US2447461A - Resonant cavity circuits - Google Patents

Resonant cavity circuits Download PDF

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Publication number
US2447461A
US2447461A US484692A US48469243A US2447461A US 2447461 A US2447461 A US 2447461A US 484692 A US484692 A US 484692A US 48469243 A US48469243 A US 48469243A US 2447461 A US2447461 A US 2447461A
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United States
Prior art keywords
circuit
cathode
tubular
electron
aperture
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Expired - Lifetime
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US484692A
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English (en)
Inventor
Andrew V Haeff
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RCA Corp
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RCA Corp
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Publication date
Priority claimed from US375029A external-priority patent/US2399223A/en
Application filed by RCA Corp filed Critical RCA Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/02—Tubes with electron stream modulated in velocity or density in a modulator zone and thereafter giving up energy in an inducing zone, the zones being associated with one or more resonators
    • H01J25/04—Tubes having one or more resonators, without reflection of the electron stream, and in which the modulation produced in the modulator zone is mainly density modulation, e.g. Heaff tube

Definitions

  • tubes utilizing conventional grids for controlling current are well adapted for operation at ultra-high frequencies and retain their characteristic advantage ofpossessing high transconductance.
  • one of thedifiiculties encountered inoperating amplifying tubes at ultra-highirequemcies is the presence of considerable'loadin in the input circuit which results in an excessive amount of power being required to drive the tube. l his decreases the 'efiective power gain of the tube when operated as an amplifier.
  • the fundamental causes of high input loading are: (1) ohmic and radiation resistance losses due to high circulating currents in electrodes and leads; (2) electron-loading which results fromthe interaction of the electron stream with the circuit, including degenerative or regenerative effects caused by lead impedance.
  • the principal object oi my invention is to pro-- vide an electron discharge device and associated circuithaving-means for substantially reducing or completely neutralizing electron loading when the device is used at ultra-high frequencies.
  • a 'still further objectxof my invention is to provide improved forms of resonant cavity tank circuits or resonators suitable for use with ultra high frequency electron discharge devices and means for tuning the same.
  • Figures 1 and 2 are diagrammatic representations of electrodes and the movement of electrons between the electrodes;
  • Figures 3 and 4 are diagrammatic representations of conventional tubes and meth ods of operating the same;
  • Figures 5 and dare curves representing the relationship of the electron loading (conductance) and the transit time of the-electrons of the tubes'in Fi-guresii and 4;
  • Figure 11 is a longitudinal section of an electron discharge device, made according to my invention;
  • Figure 11a is a section taken along the line Ilia-Ala of; Figure 11;
  • Figures 12. and 13 are.
  • the current induced in an electrode due to motion of a charge is equal tothe rate of time variation of the induced image charge on the electrode dueto the moving charge.
  • the total instantaneous current induced in the electrode by the electron stream will be found by summing. the individual currents induced by all charges moving within the interelectrode. space. If a voltage exists between electrodesv l0 and the displacement current due to the interelectrode capacitance must be also taken into account. i ,1
  • dug-Figural 7 Anoimpedancezzais in-.-
  • inductve output tube One practical embodiment of my invention incorporated in a so-called inductve output tube" is shown in detail in Figure 11.
  • Inductive output tubes and their operation are described more fully in my United States Patent 2,237,878, issued April 8', 1941, and assigned to the Radio Corporation of America.
  • this tube comprises a cathode for supplying a beam of electrons and a collector for receiving the electrons.
  • a modu lating grid is placed adjacent the cathode for modulating the beam of electrons which passes to the collector.
  • a resonant cavity circuit Surrounding the beam path is a resonant cavity circuit comprising a hollow memher having a passageway extendin therethrough through which the beam passes.
  • the passageway is provided with a gap lying in a plane transverse to the beam path. As the modulated beam of electrons passes across this gap, energy is transferred from the beam to the resonant cavity circuit-which provides the output circuit for the tube and which can be coupled to a radiator or to an amplifier.
  • the tube is provided with a concave surface cathode l5 which can be made of tantalum.
  • This cathode is heated by electron bombardment from an auxiliary cathode l6 made for example in the form of a tungsten spiral and surrounded by a focusing shield or cup I! for directing the electrons from the filament to the cathode it.
  • the cathode spiral I6 is supplied with heating current by means of leads l8 and I9 and the main cathode I5 is supported at the end of a tubular member I5 to which the oathode lead is electrically connected.
  • the electron beam is modulated by means of the grid 2
  • the accelerating and screening electrodes 22 and 23 are cylindrical and conically shaped to avoid absorbing electron current from the beam which may tend to spread.
  • the output circuit is of the closed resonant cavity type and is formed by two conically shaped metal surfaces 21 and 2'
  • the cathode I5 is mounted in the supporting tubular member 29 of cylindrical form, a collar 28 of insulating material serving to insulate the tubular cathode extension l5 from the tubular'member 29 but permitting capacity coupling therebetween.
  • the leads for the heater and cathode are shielded by means of the tubular member 29 which serves as the inner member of a concentric line circuit.
  • is supported at the end of the tubular member 30 of cylindrical form surrounding and coaxial with the inner tubular member 29 to form the outer portion of the concentric line circuit, the ends being closed by disc members 3
  • the cathode gridcircuit is formed by the tubular members 29 and 30 which constitute the inner and outer conductors of a concentric line shorted by the closure disc 3
  • This cathode-grid circuit which may be referred to also as a resonant cavity tank circuit, correspondsto impedance z of Figure 9.
  • the large capacitance between the cathode support or ex-' tension l5 and cylindrical member 29 serves to by-pass radio frequency current from the cathode to the tubular member 29.
