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We report on experimental observation and theoretical analysis of magnetic-field and gate-voltage tunable magnetoplasmon resonances in grating-gate GaN/AlGaN-based field-effect transistors suitable for detection of THz radiation.
Microbolometers based on two dimensional electron gas (2DEG) medium in GaN semiconductor were fabricated and characterized. Low contact resistance (below 0.5 Ω·mm) achieved in our devices ensures that the THz voltage primarily drops across the active region. Due to small electron momentum relaxation time, the inductive part of the impedance in our devices is small, so these sensors can be combined...
This study proposes a W-band harmonic multiplying gyro-TWT operating at lower-order modes to avoid the fundamental harmonic absolute instabilities. The W-band harmonic multiplying gyro-TWT is predicted to yield a peak output power of 100 kW at 98 GHz with an efficiency of 22.5 %, a saturated gain of 24 dB and a 3 dB bandwidth of 1.1 GHz for a 60kV, 7.42 A electron beam with an axial velocity spread...
We report on magnetotransport characterization of grating-gate GaN/AlGaN-based THz detectors. Results of our experiments show that depending on the geometry of a grating, 2D electron channel may be divided into gated and ungated regions with different concentrations and mobilities of the carriers.
Monolithically integrated microwave switches based on insulated gate transistors benefit from extremely small leakage currents crucially important for large-periphery devices. Composite fast/slow gate design and nonlinearity compensation technique allow the insulated gate switches to achieving superior performance compared to existing RF switch types.
This paper presents a highly flexible 64-electrode stimulator using 65 nm CMOS process fabricated as a stage towards a 1024-electrode epi-retinal prosthesis, which aims to restore partial vision in patients suffering from eye diseases such as retinitis pigmentosa (RP) and age-related macular degradation (AMD). The stimulator drives 64 electrodes with many flexible features, which are necessary before...
The reviews and prospects for radiometer calibration research of BIRMM (Beijing Radio Institute of Metrology and Measurement) are presented in this paper. The paper's interests are concentrated on three principal parts as follows. Firstly, the timetable about research for radiometer calibration target is shown in a figure according to time sequence since 1995. Second, the traceability link for calibration...
Amplifier performance of Nd3+-doped polymer and Al2O3 channel waveguides at 880 nm is investigated. Tapered amplifiers are embedded between optical backplane waveguides, and a maximum 0.21 dB net gain is demonstrated.
The characterization of the downstream of an oxygen atmospheric pressure plasma jet (APPJ) is performed. This APPJ is sustained by pulsed power with a repetitive frequency up to 25 kHz. The reactivity of the plasma at different operating conditions is characterized using the intensities of O2 (759 nm) and O (777 nm) optical emission lines. The jet downstream temperature is measured by a thermocouple...
The characterization of microplasmas driven by DC and AC (50∼1000 Hz) power supplies with a voltage up to 1000 V at atmospheric pressure is performed. Parallel planar aluminum electrodes with an inter-electrode gap 20∼200 mm are patterned on a glass substrate by semiconductor fabrication processes. Pure argon and helium are used as the feedstock. Filamentary-like discharges are mostly observed in...
We report on the first AlInN/GaN Heterojunction Field Effect Transistor (HFET) based Monolithic Microwave Integrated Circuit (MMIC) switch. Lattice-matched AlInN/GaN heterostructures with indium contents of ∼17% exhibit a very large conduction band discontinuity, ΔEC, of 1.7 eV. This large discontinuity results in 2DEG densities as high as 4.7×1013 cm−2 [1] and electron mobilities as high as 1617...
We have developed a solution-grown ZnO process, and scaled it up to roll-to-roll (RTR) pilot production. We have fabricated Ag/ZnO based back reflector on stainless steel web using the solution grown ZnO process. The process has been optimized to attain good device characteristics on thin film, amorphous silicon alloy (a-Si:H) based multijunction solar cells. The surface morphology and crystallographic...
The purpose of this study is to develop a patient-specific dosimetry estimation system in nuclear medicine examination using a SimSET-based Monte Carlo code. We added a dose deposition routine to store the deposited energy of the photons during their flights in SimSET and developed a user-friendly interface for reading PET and CT images. Dose calculated on ORNL phantom was used to validate the accuracy...
An experimental investigation on the laser performance of an α-oriented Tm,Ho: YAIO3 crystal end-pumped by a wavelength tunable Ti:Sapphire laser is presented in this paper. Single- and dual-wavelength operations of Tm,Ho:YAIO3 lasers have been investigated in detail. Maximum output powers of 890mW at 2119nm, 836mW at 2103nm and 487mW at 2130nm for the α-oriented Tm,Ho:YAIO3 crystal have been obtained,...
Microgrid has two typical working modes: grid-connected mode and islanded mode. The transfer between these two modes should be seamless. In a microgrid that uses master-slave strategy to avoid circumfluence in the islanded mode, to control the master converter's voltage is to control the microgrid voltage. Considering this, the master converter in this paper works as a voltage-controlled inverter...
This paper addresses the problem of Through-the-Wall Radar Imaging (TWRI) using the Multiple-Measurement Vector (MMV) compressive sensing model. TWR image formation is reformulated as a compressed sensing (CS) problem, seeking a sparse representation in the spatial domain. In traditional CS-based through-the-wall radar imaging (TWRI) methods, the measurement matrix is vectorized so that a single measurement...
Graphene and its derivatives (graphite, CNT) have very high conductivity and critical current density higher than 108 A/cm2, which can be utilized in interconnect applications. Theoretically, a doped graphene is predicted to have better performance than Cu as an interconnect conductor. However, the feasibility of graphene interconnect has not been experimentally examined systematically. In this paper,...
In this paper, we consider a single-user communication system, where an energy harvesting transmitter communicates with a receiver over a fading wireless channel. We design adaptive transmission policies that adapt to the random energy arrivals at the transmitter and random fluctuations in the channel, in order to maximize the average number of bits transmitted by a finite deadline T. We solve for...
We describe a technique for segmenting individual prostatic glands in hematoxylin-and-eosin stained prostatic tissue images. The method begins with image artifact correction, then segments the image into four tissue components using principal component analysis and k-means clustering, and finally identifies glands using a region-growing algorithm. We calculated the average gland size to distinguish...
The rapid commercialization of the IEEE 802.11n WLAN standard has increased the demand for higher data-rate and longer-range fully integrated MIMO SoCs that are backward-compatible with legacy IEEE 802.11a/b/g networks. This paper introduces a 3-stream, 3x3 MIMO WLAN SoC that utilizes three antennas to improve throughput, range, and link robustness. This chip integrates three dual-band transceivers,...
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