Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
  • H01J23/02—Electrodes; Magnetic control means; Screens
  • H01J23/04—Cathodes
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41H—ARMOUR; ARMOURED TURRETS; ARMOURED OR ARMED VEHICLES; MEANS OF ATTACK OR DEFENCE, e.g. CAMOUFLAGE, IN GENERAL
  • F41H13/00—Means of attack or defence not otherwise provided for
  • F41H13/0043—Directed energy weapons, i.e. devices that direct a beam of high energy content toward a target for incapacitating or destroying the target
  • F41H13/0068—Directed energy weapons, i.e. devices that direct a beam of high energy content toward a target for incapacitating or destroying the target the high-energy beam being of microwave type, e.g. for causing a heating effect in the target
• • 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
• • 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
  • H01J25/32—Tubes with plural reflection, e.g. Coeterier tube
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J25/00—Transit-time tubes, e.g. klystrons, travelling-wave tubes, magnetrons
  • H01J25/74—Tubes specially designed to act as transit-time diode oscillators, e.g. monotrons

Definitions

• the present invention relates to a device for generation of microwaves comprising a coaxial virtual cathode oscillator (vircator) with an outer cylindrical tube forming a cathode and connected to a transmission line for feeding the cathode with voltage pulses, and an inner cylindrical tube, at least partially transparent for electrons, forming an anode and connected to a waveguide for outputting microwave radiation generated by the formation of a virtual cathode inside an area enclosed by the anode.
• a coaxial virtual cathode oscillator virtual cathode oscillator
• an outer cylindrical tube forming a cathode and connected to a transmission line for feeding the cathode with voltage pulses
• an inner cylindrical tube at least partially transparent for electrons
• Microwave generators of this type can, among other uses, be used to knock out electronics using the high peak output that can briefly be generated.
• a device as described in the first paragraph is essentially previously known from
• One purpose of the present invention is to make a device for generation of microwaves with improved efficiency. Another purpose is to improve the device's peak output. Because the virtual cathode oscillator, the vircator, is primarily used to create microwave radiation with high output, peak output efficiency is a very important parameter.
• the purpose of the invention is achieved through a device for generation of microwaves in accordance with the first paragraph wherein the cylindrical tube of the cathode on the inside is equipped with a first electrically conductive structure transverse to the tube's longitudinal direction at a distance from the anode's, for the electron's at least partially transparent, tube and that the anode's, for the electron's at least partially transparent, tube on the outside is equipped with a second electrically conductive structure transverse to the tube's longitudinal direction at a distance from the cathode's cylindrical tube for creating resonant cavities in the virtual cathode oscillator.
• a first and second electrically conductive structure in the specified manner a reactive cavity is created with resonant phenomena in the radiation source resulting in an increased efficiency and increased peak output efficiency.
• distance di between the first electrically conductive structure arranged in the cathode's cylindrical tube and the anode's at least partially transparent tube is essentially determined by the generated microwave wavelength ⁇ in accordance with the formula:
• distance d can be essentially ⁇ /4.
• distance d 2 can be essentially ⁇ /4.
• the efficiency for the virtual cathode oscillator in the coaxial design is a pronounced improvement.
• the distances cause a positive feed back or reaction on the oscillation process that is amplified and thereby an increased efficiency is attained.
• the device comprises an adjustment mechanism for adjusting distances d and d 2 .
• the adjustment mechanism can thereby consist of a screw joint for axial offset of the first electrically conductive structure through rotation.
• the adjustment mechanism can comprise a screw joint for axial offset of the second electrically conductive structure through rotation.
• a high voltage generator connected to the cathode's transmission line is suitable for feeding the device cathode.
• the wave guide for output of the microwave radiation is connected to an antenna.
• the antenna can be, for example, a horn antenna.
• the device anode is composed, at least partially, of mesh.
• the anode can partially be composed of a thin foil.
• Figure 1 schematically depicts an example of a known coaxial virtual cathode oscillator comprised in a the device for generation of microwaves.