  • is provided with an aperture throughwhich the lead wires l8, l9 and 2!! extend and a collar or extension 32 to which the insulating cup-shaped member 33 is sealed and through which the conductors pass and are sealed.
  • the cup-shapedmember 33 hermetically seals the interior of the circuits.
  • a third tubular'member 34 of cylindrical form is co-axial with and surrounds the other two tubular members- It is provided with closure members 34 and 31, a gap 22 being provided between the closure member 3'! of tubular member 34 and closure member 3
  • the space between the cylinders 30 and 34 forms a resonant space which provides an impedance equivalent to Z2 shown in Figure 9 between the control grid and accelerating or screen electrode 22.
  • the cylinder 34 is supported on the wall of the tank circuit by the insulating glass cylinder or collar'35 sealed to the cylindrical collar members 36 and 31 supported on the cylindrical member 34 and the wall 21' of the tank circuit respectively.
  • High capacitance between the end portion 31 of the cylindrical member 34 and the adjacent wall of the tank serves to by-pass high frequency circulating current so as to reduce the radio frequency potentials between the tubular member 34 and'the wall of the tank to a negligible value.
  • the collector 25 is supported in like manner from the other wall of the tank circuit to which is attached the collar extension 38, the collector cooling jacket being provided with collar extension 39, both sealed to the insulating cylindrical member or collar 40.
  • the outer tubular member 30 is provided with a collar or extension 4
  • This re-entrant glass tube is preferably made of low loss glass or of quartz.
  • the tuning plunger 44 is inserted within the re-entrant insulating tube and may be adjusted by means of the insulating rod 45 attached to the plunger. Varying the position of the plunger changes the capacitance between the adjacent circuit elements and thus affords a means for tuning of, the internal circuits.
  • the same kind of arrangement is provided at 46, the tubular member'34 being provided with an aperture around which extends collar 4
  • a like arrangement is shown generally at 41 in the tank circuit.
  • the coupling between the cathode-grid and grid-screen circuits, which coupling corresponds to impedance Z0 in' Figure 9, is provided by means of closed loop 50, the position of which is adjustable by means of adjusting rod 5
  • An extension 48 on the outertubular member 34 surrounds an,
  • the accelerating or screen electrode I21 is secured to the wall I31 of the screen electrode-control grid circuit.
  • the resonant cavity output circuit comprises the side wall I31, the side wall I39 and the'outer ring member I40- connected at the peripheries.
  • the ring members I40 and I38 could of course be extensions of each other.
  • the accelerating electrode I28 is connected to and supported by the end wall I39.
  • a coupling and tuning of the circuits is permitted in the same manner as in the other modifications of applicant's invention, that is the envelope is provided with a number of re-entrant portions extending through'apertures in the various tank circuits and providing passageways for coupling loops or tuning condensers.
  • the driver circuit is coupled to the grid-cathode circuit by loop I4l extending within re-entrant portion MI".
  • the screen electrode-control grid tank circuit and the control grid-cathode tank circuit are inductively coupled to permit feedback by means of the loop I42 within extension I42. This loop is mounted within the re-entrant portion I42 of the envelope extending through apertures in the two tank circuits.
  • Tuning of the cathode-control grid tank circuit is accomplished by means of the tuning plunger I43 slidably mounted within the re-entrant tube I44 extending through apertures in the tank circuits and the extensions I33 and I34 between which is provided a gap.
  • Tuning of the screen electrode-control grid circuit is accomplished by means of the tuning plunger I45 mounted within the re-entrant glass tube I46.
  • the plunger I45 enters a tubular member I49, which is attached to member I34, and also projects into a tubular well I50 connected to the electrode I21.
  • a similar arrangement is provided for tuning the output circuit, the plunger I41 being slidably supported within the re-entrant tube I48 and coupling extensions II and I52.
  • the output is delivered by means of the loop I41 mounted within the extension I48, which extends through an aperture in the ring-shaped connecting member I43 of the output tank circuit.
  • Heating current is supplied by means of potential source I52 and potential difference for causing bombardment of the rear surface of the cathode I20 by voltage source I54.
  • Grid bias is furnished by means of voltage source I53.
  • the potentials required for the tank circuit and the collector are provided respectively by potential sources I55 and I55.
  • the resonator comprising the slightly dishshaped or cone-shaped walls I31-I39 closed at their peripheries by means of the collar-like element I and having the axially tubular extension I28, is that in case these resonators become heated during operation and expansion occurs, the walls I31 and I39 will move in the same direction, that is toward the right, keeping their same relative positions and the relative position of the tubular member I28 so that the gap width varies little if any.
  • the resonator may be subjectedto temperature changes, its resonant frequency remains substantially constant.
  • a resonator including a hollow conducting member having an aperture, a conducting member supported on the wall of said resonator and surrounding said aperture, a cup-shaped conducting member supported from a portion of the inner wall of said resonator and registering with said tubular member and said aperture and a reentrant member of insulating material sealing said aperture and extending through said tubular member and into said cup-shaped member, and a plunger-like conducting member extending within said re-entrant member of insulating material and movable longitudinally of the tubular member and cup-shaped member.
  • a first resonator including a first hollow conducting member having an aperture therein, a second resonator including a second hollow conducting member surrounding said first hollow conducting member and having an aperture registering with the aperture in said first hollow conducting member, a tubular shield element extending from the wall of the first hollow conducting member through the aperture in the second hollow conducting member and surrounding said aperture, and means extending through said tubular shield element into the interior of said first resonator for coupling purposes, a first tubular member within said first resonator supported on a wall portion of said first resonator and extending toward the opposite wall and a 11 second :tubularmember: positioned on the oppo site 'wall -o't' said first resonator and registering: with said firsti tubular member, and conducting means: movable longitudinally of. said tubular members for tuning said' first resonator:

