anode and the secondary-emission electrode may have the form of more or less fiat discs, which are directly sealed into a glass wall of the tube and thus incorporated in a cavity resonator.
  • a favourable form of a tube for use in a device according to the invention is that in which use is made of two cathodes arranged ou either side of the axis of the system &803378 and the secondary-emission electrode is divided into two halves, each of which co-operates with one of the two electron beams.
  • the two halves of the secondary-emission electrode may, in this case, consist of the bent ends of a Lecher line passing through the wall of the tube in the form of two fiat strips.
  • the tube is then adapted to operate in push-pun, so that the efficiency is very high.
  • Fig. 1 represents a tube with a single electron beam
  • Fig. 2 a tube having two electron beams and a divided secondaryemission electrode
  • Fig. 3 represents a tube according to the invention incorporated in an oscillating circuit.
  • Fig. l 1 designates the glass wall or envelope of the tube, 2 the anode constituted by a copper disc, 4 the secondary-emission electrode.
  • the bent part 5 of which is in the shape of a truncated cone and is located at a distance of 1.5 mms. from the anode 2 and opposite the aperturc 3 provided in the latter.
  • the hollow cathode 6 is arranged in such manner that a beam emanating therefrom and projected, through the aperture in the anode, on the part 5 of the secondary-emission electrode is at an angle of about 45 with the *anode plane.
  • concentrating members 7 and 8 respectively, to the first of which a separate voltage may be applied.
  • a plurality of supply wires 9 Into the bottom of the tube are sealed a plurality of supply wires 9, whilst on top of the secondary-emission electrode another glass wall 10 is sealed to permit the secondary-emission electrode to be cooled in a simple manner by means of a liquid.
  • a further advantage of the obliquely incident primary beam is that the seconda'y electrons have to travel in a space comprised between two fiat plates, so that the transit time dispersion is very small.
  • a toroidal cavity resonator 31 coupled galvanically with the anode 2 and capacitively through a mica ring 32 with the secondary emissive electrode 5 a coupling loop 33 serves the purpose of guiding out the energy generated.
  • 11 designates the glass wall of the tube in which an anode 12 having an aperture 19 is provided.
  • Two cathodes 13 and 14 are 'arranged on either side of the axis of the anode in such manner that the junction lines between the centre of the aperture 19 and the centres of the cathodes are at an angle of 45 with the plane of the anode.
  • concentrating members 15 and 16 In front of the two cathodes are arranged concentrating members 15 and 16 whilst in front of the aperture in the anode two concentrating members 17 and 18 are arranged which are formed as solid bodies of revolution.
  • the members 17 and 18 each have the form of two superimposed frustums of cones and are each revolved about an axis, perpendicular to the surface of the respective cathodes, and passing through the centre thereof. into the wall of the tube are sealed two Lecher wire strips 34 and 35 which terminate in sections 20 and 21 parallel to the anode. The latter sections are coated with caesiurn oxide to serve as secondary-emission electrodes. The electrons emanating from the cathode 13 are projected on the part 21 of the secondary-emission electrode and those emanating from the cathode 14 on the secondary-emission electrode 20. If the voltage on the anode is 1400 v.
  • the secondary-emission electrode 800 v oscillations may be produced in a wavelength range of from 3 to 5 cms. with an efliciency of approximately 20% at a wavelength of 5 cms.
  • the dimensions of the tube may be computed from a scale shown at the side of the latter, said scale being calibrated in mms.
  • the two electrodes 20 and 21 are connected to a Lecher wire system consisting of the strips 34 and 35, which are tuned with the aid of a tuning bridge 36.
  • Fig. 3 shows a tube according to Fig. 1 with associated resonator in a generating circuit.
  • the anode voltage s derived from a battery 37 and the secondary emssive electrode is tapped about midway between the cathode and anode.
  • the concentrating electrode 7 is tapped at 38 4 at a slightly positive or negative voltage with respect to cathode 6.
  • the heater battery is indicated at 39.
  • An electric discharge device for generating short wavelength electrical oscillations comprising an electron discharge tube, said tube including an anode electrode having a planar surface and provided with an aperture, a secondary-emissive electrode mounted on one side of said anode and spaccd therefrom a given distance, means mounted on the other side of said anode to generate a small aperturc angle electron beam forming an angle between 20 to 70 with the surface of said anode and directed towards said aperture, means for applying potentials to said anode and secondary-emissive electrode at which the transit time of secondary electrons liberated by the electron beam and travelling from the secondarr emissive electrode to the anode is about one full period of the electrical oscillations and at which the electrons produced by the generating means just strike the secondary-emissive electrode in the absence of signal potentials on the electrode& and a resonant circuit associated with the space between the anode and the secondary-emissive electrode and adapted to be excited into oscillation by the electron flow.
  • An electric discharge device for generating short wavelength electrical oscillations comprising an electron discharge tube, said tube including an anode electrode having a planar surface and provided with an aperture, a secondary-emissive electrode mounted on one side of said anode and having a plan-ar surface portion which is parallel to the anode planar surface and spaced therefrom a given distance, means mounted on the other side of said anode to generate a small aperture-angle electron beam forming an angle of about 45 with the surface of said anode and directed towards said ape'ture, means for ap plying potcntials to said anode and secondary-emissive electrode at which the transit time of secondary electrons liberated by the electron heam and travelling from the seconda'y-emissive eiectrode to the anode is about one full period of the electrical oscillations and at which the electrons produced by the generating means just strike the secondary-emissive electrode in the absence of signal potentials on the electrodcs, and a resonant circuit as
  • An electron discharge tube comprising an anode electrode having a planar surface and provided with an aperture, a first secondary-emissive electrode arranged on one side of said anode a first cathode source mounted on the other side of said anode diametrically opposite said first secondary-emissive electrode for generating a beam of electrons directed toward s said aperturc and said first emissive electrode, a second secondarycmissive electrode located on the same side of said anode as the first secondary emissive electrode, a second cathode source ar ranged on the same side of the anode as the first cathode source and diametrically opposed to said second second ary-emissive electrode for generating a beam of electrons directed towards said aperture and said second secondaryetnissive electrode, each of said electron beams forming an angle of approximately 45 with said anode and also forming an angle of approximately therebetweeu, each of said first and second cathodc sources subtending an angle of approximately l5
  • An electron discharge tube as claimed in claim 7 in which said secondary-emissivc electrode has a body portion in the form of a truncated cone mounted on one side of said anode in spaced relationship to said anode with the apex directed towards the anode, and said means to generate a small aperturc-angle electron beam comprses a cathode source mounted on the other side of said anode, said cathode source subtending an angle of approximately 15 with said aperture, a first concentrating electrode in the form of a frustum of a cone with its apex in the direction of said cathode source and having a voltage applied thereto and in aligned spaced relation with said cathode for concentrating said electron beam, and a second concentrating electrode positioned between said first concentrating electrode and said anode and aligned with said aperture in said anode and having an offset aperture aligned with said first concentrating electrode, said second concentrating electrode having a voltage applied thereto for concentrating said electron beam
  • An electron discharge tube comprising an anode electrode having a planar surface and provided with an aperture, a first secondary-emissive electrode arranged on one side of said anode, a first cathode source arranged on the other side of said anode diametrically opposite said first secondary-emissive electrode for generating a beam of electrons as directed towards said aperture and said first secondary-emissive electrode, a second secondary-emissve electrode located on the same side of said anode as the first seconda'y-emissve electrode, a second cathode source arranged on the same side of the anode as the first cathode and diametrically opposed to said second secondaryemissive electrode for generating a beam of electrons directed towards said aperture and said second secondaryemissive electrode, each of said electron beams forming an angle of 45 With said anode and also forming an angle of approximately 90" therebetween, each of said first and second cathode sources also subtending an angle of ap proximately 15" with said aperture
  • An electric discharge device for generating short wavelength electrical oscillations comprising an eiectron discharge tube, said tube including an anode electrode having a planar surface and provided with an aperture, a Lecher line mounted on one side of said anode, said line being constituted by a pair of flat strips each having bent ends facing said anode and spaced therefrom a given distance, a secondary-electron-emissive material on said bent ends, first electron-beam generating means mounted on the other side of said anode diametrcally opposite one of said bent ends for generating an electron beam directed towards said aperture and said one bent end, second electron-beam generating means mounted on the same side of the anode on the first generating means and diametrically opposite the other of said bent ends for generating an electron beam directed towards said aperture and said other bent end, each of said electron beams forming an angle of approximately with said anode, each of said generating means subtending a small angle with said aperture, and means for applying potentials to said Lecher line and said

