CA1222563A - Emitron: microwave diode - Google Patents
Emitron: microwave diodeInfo
- Publication number
- CA1222563A CA1222563A CA000426104A CA426104A CA1222563A CA 1222563 A CA1222563 A CA 1222563A CA 000426104 A CA000426104 A CA 000426104A CA 426104 A CA426104 A CA 426104A CA 1222563 A CA1222563 A CA 1222563A
- Authority
- CA
- Canada
- Prior art keywords
- resonant frequency
- frequency microwave
- cathode
- anode
- plate
- 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
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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
- H01J25/74—Tubes specially designed to act as transit-time diode oscillators, e.g. monotrons
Abstract
EMITRON: MICROWAVE DIODE
Abstract of the Disclosure The invention comprises a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves by utilizing the interaction of electromagnetic waves with electron flow in diodes not requiring an external magnetic field. Anode and cathode surfaces (14, 16, 44, 46, 70 and 72) are electrically charged with respect to one another by electron flow, for example caused by a Marx bank voltage source (30, 58), or by other charged particle flow, for example by a high energy charged particle beam (80). This produces an electric field which stimulates an emitted electron beam to flow in the anode-cathode region. The emitted electrons are accelerated by the electric field and coherent microwaves are produced by the three dimensional spatial and temporal interaction of the accelerated electrons with geometrically allowed microwave modes which results in the bunching of the electrons and the pumping of at least one dominant microwave mode.
Abstract of the Disclosure The invention comprises a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves by utilizing the interaction of electromagnetic waves with electron flow in diodes not requiring an external magnetic field. Anode and cathode surfaces (14, 16, 44, 46, 70 and 72) are electrically charged with respect to one another by electron flow, for example caused by a Marx bank voltage source (30, 58), or by other charged particle flow, for example by a high energy charged particle beam (80). This produces an electric field which stimulates an emitted electron beam to flow in the anode-cathode region. The emitted electrons are accelerated by the electric field and coherent microwaves are produced by the three dimensional spatial and temporal interaction of the accelerated electrons with geometrically allowed microwave modes which results in the bunching of the electrons and the pumping of at least one dominant microwave mode.
Description
EMITRON: MICROWAVE DIODE
Background of the Invention The invention described herein relates generallyto method and apparatus for producing microwaves, and more particularly to method and apparatus for producing coherent microwaves with a new class of microwave device, driven by electron or other charged particle flow, ~y utili~ing the interaction of electromagnetic waves with electron flow in diodes in the absence of an e~ternal magnetic field.
MicrowaYes occupy the region of the electromag-netic spectrum bounded by radio waves on the side of longer wavelengths and by infrared waves on the side of shorter wavelengths. Although there are no sharp bound-aries bet~een these regions, microwaves are often con-sidered to have ~requencies in the range between lO9 Hz and 3xlOll Hz or, equivalently, to have free space wave-lengths in the range between about l mm and 30 cm. Micro-waves are used for many purposes. Some of these purposes are: for pulsed radiation sources for radar tracking, for carrier waves in relay links for the multichannel trans-mission of telephone, telegraph and television signals;
for microwave spectroscopy to study the structure of numerous molecules and crystals; for use in atomic clocks which use microwave resonance interactions with either cesium atoms or ammonia molecules; for use in solid-state masers, which can be virtually noiseless amplifiers; for use in radio astronomy; for use in the cooking of food;
/
~2~22~3 and, for use in high-energy linear accelerators and similar machines.
Low power multi-frequency microwaves can be simply generated as thermal radiation from warm bodies, or as direct incoherent radiation From electrical sparks estab-lished across high voltage spark gaps. However, for present day applications~ almost all modern microwave generators are electronic devices which produce frequency tunable continuous-wave (CW) oscillations. These devices include magnetrons, klystrons, and traveling-wave tubes.
A magnetron functions by having electrons, generated from a cathode and moving under the combined force of a radial electric field and an external axial magnetic field, interact synchronously with traveling-wave components of a microwave standing-wave pattern in such a manner that electron potential energy is converted to microwave energy.
Relativistic electron beam smooth-bore and conventional magnetrons are discussed by Orzechowski and Bekefi in Phys.
Fluids 22, 978 (1979), and by Palevsky and 8ekefi in Phys.
Fluids 22, 986 (1979), respectively. A relativistic elec-tron beam crossed-field magnetron device is disclosed in U.S. Patent No. 4,200,821 issued April 29, 1980 to Bekefi and Orzechowski. A disadvantage of the magnetron, when it is used to generate high intensity coherent microwaves9 is the requirement that it have a very large external magnet, which greatly contributes to its size and weight.
A klystron functions by having a velocity-modulated bunched electron beam pass through an output cavity and transfer its ac energy thereto for subsequent coupling into a microwave transmission line. An external magnetic field parallel to the electron beam axis holds the beam together, overcoming the electrostatic repulsion between electrons which would otherwise make the beam spread out rapidly. A traveling-wave tube functions as an Z~63 amplifier by having a beam of electrons, retained through-out the length of the tube by focusing means such as an external longitudinal fixed magnetic field, interact con-tinuously and over an appreciable distance with microwaves propagating along a slow-wave circuit. It is also conven-tional for microwave energy~ to be generated by various active solidstate microwave devices.
Additionally, microwaves may be yenerated by some less well known devices such as the femitron as discussed by Charbonnier, et al, in "Basic and Applied Studies of Field Emission at Microwave Frequencies", Proceedings of the IEEE, 51, 991-1004, July 1963. The femitron, which in many ways resembles a klystron, functions by exploiting the strong nonlinearity of the field-emission characteris-tic of a cold cathode located in the gap of a cavityresonator to achieve direct longitudinal bunching of the field-emitted electron beam. The femitron employs multiple-needle cathodes emitting electrons in acc~rdance with the Fowler-Nordheim field-emission law. The elec~ron 20 emission is not space charge limited Child-Langmuir flow.
Further, there are many extant variants of the known microwave devices. For example Gurewitsch, in U.S. Patent No. 2,513,933 issued July 4, 1950, discloses a novel con-struction for cathodes of the cold emission type such as 25 may be used for various microwave devices, particularly those of the magnetron class.
Thus, at the present time there exist many dif-ferent classes of electronic device capable of producing microwaves at various power levels and efficienc;es. How-ever, particularly in view of the importance and extremevariety of microwave technology, there remains a continuing need for innovative and structurally simple new classes of device for the production of coherent microwaves. It would be advantageous if these new classes of device could be driven by electron, or other charged particle, flow.
.....
~2Z~i63 Summary of ~he-Invention It is therefore an object of the invention to provide a new class of device which can produce coherent microwaves by the interaction of electromagnetic waves with electron flow in diodes.
It is also an object of the invention to provide a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves.
It is a further object of the invention to provide a new class of device which can produce high power coherent microwaves by the interaction of electromagnetic waves with electron flow in small and light weight diodes not requir-ing an external magnetic field.
