US3484649A - Helix coupled vane circuit with the helix connected centrally of the vanes - Google Patents

Helix coupled vane circuit with the helix connected centrally of the vanes Download PDF

Info

Publication number
US3484649A
US3484649A US660270A US3484649DA US3484649A US 3484649 A US3484649 A US 3484649A US 660270 A US660270 A US 660270A US 3484649D A US3484649D A US 3484649DA US 3484649 A US3484649 A US 3484649A
Authority
US
United States
Prior art keywords
helix
circuit
vanes
vane
helices
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US660270A
Other languages
English (en)
Inventor
George K Farney
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Varian Medical Systems Inc
Original Assignee
Varian Associates Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Varian Associates Inc filed Critical Varian Associates Inc
Application granted granted Critical
Publication of US3484649A publication Critical patent/US3484649A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/50—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field
    • H01J25/52—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode
    • H01J25/58—Magnetrons, i.e. tubes with a magnet system producing an H-field crossing the E-field with an electron space having a shape that does not prevent any electron from moving completely around the cathode or guide electrode having a number of resonators; having a composite resonator, e.g. a helix
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
    • H01J25/34—Travelling-wave tubes; Tubes in which a travelling wave is simulated at spaced gaps
    • H01J25/42—Tubes in which an electron stream interacts with a wave travelling along a delay line or equivalent sequence of impedance elements, and with a magnet system producing an H-field crossing the E-field

