Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: A method for operating an amplifier module of a communication satellite involves saving at least one configuration parameter of the amplifier module in a non-volatile memory designed to store the configuration parameter when the amplifier module is not energized. The configuration parameter can be loaded from the non-volatile memory and used to configure the amplifier module.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: The present invention relates to the formation of a vacuum electronics circuit by the fusion bonding of multiple substrate wafers, e.g., silicon, copper, or other suitable conductive material, each etched using DRIE, cut using EDM, or machined by other suitable means. Other aspects of the invention relate to the alignment of a cathode with tube by fusion bonding the cathode wafer to a tube built using the fabrication methods described herein. Yet other aspects involve the alignment of dies or wafers during the fabrication of a vacuum electronics device using the “lego” technique outlined herein. In yet other aspects, fabrication methods are described.

Abstract: Various apparatuses and methods for a vacuum electronic device are disclosed herein. In one embodiment, a vacuum electronic device includes a vacuum housing, an array of slow wave structures inside the vacuum housing sharing a common electron beam tunnel, an electron beam input port at a first end of the common electron beam tunnel, and an electron beam output port at a second end of the common electron beam tunnel.

Abstract: A voltage control apparatus used for an electron tube or a power supply apparatus includes a detecting circuit for detecting current flowing through a helix electrode, a voltage-limiting circuit for controlling a potential difference between the helix electrode and the anode electrode based on a predetermined voltage level; and a switch for switching based on an output from the detecting circuit. The switch connects the helix electrode and the anode electrode through the voltage-limiting circuit, or causes a short circuit between the helix electrode and the anode electrode.

Abstract: Disclosed herein is a class of mm and sub mm wavelength amplifiers and oscillators operating with miniature helical slow wave circuits manufactured using micro fabrication technology. The helices are supported by diamond dielectric support rods. Diamond is the best possible thermal conductor, and it can be bonded to the helix. The electron beam is transmitted, not through the center of the helix, but around the outside. In some configurations the RF power produced may be radiated directly from the slow wave circuit. The method of fabrication, which is applicable above 60 GHz, is compatible with mass production.

Abstract: Controlling the performance of the thermionic tube (102) having a cathode (103), a plate (104) and a grid (105) is disclosed. The tube is configured to provide amplification of an audio derived signal (106) and is arranged to apply a grid bias voltage to the grid. The absence of an input audio signal is detected whereafter output current between cathode and plate is measured to identify actual output current. The actual output current is compared against a preferred output current and the grid bias voltage is adjusted so as to bring the actual output current value towards the preferred output current value.

Abstract: Controlling the performance of the thermionic tube (102) having a cathode (103), a plate (104) and a grid (105) is disclosed. The tube is configured to provide amplification of an audio derived signal (106) and is arranged to apply a grid bias voltage to the grid. The absence of an input audio signal is detected whereafter output current between cathode and plate is measured to identify actual output current. The actual output current is compared against a preferred output current and the grid bias voltage is adjusted so as to bring the actual output current value towards the preferred output current value.

Abstract: A power supply apparatus for a traveling-wave tube includes an electrical discharge switch and a first resistor that are serially connected, and that are connected between a cathode electrode and a first collector electrode; N (N denotes a positive integer) arresters that are serially connected, and that are inserted between a ground potential and a connection node of the electrical discharge switch and the first resistor; N second resistors that are inserted between the N arresters and a second collector electrode to an Nth collector electrode and a ground potential, respectively; and an electrical discharge control circuit that turns off the electrical discharge switch at a time of normal operation of the power supply apparatus and turns on the electrical discharge switch when stopping operation of the power supply apparatus.

Abstract: A resonant cavity with a bowtie shape supports an electromagnetic field used to deflect the trajectory of an electron beam passing through the cavity. The short transit time of the beam across the gap maintains the cavity fields at near-optimal phase, improving interaction efficiency even for relatively low-energy beams. High interaction impedance ensures good drive-power-to-deflection conversion efficiency. The uniform field achieved across the gap enforces uniform deflection across the beam profile to maintain beam quality. Multiple bowtie cavities can be arranged to allow arbitrary two-dimensional deflections.