Additional objects, advantages and novel features 15 of the invention wi71 be set forth in part in the descrip-tion which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized 20 and attained by means of the instrumentalities and combi-nations particularly pointed out in the appended claims.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and 25 apparatus ~or producing coherent microwave radiation of this invention may comprise providing an anode having an anode surface and a separated cathode having a cathode surface with the two surfaces comprising structure capable of supporting a plurali~y of microwave modes particularly including a resonant frequency microwave mode. A dc elec-tric field is imposed, over a time of at least one period of the resonant frequency microwave mode, within the ~f~;63 spatial volume occupied by the microwave modes. The electric field stimulates a beam of electrons to undergo accelerated flow from the cathode surface into the spatial volume. The collective motion of the accelerated electron beam interacts with the resonant frequency microwave mode by fundamentally altering its pattern9 by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching the electron beam, and by pumping the resonant frequency microwave mode. The resonant frequency microwave radiation is coupled out of the apparatus. In some embodiments of the invention, the beam may comprise a beam of thermionic or field emitted electrons stimulated by the dc electric field to flow from the cathode surface.
And, in some embodiments of the invention the dc electric field may be established by charging the anode positively with respect to the cathode with a Marx bank voltage source. Ad~itionally, in so~e embodiments of the inven-tion the dc electric field may be established by charging the anode or the cathode by substantially imbedding a charged particle beam in either one or the other.
In some embodiments of the method and apparatus for producing coherent microwave radiation of this inven-tion, it is preferred that the cathode comprise the center conductor of a coaxial line and that the anode comprise the outer conductor of the coaxial line, with the cathode surface comprising at least part of the outer surface of the center conductor and with the anode surface comprising at least part of the inner surface of the outer conductor.
In some embodiments of the method and apparatus for producing coherent microwave radiation of this inven-tion, it is preferred that the cathode and anode comprise two disks, with the cathode surface comprising part of a planar surface of the first disk, with the anode surface comprising part of a planar surface of the other disk, with the two disks juxtaposed with coincident axes, and ~2~;63 with the two planar surfaces acting as cathode and anode surfaces facing one another.
In a further aspect of the present invention, in accordance with its objects and purposes, the method and apparatus for producing coherent microwave radiation of this invention may comprise providing a hollow metal can, or housing having an internal housing chamber, and posi-tioning a disk shaped plate within the can so that from every location on the plate the closest distance to the interior surface of the can is approximately constant.
The plate and interior surface of the can comprise struc-ture capable of geometrically supporting a plurality of microwave modes particularly including a resonant fre-quency microwave mode. A large voltage difference is established between the plate and the can by substantially imbedding a charged particle beam in the plate. This voltage imposes a dc electric field~ over a time of at least one period of the resonant frequency microwave mode, within the spatial volume occupied by the microwave modes.
The electric field stimulates a beam of electrons to under-go accelerated flow into the spatial volume from the plate or the can, whichever has been charged negatively. The collective motion of the accelerated electron beam inter-acts with the resonant frequency microwave mode by funda-mentally altering its pattern, by producing electromag-netic fields, by longitudinally and transversely spatially bunching the electron beam, and by pumping the resonant frequency microwave mode. The resonant frequency microwave radiation is coupled out of the can.
The benefits and advantages of the present inven-tion, as embodied and broadly described herein9 include, inter alia, the provision of a new class of device, driven by electron or other charged particle flow, for producing coherent microwave radiation by the interaction of elec-tron flow with electromagnetic waves in small and light weight diodes not requiring an external magnetic field.
. .
.... .
~LZ~r6 Brief Description of the Drawings The accompanying drawings, which are incorporated in and form a part of the specification, illustrate three embodiments of the present invent-ion and, together with ~the description, serve to explain the principles of the invention. In the drawings:
Figure l is a perspective view, partially schema-tic and partially in cross section, of a first embodiment of a diode for producing coherent microwave radiation made in accordance with the invention.
Figure 2 is a perspective view, partially sche-matic and partially in cross section, of a second embodi-ment of a diode for producing coherent microwave radiation made in accordance with the invention.
Figure 3 is a perspective view, partially sche-matic and partially in cross section, of a third embodi-ment of a diode for producing coherent microwave radiation made in accordance with the invention.
Detailed Description of the Invention Re~erence will now be made in detail to the pres-ent preferred embodiment of the invention, examples of which are illustrated in the accompanying drawings. The invention is of a new class of device~ driven by electron or other charged particle flow, which can produce coherent microwaves by the interaction of electromagnetic waves with electron flow in diodes. The electron flow may be caused by electron emission or injection. No external magnetic field is required~ The new device has been given the name "emitron". The principle features of the diode are an anode having an anode surface, a cathode having a cathode surface, and a gap therebetween. Open or closed Z2~3 geometries capable of supporting microwave modes and allowing the maintenance of a dc electric field over some portion of the anode and cathode surfaces are permissible.
By mode is meant, herein, a form of natural electromagnetic oscillation characterized by a particular field pattern.
The device is driven, or powered, by electron or other charged particle flow: in other ~ords, the anode may be charged relative to the cathode b~ a conventional voltage source or by a charged particle beam. As a consequence of charging, a dc electric field extending from one electrode surface to the other accelerates an electron beam. This beam may be composed of thermionic or field emitted elec-trons flowing from the cathode. However, in some embodi-ments of the invention the beam may comprise electrons from any other appropriate source. Coherent microwaves are produced by the strong interaction of the electron beam with one or more of the microwave modes allowed by the specific geometry of the particular diode. This com-plex synergism results in the three-dimensional spatial 20 bunching, both longitudinal and transverse to the direction of electron beam flow, of the electron beam and the pumping of one or more dominant microwave modes. That is, during the interaction the amplitudes of the microwave modes are constantly changing as a function of both position and 25 time. Also, at the same time and as a consequence thereof, the electron beam is undergoing a spatial and temporal evolution which may be termed bunching. The frequencies of the dominant modes are a function of electrode spacing and the magnitude of the dc electric field. If so desired, these frequencies can be shifted or quenched by the appli-cation of a small magnetic field perpendicular to the dc electric field. If operated in this way, the invention can have applicability to circuitry involving feedback loops for frequency tuning and/or logic gating. Where used, the invention will greatly simplify microwave tube construction because the diode does not require the large external magnetic field of the magnetron tube nor the .....
Z~i63 g additional electrodes of the triode and tetrode tubes.
The invention is a consequence of some unanticipated results of calculations performed using Lawrence Livermore National Laboratory's MASK computer code. The MASK code is a 2-1/2 dimensional, electromagnetic, relativistic particle-in-cell code which has been used to reliably model conventional electron and ion beam diodes.
Reference is now made to Figure 1 which shows a first embodiment of an electronic diode for producing coherent microwave radiation made in accordance with the invention. The smooth bore coaxial diode comprises a center conductor 10 which forms a cathode, and an outer conductor 12 which forms an anode. A cathode surface 14 comprises at least part of the outer surface of center conductor 10, and an anode surface 16 comprises at least part of the inner surface of outer conductor 12. Note that the electron emission characteristics of a surface may be modified by surface treatment, as by scoring, to localize electron emission from only part of the surface.
