The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Claudio Paoloni - One of the best experts on this subject based on the ideXlab platform.
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Nano-CNC Machining of Sub-THz Vacuum Electron Devices
IEEE Transactions on Electron Devices, 2016Co-Authors: Diana Gamzina, Robert Barchfeld, Logan G. Himes, Branko K. Popovic, Eunmi Choi, Claudio Paoloni, Yuan Zheng, Neville C. LuhmannAbstract:Nano-computer numerical control (CNC) machin- ing technology is employed for the fabrication of sub-THz (100–1000 GHz) vacuum Electron Devices. Submicron feature tolerances and placement accuracy have been achieved and surface roughness of a few tens of nanometers has been demonstrated providing high-quality radio frequency (RF) trans- mission and reflection parameters on the tested circuit struc- tures. Details of the manufacturing approach are reported for the following Devices: W-band sheet beam (SB) klystron, two designs of a 220-GHz SB double-staggered grating traveling wave tube (TWT), 263-GHz SB TWT amplifier for an Electron paramagnetic resonance spectrometer, 346-GHz SB backward wave oscillator for fusion plasma diagnostics, 346-GHz pencil beam backward wave oscillator, and 270-GHz pencil beam folded waveguide TWT self-driving amplifier. Application of the nano- CNC machining to nanocomposite scandate tungsten cathodes as well as to passive RF components is also discussed.
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photonic crystal structures for thz vacuum Electron Devices
IEEE Transactions on Electron Devices, 2015Co-Authors: Rosa Letizia, Mauro Mineo, Claudio PaoloniAbstract:The technology of photonic crystals (PhCs) is investigated here to improve the performance of THz vacuum Electron Devices. Compared with conventional metallic waveguides, the PhC arrangement alleviates typical issues in THz vacuum Electron tubes, i.e. difficult vacuum pumping process and assembling, and improves the input/output coupling. A slow-wave structure (SWS) based on a corrugated waveguide assisted by PhC lateral walls and the efficient design of a PhC coupler for sheet-beam interaction Devices are demonstrated. Based on the proposed technology, a backward-wave oscillator (BWO) is designed in this paper. Cold parameters of the novel PhC SWS as well as 3-D particle-in-cell simulations of the overall BWO are investigated, obtaining more than 70-mW-peak output power at 0.650 THz for beam voltage of 11 kV and beam current of 6 mA.
Richard J. Temkin - One of the best experts on this subject based on the ideXlab platform.
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metamaterial inspired vacuum Electron Devices and accelerators
IEEE Transactions on Electron Devices, 2019Co-Authors: Zhao Yun Duan, Michael A Shapiro, Yubin Gong, Edi Schamiloglu, Nader Behdad, John H. Booske, B N Basu, Richard J. TemkinAbstract:Metamaterials (MTMs) are structured materials with subwavelength features that can be engineered to have some unique properties not found in nature, such as negative refractive index, reversed Doppler effect, and reversed Cherenkov radiation. Based on these novel MTMs, several important research groups have made great attempts to develop novel MTM-inspired vacuum Electron Devices (VEDs) and accelerators. Just as solid-state power Devices are innovated by incessant emerging of new semiconductor materials, VEDs can also be inspired by MTMs to have very remarkable advantages, such as smaller size, higher power, higher efficiency, and/or larger gain relative to conventional VEDs, such as traveling-wave tubes, backward-wave oscillators, and klystrons. Similarly, relative to conventional accelerators, MTM-inspired accelerators have obvious advantages, such as smaller size and higher accelerating gradient. Furthermore, MTM-inspired Devices have promising applications in areas such as radar, communication, Electronic warfare, microwave heating, and imaging.
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Review of metamaterial-inspired vacuum Electron Devices
2018 IEEE International Vacuum Electronics Conference (IVEC), 2018Co-Authors: Zhao Yun Duan, Michael A Shapiro, Yubin Gong, Edi Schamiloglu, Nader Behdad, John H. Booske, Baidyanath Basu, Richard J. TemkinAbstract:Metamaterials are subwavelength structure material engineered to have some unique properties that are not found in nature, such as reversed Cherenkov radiation (RCR). Based on the RCR, some important research groups in the world have made great attempts to develop novel metamaterial-inspired vacuum Electron Devices. These research results clearly show that metamaterial-inspired vacuum Electron Devices have very remarkable advantages, such as small size, high power, high efficiency, and high gain. These brand new metamaterial-inspired Devices have promising applications in radar, communications, Electronic warfare, microwave heating, accelerators, imaging, and many other areas.