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  • Particle Accelerators (AREA)
  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
  • Microwave Tubes (AREA)
US484692A 1941-01-18 1943-04-27 Resonant cavity circuits Expired - Lifetime US2447461A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US375029A US2399223A (en) 1941-01-18 1941-01-18 Electron discharge device

Publications (1)

Publication Number Publication Date
US2447461A true US2447461A (en) 1948-08-17

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US484692A Expired - Lifetime US2447461A (en) 1941-01-18 1943-04-27 Resonant cavity circuits
US610700A Expired - Lifetime US2528138A (en) 1941-01-18 1945-08-14 High-frequency electron discharge device

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Application Number Title Priority Date Filing Date
US610700A Expired - Lifetime US2528138A (en) 1941-01-18 1945-08-14 High-frequency electron discharge device

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US (2) US2447461A (de)
BE (1) BE474640A (de)
DE (1) DE857550C (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090023360A1 (en) * 2007-07-17 2009-01-22 Li-Chen Wang Hand-gripped clapping device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE976519C (de) * 1941-03-25 1963-10-17 Siemens Ag Klystron

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2169396A (en) * 1936-05-08 1939-08-15 Bell Telephone Labor Inc Signal-translating apparatus
US2239421A (en) * 1940-03-09 1941-04-22 Rca Corp Electron discharge device
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2281717A (en) * 1941-01-21 1942-05-05 Bell Telephone Labor Inc Electron discharge apparatus
US2311520A (en) * 1941-08-13 1943-02-16 Westinghouse Electric & Mfg Co Coupling loop
US2328561A (en) * 1941-08-05 1943-09-07 Stephen D Lavoie Oscillatory apparatus
US2337219A (en) * 1937-01-21 1943-12-21 Rca Corp Short wave tuned circuit arrangement
US2350907A (en) * 1939-09-22 1944-06-06 Rca Corp Ultra short wave apparatus

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2227372A (en) * 1938-07-21 1940-12-31 Univ Leland Stanford Junior Tunable efficient resonant circuit and use thereof
NL61321C (de) * 1939-09-13
US2278210A (en) * 1940-07-05 1942-03-31 Bell Telephone Labor Inc Electron discharge device
US2293152A (en) * 1940-10-15 1942-08-18 Int Standard Electric Corp Velocity modulated tube with removable resonator
US2353742A (en) * 1941-08-26 1944-07-18 Gen Electric High-frequency apparatus
US2400752A (en) * 1942-04-04 1946-05-21 Rca Corp Electron discharge device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2169396A (en) * 1936-05-08 1939-08-15 Bell Telephone Labor Inc Signal-translating apparatus
US2337219A (en) * 1937-01-21 1943-12-21 Rca Corp Short wave tuned circuit arrangement
US2259690A (en) * 1939-04-20 1941-10-21 Univ Leland Stanford Junior High frequency radio apparatus
US2350907A (en) * 1939-09-22 1944-06-06 Rca Corp Ultra short wave apparatus
US2239421A (en) * 1940-03-09 1941-04-22 Rca Corp Electron discharge device
US2281717A (en) * 1941-01-21 1942-05-05 Bell Telephone Labor Inc Electron discharge apparatus
US2328561A (en) * 1941-08-05 1943-09-07 Stephen D Lavoie Oscillatory apparatus
US2311520A (en) * 1941-08-13 1943-02-16 Westinghouse Electric & Mfg Co Coupling loop

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090023360A1 (en) * 2007-07-17 2009-01-22 Li-Chen Wang Hand-gripped clapping device

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Publication number Publication date
BE474640A (de)
US2528138A (en) 1950-10-31
DE857550C (de) 1952-12-01

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