Definitions

  • Helix coupled vane type slow wave circuits are disclosed, together with tubes using same.
  • the helix coupled vane circuit is characterized by an array of vane resonators coupled together by means of one or more helices.
  • Electronic interaction with the slow wave circuit is obtained between the fringing fields at the tips of the vanes and a stream of electrons adjacent the tip of the vanes.
  • This type of slow wave circuit is especially useful in magnetron-type tubes operating at microwave frequencies as the helices improve the mechanical and thermal properties of the circuit.
  • the interaction impedance of the helix coupled vane slow wave circuit is improved by Coupling the helices to the vanes at a point approximately midway along the length of the vanes, whereby the vane segment between the helices and the vane tips serves to provide an impedance transformer to increase the electric field intensity at the tips of the vanes and, thus, improve the interaction impedance of the circuit.
  • helix coupled vane slow wave circuits have been employed for interaction circuits in microwave tubes. Such circuits are disclosed and claimed in US. patent ap plication 454,140, now Patent No. 3,387,170 filed May 7, 1965 and US. 514,088 now Patent No. 3,427,495 filed Dec. 15, 1965, both assigned to the same assignee as the present invention.
  • the helix was connected to the vanes near the tips of the vanes.
  • the problem with this arrangement is that the resultant slow wave circuit has a relatively low interaction impedance such as, for example, an impedance of 40 ohms. While such circuits have extremely good mechanical and thermal properties combined with relatively wide band operation, it is desirable to improve their interaction impedance.
  • the principal object of the present invention is the provision of improved helix coupled slow wave circuits and tubes using same.
  • One feature of the present invention is the provision, in a helix coupled vane slow wave circuit, of connecting the helix centrally of the vane members, whereby the portion of the vane extending from the helix to the tips of the vanes serves as an impedance transformer for increasing the electric fields developed by the circuit and, thus, the interaction impedance.
  • Another feature of the present invention is the same as the preceding feature wherein the circuit includes a pair of contrawound helices connected intermediate the length of the vanes as aforedescribed for improving the interaction impedance.
  • Another feature of the present invention is the same as any one or more of the preceding features wherein the helix coupled circuit is arranged in a cricular array for interaction with an electron stream in a magnetron-type interaction region to produce a microwave output signal.
  • FIG. 1 is a schematic cross-section view of a magnetrontype tube employing a prior art helix coupled vane circuit
  • FIG. 2 is an enlarged sectional view of a portion of the structure of FIG. 1 taken along line 22 in the direction of the arrows, and
  • FIG. 3 is a plot of interaction impedance in ohms vs. frequency in gHz. for the prior art helix coupled vane circuit depicted in Insert A and for the helix coupled vane circuit of the present invention shown in Insert B.
  • cross-field amplifier tube 1 includes a cylindrical vacuum envelop 2, as of copper, evacuated to a suitably low pressure such as 10- torr.
  • a cylindrical cathode emitter 3 is centrally disposed of the envelope 2.
  • An array of conductive vanes 4 project inwardly toward the cathode emitter 3 from the inside 'wall of the cylindrical vacuum envelope 2.
  • a pair of contrawound helices 5 and 6 are disposed on opposite sides of the vanes 4 and serve to electromagnetically couple adjacent vane members 4.
  • the helices 5 and 6 are conveniently made by means of a pair of metal toroids of rectangular cross-section which are brazed to the vanes near the tips thereof.
  • the toroids are then axially slotted from the vane 4 toward the outer axial ends of both toroids such that each toroid has three of its sides slotted in alignment with the slots between adjacent vane members 4.
  • the outer axial walls of the toroids are then slotted by an array of diagonal slots having a pitch such that the member defined between adjacent slots serves to interconnect adjacent turns of the helix.
  • the diagonal slots for the upper toroid 5 define diagonal members 7 to produce a helix having a first sense of rotation, whereas the diagonal slots in the lower toroid define diagonal interconnecting members 8 causing the helix 6 to advance with the opposite sense of rotation.
  • contrawound helices 5 and 6 are formed on the helix coupled vane structure.
  • the contrawound helices serve to prevent setting up of certain undesired modes of propagation on the helix coupled circuit which might otherwise tend to cancel the desired electric fields at the tips of the vanes 4.
  • An annular magnetron-type interaction region 9 is defined in the space between the slow wave circuit which is operated at anode potential and the cathode 3.
  • a magnet not shown, produces an axially directed magnetic field B in the magnetron interaction region 9.
  • An input terminal 11 is provided at one end of the slow Wave circuit and an output terminal 12 is provided at the other end of the circuit.
  • a circuit sever 13, as of copper, is provided in the anode between the input terminal 11 and the output terminal 12 to prevent RF feedback from the output end of the slow wave circuit to the input end which would otherwise produce oscillations which would interfere with proper operation of the crossed-field amplifier tube 1.
  • Curve A shows the interaction impedance versus frequency for a prior art C-band dual helix coupled vane circuit having dimensions as shown in Insert A. More particularly, it is seen that the interaction impedance for the circuit, as indicated in A, is about 40 ohms.
  • the circuit of the present invention is shown in insert B and is essentially the same as that of the prior art except that the dual helices are connected to the vanes at a point substantially midway along the length of the vane 4 such that a short transformer section 15 is provided between the helices and the tips of the vanes 4. These transformer sections 15 serve to transform the relatively low voltages developed near the helices 5 and 6 into relatively higher voltages at the tips of the vanes 4.
  • the dual helix coupled vane circuits having dimensions as indicated in insert B provided a measured interaction impedance as shown by curve B.
  • curve B By comparing curves A and B it is seen that providing the impedance transformer sections 15 approximately doubles the interaction impedance of the circuit. Increasing the interaction impedance of the circuit improves the electronic efiiciency and, thus, the power output and gain that can be obtained for a given circuit length.
  • the circuit of the present invention has substantially the same improved mechanical and thermal properties of the prior art circuit exemplified by detail A.
  • the helices 5 and 6 are preferably connected substantially midway along the length of the vanes 4. However, it is not necessary that the helices be connected precisely midway of the length of the vanes 4. More specifically, helices may be connected such that the spacing from the helix to the back wall 2 is from one-third to three times the spacing from the helix to the tips of the vanes 4. The aforecited measurements are made in the direction along the vane from the nearest side of the helix to the wall or to the vane tip. The helices 5 and 6 should not be too closely spaced to the backwall 2 as this tends to short out the helices.
  • the circuit may employ only a single helix for coupling the vane array. In such a case, the helix would be coupled to the vane array in the same manner as previously described with regard to insert B.
  • the circuit is useful in linear beam tubes as well as in circular beam tubes.
  • a high frequency apparatus means forming a conductive wall structure, means forming an array of conductive members connected to and projecting away from said wall to define root portions of said members where they are connected to said wall and tip portions at the opposite ends of said members, means forming a conductive helix structure interconnecting said members of said array, means for producing a stream of electrons adjacent said tip portions of said array of conductive members for interaction with the radio frequency fields on said helix coupled array of members to produce a radio frequency output, the improvement wherein, said helix is connected to said members intermediate their length with the spacing from said helix to said wall taken in a direction along said members being from onethird to three times the spacing from said helix to said tip portion of said members taken in the direction along said members.
  • said helix structure includes a pair of contrawound helices disposed on opposite sides of said conductive members.
  • said helix coupled members are vanes
  • said array is a curved array
  • the apparatus of claim 5 including means forming an input terminal on said helix coupled array for applying radio frequency signals to be amplified, means forming an output terminal on said helix coupled array for extracting the amplified radio frequency output signal, and means forming a circuit sever disposed between said input and said output terminals of said helix coupled array for preventing propagation of radio frequency output signals to said input terminal.