Center conductor 10 and outer conductor 12 form a coaxial line. Cathode surface 14 may have a radius of 1.86 cm, and anode surface 16 may have a radius of 2.20 cm. First end plate 18 and second end plate 20 are attached to the ends of outer conductor 12, forming air-tight seals there-with. Center conductor 10 is secured within outer conduc-tor 12 by means of insulational supports 22 and 24, which are schematically indicated. It will be appreciated, how-ever, that the present invention is in no way limited to a specific support structure and that center conductor 10 may be secured within outer conductor 12 by any other suitable means. The assembly is evacuated by means of vacuum port 26 and vacuum pump 28, which are schematically indicated. It will be appreciated, however, that the present invention is in no way limited to a specific vacuum system and that the assembly may be evacuated by . , .
~f~ fi3 1 o --any other suitable means. For optimal operating condi-tions it is desirable at early times to minimize the loss of microwave radiation from the apparatus. This may be accomplished by end plates 18 and 20, which prevent radia-tion leakage, and by having the axial length of the anodeto cathode gap greater than the circumference of center conductor 10. A plurality of microwave modes, particularly including at least one resonant frequency microwave mode, are capable of being supported within the anode to cathode gap. High voltage source 30, which is schematically rep-resented, provides means for maintaining a dc electric field between center conductor lO and outer conductor 12 over a time of at least one period of a resonant frequency microwave mode. Source 30 may be a 350 kV source having a rise time of 0.5 ns. Preferably high voltage source 30 may be a Marx bank voltage source. High voltage source 30 may also represent charging the anode positively with respect to the cathode by substantially imbedding a charged particle beam in either the cathode or the anode. The dc 20 electric field causes an electron current to undergo accelerated flow across the anode to cathode gap in a radial direction. The current may comprise thermionic or field emitted electrons. At first the electron current is uniformly distributed in the azimuthal direction in 25 agreement with the Child-Langmuir V3/2 law for space charge limited flow in cylindrical geometry. The value of the voltage applied by high voltage source 30 should be such as to cause electrons to cross the anode to cathode gap in ayproximately one period, or integral multiple 30 thereof, of the resonant frequency microwave mode being supported within the anode to cathode gap. Later in time, the space charge flow excites strong microwave oscillations and the space charge flow becomes longitudinally and trans-versely spatially bunched with respect to the direction of 35 electron flow. The microwave field energy rises and oscil-lates coherently. Thus, the collective motion of the accelerated electrons interacts with the allowed microwave ~L~2;2;2S~i3 modes by fundamentally altering their pattern, producing electromagnetic fields, longitudinally and transversely spatially bunching the electrons, and pumping at least one dominant microwave mode. Dominant microwave mode micro-wave radiation, which in this embodiment may have a valueof 35 GHz, is coupled out of the diode by means of micro-wave horn and aperture 32, which is schematically indi-cated. It will be appreciated, however, that the present invention is in no way limited to a specific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
Reference is now made to Figure 2 which shows a second embodiment of an electronic diode for producing coherent microwave radiation made in accordance with the invention. First disk 40 forms a cathode and second disk 42 forms an anode. By disk is meant, herein, a thin cir-cular object. A cathode surface 44 comprises at least part of a planar surface of disk 40, and an anode surface 46 comprises at least part of a planar surfa e of disk 42.
Note that the electron emission characteristics of a sur-face may be modified by surface treatment, as by scoring, to localize electron emission from only part of the sur-face. Disks 40 and 42 are disposed within housing 48.
Disk 40 is secured within housing 48 by means of first insulational support 50, and disk 42 is secured within housing 48 by means of second insulational support 52.
Housing 48 and supports 50 and 52 are all schematically indicated. It will be appreciated that the present inven-tion is in no way limited to a specific housing and support structure and that disks 40 and 42 may be disposed and secured by any other suitable means. The assembly is evacuated by means of vacuum port 54 and vacuum pump 56, which are schematically indicated. I~ will be appreciated, however, that the present invention is in no way limited to a specific vacuum system and that the assembly may be evacuated by any other suitable means. Disks 40 and 42 ~22Z~;Çi3 are juxtaposed with coincident axes, and cathode surface 44 and anode surface 46 are facing one another. A plural-ity of microwave modes, particularly including at least one resonant frequency microwave mode, are capable of being supported within the anode to cathode gap. To minimize the loss of microwave radiation from the diode at early times, the radius of each of disks 40 and 42 must be larger than the spacing of the gap between the disks.
High voltage source 58, which is schematically represented, provides means for maintaining a dc electric field between - first disk 40 and second disk 42 over a time of at least one period of the resonant frequency microwave mode.
Preferably high voltage source 58 may be a Marx bank vol-tage source. High voltage source 58 may also represent charging the anode positively with respect to the cathode by substantially imbedding a charged particle beam in either the cathode or the anode. The dc electric field causes an electron current to undergo accelerated flow across the anode to cathode gap by causing electrons to be drawn from cathode surface 44. Although not required, a small guide magnetic field may be employed to keep the current from spreading apart. The current may comprise thermionic or field emitted electrons. At first the elec-tron current is uniformly distributed and agrees with classical theory~ The value of the voltage applied by high voltage source 58 should be such as to cause elec-trons to cross the anode to cathode gap in approximately one period, or integral multiple thereof, of the resonant frequency microwave mode being supported within the anode 3~ to cathode gap. Later in time, the space charge flow excites strong microwave oscillations and the space charge flow becomes longitudinally and transversely spatially bunched with respect to the direction of electron flow.
The microwave field energy rises and oscillates coherently.
Thus, the collective motion of the accelerated electrons interacts with the allowed microwave modes by fundamentally altering their pattern, producing electromagnetic fields, longitudinally and transversely spatially bunching the electrons, and pumping at least one dominant microwave mode. Dominant microwave mode microwave radiation is coupled out of the diode by means of microwave horn and 5 aperture 60, which is schematically indicated. It will be appreciated, however, that the present invention is in no way limited to a specific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
Reference is now made to Figure 3 which shows a third embodiment of a diode for producing coherent micro-wave radiation made in accordance with the invention. The diode comprises hollow can 70 and disk shaped plate 72.
By disk is meant, herein, a thin circular object. Can 70 15 is, quite simply, a housing having an internal housing chamber. Plate 72 is secured within can 70 by means of insulating support 74, which is schematically indicated.
It will be appreciated, however, that the present inven-tion is in no way limited to a specific support structure 20 and that plate 72 may be sec~red withing can 70 by any other suitable means. The assembly is evacuated by m~ans of vacuum port 76 and vacuum pump 78, which are schematic-ally indicated. It will be appreciated, however, that the present invention is in no way limited to a specific vacuum 25 system and that the assembly may be evacuated by any other suitable means. Plate 72 is positioned so that a gap exists between plate 72 and can 70 with the closest dis-tance from every location on plate 72 to the internal sur-face of hollow can 70 being an approximate constant.
30 Plate 72 and can 70 are capable of supporting a plurality of microwave modes~ particularly including at least one resonant frequency microwave mode, within the gap separat-ing plate 72 and can 70. To minimize the loss of micro-wave radiation from the diode at early times, the radius 35 of plate 72 is larger than the distance across the gap separating can 70 from plate 72. High energy charged ~ 6 particle beam 80, which is schematically represented, provides a means for imposing a dc electric field within the gap separating plate 72 from can 70 over a time of at least one period of the resonant frequency microwave mode.
