A5046749341- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Radio Frequency Integrated Circuit Design
- Semiconductor Quantum Structures and Devices
- Fluid Dynamics and Turbulent Flows
- Ga2O3 and related materials
- Advancements in Semiconductor Devices and Circuit Design
- Silicon Carbide Semiconductor Technologies
- Photonic and Optical Devices
- Wind and Air Flow Studies
- Advanced Power Amplifier Design
- Nanowire Synthesis and Applications
- Energy Harvesting in Wireless Networks
- Antenna Design and Analysis
- Integrated Circuits and Semiconductor Failure Analysis
- Semiconductor Lasers and Optical Devices
- Electromagnetic Scattering and Analysis
- Microwave Engineering and Waveguides
- Image and Signal Denoising Methods
- Electromagnetic Simulation and Numerical Methods
- Particle Detector Development and Performance
- Nonlinear Optical Materials Research
- Antenna Design and Optimization
- Meteorological Phenomena and Simulations
- ZnO doping and properties
Fujitsu (Japan)
2016-2025
Fujitsu (China)
2019-2025
Kindai University
1971-2025
University of Tsukuba
2023
Kyushu University
2020-2022
Nara Institute of Science and Technology
2011-2022
Fujitsu (United States)
2021
Aichi Institute of Technology
2021
Keio University
2009-2020
Higashi Osaka City General Hospital
2020
This letter reports on an InAlGaN/GaN high-electron-mobility transistor (HEMT) employing a SiC/diamond-bonded heat spreader with record high output power density of 22.3 W/mm. A quaternary In-added InAlGaN barrier enabled both the large current over 1 A/mm and breakdown voltage 257 V. The drain bias was increased as 100 V for S-band load-pull measurement, leading to operation. Furthermore, thermal resistance reduced by 60%, from 18.8 7.2°C/W, SiC/diamond spreader. dissipation effect clearly...
Coherent vortices are extracted from data obtained by direct numerical simulation (DNS) of three-dimensional homogeneous isotropic turbulence performed for different Taylor microscale Reynolds numbers, ranging Reλ=167 to 732, in order study their role with respect the flow intermittency. The wavelet-based extraction method assumes that coherent what remains after denoising, without requiring any template shape. Hypotheses only made on noise that, as simplest guess, is considered be additive,...
In this work, we demonstrated an excellent output power (Pout) density of 3.0 W/mm at 96 GHz using a novel collapse-free InAlGaN/GaN-HEMT with 80-nm gate for millimeter-wave amplifier. The developed devices showed basic reliability commercial products. To eliminate the current collapse, unique double-layer silicon nitride (SiN) passivation film that has oxidation resistance was adopted. We proved potential our device technology experimentally and analytically.
We demonstrated a W-band high-power-density MMIC power amplifier with 80 nm InAlGaN/GaN HEMTs. The consists of two-stage cascade units, each which has two transistors the same gate periphery for high gain and low-loss matching circuit. achieved maximum output 1.15 W PAE 12.3 % at 86 GHz under CW operation. Its density reached 3.6 W/mm, representing highest performance GaN HEMT amplifier.
An X-band transceiver frontend monolithic microwave integrated circuit (MMIC) has been successfully developed by using GaN HEMT technology. The MMIC contains a power amplifier (PA) with output higher than 19 W at 10.5 GHz, low-noise (LNA) gain of 18.5 dB and noise figure (NF) 2.3 10 an SPDT switch. fabricated occupying only 3.6 × 3.3 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> delivers 6.3 W. To the authors' knowledge, this is...
GaN-based high-electron-mobility transistors (HEMTs) fabricated on SiC substrates were successfully bonded to single-crystal diamond heat spreader by a surface activated bonding method with thin titanium (Ti) cover layer. A Ti layer the improved strength of SiC/diamond interface since formation an amorphous was suppressed. This process applied high-output power InAlGaN/GaN HEMTs spreaders. The structure reduced thermal resistance devices and enabled their high-power operation.
Objectives The purpose of this study was to clarify the appearance reparative tissue on articular surface and analyse properties after hemicallotasis osteotomy (HCO) using MRI T1ρ T2 mapping. Methods Coronal mapping three-dimensional gradient-echo images were obtained from 20 subjects with medial knee osteoarthritis. We set regions interest (ROIs) full-thickness cartilage femoral condyle (MFC) tibial plateau (MTP) measured thickness (mm) relaxation times (ms). Statistical analysis...