Abstract: An input circuit of a microwave amplification tube achieves improved instantaneous bandwidth. By directly coupling the transmission line carrying a modulating radio frequency signal to a control grid, a low-Q input circuit is created that increases the fractional bandwidth of the system. A resonant cavity may be used to generate a voltage across the gap between the cathode and the control grid. Alternative geometries are presented whereby the electron beam is emitted from a cathode connected either to the center conductor of the transmission line or to the outer conductor of the transmission line. Alternatively, the electric field of the radio-frequency signal propagating through the transmission line may be used to create a voltage across the gap between the cathode and the control grid without using a resonant cavity. Likewise, alternative geometries are presented by which the electron beam is emitted from a cathode connected either to the center conductor or to the outer conductor of the transmission line.

Abstract: An input circuit of a microwave amplification tube achieves improved instantaneous bandwidth. By directly coupling the transmission line carrying a modulating radio frequency signal to a control grid, a low-Q input circuit is created that increases the fractional bandwidth of the system. A resonant cavity may be used to generate a voltage across the gap between the cathode and the control grid. Alternative geometries are presented whereby the electron beam is emitted from a cathode connected either to the center conductor of the transmission line or to the outer conductor of the transmission line. Alternatively, the electric field of the radio-frequency signal propagating through the transmission line may be used to create a voltage across the gap between the cathode and the control grid without using a resonant cavity. Likewise, alternative geometries are presented by which the electron beam is emitted from a cathode connected either to the center conductor or to the outer conductor of the transmission line.

Abstract: A biasing system for use with a multi-stage depressed collector of a high power amplifier includes one or more adjustable power sources. A power controller provides control signals to the power sources depending on the operational RF power level. For low power applications, biasing of collector electrodes is reduced such that savings in energy costs are realized, and operational temperature and wear are reduced. The control signals are based on values stored in a look-up table. For multiple depressed electrodes, biasing can be controlled in tandem or independently.

Abstract: An electron beam tube of the type for amplification of RF signals comprising an electron gun, an interaction region within a vacuum, an RF input and an RF output arrangement, the RF output arrangement comprising an output coaxial line and a coaxial divider, wherein the coaxial divider is arranged to divide a signal on the coaxial line into a plurality of signals and wherein the vacuum within the interaction region extends into the coaxial divider.

Abstract: The present invention pertains to an amplification device for a high-frequency signal. The invention is particularly adapted for the transmission of radiofrequency signals used for television of radio under frequency modulation. The amplification device for a high-frequency signal comprises of two amplification stages arranged in series, the first amplification stage being formed of a semiconductor preamplifier, the second amplification stage being formed of an electron tube cooled by the circulation of a fluid, the electron tube being arranged inside an enclosure intended to receive it. The semiconductor preamplifier is arranged in the enclosure and the preamplifier is cooled by the circulation of the fluid. The electron tube comprises a collector needing to be cooled by the circulation of the fluid, and the fluid circulates around a cooling circuit, in which the collector is connected in parallel with the preamplifier.

Abstract: A traveling wave tube (TWT) amplifier includes a beam forming electrode (BFE) and a BFE modulator having a bias-based keyer so that the TWT amplifier signals are keyed off during periods when RF power is not to be amplified. Biasing the beam forming electrode voltage off relative to cathode voltage effectively shuts down the electron beam without shutting down the power supply minimizes power supply stress and significantly improves reliability, so that low-level RF signal input is not amplified, and no significant RF power is output. Likewise, given that no amplification has taken place, no power associated with the TWT amplification function is consumed. Thus, the only power consumed by the TWT amplifier is that associated with the cathode heater and the electronic power conditioner (EPC) used as the electron beam source.