Beam 80 is injected through a surface of can 70 and is substantially imbedded in plate 72 thereby causing a large voltage difference to be established between plate 72 and can 70. Some examples of changed particles of which beam 80 may be composed are electrons, positions, protons, antiprotons, alpha particles, any ions, quarks and various short lived particles such as pions and muons. The portion of the wall of can 70 through which beam 80 is injected must be sufficiently thin to allow most of beam 80 to pass unimpededly therethrough. The polarity of the voltage difference, and the direction of the resultant dc electric field, is a function of the sign, positive or negative, of the particles comprising beam 80. A stream of thermionic or field emitted electrons is emitted from either can 70 or plate 72, depending on the direction of the dc electric field, and stimulated to undergo accelerated flow into the gap separating plate 72 and can 70. Note that the electron emission characteristics of a surface may be modified by surface treatment, as by scoring, to localize electron emission ~rom only part of the surface. The value of the voltage established across the gap separating plate 72 and can 70 should be such as to cause electrons to cross that gap in approximately one period, or integral multiple thereof, of the resonant frequency microwave mode being supported therein. Although not required~ a small guide magnetic field may be employed to keep the current from spreading apart. At first the electron current, most of which occurs in the gap separating plate 72 and can 70, is uniformly distributed and agrees with classical theory.
Later in time, the space charge flow excites strong micro-wave oscillations and the space charge flow becomes longi-tudinally and transversely spatially bunched with respect to the direction of elctron flow. The microwave field ,;.~. . .
~L~2Z~5~i3 - ~5 -energy rises and oscillates coherently. Thus, the collec-tive motion of the accelerated electrons interacts with the allowed microwave modes by fundamentally altering their pattern, producing electromagnetic fields, longitu-dinally and transversely spatially bunching the electrons,and pumping at least one dominant microwave mode. Dominant microwave mode microwave radiation is coupled out of the diode by means of microwave horn and aperature 82, which is schematically indicated. It will be appreciated, how-ever, that the present invention is in no way timited to aspecific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
The three embodiments of the invention shown in Figures l to 3 are each members of a new class of device, driven by electron or other charged particle flow, which can produce coherent microwaves by the interaction of electromagnetic waves with electron flo~ in small and light weight diodes not requiring an external magnetic 20 field.
The foregoing description of a preferred embodi-ment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form 25 disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodi-ment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best uti-lize the invention in various embodiments and with variousmodifications as are suited to the particular use contem-plated. It is intended that the scope of the invention be defined by the claims appended hereto.
Background of the Invention The invention described herein relates generallyto method and apparatus for producing microwaves, and more particularly to method and apparatus for producing coherent microwaves with a new class of microwave device, driven by electron or other charged particle flow, ~y utili~ing the interaction of electromagnetic waves with electron flow in diodes in the absence of an e~ternal magnetic field.
MicrowaYes occupy the region of the electromag-netic spectrum bounded by radio waves on the side of longer wavelengths and by infrared waves on the side of shorter wavelengths. Although there are no sharp bound-aries bet~een these regions, microwaves are often con-sidered to have ~requencies in the range between lO9 Hz and 3xlOll Hz or, equivalently, to have free space wave-lengths in the range between about l mm and 30 cm. Micro-waves are used for many purposes. Some of these purposes are: for pulsed radiation sources for radar tracking, for carrier waves in relay links for the multichannel trans-mission of telephone, telegraph and television signals;
for microwave spectroscopy to study the structure of numerous molecules and crystals; for use in atomic clocks which use microwave resonance interactions with either cesium atoms or ammonia molecules; for use in solid-state masers, which can be virtually noiseless amplifiers; for use in radio astronomy; for use in the cooking of food;
/
~2~22~3 and, for use in high-energy linear accelerators and similar machines.
Low power multi-frequency microwaves can be simply generated as thermal radiation from warm bodies, or as direct incoherent radiation From electrical sparks estab-lished across high voltage spark gaps. However, for present day applications~ almost all modern microwave generators are electronic devices which produce frequency tunable continuous-wave (CW) oscillations. These devices include magnetrons, klystrons, and traveling-wave tubes.
A magnetron functions by having electrons, generated from a cathode and moving under the combined force of a radial electric field and an external axial magnetic field, interact synchronously with traveling-wave components of a microwave standing-wave pattern in such a manner that electron potential energy is converted to microwave energy.
Relativistic electron beam smooth-bore and conventional magnetrons are discussed by Orzechowski and Bekefi in Phys.
Fluids 22, 978 (1979), and by Palevsky and 8ekefi in Phys.
Fluids 22, 986 (1979), respectively. A relativistic elec-tron beam crossed-field magnetron device is disclosed in U.S. Patent No. 4,200,821 issued April 29, 1980 to Bekefi and Orzechowski. A disadvantage of the magnetron, when it is used to generate high intensity coherent microwaves9 is the requirement that it have a very large external magnet, which greatly contributes to its size and weight.
A klystron functions by having a velocity-modulated bunched electron beam pass through an output cavity and transfer its ac energy thereto for subsequent coupling into a microwave transmission line. An external magnetic field parallel to the electron beam axis holds the beam together, overcoming the electrostatic repulsion between electrons which would otherwise make the beam spread out rapidly. A traveling-wave tube functions as an Z~63 amplifier by having a beam of electrons, retained through-out the length of the tube by focusing means such as an external longitudinal fixed magnetic field, interact con-tinuously and over an appreciable distance with microwaves propagating along a slow-wave circuit. It is also conven-tional for microwave energy~ to be generated by various active solidstate microwave devices.
Additionally, microwaves may be yenerated by some less well known devices such as the femitron as discussed by Charbonnier, et al, in "Basic and Applied Studies of Field Emission at Microwave Frequencies", Proceedings of the IEEE, 51, 991-1004, July 1963. The femitron, which in many ways resembles a klystron, functions by exploiting the strong nonlinearity of the field-emission characteris-tic of a cold cathode located in the gap of a cavityresonator to achieve direct longitudinal bunching of the field-emitted electron beam. The femitron employs multiple-needle cathodes emitting electrons in acc~rdance with the Fowler-Nordheim field-emission law. The elec~ron 20 emission is not space charge limited Child-Langmuir flow.
Further, there are many extant variants of the known microwave devices. For example Gurewitsch, in U.S. Patent No. 2,513,933 issued July 4, 1950, discloses a novel con-struction for cathodes of the cold emission type such as 25 may be used for various microwave devices, particularly those of the magnetron class.
Thus, at the present time there exist many dif-ferent classes of electronic device capable of producing microwaves at various power levels and efficienc;es. How-ever, particularly in view of the importance and extremevariety of microwave technology, there remains a continuing need for innovative and structurally simple new classes of device for the production of coherent microwaves. It would be advantageous if these new classes of device could be driven by electron, or other charged particle, flow.
.....
~2Z~i63 Summary of ~he-Invention It is therefore an object of the invention to provide a new class of device which can produce coherent microwaves by the interaction of electromagnetic waves with electron flow in diodes.