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Sub-wavelength waveguide loaded by a complementary electric metamaterial for vacuum Electron Devices
Physics of Plasmas, 2014Co-Authors: Zhao Yun Duan, Jason S. Hummelt, Michael A Shapiro, Richard J. TemkinAbstract:We report the electromagnetic properties of a waveguide loaded by complementary electric split ring resonators (CeSRRs) and the application of the waveguide in vacuum Electronics. The S-parameters of the CeSRRs in free space are calculated using the HFSS code and are used to retrieve the effective permittivity and permeability in an effective medium theory. The dispersion relation of a waveguide loaded with the CeSRRs is calculated by two approaches: by direct calculation with HFSS and by calculation with the effective medium theory; the results are in good agreement. An improved agreement is obtained using a fitting procedure for the permittivity tensor in the effective medium theory. The gain of a backward wave mode of the CeSRR-loaded waveguide interacting with an Electron beam is calculated by two methods: by using the HFSS model and traveling wave tube theory; and by using a dispersion relation derived in the effective medium model. Results of the two methods are in very good agreement. The proposed all-metal structure may be useful in miniaturized vacuum Electron Devices.
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Vacuum Electron Devices for Applications in " Big Science"
2006 IEEE International Vacuum Electronics Conference held Jointly with 2006 IEEE International Vacuum Electron Sources, 1Co-Authors: Richard J. TemkinAbstract:Vacuum Electron Devices (VEDs) are the most powerful and efficient sources of coherent radiation throughout the microwave and millimeter wave bands. Traditional applications of powerful VEDs are in such areas as defense, radar, communications, or industrial heating. This presentation will review prospects for new applications in scientific research, especially in large scale applications, sometimes referred to as " Big Science. " Opportunities are promising in at least three fields: plasma heating in the program of nuclear fusion energy research; particle acceleration; and Terahertz technology.
William L. Menninger - One of the best experts on this subject based on the ideXlab platform.
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Special Issue on Vacuum Electron Devices
IEEE Transactions on Electron Devices, 2009Co-Authors: William L. MenningerAbstract:The 39 papers in this special issue focus on vacuum Electron Devices. The papers are grouped by device type: high frequency/microfabrication; sheet beams; cathodes; gyro-Devices; klystrons/multi-beam klystrons; and traveling-wave tube.
Fabio Filicori - One of the best experts on this subject based on the ideXlab platform.
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Breakdown walkout investigation in Electron Devices under nonlinear dynamic regime
2008 Workshop on Integrated Nonlinear Microwave and Millimetre-Wave Circuits, 2008Co-Authors: V. Di Giacomo, Giorgio Vannini, S. Di Falco, Antonio Raffo, Pier Andrea Traverso, Alberto Santarelli, Fabio FilicoriAbstract:In this paper, the breakdown walkout in microwave Electron Devices is investigated by means of a recently proposed measurement set-up. This innovative setup allows to apply a stress procedure not only in classical static conditions, but also under dynamic regime by applying a large-amplitude excitation signal at moderately high frequency at either the input or the output port of the device. As a matter of fact, for the very first time, experimental data can be collected for fully investigating the walkout behaviour under both static and dynamic operations.