Abstract: An inductive output tube (IOT) provides improved efficiency and larger bandwidth. In one embodiment, an IOT is provided with an electron gun that generates an electron beam, a tube body, a collector for collecting the electron beam, and an extended-interaction output circuit. The electron beam travels through the tube body and the extended-interaction output circuit. The extended-interaction output circuit is located within the tube body. The extended-interaction output circuit comprises a short- circuited resonant structure. The extended-interaction output circuit is used for reducing undesired components of a radio frequency (RF) wave, increasing desired components of the RF wave, and slowing down the propagation of the RF wave. (That is the circuit increases the integral of the electric field along the path of the beam electrons while decreasing the stored energy associated with those fields.) The extended-interaction output circuit also provides the IOT with larger bandwidth operation.

Abstract: The invention pertains to an amplification device for a high-frequency signal. The invention is particularly adapted for the transmission of radiofrequency signals used for television or radio under frequency modulation.

Abstract: A radio frequency (RF) modulated electron gun includes a cathode, electrically coupled to operate as a source of charged particles, and a grid, positioned apart from the cathode. The grid and the cathode are electrically coupled to a grid voltage source and to a RF source. The grid voltage source places the grid at a first potential, and the RF source places the grid at a second potential selected to produce groups of the charged particles. The groups of charged particles are produced with each period of a signal received from the RF source.

Abstract: An electromagnetic wave amplifier and an electromagnetic wave generator operate using electron beams in a vacuum environment. The amplifier, arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an amplifying section for amplifying an inputted electromagnetic wave in one direction by utilizing energy received from an electron beam emitted from the electron emitting section and traveling in the vacuum along a dielectric waveguide having a wave-shaped form. The generator, also arranged in a vacuum environment, comprises an electron emitting section for emitting electron beams and an oscillating section for generating an electromagnetic wave by utilizing electron beams emitted from the electron emitting section and travelling in the vacuum along a dielectric waveguide having a composite wave-shaped form.

Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas at a concentration of about 8 to 13 percent to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a first layer of carbon-based material to a thickness greater than about 0.5 micrometers, subsequently reducing the concentration of the carbon-containing gas and continuing to grow a second layer of carbon-based material, the second layer being much thicker than the first layer. The substrate is subsequently removed from the first layer and an electrode is applied to the second layer. The surface of the substrate may be patterned before growth of the first layer to produce a patterned surface on the field emission device. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes.

Abstract: The disclosure relates to a radiofrequency generator including an Inductive Output Tube with an electron gun followed by an anode, the gun being raised to a high voltage in use, means producing an input radiofrequency signal and means of transmitting it to said IOT such that it provides an output signal whose power is amplified compared to said input signal, wherein said means producing said input radiofrequency signal, said means transmitting it to said IOT and said gun are confined in an electrostatically screened enclosure that is electrically isolated from the potential of the anode and can be raised to a high voltage, said gun receiving its high voltage from said screened enclosure. The invention is applicable to very high power radiofrequency generators.

Abstract: An inductive output tube (IOT) amplifier system is presented for receiving an RF input signal and providing therefrom an amplified RF output signal. The system includes a high tension DC voltage supply and an IOT tube. The IOT tube includes a cathode coupled to the voltage supply for emitting electrons, an anode coupled to the supply for accelerating the electrons, a collector located downstream from the anode that collects the electrons, and a grid located between the cathode and the anode for controlling electron emission from the cathode. The tube has an input for receiving a modulated RF input signal between the grid and the cathode. An output resonant cavity is interposed between the anode and the collector. An output is coupled to the cavity for providing amplified RF output signal. The tube exhibits an inherent interelectrode capacitance which may cause distortions in the output signal.