It is also an object of the invention to provide a new class of device, driven by electron or other charged particle flow, for producing coherent microwaves.
It is a further object of the invention to provide a new class of device which can produce high power coherent microwaves by the interaction of electromagnetic waves with electron flow in small and light weight diodes not requir-ing an external magnetic field.
Additional objects, advantages and novel features 15 of the invention wi71 be set forth in part in the descrip-tion which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized 20 and attained by means of the instrumentalities and combi-nations particularly pointed out in the appended claims.
To achieve the foregoing and other objects and in accordance with the purpose of the present invention, as embodied and broadly described herein, the method and 25 apparatus ~or producing coherent microwave radiation of this invention may comprise providing an anode having an anode surface and a separated cathode having a cathode surface with the two surfaces comprising structure capable of supporting a plurali~y of microwave modes particularly including a resonant frequency microwave mode. A dc elec-tric field is imposed, over a time of at least one period of the resonant frequency microwave mode, within the ~f~;63 spatial volume occupied by the microwave modes. The electric field stimulates a beam of electrons to undergo accelerated flow from the cathode surface into the spatial volume. The collective motion of the accelerated electron beam interacts with the resonant frequency microwave mode by fundamentally altering its pattern9 by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching the electron beam, and by pumping the resonant frequency microwave mode. The resonant frequency microwave radiation is coupled out of the apparatus. In some embodiments of the invention, the beam may comprise a beam of thermionic or field emitted electrons stimulated by the dc electric field to flow from the cathode surface.
And, in some embodiments of the invention the dc electric field may be established by charging the anode positively with respect to the cathode with a Marx bank voltage source. Ad~itionally, in so~e embodiments of the inven-tion the dc electric field may be established by charging the anode or the cathode by substantially imbedding a charged particle beam in either one or the other.
In some embodiments of the method and apparatus for producing coherent microwave radiation of this inven-tion, it is preferred that the cathode comprise the center conductor of a coaxial line and that the anode comprise the outer conductor of the coaxial line, with the cathode surface comprising at least part of the outer surface of the center conductor and with the anode surface comprising at least part of the inner surface of the outer conductor.
In some embodiments of the method and apparatus for producing coherent microwave radiation of this inven-tion, it is preferred that the cathode and anode comprise two disks, with the cathode surface comprising part of a planar surface of the first disk, with the anode surface comprising part of a planar surface of the other disk, with the two disks juxtaposed with coincident axes, and ~2~;63 with the two planar surfaces acting as cathode and anode surfaces facing one another.
In a further aspect of the present invention, in accordance with its objects and purposes, the method and apparatus for producing coherent microwave radiation of this invention may comprise providing a hollow metal can, or housing having an internal housing chamber, and posi-tioning a disk shaped plate within the can so that from every location on the plate the closest distance to the interior surface of the can is approximately constant.
The plate and interior surface of the can comprise struc-ture capable of geometrically supporting a plurality of microwave modes particularly including a resonant fre-quency microwave mode. A large voltage difference is established between the plate and the can by substantially imbedding a charged particle beam in the plate. This voltage imposes a dc electric field~ over a time of at least one period of the resonant frequency microwave mode, within the spatial volume occupied by the microwave modes.
The electric field stimulates a beam of electrons to under-go accelerated flow into the spatial volume from the plate or the can, whichever has been charged negatively. The collective motion of the accelerated electron beam inter-acts with the resonant frequency microwave mode by funda-mentally altering its pattern, by producing electromag-netic fields, by longitudinally and transversely spatially bunching the electron beam, and by pumping the resonant frequency microwave mode. The resonant frequency microwave radiation is coupled out of the can.
The benefits and advantages of the present inven-tion, as embodied and broadly described herein9 include, inter alia, the provision of a new class of device, driven by electron or other charged particle flow, for producing coherent microwave radiation by the interaction of elec-tron flow with electromagnetic waves in small and light weight diodes not requiring an external magnetic field.
. .
.... .
~LZ~r6 Brief Description of the Drawings The accompanying drawings, which are incorporated in and form a part of the specification, illustrate three embodiments of the present invent-ion and, together with ~the description, serve to explain the principles of the invention. In the drawings:
Figure l is a perspective view, partially schema-tic and partially in cross section, of a first embodiment of a diode for producing coherent microwave radiation made in accordance with the invention.
Figure 2 is a perspective view, partially sche-matic and partially in cross section, of a second embodi-ment of a diode for producing coherent microwave radiation made in accordance with the invention.
Figure 3 is a perspective view, partially sche-matic and partially in cross section, of a third embodi-ment of a diode for producing coherent microwave radiation made in accordance with the invention.
Detailed Description of the Invention Re~erence will now be made in detail to the pres-ent preferred embodiment of the invention, examples of which are illustrated in the accompanying drawings. The invention is of a new class of device~ driven by electron or other charged particle flow, which can produce coherent microwaves by the interaction of electromagnetic waves with electron flow in diodes. The electron flow may be caused by electron emission or injection. No external magnetic field is required~ The new device has been given the name "emitron". The principle features of the diode are an anode having an anode surface, a cathode having a cathode surface, and a gap therebetween. Open or closed Z2~3 geometries capable of supporting microwave modes and allowing the maintenance of a dc electric field over some portion of the anode and cathode surfaces are permissible.
By mode is meant, herein, a form of natural electromagnetic oscillation characterized by a particular field pattern.
The device is driven, or powered, by electron or other charged particle flow: in other ~ords, the anode may be charged relative to the cathode b~ a conventional voltage source or by a charged particle beam. As a consequence of charging, a dc electric field extending from one electrode surface to the other accelerates an electron beam. This beam may be composed of thermionic or field emitted elec-trons flowing from the cathode. However, in some embodi-ments of the invention the beam may comprise electrons from any other appropriate source. Coherent microwaves are produced by the strong interaction of the electron beam with one or more of the microwave modes allowed by the specific geometry of the particular diode. This com-plex synergism results in the three-dimensional spatial 20 bunching, both longitudinal and transverse to the direction of electron beam flow, of the electron beam and the pumping of one or more dominant microwave modes. That is, during the interaction the amplitudes of the microwave modes are constantly changing as a function of both position and 25 time. Also, at the same time and as a consequence thereof, the electron beam is undergoing a spatial and temporal evolution which may be termed bunching. The frequencies of the dominant modes are a function of electrode spacing and the magnitude of the dc electric field. If so desired, these frequencies can be shifted or quenched by the appli-cation of a small magnetic field perpendicular to the dc electric field. If operated in this way, the invention can have applicability to circuitry involving feedback loops for frequency tuning and/or logic gating. Where used, the invention will greatly simplify microwave tube construction because the diode does not require the large external magnetic field of the magnetron tube nor the .....
Z~i63 g additional electrodes of the triode and tetrode tubes.
The invention is a consequence of some unanticipated results of calculations performed using Lawrence Livermore National Laboratory's MASK computer code. The MASK code is a 2-1/2 dimensional, electromagnetic, relativistic particle-in-cell code which has been used to reliably model conventional electron and ion beam diodes.