Abstract This paper demonstrates highly efficient GaN high-electron-mobility transistors (HEMTs) on substrates with reduced interface contamination. By applying a hydrofluoric acid-based pre-growth treatment to substrate, the Si impurity concentration at between substrate and epitaxial layer can successfully be reduced. RF performance was enhanced by owing suppression of Si-induced parasitic loss. As result, HEMTs exhibited an excellent power-added efficiency 82.8% 2.45 GHz. To best our...
Abstract In this letter, we successfully achieved high-power radio frequency (RF) operation of AlGaN/GaN high electron mobility transistors (HEMTs) fabricated on free-standing AlN substrate at X-band. The developed HEMT comprised a 200 nm thick GaN channel and AlGaN buffer with an Al composition 30%. Thanks to breakdown voltage the substrate, demonstrated 15.2 W mm −1 output power density operating voltages 70 V even without device technologies such as source-field plate optimization...
We demonstrate high voltage HFET operation with suppression of gm dispersion and current collapse using an n-type thin GaN cap layer combined SiN passivation a recessed ohmic structure. Polarization-induced surface charge was controlled. Off state on-state breakdown voltages were 140 V 70 V. obtained power HFETs CW 35 without any heat sinking method.
Light-induced self-written (LISW) polymeric optical waveguides were fabricated in a photopolymerizing resin mixture solution using single-mode fiber. In order to realize straight waveguide core, pre-UV treatment was performed before core formation. Single-mode propagation of laser light at 1310 nm realized by appropriately controlling the ratio resins for first time. Moreover, interconnection between two fibers demonstrated based on this technology.
In this paper, we report a C-band power amplifier with over 340-W output using 0.8-mum GaN-HEMTs and an X-band 100-W 0.25-mum GaN-HEMTs. We used two-chip configurations the three-stage impedance transformers to extend bandwidth for both circuits. The input lines adjacent each chip are divided by four suppress non-uniform heat distribution in at high frequencies. As result, obtained 343-W 53-% added efficiency (PAE) 4.8 GHz. This is highest ever reported amplifiers. also 101-W PAE 9.8...
This paper presents W-band monolithic microwave integrated circuit (MMIC) amplifiers with grounded coplanar waveguide (GCPW) in 0.12μm GaN HEMT technology. A fabricated four-stage low-noise amplifier (LNA) exhibited a record gain of 23 dB at 76.5 GHz and first reported noise figure (NF) 3.8 80 for any MMIC. Another MMIC power (PA) delivered an output 25.4 dBm continuous wave (CW) operation. To our knowledge, this is the demonstration LNA as well MMICs GCPW W-band. In addition, practical...
In this paper, we describe highly reliable GaN high electron mobility transistors (HEMTs) for high-power and high-efficiency amplifiers. First, present the reliability mechanisms progress on previously reported HEMTs. Next, introduce our specific device structure HEMTs improving reliability. An n-GaN cap optimized buffer layer are used to realize efficiency by suppressing current collapse quiescent (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML"...
Matrix equations are given for computing the scattered wave of a homogeneous gyrotropic cylinder. An incident with arbitrary polarization is assumed to normally illuminate cylinder, which magnetized along its axis. The reciprocity theorem first applied interior According boundary condition, one can replace tangential components total on inside surface by that sum and waves outside surface; expanded in terms series Hankel functions. Making use idea Waterman's extended integral equation,...
Abstract. We propose a method for the precise 3D see-through imaging, or transparent visualization, of large-scale and complex point clouds acquired via laser scanning cultural heritage objects. Our is based on stochastic algorithm directly uses points, which are using scanner, as rendering primitives. This achieves correct depth feel without requiring sorting primitives along line sight. Eliminating this need allows us to avoid long computation times when creating natural views...
Abstract High-performance liquid chromatography (HPLC) is the most common analytical method practiced in various fields and used for analysis of almost all drug compounds pharmaceutical industries. During development, an evaluation potential interaction with cytochrome P450 (CYP) essential. A “cocktail” approach often development to evaluate effect a candidate on multiple CYP enzymes single experiment. So far, simultaneous substrates, which have greatly different structure physicochemical...
We present a multilayered optical memory for use in reading data with confocal reflection microscope system. recording medium which photosensitive thin films and nonphotosensitive transparent are stacked alternately. Since the thinner than depth of focus beam, spatial frequency distribution recorded bit is extended axial direction. The overlaps coherent transfer function reflection-type microscope. Urethane–urea copolymer film used as material. two layers demonstrated.