A5100777956- Particle accelerators and beam dynamics
- Microwave Engineering and Waveguides
- Antenna Design and Analysis
- Magnetic confinement fusion research
- Plasma Diagnostics and Applications
- Plasmonic and Surface Plasmon Research
- Advanced Antenna and Metasurface Technologies
- Particle Accelerators and Free-Electron Lasers
- Superconducting Materials and Applications
- Metal and Thin Film Mechanics
- Photonic and Optical Devices
- Fusion materials and technologies
- Antenna Design and Optimization
- Pulsed Power Technology Applications
- Nuclear Physics and Applications
- Gaze Tracking and Assistive Technology
- Gyrotron and Vacuum Electronics Research
- Magneto-Optical Properties and Applications
- Energy Harvesting in Wireless Networks
- Usability and User Interface Design
- Semiconductor materials and devices
- Optical Systems and Laser Technology
- Photonic Crystals and Applications
- Optical Coatings and Gratings
- Sensorless Control of Electric Motors
PLA Army Engineering University
2015-2021
University of Pisa
2015
General Atomics (United States)
1996-2009
National Taiwan University of Science and Technology
2005
University of California, Irvine
1988
In this communication, a novel wideband fixed-beam leaky-wave antenna (LWA) is proposed. The designed based on air-filled substrate integrated waveguide (SIW), which composed of one layer printed circuit board (PCB) in the middle and two layers thin copper plates top bottom. different are aligned fixed by screws. A long slot etched surface SIW as radiator. Due to dispersive characteristic SIW, can radiate at direction over wideband. To best our knowledge, first time that adopted for LWA...
In this letter, a wideband beam-scanning antenna with circular polarization (CP) characteristics is proposed. The designed based on an air-filled substrate-integrated waveguide (SIW), which composed of three layers printed circuit board. Since the medium dug out, transmission structure has low-loss characteristics. An array slots etched top layer as radiating elements. Due to fast-wave characteristic SIW, can radiate over wide bandwidth. proposed designed, fabricated, and tested. Within...
In this paper, a novel mode composite waveguide based on hybrid substrate integrated and spoof surface plasmon polariton (SIW-SSPP) is proposed. Through different feeding methods, the odd even of SSPP are excited simultaneously operate at same frequency band. Thus, co-frequency multiplexing achieved for proposed odd-even (OEMCW). The design principle characteristics OEMCW analyzed in work. A prototype fabricated measured to demonstrate its transmission performance. results indicate that can...
Water flow calorimetry is utilized at DIII-D to quantify injected neutral beam power. As part of the system upgrades for past year, old CAMAC-based telemetry WFC diagnostic was replaced by a fiber optic Ethernet-based system. The difficulty obtain replacement CAMAC hardware and prospect lower noise spurious signal sensitivity motivated move telemetry. new installed tested during 2006 physics campaign startup phase. Both were used acquire data from one common ion source in current year....
Propagation of a charge-neutralized ion beam, in transverse magnetic field (Bz <400 G) and magnetized plasma, has been studied. Measurements indicate that the beam propagation mechanism is due to E×B drift region high β (1<β<400), where ratio kinetic energy energy. Diamagnetic measurements, both internal external propagating confirm fast diffusion Bz into on time scale much shorter than rise 10−7 s. When injected plasma electric shorted degree increases with increasing...
A broadband circularly polarised (CP) stacked antenna with a sequential‐phase feed technique is proposed in this study. The contains square ring that encircled by four driven patches. gap‐coupled method used to transfer energy from the Moreover, patches are placed above bottom layer enhance impedance and CP bandwidths. measured results yield an bandwidth of 33.6% (4.78–6.71 GHz) wide 3 dB axial ratio 19.4% (4.90–5.95 obtained. average gain ∼9 dBi variation <1 within bandwidth.
In this letter, a planar broadband higher-order mode millimeter-wave (MMW) microstrip patch antenna array with low sidelobe level (SLL) is presented. For the element, antiphase-TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sub> excited by unequally etching radiating two transverse slots. Meanwhile, an SIW-based pin-loaded slot coupling feeding structure introduced to achieve merits of broadband, cross polarization, and backward...
In this paper, we present a compact effective surface plasmon polariton (ESPP) frequency splitter induced by structural dispersion in substrate integrated waveguide (SIW). The consists of three SIW layers. Periodic wire arrays are placed on the interface layers with relative permittivity opposite sign to support ESPP propagation, which can introduce transmission zero. By properly placing substrates, two passbands spatially isolated from each other. designed is numerically simulated and...