Reference is now made to Figure 1 which shows a first embodiment of an electronic diode for producing coherent microwave radiation made in accordance with the invention. The smooth bore coaxial diode comprises a center conductor 10 which forms a cathode, and an outer conductor 12 which forms an anode. A cathode surface 14 comprises at least part of the outer surface of center conductor 10, and an anode surface 16 comprises at least part of the inner surface of outer conductor 12. Note that the electron emission characteristics of a surface may be modified by surface treatment, as by scoring, to localize electron emission from only part of the surface.
Center conductor 10 and outer conductor 12 form a coaxial line. Cathode surface 14 may have a radius of 1.86 cm, and anode surface 16 may have a radius of 2.20 cm. First end plate 18 and second end plate 20 are attached to the ends of outer conductor 12, forming air-tight seals there-with. Center conductor 10 is secured within outer conduc-tor 12 by means of insulational supports 22 and 24, which are schematically indicated. It will be appreciated, how-ever, that the present invention is in no way limited to a specific support structure and that center conductor 10 may be secured within outer conductor 12 by any other suitable means. The assembly is evacuated by means of vacuum port 26 and vacuum pump 28, which are schematically indicated. It will be appreciated, however, that the present invention is in no way limited to a specific vacuum system and that the assembly may be evacuated by . , .
~f~ fi3 1 o --any other suitable means. For optimal operating condi-tions it is desirable at early times to minimize the loss of microwave radiation from the apparatus. This may be accomplished by end plates 18 and 20, which prevent radia-tion leakage, and by having the axial length of the anodeto cathode gap greater than the circumference of center conductor 10. A plurality of microwave modes, particularly including at least one resonant frequency microwave mode, are capable of being supported within the anode to cathode gap. High voltage source 30, which is schematically rep-resented, provides means for maintaining a dc electric field between center conductor lO and outer conductor 12 over a time of at least one period of a resonant frequency microwave mode. Source 30 may be a 350 kV source having a rise time of 0.5 ns. Preferably high voltage source 30 may be a Marx bank voltage source. High voltage source 30 may also represent charging the anode positively with respect to the cathode by substantially imbedding a charged particle beam in either the cathode or the anode. The dc 20 electric field causes an electron current to undergo accelerated flow across the anode to cathode gap in a radial direction. The current may comprise thermionic or field emitted electrons. At first the electron current is uniformly distributed in the azimuthal direction in 25 agreement with the Child-Langmuir V3/2 law for space charge limited flow in cylindrical geometry. The value of the voltage applied by high voltage source 30 should be such as to cause electrons to cross the anode to cathode gap in ayproximately one period, or integral multiple 30 thereof, of the resonant frequency microwave mode being supported within the anode to cathode gap. Later in time, the space charge flow excites strong microwave oscillations and the space charge flow becomes longitudinally and trans-versely spatially bunched with respect to the direction of 35 electron flow. The microwave field energy rises and oscil-lates coherently. Thus, the collective motion of the accelerated electrons interacts with the allowed microwave ~L~2;2;2S~i3 modes by fundamentally altering their pattern, producing electromagnetic fields, longitudinally and transversely spatially bunching the electrons, and pumping at least one dominant microwave mode. Dominant microwave mode micro-wave radiation, which in this embodiment may have a valueof 35 GHz, is coupled out of the diode by means of micro-wave horn and aperture 32, which is schematically indi-cated. It will be appreciated, however, that the present invention is in no way limited to a specific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
Reference is now made to Figure 2 which shows a second embodiment of an electronic diode for producing coherent microwave radiation made in accordance with the invention. First disk 40 forms a cathode and second disk 42 forms an anode. By disk is meant, herein, a thin cir-cular object. A cathode surface 44 comprises at least part of a planar surface of disk 40, and an anode surface 46 comprises at least part of a planar surfa e of disk 42.
Note that the electron emission characteristics of a sur-face may be modified by surface treatment, as by scoring, to localize electron emission from only part of the sur-face. Disks 40 and 42 are disposed within housing 48.
Disk 40 is secured within housing 48 by means of first insulational support 50, and disk 42 is secured within housing 48 by means of second insulational support 52.
Housing 48 and supports 50 and 52 are all schematically indicated. It will be appreciated that the present inven-tion is in no way limited to a specific housing and support structure and that disks 40 and 42 may be disposed and secured by any other suitable means. The assembly is evacuated by means of vacuum port 54 and vacuum pump 56, which are schematically indicated. I~ will be appreciated, however, that the present invention is in no way limited to a specific vacuum system and that the assembly may be evacuated by any other suitable means. Disks 40 and 42 ~22Z~;Çi3 are juxtaposed with coincident axes, and cathode surface 44 and anode surface 46 are facing one another. A plural-ity of microwave modes, particularly including at least one resonant frequency microwave mode, are capable of being supported within the anode to cathode gap. To minimize the loss of microwave radiation from the diode at early times, the radius of each of disks 40 and 42 must be larger than the spacing of the gap between the disks.
High voltage source 58, which is schematically represented, provides means for maintaining a dc electric field between - first disk 40 and second disk 42 over a time of at least one period of the resonant frequency microwave mode.
Preferably high voltage source 58 may be a Marx bank vol-tage source. High voltage source 58 may also represent charging the anode positively with respect to the cathode by substantially imbedding a charged particle beam in either the cathode or the anode. The dc electric field causes an electron current to undergo accelerated flow across the anode to cathode gap by causing electrons to be drawn from cathode surface 44. Although not required, a small guide magnetic field may be employed to keep the current from spreading apart. The current may comprise thermionic or field emitted electrons. At first the elec-tron current is uniformly distributed and agrees with classical theory~ The value of the voltage applied by high voltage source 58 should be such as to cause elec-trons to cross the anode to cathode gap in approximately one period, or integral multiple thereof, of the resonant frequency microwave mode being supported within the anode 3~ to cathode gap. Later in time, the space charge flow excites strong microwave oscillations and the space charge flow becomes longitudinally and transversely spatially bunched with respect to the direction of electron flow.
The microwave field energy rises and oscillates coherently.
Thus, the collective motion of the accelerated electrons interacts with the allowed microwave modes by fundamentally altering their pattern, producing electromagnetic fields, longitudinally and transversely spatially bunching the electrons, and pumping at least one dominant microwave mode. Dominant microwave mode microwave radiation is coupled out of the diode by means of microwave horn and 5 aperture 60, which is schematically indicated. It will be appreciated, however, that the present invention is in no way limited to a specific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
Reference is now made to Figure 3 which shows a third embodiment of a diode for producing coherent micro-wave radiation made in accordance with the invention. The diode comprises hollow can 70 and disk shaped plate 72.
By disk is meant, herein, a thin circular object. Can 70 15 is, quite simply, a housing having an internal housing chamber. Plate 72 is secured within can 70 by means of insulating support 74, which is schematically indicated.
It will be appreciated, however, that the present inven-tion is in no way limited to a specific support structure 20 and that plate 72 may be sec~red withing can 70 by any other suitable means. The assembly is evacuated by m~ans of vacuum port 76 and vacuum pump 78, which are schematic-ally indicated. It will be appreciated, however, that the present invention is in no way limited to a specific vacuum 25 system and that the assembly may be evacuated by any other suitable means. Plate 72 is positioned so that a gap exists between plate 72 and can 70 with the closest dis-tance from every location on plate 72 to the internal sur-face of hollow can 70 being an approximate constant.
