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Pseudospark (PS) electron beams of outstanding performance have been studied recently with their application to a demanding field of millimeter-wave and terahertz radiation generation. To this end, the PS discharge process itself has been studied and millimeter wave sources which utilize a PS sourced electron beam in different beam-wave interaction structures have been designed and modelled using...
Broadband windows are critical components in gyro-TWAs and pose a great challenge to manufacture. They are required to have very low reflection whilst coupling in microwave power. Presented in this paper is the design, simulation and measurement of a wide-band (90 to 100 GHz) multilayer microwave window using the HE11 mode as the input microwave mode. The simulated performance shows a better than...
Latest results of a W-band gyro-TWA with a helically corrugated waveguide and a cusp electron gun for operation at a high pulse repetition rate are presented. Performance upgrades of input coupler, output window, corrugated horn, pulsed power system and beam collector with water-cooling capability were realized. With an input seed signal from an 1.5 W, 90–96 GHz solid state source the amplification...
Numerical study of a G-band Extended Interaction Oscillator (EIO) based on a pseudospark-sourced electron beam is presented. Preliminary results show a new way to generate several hundred watts of pulse power in millimeter and even terahertz frequency range in a compact and affordable way.
There has been limited focus on evaluation of Sub-synchronous Resonance (SSR) risk between reciprocating engine based generation and series compensated transmission networks. This paper aims to provide an analytical approach for investigating SSR issues associated with reciprocating engine based generators and series compensated transmission lines. Eigen value analysis is performed to determine the...
In this paper, we study the power control problem for energy-harvesting wireless network (EHWN). In an EHWN, if there are some nodes whose energy- harvesting rate is less than its transmit power, power oscillation will be caused even when the system is feasible. In order to avoid the power oscillation, we take energy-harvesting node's energy status, i.e., energy-harvesting rate, transmit power and...
The pseudospark discharge is a form of low-pressure gas discharge capable of generating extremely high currents with short rise times by means of a unique hollow cathode structure [1-6]. A high-quality electron beam is generated during the later phases of the discharge process, which possesses high current density and brightness, as well as the ability to self-focus via ion channel focusing. This...
Millimeter-wave radiation has been successfully generated by a ∼100GHz BWO driven by a high brightness electron beam derived from a 14-gap pseudospark discharge. Pseudospark electron beams have been studied recently with their application to millimeter-wave and terahertz radiation generation. A BWO utilizing the interaction between an axial electron beam and a slow-wave structure was designed and...
Cold test results of a G-band sheet beam backward wave oscillator (BWO) with a double grating waveguide, fabricated by wire cutting and a 3D printing technique, are presented in this paper. The dispersion curve and S-parameters of the BWO slow wave circuit and Bragg reflector were measured and the results compared to the numerical modelling and analytical theory.
Experimental results are presented of the first successful low-terahertz region operation of a pseudospark-driven backward wave oscillator (BWO) in the frequency range of 140 GHz to 220 GHz. The experiment agrees well with 3D particle-in-cell numerical simulations.
The pseudospark discharge is a form of low-pressure gas discharge, capable of generating extremely high currents within short rise times by means of a unique hollow cathode structure [1–2]. A high-quality electron beam is generated during the later phases of the discharge process, which possesses high current density and brightness as well as the ability to self-focus via ion channel focusing. This...
Micro-reentrant square cavities operating at high order modes have been demonstrated to be a viable solution for the realization of millimeter wave klystrons. However, the excitation of the required high order mode is a challenging task. The realization and measurement of a novel coupler for high order mode cavities is proposed.
Pseudospark electron beams have been studied recently with their application to millimetre-wave and terahertz radiation generation. To this end, backward wave oscillators (BWO), a form of vacuum tube which utilises the interaction between an axial electron beam and a slow-wave structure has been designed and modelled using the particle-in-cell code MAGIC and VORPAL. Millimetre radiation has been generated...
Pseudospark electron beams of micro-sizes have been measured recently and their application to millimeter-wave and terahertz radiation generation is being investigated. A three cavity 94 GHz klystron using a micro-sized beam has been designed and simulated and is currently being constructed.
High frequency radiation sources in sub-terahertz frequency range (0.1–1 THz) are currently very attractive for both research and technical applications. To generate the high frequency radiation, a pseudospark (PS)-sourced electron beam is ideal because of its scalability accompanied with high intensity and high quality beam generation [1, 2]. The propagation of a PS electron beam is aided by an ion...
This is the second part of a two-paper series. The first paper presented the tools and techniques for investigation of sub-synchronous control and torsional interaction in Wind Power Plants (WPPs). This paper presents a comprehensive Electro-Magnetic Transient (EMT) simulation based case study to investigate potential Sub-Synchronous Control Interaction (SSCI) issues. The Electric Reliability Council...
A range of pulsed microwave sources, under investigation at the University of Strathclyde, require the generation of multi-kilo-ampere, relativistic, electron beams1,2. These may be mono-energetic or varying in energy throughout the duration of the pulse (dependant on the source in question), however all require a driving supply capable of dealing with potentially rapid changes in the accelerating...
A micro-klystron is one kind of compact device which can generate high power Terahertz radiation to meet the requirements of fast growing applications in Terahertz technology. The device needs a very thin electron beam with high energy to drive the beam-wave interaction. Pseudospark discharged electron beam has demonstrated its ability to provide a high current density in a small diameter (< 0...
Electron beams of micro sizes have been recently extracted from a pseudospark discharge. A three cavity pseudospark-driven 94 GHz klystron has been designed and simulated using the particle-in-cell (PiC) code MAGIC-2D and modeled with CST Microwave Studio. The simulation results to date look promising.
This paper presents the first-principles study of an ultra-thin HfO2 on SiGe/Si substrate. The strong stress in hafnia layer caused by lattice mismatch significantly deforms the structure in this layer, and alters the valence-band offset between HfO2 and SiGe. These phenomena should significantly affect the properties of CMOS devices associated with an ultra-thin HfO2 dielectric film.
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