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A Ka-band high power sheet beam backward wave oscillator (BWO) has been presented in this paper. In which the double-grating rectangular waveguide is used as the slow wave structure. A high power sheet beam with cross section 30mm×1mm is produced by a thin cathode. The output power exceeds 35 MW at 31.1 GHz. The beam-wave interaction efficiency is about 14.7%.
The technique of resonance effects analysis in the quantum exchange interaction of the electron and positron flows is developed. At the framework of macroscopic quantum theory conducted a joint decision of the Schrödinger and Poisson equations for the macroscopic wave function of the electrons and positrons. Resonance effects in the quantum exchange interaction leads to self-organization of the active...
Electric fields at metal-dielectric contact were calculated analytically and numerically. The obtained field exhibited enhancements strong enough to cause breakdown at a triple junction and more apparently at a quadruple junction. Such field enhancements may lead to a noble type of cold cathode.
With the help of the finite-difference equation of excitation of periodic waveguides obtained the characteristic equation of the electron waves formed by the interaction of an electron beam with the forward and backward electromagnetic waves periodic slow-wave systems (SWS). The resulting characteristic equation describes the electron-wave interaction in the passband and stopband of periodic SWS....
A novel model of the compact high power 264 GHz CW Extended Interaction Oscillator has been developed by CPI Canada. By combination of mechanical tuning and electronic switching between two operating modes, this EIO provides over 1 W of power in the range of 258 to 270 GHz. Liquid cooling is used to stabilize RF circuit temperature and prevent frequency detuning. Further development is ongoing to...
In this paper, the design and optimization of a V-band helix TWT is carried out and prototype tubes have been assembled. The test results show that the output power of the TWT is over 15W with the overall efficiency of over 14.5% and a gain of over 43dB. The beam transmission experiment shows that a transmission ratio is over 97%.
A nonlinear steady-state multimode theory is developed to investigate mode competition in gyro-TWT. Calculation shows that competition mode may be suppressed by a large driving power in a particular range.
Based on the mode-matching technique and simulation software CST, this paper analyzes and simulates the input cavity of gyroklystron amplifier, and gets the structure model of TE01 mode W-band gyroklystron input cavity. Then it contrasts the influence of the size of coupling slots to the coupling frequency and Q-value.
One-dimensional (SUNRAY-1D), and two and half dimensional (SUNRAY-2.5D) codes are developed for accurate, fast and reliable multi-signal large signal analysis of a complete helix-type space TWT. Detailed beam and rf field parameters including inter-modulation components and higher-order time harmonics are simulated accurately for a high efficiency space TWT. The spent electron beam data of SUNRAY-2...
Electron emission characteristics of a triode surface-conduction field emission display were simulated with finite element analysis method and MATLAB. The parameters of the display structure were optimized based on the simulation results. Field emission from the carbon nanotubes and ZnO nanotetrapod compound cathodes were also simulated and studied.
The experimental study of a Q-band gyrotron-travelling-wave tube (gyro-TWT) amplifier operating in the circular TE01 mode at fundamental cyclotron harmonic is presented. A periodic dielectric loaded structure is adopted in the interaction circuit of the gyro-TWT to suppress spurious modes TE11 and TE21. A saturated peak power of 175 kW is obtained corresponding to saturated gain of 53 dB and an efficiency...
This paper presents the development of W-band folded waveguide pulsed TWT. We have obtained experimentally over 100W output power with 5GHz instantaneous bandwidth and 33dB gain at 20% duty cycle.
A three-dimensional (3-D) large signal model of beam-wave interaction in a folded waveguide (FW) slow wave circuit is described. The 3-D code carries out with numerical solutions of the structure, without using the analytical formulations of the eigenmodes. This model can also be used in helix TWTs and coupled-cavity TWTs.
This paper presents theory and analysis of single-tip field emission and electron beam propagation in the electrostatic focusing fields. It is shown that two gate apertures with a focusing anode allow transport of narrow electron beams over long distances without need for a confining magnetic field. Physical mechanisms of the beam formation, transport, intrinsic emittance with thermal effects, the...
A time-dependent self-consistent large-signal simulation code for gyroklystron is developed and the key technologies involved are introduced. To validate the code, a Ka-Band gyroklystron amplifier is simulated and the effects of time step and space step are observed, which lead up to a coarse criterion about the choice of appropriate time step and space step so as to take consideration of both computation...
One dimensional beam wave interaction simulator for klystron (BWIS_KLY) which is one module of the microwave-tube simulator (MTSS) was developed. The main features of BWIS_KLY are described.
Semicon Associates is a world-class producer of dispenser cathodes for traveling wave tubes, cathode ray tubes, ion lasers and space qualified cathode assemblies. The research objective is to allow Semicon Associates to determine the effects of mass load on cathode etching and Hydrogen (H) gas consumption during the impregnation process. Hydrogen (H) is a chemical element with symbol H, atomic number...
We apply an external circuit model to our simulations of (MIG) Magnetron Injection Guns to improve fidelity and encompass additional physics relating to the voltage and current delivery systems which, to date, have not been included in out models. These studies are primarily intended to look at (LFO) Low Frequency Oscillations, and so inclusion of the external circuit can represent external geometry...
For state of the art cathodes for space applications, a stable operation during the entire life cycle has to be guaranteed. Therefore, at Thales, such devices are characterized thoroughly to assure the level of confidence regarding its long term behaviour. Since the introduction of the MM-type cathode, TED follows strictly a dedicated life test philosophy for space cathodes providing a considerable...
The radiation of slit modes excited by convection electron inside a perfect metal film perforated with one dimensional array of cut-through slit is studied. The radiations of non radiating slit modes are achieved by grating coupler which provides the required momentum shift to them. Numerical simulation shows that the radiation intensity of these momentum shifted slit modes are more than that of Smith-Purcell...
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