30 Plate 72 and can 70 are capable of supporting a plurality of microwave modes~ particularly including at least one resonant frequency microwave mode, within the gap separat-ing plate 72 and can 70. To minimize the loss of micro-wave radiation from the diode at early times, the radius 35 of plate 72 is larger than the distance across the gap separating can 70 from plate 72. High energy charged ~ 6 particle beam 80, which is schematically represented, provides a means for imposing a dc electric field within the gap separating plate 72 from can 70 over a time of at least one period of the resonant frequency microwave mode.
Beam 80 is injected through a surface of can 70 and is substantially imbedded in plate 72 thereby causing a large voltage difference to be established between plate 72 and can 70. Some examples of changed particles of which beam 80 may be composed are electrons, positions, protons, antiprotons, alpha particles, any ions, quarks and various short lived particles such as pions and muons. The portion of the wall of can 70 through which beam 80 is injected must be sufficiently thin to allow most of beam 80 to pass unimpededly therethrough. The polarity of the voltage difference, and the direction of the resultant dc electric field, is a function of the sign, positive or negative, of the particles comprising beam 80. A stream of thermionic or field emitted electrons is emitted from either can 70 or plate 72, depending on the direction of the dc electric field, and stimulated to undergo accelerated flow into the gap separating plate 72 and can 70. Note that the electron emission characteristics of a surface may be modified by surface treatment, as by scoring, to localize electron emission ~rom only part of the surface. The value of the voltage established across the gap separating plate 72 and can 70 should be such as to cause electrons to cross that gap in approximately one period, or integral multiple thereof, of the resonant frequency microwave mode being supported therein. Although not required~ a small guide magnetic field may be employed to keep the current from spreading apart. At first the electron current, most of which occurs in the gap separating plate 72 and can 70, is uniformly distributed and agrees with classical theory.
Later in time, the space charge flow excites strong micro-wave oscillations and the space charge flow becomes longi-tudinally and transversely spatially bunched with respect to the direction of elctron flow. The microwave field ,;.~. . .
~L~2Z~5~i3 - ~5 -energy rises and oscillates coherently. Thus, the collec-tive motion of the accelerated electrons interacts with the allowed microwave modes by fundamentally altering their pattern, producing electromagnetic fields, longitu-dinally and transversely spatially bunching the electrons,and pumping at least one dominant microwave mode. Dominant microwave mode microwave radiation is coupled out of the diode by means of microwave horn and aperature 82, which is schematically indicated. It will be appreciated, how-ever, that the present invention is in no way timited to aspecific radiation coupling system and that microwave radiation may be coupled out of the diode by any suitable means.
The three embodiments of the invention shown in Figures l to 3 are each members of a new class of device, driven by electron or other charged particle flow, which can produce coherent microwaves by the interaction of electromagnetic waves with electron flo~ in small and light weight diodes not requiring an external magnetic 20 field.
The foregoing description of a preferred embodi-ment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form 25 disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodi-ment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best uti-lize the invention in various embodiments and with variousmodifications as are suited to the particular use contem-plated. It is intended that the scope of the invention be defined by the claims appended hereto.
Claims (10)
1. A method for producing coherent resonant frequency microwave radiation, the method comprising the steps of:
imposing a dc electric field within a spatial volume defined by an anode having an anode surface and a cathode having a cathode surface in a spaced apart rela-tionship, with said cathode surface and said anode surface comprising a structure capable of supporting a resonant frequency microwave mode within said spatial volume, over a time of at least one period of said resonant frequency microwave mode, with said electric field acting to stimu-late a beam of electrons to undergo accelerated flow from said cathode surface into said spatial volume, with the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinaly and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and coupling out said resonant frequency microwave radiation from said spatial volume.
imposing a dc electric field within a spatial volume defined by an anode having an anode surface and a cathode having a cathode surface in a spaced apart rela-tionship, with said cathode surface and said anode surface comprising a structure capable of supporting a resonant frequency microwave mode within said spatial volume, over a time of at least one period of said resonant frequency microwave mode, with said electric field acting to stimu-late a beam of electrons to undergo accelerated flow from said cathode surface into said spatial volume, with the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinaly and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and coupling out said resonant frequency microwave radiation from said spatial volume.
2. A method according to Claim 19 wherein the imposing step comprises charging said anode positively with respect to said cathode with a Marx bank voltage source.
3. A method according to Claim 1, wherein the imposing step comprises charging said anode positively with respect to said cathode by substantially imbedding a charged particle beam in either said cathode or said anode.
4. A method for producing coherent resonant frequency microwave radiation, the method comprising the steps of:
positioning a disk shaped plate within a housing having an internal housing chamber, with the closest distance from every location on the plate to the surface of the internal housing chamber being an approximate constant, with said plate and said housing comprising a structure capable of supporting a resonant frequency microwave mode within a spatial volume disposed within said housing chamber and in the gap separating said plate from said housing, and with the radius of said plate being larger than the distance across the gap separating said plate from said housing;
imbedding substantially a charged particle beam in said plate, with said imbedded beam acting to establish a large voltage difference between said plate and said housing and thereby imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, with said electric field acting to stimulate a beam of electrons to undergo accelerated flow into said spatial volume, with the col-lective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and coupling out said resonant frequency microwave radiation from said housing.
positioning a disk shaped plate within a housing having an internal housing chamber, with the closest distance from every location on the plate to the surface of the internal housing chamber being an approximate constant, with said plate and said housing comprising a structure capable of supporting a resonant frequency microwave mode within a spatial volume disposed within said housing chamber and in the gap separating said plate from said housing, and with the radius of said plate being larger than the distance across the gap separating said plate from said housing;
imbedding substantially a charged particle beam in said plate, with said imbedded beam acting to establish a large voltage difference between said plate and said housing and thereby imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, with said electric field acting to stimulate a beam of electrons to undergo accelerated flow into said spatial volume, with the col-lective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and coupling out said resonant frequency microwave radiation from said housing.
5. An electronic diode for producing coherent resonant frequency microwave radiation, the diode com-prising:
an anode having an anode surface;
a cathode having a cathode surface, said cathode spaced apart from said anode, said cathode surface and said anode surface comprising a structure capable of supporting a resonant frequency MiCrOwave mode within a spatial volume;
means, electrically related to said cathode and said anode, for imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, said electric field acting to stimulate a beam of electrons to undergo accelerated flow from said cathode surface into said spatial volume, the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing electromagnetic fields, by longitu-dinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and means to couple out said resonant frequency microwave radiation from said spatial volume.
an anode having an anode surface;
a cathode having a cathode surface, said cathode spaced apart from said anode, said cathode surface and said anode surface comprising a structure capable of supporting a resonant frequency MiCrOwave mode within a spatial volume;
means, electrically related to said cathode and said anode, for imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, said electric field acting to stimulate a beam of electrons to undergo accelerated flow from said cathode surface into said spatial volume, the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing electromagnetic fields, by longitu-dinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and means to couple out said resonant frequency microwave radiation from said spatial volume.
