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On behalf of the IVEC 2016 Program Committee and the IEEE Electron Devices Society (EDS) Technical Committee on Vacuum Electronics, I would like to welcome you to the 17th IEEE International Vacuum Electronics Conference!
This paper describes a fan-shaped metal-loaded helix slow-wave structure (SWS) to develop ultra-wideband traveling-wave tube with low gain fluctuation. The electromagnetic characteristics and beam-wave interaction of this structure are calculated. The simulation results show that the helix TWT gain is more than 42dB and the signal gain fluctuation of the TWT is less than 2.5dB in a frequency range...
A 140GHz traveling-wave tube (TWT) by utilizing the sine waveguide slow wave structure (SWS) combined with the electron sheet beam is designed to develop the high power millimeter-wave radiation source. The investigation results reveal that this TWT can produce over 30W output power in the range from 135GHz to 151GHz. The maximum output power reaches 68.63W at 138GHz, which corresponds to a gain of...
Using the Briggs-Bers criterion, we find that the lower band edge of linear beam TWTs is not subjected to absolute instability. At the upper band edge, we find a threshold beam current beyond which absolute instability is excited. In general, an absolute instability would occur in a linear beam tube if the cold-tube circuit dispersion curve in the frequency-wavenumber (ω-k) plane is locally convex...
This paper describes the Space Systems Loral (SSL) Satellite Fleet downlink amplifiers (TWTAs only) reliability FIT rate evolution over time. In addition, this paper attempts to provide insight into the age and distribution of the failures that do occur. For TWTAs, an attempt is made to better understand the source of the TWTA failure breaking it out into TWT, EPC or unknown.
Calabazas Creek Research, Inc. is developing a broadband system to couple RF power from MW-class gyrotrons that eliminates the external matching optical unit. A critical component is a Brewster window in HE11 waveguide. This paper describes progress in fabrication and testing of the window.
Thyratrons in high-power, short-pulse accelerators have a limited lifetime, making it desirable to replace the thyratrons with solid-state devices. One possibility, thyristors, are being developed for this application; they have not, to date, demonstrated the reliability needed for installation in the short pulse, high peak power RF stations used in many pulsed electron accelerators. An alternate...
According to the theory of non-relativistic electron beam can produce high harmonic wave, a new type of terahertz source—high harmonic traveling wave tube was designed and fabricated. Simulation shows the device can deliver 144.5W@138GHz with 300mW@46GHz input signal. The beam voltage is 18.4kV and the beam current is 120mA. The prototype tube is developed and will be test in near future.
Recently a new feature was added to the NRL 2.5D Klystron code called TESLA in collaboration with CPI. The feature involves modeling a klystron with a filter-loaded output cavity. The latter replaces a conventional unloaded single-gap output cavity in a klystron when wide bandwidth is needed. The feature was first evaluated by comparing with cold test data for a stand-alone output cavity. Later the...
The Brillouin flow is the dominant flow in crossed-field devices. We systematically study its stability in conventional, planar, and inverted magnetron. We find that the negative mass effect in the inverted magnetron tends to destabilize the planar flow, and that the positive mass effect in the conventional magnetron tends to stabilize the planar flow. We find that the presence of a slow-wave structure,...
The Multi-Frequency Recirculating Planar Magnetron (MFRPM) is a crossed-field oscillator capable of producing high-power microwaves (HPM). The MFRPM-6+8 is the first prototype MFRPM, which consists of a 6-cavity 1-GHz and 8-cavity 2-GHz set of planar cavity arrays coupled by cylindrical electron beam / RF recirculation bends. Recent experimental work conducted using a −300 kV, 200–300 ns voltage pulse,...
In a klystron, charge overtaking of electrons leads to an infinity of AC current. The harmonic content therein can be calculated exactly, with or without space charge effects. This paper extends the klystron theory to a traveling wave tube (TWT). We assume that the electron motion is described by linear theory. The crowding of these linear orbits may lead to harmonic generation, as in a klystron....
The importance of taking into account thermal electrons when designing the beam optics of a TWT is shown on the example of Ku-Band space TWT with a high beam efficiency.
An Extended Interaction Klystron (EIK) design has been developed to the support extreme signal stability requirements of space-borne interferometric applications. This is an unprecedented set of requirements for an EIK. In conjunction with the Canadian Space Agency (ASC/CSA)and Jet Propulsion Laboratory, Communications and Power Industries, Canada (CPI) advanced this development through testing of...
A method of screen printing carbon nanotubes (CNTs) in a dielectric binder to produce low-cost, large area field emission electron sources is presented. Imaging under the scanning electron microscope (SEM) shows the nanotubes forming dense clusters on the substrate surface with protruding CNTs in random orientations. The printed device gives an emission current of 45 mAcm−2 at an applied field of...
Northrop Grumman has extended its development of compact, microfabricated vacuum electronic amplifiers to 1.0 THz. Most recently, our 1.030 THz amplifier produced 29 mW at 1.03 THz with 20 dB of gain at saturation and 5 GHz of instantaneous bandwidth. The compact power amplifier is based on an electroplated, Si-DRIE folded waveguide slow-wave circuit, together with a high current density thermionic...
We designed a 90 GHz band backward-wave oscillator (BWO) with a double-vane slow-wave structure (SWS). A double periodic alignment of metal vanes serves as an SWS wherein electromagnetic waves propagate along a staggered path. We determined the scale parameters of the SWS by dispersion curves and calculated interaction impedance using CST Studio Suite simulation software. Using particle-in-cell (PIC)...
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