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A Nonquasi-Static Empirical Model of Electron Devices
IEEE Transactions on Microwave Theory and Techniques, 2006Co-Authors: Alberto Santarelli, Giorgio Vannini, V. Di Giacomo, Antonio Raffo, Pier Andrea Traverso, Fabio FilicoriAbstract:A new nonquasi-static nonlinear model of Electron Devices is proposed by adopting a perturbed charge-controlled approach. The model is based on the definition of a virtual quasi-static device, associated with the actual one, which is controlled by means of equivalent voltage sources. The advantage of this approach is that conventional purely quasi-static models can be still adopted even at very high frequencies, if suitable equivalent voltages are applied. Identification from small-signal measurements and implementation into commercially available computer-aided design tools of the new nonquasi-static model are described in this paper. Finally, by considering a GaAs p-high Electron mobility transistor, accurate prediction capabilities at microwaves and millimeter frequencies are experimental verified and compared with a more conventional equivalent-circuit-based model
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A simple non-quasi-static non-linear model of Electron Devices
2005Co-Authors: Alberto Santarelli, Fabio Filicori, Giorgio Vannini, V. Di Giacomo, Antonio Raffo, Pier Andrea Traverso, M.a. MonacoAbstract:A technology-independent, non-quasi-static non-linear model of Electron Devices capable of accurate predictions at microwave and millimetre waves is proposed in this paper. The model is based on the definition of a quasi-static associated device, which is controlled by means of equivalent voltages. In particular, in the paper it is shown how to define and experimentally identify suitable voltage-controlled voltage sources, which modify the original domain of applied voltages and create a suitable control environment for the purely-quasi-static associated device. The advantage of this approach is that conventional purely quasi-static models can still be adopted even at very high frequencies, if suitable equivalent voltages are applied. Preliminary experimental validation of the approach is provided in the paper by means of a GaAs PHEMT.
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Technology independent nonlinear integral model of microwave Electron Devices
1992Co-Authors: Fabio Filicori, V.a. Monaco, Giorgio VanniniAbstract:The paper describes a new technology-independent model for the large-signal performance prediction of Electron Devices. The Nonlinear Integral Model (NIM) is rigorously derived from the Volterra series through suitable modifications so that fast convergence can be achieved even under large-signal strongly nonlinear operation. In particular, the NIM, which can be directly used for Harmonic-Balance circuit analysis, enables the large-signal dynamic response of Electron Devices to be directly computed on the basis of data obtained either by conventional measurements or physics-based numerical simulations. This property makes the NIM particularly convenient for linking accurate device simulation based on carrier transport physics and Harmonic-Balance circuit analysis. Simulations and experimental results confirm the validity of the proposed modelling approach.
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A nonlinear integral model of Electron Devices for HB circuit analysis
IEEE Transactions on Microwave Theory and Techniques, 1992Co-Authors: Fabio Filicori, Giorgio Vannini, V.a. MonacoAbstract:A technology-independent large-signal model of Electron Devices, the nonlinear integral model (NIM), is proposed. It is rigorously derived from the Volterra series under basic assumptions valid for most types of Electron Devices and is suitable for harmonic-balance circuit analysis. Unlike other Volterra-based approaches, the validity of the NIM is not limited to weakly nonlinear operation. In particular, the proposed model allows the large-signal dynamic response of an Electron device to be directly computed on the basis of data obtained either by conventional measurements or by physics-based numerical simulations. In this perspective, it provides a valuable tool for linking accurate device simulations based on carrier transport physics and harmonic-balance circuit analysis algorithms. Simulations and experimental results, which confirm the validity of the NIM, are also presented. >
Rosa Letizia - One of the best experts on this subject based on the ideXlab platform.
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photonic crystal structures for thz vacuum Electron Devices
IEEE Transactions on Electron Devices, 2015Co-Authors: Rosa Letizia, Mauro Mineo, Claudio PaoloniAbstract:The technology of photonic crystals (PhCs) is investigated here to improve the performance of THz vacuum Electron Devices. Compared with conventional metallic waveguides, the PhC arrangement alleviates typical issues in THz vacuum Electron tubes, i.e. difficult vacuum pumping process and assembling, and improves the input/output coupling. A slow-wave structure (SWS) based on a corrugated waveguide assisted by PhC lateral walls and the efficient design of a PhC coupler for sheet-beam interaction Devices are demonstrated. Based on the proposed technology, a backward-wave oscillator (BWO) is designed in this paper. Cold parameters of the novel PhC SWS as well as 3-D particle-in-cell simulations of the overall BWO are investigated, obtaining more than 70-mW-peak output power at 0.650 THz for beam voltage of 11 kV and beam current of 6 mA.