Landscapes

  • Microwave Tubes (AREA)
  • Coils Or Transformers For Communication (AREA)
US660270A 1967-08-14 1967-08-14 Helix coupled vane circuit with the helix connected centrally of the vanes Expired - Lifetime US3484649A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US66027067A 1967-08-14 1967-08-14

Publications (1)

Publication Number Publication Date
US3484649A true US3484649A (en) 1969-12-16

Family

ID=24648804

Family Applications (1)

Application Number Title Priority Date Filing Date
US660270A Expired - Lifetime US3484649A (en) 1967-08-14 1967-08-14 Helix coupled vane circuit with the helix connected centrally of the vanes

Country Status (4)

Country Link
US (1) US3484649A (enrdf_load_stackoverflow)
DE (1) DE1766858C2 (enrdf_load_stackoverflow)
FR (1) FR1571805A (enrdf_load_stackoverflow)
GB (1) GB1228436A (enrdf_load_stackoverflow)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4381475A (en) * 1979-10-13 1983-04-26 Thomson - Csf Variable coupling resistance delay line for crossed field tube
US20030178212A1 (en) * 2002-02-12 2003-09-25 Dennis Larry A. Post Driver

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2708149B1 (fr) * 1993-07-23 1995-09-01 Thomson Tubes Electroniques Procédé de fabrication d'une ligne à hélice et ailettes couplées, ligne obtenue par le procédé et tube électronique comportant une telle ligne.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1074092B (de) * 1955-12-28 1960-01-28 Siemens & Halske Aktiengesellschaft, Berlin und München Verzögerungsleitung mit Filtercharakteristik für Wanderfeldröhren
US2939035A (en) * 1954-07-16 1960-05-31 Csf Helical delay lines
US3054017A (en) * 1957-05-06 1962-09-11 Gen Electric Electron discharge devices

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1478916A (enrdf_load_stackoverflow) * 1967-07-17

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2939035A (en) * 1954-07-16 1960-05-31 Csf Helical delay lines
DE1074092B (de) * 1955-12-28 1960-01-28 Siemens & Halske Aktiengesellschaft, Berlin und München Verzögerungsleitung mit Filtercharakteristik für Wanderfeldröhren
US3054017A (en) * 1957-05-06 1962-09-11 Gen Electric Electron discharge devices

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4381475A (en) * 1979-10-13 1983-04-26 Thomson - Csf Variable coupling resistance delay line for crossed field tube
US20030178212A1 (en) * 2002-02-12 2003-09-25 Dennis Larry A. Post Driver

Also Published As

Publication number Publication date
DE1766858B1 (de) 1973-06-07
GB1228436A (enrdf_load_stackoverflow) 1971-04-15
FR1571805A (enrdf_load_stackoverflow) 1969-06-20
DE1766858C2 (de) 1974-01-03

Similar Documents

Publication Publication Date Title
US4158791A (en) Helix traveling wave tubes with resonant loss
US2802135A (en) Traveling wave electron tube
US3346766A (en) Microwave cold cathode magnetron with internal magnet
US5477107A (en) Linear-beam cavity circuits with non-resonant RF loss slabs
US3576460A (en) Impedance match for periodic microwave circuits and tubes using same
US3484649A (en) Helix coupled vane circuit with the helix connected centrally of the vanes
US3886397A (en) Hybrid slow wave circuit
US3223882A (en) Traveling wave electric discharge oscillator with directional coupling connections to a traveling wave structure wherein the number of coupling connections times the phase shift between adjacent connections equal an integral number of wavelengths
US3479556A (en) Reverse magnetron having an output circuit employing mode absorbers in the internal cavity
US3376463A (en) Crossed field microwave tube having toroidal helical slow wave structure formed by a plurality of spaced slots
US4019089A (en) Wideband multi-cavity velocity modulation tube
US3538377A (en) Traveling wave amplifier having an upstream wave reflective gain control element
US2758244A (en) Electron beam tubes
US4682076A (en) Microwave tube with improved output signal extracting structure
US4742271A (en) Radial-gain/axial-gain crossed-field amplifier (radaxtron)
US3292033A (en) Ultra-high-frequency backward wave oscillator-klystron type amplifier tube
US3594605A (en) Mode suppression means for a clover-leaf slow wave circuit
US5196765A (en) High RF isolation crossed-field amplifier
US3370197A (en) Travelling wave tubes
US2887608A (en) Travelling wave tube
US3437875A (en) Mixed line composite magnetron interaction circuits of forward wave and backward wave types
US3308336A (en) Periodic slow wave circuit having capacitive coupling between alternate periodic elements
US4099094A (en) Electronic tube of magnetron type operating as a oscillator or an amplifier
US3374390A (en) Traveling-wave tube having a slow-wave structure of the cloverleaf type wherein the height of the cloverleaf sections are tapered
US3289036A (en) Inverted magnetron having adjacent anode cavities coupled in opposite phase to a central stabilizing cavity