The low aspect ratio tokamak or spherical torus (ST) approach offers the two key elements needed to enable magnetic confinement fusion make transition from a government-funded research program commercial marketplace: cost, power, small size market entry vehicle and strong economy of scale in larger devices. Within ST concept, very device (A = 1.4, major radius about 1 m, similar DIII-D tokamak) could be built that would produce ~800 MW thermal, 250 net electric, have gain, defined as QPLANT...
The purpose of this paper is to determine the controller parameter tuning range for a speed sensorless vector-controlled induction motor drive from system stability point-of-view. rules conventional PI controllers are mostly based on experience, Trial-and-error procedures used tune values parameters. relationship between tuned parameters and stable operating control generally not known. approach starts establishing complete dynamic models drive. nonlinear linearized around chosen point...
The DIII-D fusion science research facility employs positive-ion based neutral beam ion sources for plasma heating and current drive experiments. Ion species produced inside the arc chamber of an source determine composition beams injected into in turn affect energy deposition along cross section plasma. Arc design operation schemes are predominant factors mix when discharge is chamber. When deuterium gas used three (atomic D/sub 1//sup +/ molecular 2//sup 3//sup +/) source. Atomic has...
The unconditionally stable associated Hermite (AH) finite-difference time domain (FDTD) with Mur's absorbing boundary condition is extended into the cylindrical coordinates system. With AH expansion and paralleling-in-order scheme, time-domain Maxwell's equations in are transformed to five-point equations. And, Ampere's law applied treat central axis formulation by using differential operator. numerical results demonstrate a good accuracy higher efficiency for proposed method when compared...
A low-profile antenna with end-fire radiation and vertical polarization is presented in this paper. It employs a top-open dielectric-filled waveguide to propagate the electromagnetic waves, which radiated by gradually deducing height of waveguide. The proposed has low profile 0.1λL (λL wavelength at lowest operating frequency), embedded large ground plane. Simulation results show that fractional impedance bandwidth 23.6%, maximum gain 8.4 dBi, an achieved, indicating should be useful...
In this paper, an asymmetric sinusoidal modulated substrate integrated waveguide-spoof surface plasmon polariton (SIW-SSPP) leaky-wave antenna with open stopband suppressed is proposed. The SSPP transmission line can covert the guided waves to radiations frequency-scanning properties due modulation. Using model effective method restrain stopband. radiating element π/2 phase difference between upper and lower sides of top introduced in realize zero-crossing beam scanning unidirectional...
The slow increase of arc and beam currents during the pulse is an intrinsic characteristics neutral long ion source installed on DIII-D tokamak. This ramping attributed to heating filaments by energetic electrons backstreaming from accelerator into chamber. corresponding change in perveance causes optics vary a pulse, often resulting overdense condition. Stepping down voltage applied at turn-on was helpful, but its disadvantages called for better scheme. A technique using Langmuir probe...
The electric field derivative (dE/dt) radiation from lightning leaders are usually very weak, and it is hard to be recognized if the strike far observation site. In this paper, Fourier analysis of a segment noise contaminated dE/dt signal conducted. Based on identification noisy source leader spectrum, wavelet packed based method for detecting signatures proposed performed. application data show that obvious characteristic in waveforms could retrieved weak radiations, pulse coincide with...
The fundamental parameters by which injected DIII-D neutral beam power is calculated have all been recently measured using waterflow calorimetry and target tile thermocouples. neutralization efficiency 66%, close to the modeled equilibrium value of 70% for a 75 kV deuterium beam. Waterflow has proven be useful tool measure efficiency, contrary earlier results. beamline transmission each independently, averages about 78% among beams. Finally, drift duct reionization survival rate 95%. By...
The neutral beam injector systems on the DIII-D tokamak are currently limited to 3 seconds of total time with existing line components. To achieve high performance discharges a fraction non-inductive current drive for pulse lengths longer than resistive time, long upgrades planned both and power supplies that it. will be extended 10 provide full throughout shot. This paper discusses calculations, simulations measurements identify component modifications required operations. examined voltage...
The DIII-D fusion research tokamak utilizes seven neutral beam ion sources for plasma heating and current drive. These the system have performed with high availability reliability since 1987. Experimental has accomplished extensive understanding insights of physics, requires more capability to provide flexibility enhancing scope physics experiments. Extending pulse length without lowering power is one goals next 5 years. Currently, deuterium source operated at 80 keV limited 3 s due heat...
Power divider is of great importance in the modern microwave and communication system. With good performance spoof surface plasmons polariton (SPP) lower band, mimicking SPP at optical it's a wise choice to put it into design fabrication power dividers. Therefore, by etching corrugated double symmetrical gratings two single separated with periodic rectangular grooves using polariton, wideband out-of-phase presented equal division. Furthermore, transition employed excite odd-mode SSPP waves,...