Abstract: A signal output assembly for an inductive output amplifier comprises a primary output cavity including a drift tube enclosing a modulated electron beam. The density modulated beam passes across a gap separating portions of the drift tube and induces an amplified RF signal into the primary output cavity. A secondary output cavity comprises a coaxial resonator terminated in an inductive coupling loop, and a waveguide having a ridge. The coaxial resonator and the inductive coupling loop have a combined electrical length approximately equivalent to an odd multiple of one-quarter wavelengths of the input signal (n&lgr;/4), where n is an odd integer. The coaxial resonator is electrically connected perpendicularly to a center of the ridge such that first and second portions of the ridge extend in opposite directions from the connection with the coaxial resonator to respective ends of the waveguide.

Abstract: A linear beam amplification device includes an axially centered electron emitting cathode and an anode spaced therefrom. The cathode provides an electron beam in response to a relatively high voltage potential defined between the cathode and the anode. A control grid is spaced between the cathode and anode for modulating the electron beam in accordance with an input signal. A signal input assembly of the linear beam amplification device comprises an axial input cavity into which the input signal is inductively coupled. The grid-cathode region is electrically connected to the input cavity. A low impedance grid-anode cavity is disposed coaxially with the input cavity and is in electrical communication with an interaction region defined between the grid and the anode. The low impedance of the grid-anode cavity is provided by constructing the cavity of a material having a relatively high surface resistivity, such as iron.

Abstract: A thin diamond electron beam amplifier. The illumination side of a thin diamond is illuminated by a seed electron beam creating electron-hole pairs in the diamond. A voltage potential provides an electric field between the illumination side of the diamond and an acceleration grid opposite the emission side of the diamond. Electrons released in the diamond are accelerated through the emission side of the diamond toward the acceleration grid creating an amplified electron beam. Preferred embodiments of the present invention are useful to provide flat panel displays and replacements for thermionic cathodes.

Abstract: A thin diamond electron beam amplifier. The illumination side of a thin diamond is illuminated by a seed electron beam creating electron-hole pairs in the diamond. A voltage potential provides an electric field between the illumination side of the diamond and an acceleration grid opposite the emission side of the diamond. Electrons released in the diamond are accelerated through the emission side of the diamond toward the acceleration grid creating an amplified electron beam. Preferred embodiments of the present invention are useful to provide flat panel displays and replacements for thermionic cathodes, cathode ray tubes, fast photodetectors and image intensifiers.

Abstract: A vacuum tube for handling an r.f. signal having a predetermined frequency range comprises a cathode, a heater, and a non-electron emissive grid. The grid is positioned from the cathode by the distance an emitted electron from the cathode can travel in a quarter cycle of the r.f. signal. Outer and inner metal tubes forming a resonant line of a signal coupler are respectively connected to the grid and cathode. R.F. absorbers absorb r.f. fields in an interaction region between an anode and the grid. In one embodiment a coupling loop is between metal tubes at an end of the tubes spaced n.lambda./4 from the grid and cathode. In a second embodiment the coupler includes a coaxial line having an inner conductor connected to a first metal face, spaced from a second opposed metal face by a solid dielectric. An outer conductor is connected to a third metal face, spaced from a fourth opposed metal face by the dielectric. The third and fourth faces surround the first and second faces.

Abstract: An r.f. radiation absorbing material able to hold off a 30 to 40 kV voltage difference is described as formed by a silicon rubber loaded with ferrite particles. The material is used to reduce self-oscillation in amplifiers.

Abstract: An electron beam device includes a diamond layer positioned downstream from and in the path of an electron beam. This diamond layer has a conductance that is responsive to the electron beam. Two electrical contacts on the diamond layer provide connections to a power source and a load. When the electron beam is on, the diamond layer becomes conductive allowing electrical power to flow from the power source through the diamond layer to the load. Accordingly, the electron beam device can act as a switch, or the electron beam can be modulated to provide an amplifier. The diamond layer is capable of high temperature operation, resists crystal damage, resists corrosion, and provides a high breakdown voltage. At least one of the electrical contacts on the diamond layer preferably comprises a degeneratively doped diamond surface portion.