• Figure 2 schematically depicts an example of a coaxial virtual cathode oscillator in accordance with the present invention comprised in a device for generation of microwaves.
• Figure 3 schematically depicts a more detailed example of a coaxial virtual cathode oscillator in accordance with the present invention comprised in a device for generation of microwaves.
• Figure 4 schematically in block form depicts a complete device for generation of microwaves comprising a coaxial virtual cathode oscillator in accordance with the present invention.
• the known coaxial virtual cathode oscillator 1 schematically depicted in Figure 1, contains a cathode 2 in the form an outer cylindrical tube and an anode 3 in the form of an inner cylindrical tube.
• the cathode oscillator is a very simple geometric design and is based on a so-called virtual cathode 4 occurring inside of the anode under certain conditions. As is depicted in the figure, there are no limiting walls in the axial direction in connection with the cathode and anode.
• Figure 2 depicts on the schematic level a modification of the known coaxial virtual cathode oscillator for improving efficiency and increasing peak output. In accordance with this design two electrically conductive structures 5 and 6 are introduced.
• the structure 5 is arranged on the outside of the anode's cylindrical tube and transverse to the tube's longitudinal direction.
• the structure 6 is arranged on the inside of the cathode's cylindrical tube and transverse to the tube's longitudinal direction.
• the distance between the cathode's end and the structure 5 is depicted as d 2 and the distance between the anode's end against the cathode and structure 6 is depicted as d 1 .
• Distances d ⁇ and d 2 are determined from the generated wavelength in accordance with the formula:
• the coaxial virtual cathode oscillator 1 can be a component of the device for generation of microwaves depicted in Figure 4 and including a high voltage generator 7 connected to the cathode oscillator input and an antenna 8 connected to the cathode oscillator output.
• the antenna can be a horn antenna.
• the cathode oscillator with peripherals is depicted and described in more detail in reference to Figure 3, both regarding design and function. Reference designations that correspond to previously described figures have been given the same reference designations in Figure 3.
• the anode 3 and the cathode 2 are arranged in a vacuum chamber 9 with a connection 10 for a vacuum pump (not depicted in the figure).
• a screw joint 1 1 enables the adjustment of the structure's 6 distance dj to the anode 3 through rotation.
• a corresponding screw joint can be arranged for adjustment of the structure's 5 distance d 2 to the cathode 2.
• the anode 3 is equipped with a mesh 12 that partially is transparent to free, electrically charged particles.
• the anode 3 passes to an outgoing waveguide 13, while the cathode 2 is feed by a transmission line 14.
• the cathode oscillator's design is based on the fact that a so-called virtual cathode occurs under certain conditions.
• a voltage pulse with negative potential is fed via the transmission line 14 to the cathode 2
• a high electric field occurs between the cathode 2 and the anode 3.
• This causes electrons to be field emitted from the cathode material.
• the electrons accelerate after that toward the anode structure and the majority of the electrons will even pass the anode and begin to decelerate. If certain conditions are met, a virtual cathode 4 will occur inside the anode structure.
• microwave generation Because the process is strongly non-linear, the phenomena that cause the microwave radiation to be generated occur. The more detailed conditions for microwave generation are not described here because they are part of the competence for expert in the field. Under the correct conditions, very high output is generated for a short period with a typical magnitude of 50-100 ns prior to shortcircuiting. Generated microwaves leave the cathode oscillator anode via the waveguide 13 connected to the anode and that waveguide has essentially the same radius as the anode 3.
• the electrically conductive structures 5 and 6 contribute to the creation of a resonant phenomenon that results in increased efficiency and peak output.

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• Engineering & Computer Science (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• General Engineering & Computer Science (AREA)
• Microwave Tubes (AREA)

Priority Applications (2)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (2)

Cited By (2)

Citations (6)

• 2009
  • 2009-09-25 WO PCT/SE2009/000424 patent/WO2011037498A1/en not_active Ceased
  • 2009-09-25 IN IN3098DEN2012 patent/IN2012DN03098A/en unknown

Patent Citations (6)

Non-Patent Citations (1)

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