6. An electronic diode for producing coherent resonant frequency microwave radiation, as recited in Claim 5, in which said dc electric field imposing means comprises a Marx bank voltage source used to charge said anode positively with respect to said cathode.
7. An electronic diode for producing coherent resonant frequency microwave radiation, as recited in Claim 5, in which said dc electric field imposing means comprises charging said anode positively with respect to said cathode by substantially imbedding a charged particle beam in either said cathode or said anode.
8. An electronic diode for producing coherent resonant frequency microwave radiation, as recited in Claims 5, 6 or 7, in which said cathode comprises the center conductor of a coaxial line with said cathode surface comprising at least part of the outer surface thereof, in which said anode comprises the outer conductor of said coaxial line with said anode surface comprising at least part of the inner surface thereof, and with the axial length of the anode to cathode gap much greater than the circumference of the center conductor.
9. An electronic diode for producing coherent resonant frequency microwave radiation, as recited in Claims 5, 6 or 7, in which said cathode comprises a first disk with said cathode surface comprising at least part of a first planar surface thereof, in which said anode com-prises a second disk with said anode surface comprising at least part of a second planar surface thereof, wherein said first disk and said second disk are juxtaposed with coincident axes and with said first planar surface facing said second planar surface, and wherein the radius of the first disk and the radius of the second disk are each larger than the spacing of the gap between the first disk and the second disk.
10. An electronic diode for producing coherent resonant frequency microwave radiation, the diode com-prising:
a housing having an internal housing chamber;
a disk shaped plate within said housing chamber, positioned with the closest distance from every location on the plate to the surface of the internal housing chamber being an approximate constant, said plate and said housing comprising a structure capable of supporting a resonant frequency microwave mode within a spatial volume disposed within said housing chamber and in the gap separating said plate from said housing, and the radius of said plate being larger than the distance across the gap separating said plate from said housing;
means for substantially imbedding a charged particle beam in said plate, said imbedded beam acting to establish a large voltage difference between said plate and said housing and thereby imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, said electric field acting to stimulate a beam of electrons to undergo accelerated flow into said spatial volume, the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and means to couple out said resonant frequency microwave radiation from said housing.
a housing having an internal housing chamber;
a disk shaped plate within said housing chamber, positioned with the closest distance from every location on the plate to the surface of the internal housing chamber being an approximate constant, said plate and said housing comprising a structure capable of supporting a resonant frequency microwave mode within a spatial volume disposed within said housing chamber and in the gap separating said plate from said housing, and the radius of said plate being larger than the distance across the gap separating said plate from said housing;
means for substantially imbedding a charged particle beam in said plate, said imbedded beam acting to establish a large voltage difference between said plate and said housing and thereby imposing a dc electric field within said spatial volume over a time of at least one period of said resonant frequency microwave mode, said electric field acting to stimulate a beam of electrons to undergo accelerated flow into said spatial volume, the collective motion of said accelerated electron beam serving to interact with said resonant frequency microwave mode by fundamentally altering its pattern, by producing elec-tromagnetic fields, by longitudinally and transversely spatially bunching said electron beam, and by pumping said resonant frequency microwave mode; and means to couple out said resonant frequency microwave radiation from said housing.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US37552982A | 1982-05-06 | 1982-05-06 | |
| US375,529 | 1982-05-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1222563A true CA1222563A (en) | 1987-06-02 |
Family
ID=23481237
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000426104A Expired CA1222563A (en) | 1982-05-06 | 1983-04-18 | Emitron: microwave diode |
Country Status (6)
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| JP (1) | JPS58204443A (en) |
| CA (1) | CA1222563A (en) |
| DE (1) | DE3315689A1 (en) |
| FR (1) | FR2526582A1 (en) |
| GB (1) | GB2120008B (en) |
| IT (1) | IT1163321B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6872927B2 (en) | 2001-12-26 | 2005-03-29 | Lambda Technologies, Inc. | Systems and methods for processing pathogen-contaminated mail pieces |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101941166B1 (en) * | 2011-06-10 | 2019-01-23 | 삼성전자주식회사 | Electromagnetic wave generator and optical shutter using the same |
| JP6140397B2 (en) * | 2011-06-10 | 2017-05-31 | 三星電子株式会社Ｓａｍｓｕｎｇ Ｅｌｅｃｔｒｏｎｉｃｓ Ｃｏ．，Ｌｔｄ． | Electromagnetic wave generator and electromagnetic wave generator array |
| DE102013203903A1 (en) * | 2013-03-07 | 2014-09-11 | Robert Bosch Gmbh | steam turbine |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USRE23234E (en) * | 1950-05-30 | Electron beam oscillator | ||
| FR727322A (en) * | 1931-12-02 | 1932-06-16 | Improvements in the production and reception of very high frequency microwave waves | |
| GB483062A (en) * | 1935-07-06 | 1938-04-07 | Ernst Eduard Wilhelm Kassner | Plate circuit element systems and plate oscillators for the generation of oscillations in the ultra-short wave range |
| US2190668A (en) * | 1937-07-31 | 1940-02-20 | Bell Telephone Labor Inc | Diode oscillator |
| FR851943A (en) * | 1938-01-22 | 1940-01-18 | ||
| GB537490A (en) * | 1939-12-22 | 1941-06-24 | Standard Telephones Cables Ltd | Improvements in or relating to electron discharge apparatus |
| US2402184A (en) * | 1941-05-03 | 1946-06-18 | Bell Telephone Labor Inc | Ultra high frequency electronic device contained within wave guides |
| US2385783A (en) * | 1942-09-30 | 1945-10-02 | Standard Telephones Cables Ltd | Antenna construction |
| US2404078A (en) * | 1943-04-28 | 1946-07-16 | Rca Corp | Electron discharge device |
| FR903316A (en) * | 1943-05-17 | 1945-09-29 | Lorenz C Ag | Diode generator |
| US2437274A (en) * | 1944-07-06 | 1948-03-09 | Bell Telephone Labor Inc | Electron discharge apparatus |
-
1983
- 1983-04-18 CA CA000426104A patent/CA1222563A/en not_active Expired
- 1983-04-18 GB GB08310443A patent/GB2120008B/en not_active Expired
- 1983-04-29 DE DE19833315689 patent/DE3315689A1/en not_active Withdrawn
- 1983-05-04 JP JP58078860A patent/JPS58204443A/en active Pending
- 1983-05-05 FR FR8307533A patent/FR2526582A1/en active Pending
- 1983-05-06 IT IT8320986A patent/IT1163321B/en active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6872927B2 (en) | 2001-12-26 | 2005-03-29 | Lambda Technologies, Inc. | Systems and methods for processing pathogen-contaminated mail pieces |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2120008A (en) | 1983-11-23 |
| IT1163321B (en) | 1987-04-08 |
| IT8320986A0 (en) | 1983-05-06 |
| DE3315689A1 (en) | 1983-11-10 |
| FR2526582A1 (en) | 1983-11-10 |
| GB8310443D0 (en) | 1983-05-25 |
| GB2120008B (en) | 1987-05-20 |
| JPS58204443A (en) | 1983-11-29 |
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