Abstract: An inductive output tetrode includes a cylindrical ceramic envelope within which is located an electron gun including a cathode and grid. An annular resonant input cavity into which a high frequency signal is coupled surrounds the envelope and is located adjacent the electron gun so as to provide a modulating electric field in the cathode-grid region to density modulate the electron beam. The input cavity is connected to two metal cylinders arranged immediately adjacent to the outside of the envelope. Metallic portions located within the envelope are co-extensive with cylinders with the material of the envelope 1 being located between them. These structures act as r.f. chokes to reduce high frequency losses from the input cavity. Tuning of the resonant cavity may be achieved by adjusting a tuning member which is at distance of quarter of a wavelength at the resonant frequency from the cathode-grid region.

Abstract: The invention relates to a device for producing microwave energy from an electron beam. The device includes:an electron gun (1), allowing the production of an electron beam (8) in a so-called injection zone (3);a microwave modulation circuit (7), allowing the superimposition of an alternating voltage at a given frequency on the voltage of the beam in the injection zone; the amplitude of this voltage is sufficient for ensuring, during one of its alternations, the transition between the passing state and the virtual cathode state, thus causing a modulation of the current carried by the electron beam;an output microwave circuit (4) functioning at the frequency of the modulation signal and excited by the previous modulated current.

Abstract: Two or more signal interaction structures (16,18), which may be klystron or traveling wave structures (32,50), are axially disposed in series between an electron gun (12) and a collector (14) for selectively velocity modulating an electron beam (20) generated by the gun (12) with a microwave input signal (IN1,IN2) and extracting a resulting amplified microwave output signal (OUT1,OUT2) from the beam (20). The interaction structures (16,18) are designed to operate in different frequency bands, for example the X and Ku bands, with only one of the structures (16,18) having an input signal (IN1,IN2) applied thereto at any given time. The interaction structures (16,18) are further designed such that the structures (16,18) which are not being used do not affect the structure (16,18) which is being used.

Abstract: A linearity correction circuit for television transmission operates at intermediate frequency to introduce appropriate pre-distortion into the amplitude envelope to compensate for non-linearity in the power amplifier states. An array of parallel current sources (11), each of which is independently adjustable in response to the perceived requirement for pre-distortion over a corresponding amplitude band, to inject a current sufficient to introduce an appropriate differential voltage at the output. The circuit provides for the independent correction of each amplitude band, so that it is capable of operation under microprocessor control in real time.

Abstract: In a multicavity klystron amplifier, the drift-tube bore is larger (46) in proportion to the beam size (10) in the non-interacting space between gaps (28) than its size (22) at the gaps (28). This decreases the spacecharge wavelength so that the overall physical length of the klystron is shortened.

Abstract: A television transmitter includes a klystron power amplifier, a non-linearity pre-correction circuit in a stage preceding the klystron power amplifier, a non-linearity detection circuit for detecting the non-linearity of the output of the klystron power amplifier, a first level controlling circuit for controlling the level of the output of the non-linearity pre-correction circuit in response to the output of the non-linearity detection circuit, a hum frequency component detection circuit for detecting a hum frequency component of the output of the klystron power amplifier and a second level controlling circuit for controlling the level of either the input or the output of the non-linearity pre-correction circuit in response to the detected hum frequency component. The first and second level controlling level circuits are preferably variable attenuators.

Abstract: The present invention discloses a cross-field amplifier having an anode and cathode with a pair of permanent magnets which create a magnetic field perpendicular to an electric field created between the anode and cathode. An electric bias circuit is connected between the cathode and a power supply that normally supplies energy to an oxygen source within the amplifier. This bias circuit supplies a negative DC voltage to the cathode. After the amplifier is turned off, the DC bias holds electrons within the interaction area between the cathode and anode for supplying the electrons needed to quickly restart the amplifier.