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
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US430964A 1947-03-06 1954-05-19 Device for generating electrical oscillations Expired - Lifetime US2803778A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL266223X 1947-03-06

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US2803778A true US2803778A (en) 1957-08-20

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US (1) US2803778A (fr)
BE (1) BE480960A (fr)
CH (1) CH266223A (fr)
FR (1) FR962892A (fr)
GB (1) GB687194A (fr)
NL (1) NL80440C (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3663853A (en) * 1969-07-29 1972-05-16 Alcatel Sa Triode electron gun with positive grid and modular cathode

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2128232A (en) * 1934-02-23 1938-08-30 Meaf Mach En Apparaten Fab Nv Electron tube
US2170219A (en) * 1936-10-16 1939-08-22 Telefunken Gmbh Ultra high frequency oscillator
US2416303A (en) * 1941-02-05 1947-02-25 Bell Telephone Labor Inc Secondary emissive shell resonator tube
US2425748A (en) * 1941-03-11 1947-08-19 Bell Telephone Labor Inc Electron discharge device
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2128232A (en) * 1934-02-23 1938-08-30 Meaf Mach En Apparaten Fab Nv Electron tube
US2170219A (en) * 1936-10-16 1939-08-22 Telefunken Gmbh Ultra high frequency oscillator
US2416303A (en) * 1941-02-05 1947-02-25 Bell Telephone Labor Inc Secondary emissive shell resonator tube
US2425748A (en) * 1941-03-11 1947-08-19 Bell Telephone Labor Inc Electron discharge device
US2581408A (en) * 1947-04-16 1952-01-08 Sperry Corp High-frequency electron discharge device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3663853A (en) * 1969-07-29 1972-05-16 Alcatel Sa Triode electron gun with positive grid and modular cathode

Also Published As

Publication number Publication date
CH266223A (de) 1950-01-15
BE480960A (fr)
FR962892A (fr) 1950-06-22
GB687194A (en) 1953-02-11
NL80440C (fr)

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