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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 217 records · Page 12

Demonstration of a Sub-Millimeter Wave Integrated Circuit (S-MMIC) using InP HEMT with a 35-nm Gate

In this paper, we present two single stage MMIC amplifiers with the first demonstrating a measured S21 gain of 3-dB at 280-GHz and the second demonstrating 2.5-dB gain at 300- GHz, which is the threshold of the sub-millimeter wave regime. The high-frequency operation is enabled by a high-speed InP HEMT with a 35-nm gate. This is the first demonstrated S21 gain at sub-millimeter wave frequencies in a MMIC.

millimeter - wave↗

Compact, Single-Stage MMIC InP HEMT Amplifier

A monolithic micro - wave integrated-circuit (MMIC) singlestage amplifier containing an InP-based high-electron-mobility transistor (HEMT) plus coplanar-waveguide (CPW) transmission lines for impedance matching and input and output coupling, all in a highly miniaturized layout as needed for high performance at operating frequencies of hundreds of gigahertz is described.

Pukala, David↗

Hybrid CMOS System-on-Chip / InP MMIC Systems for Deep-Space Planetary Exploration at mm-Wave and THz

This paper discusses the applicability of hybrid CMOS/InP-MMIC mm-Wave systems to remote sensing instrumentation for space exploration in Earth and Planetary science. We review the need for lower power and lighter weight instruments to accommodate the limited payload resources of exploration spacecraft, and then demonstrate how hybrid systems can address these challenges. An example hybrid CMOS-InP radiometer operating at 100 GHz is discoursed in detail including circuit & system design, interfacing and packaging techniques. Measurements are presented showing that the hybrid approach does not compromise instrument sensitivity.

Tang, Adrian↗

InP MMIC chip set for power sources covering 86-170 GHz

We will present a Monolithic Millimeter-wave Integrated Circuit (MMIC) chip set which provides high output-power sources for driving diode frequency multipliers into the terahertz range. The chip set was fabricated at HRL Laboratories using a 0.l-μm gatelength InAI/InGaAs/InP high electron mobility transistor (HEMT) process, and features transistors with an fmax above 600 GHz. The HRL InP HEMT process has already demonstrated amplifiers in the 60-200 GHz range. In this paper, these high frequency HEMTs form the basis for power sources up to 170 GHz.

Ngo, Catherine↗

Models and Measurements Quantify Photon Recycling, Charge-Carrier Diffusion and Photon Scattering Contributions to Photoluminescence in InP Nanowire Arrays

Nanowire arrays present many unique advantages for solar-to-chemical energy conversion. One possible advantage is that photon recycling between neighboring nanowires has the potential to increase solar energy conversion efficiencies. Here, in this work, we explore three underlying mechanisms of optical and electronic coupling between neighboring nanowires─incident photon scattering, photon recycling, and charge-carrier transport from the photoexcited nanowire to the neighboring nanowire via the underlying substrate─using single nanowire-level microscopy and spectroscopy measurements. We present a comprehensive analysis of light absorption and emission of a single nanowire at open circuit, and subsequent re-absorption and re-emission by a neighboring nanowire. We developed a novel correlated single nanowire microspectroscopy and widefield imaging methodology to spatially resolve photon communication pathways between neighboring nanowires and selectively image re-emitted and reflected photons. We developed unique multiphysics models to couple wave optics and semiconductor photophysics to especially isolate contributions from photon recycling and electronic transport to photon emission from neighboring nanowires. By systematically varying the morphologies of the nanowires modeled, we identified pathways to maximize photon recycling between neighboring nanowires. We concluded that the measured photoluminescence is more strongly influenced by the diffusion of charge carriers as compared to photon recycling in materials with moderate-to-large charge-carrier mobilities (>10 cm 2 V –1 s –1 ), and that photon recycling dictates photoluminescence intensity only when the charge-carrier mobility is low (<1 cm 2 V –1 s –1 ). The experimental and simulation platforms developed herein for photon management strategies can be leveraged by the semiconductor photocatalysis community to enhance solar-to-chemical conversion efficiencies in semiconductor nanowire arrays.

25 ENERGY STORAGE↗

Collection of relevant results obtained with the ERTS-1 satellite images by the Institute for Space Research (INPE), volume 2

The author has identified the following significant results. Soil resource studies in Brazil have concluded that: areas with agricultural activities appear surrounding urban centers; some areas are suffering a strong erosion action; there exist two drainage systems near Paraguai River and Parana River; and this region possesses great variety of soil types. It is possible to count the number of lakes and sluices as well as their superficial area using a channel 7 photographic enlargement. The great concentration of water bodies along the Jacui River determines the large rice crops. Data concerning regions around Teresina City, Presidente Prudente, Piracicaba City, Dourados, and Tres Marias Dam revealed several characteristics concerning the soil and water resources. Two basic maps were made of the natural vegetation distribution over central eastern Brazil from data ERTS-1 data. One map shows the drainage system, the road system, and cities; while the second shows the natural vegetation. It was possible to identify old reforestation, new reforestation, natural forest in flat lands, and natural forest in rolling lands from the ERTS images. Different pasture plant species could be identified by multispectral remote sensing. Data obtained along different wavelength bands provide essential data for the range manager to evaluate his range and to establish a suitable policy. Hydrographic mapping was done using the ERTS images.

Demendonca, F.↗

INPE LANDSAT system

There are no author identified significant results in this report.

Dejesusparada, N.↗