Abstract: A fully monolithic solid state device compatible with standard semiconduc processing for amplifying radio frequency (RF) microwave and/or millimeter wave signals is disclosed. The device includes an input microstrip transmission line which capacitively couples an input RF signal to input underlying grating fingers which, in turn, mode-couple the signal to an interaction grating region by way of an input finger taper region. The RF is amplified in the interaction grating region through its interaction with a space charge wave. Then the amplified RF signal is mode-coupled to output underlying grating fingers by way of an output finger taper region before it is capacitively coupled to an output microstrip transmission line.

Abstract: Microwave oscillators and amplifiers which utilize a superconducting slow-wave circuit. The slow circuit is made from materials which exhibit superconductivity at relatively high critical temperatures. The slow wave circuit is integral with the device's vacuum housing. Coolant exterior to the vacuum housing maintains the circuit in the superconducting state. The slow-wave circuit, which protrudes into the vacuum housing provides modulation of an electron beam which traverses the interior of the vacuum housing. Output power is ultimately extracted from the slow wave circuit.

Abstract: A crossed-field amplifier has a cathode in the form of a P-N junction semiconductor which is biased to the conductive state to cause the crossed-field amplifier to amplify. The P and N regions of the semiconductor are connected to an energy source which is pulsed to produce conduction in the P-N junction and thereby allow secondary emission from the cathode. A reverse bias voltage prevents secondary emission from the cathode. The tube requires only low voltages to be applied to the cathode P-N junction to completely deactivate the crossed-field amplifier tube without requiring the removal of the RF drive pulse applied to the cathode- or anode-slow-wave circuit and without requiring the removal of the DC high voltage power supply which therefore need not be pulsed.

Abstract: An RF amplifier wherein an IREB interacts with RF energy from an RF energy source coupled via an RF cavity to a tube drift region where the IREB is modulated at the frequency of the RF energy source, to provide high gain amplification at high power and high efficiency.

Abstract: This disclosure relates to a microwave amplifier (22) having an active X-Band microwave cavity (33) for use in electron paramagnetic resonance (EPR) measurements on large, lossy, irradiated, samples such as a human finger. The amplifier comprises an input section (31), a drift section (32) and an output section (33) which is the aforementioned active microwave cavity. An electron beam is used to input RF energy into the cavity. The input and output section have small helical couplers (34) for coupling RF energy onto and off of the electron beam. The RF wave is essentially "trapped" in the cavity because of the non-reciprocal nature of the electron beam medium and because the guide (i.e., drift section) at the input to the cavity has dimensions such that the frequency of the RF microwave energy is below the guides lower cut-off frequency. Also, a frequency "locking" effect occurs in the output cavity. The input frequency can be varied from 1-2% yet the output frequency does not change.

Abstract: High efficiency amplification of radio frequencies to very high power levels including: establishing a cylindrical cloud of electrons; establishing an electrical field surrounding and coaxial with the electron cloud to bias the electrons to remain in the cloud; establishing a rotating electrical field that surrounds and is coaxial with the steady field, the circular path of the rotating field being one wavelength long, whereby the peak of one phase of the rotating field is used to accelerate electrons in a beam through the bias field in synchronism with the peak of the rotating field so that there is a beam of electrons continuously extracted from the cloud and rotating with the peak; establishing a steady electrical field that surrounds and is coaxial with the rotating field for high-energy radial acceleration of the rotating beam of electrons; and resonating the rotating beam of electrons within a space surrounding the second field, the space being selected to have a phase velocity equal to that of the rota

Abstract: A combined pulse modulated laser in which a modulated cold cathode device is utilized to excite a combined electron beam bombarded semiconductor device grown integrally with a crystal laser to achieve modulation of the laser output with fast rise and fall times under low voltage and high current conditions.

Abstract: A multi-stage microwave gyrotwystron amplifier is disclosed having two or more stages comprising rectangular cavities to facilitate tuning. The first two stages comprise rectangular tuneable cavities that are oriented orthogonal to each other which produces a homogeneously modulated electron beam that is directed to a cylindrical output cavity which increases its power output as compared to prior art devices havig an output cylindrical cavity excited with a non-homogeneously modulated electron beam.