Special Coverage

Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research
Small Robot Has Outstanding Vertical Agility
Smart Optical Material Characterization System and Method
Lightweight, Flexible Thermal Protection System for Fire Protection

Fast Electromechanical Switches Based on Carbon Nanotubes

Potential applications include computer memory, cell phones, and scientific instruments. Electrostatically actuated nano- electromechanical switches based on carbon nanotubes have been fabricated and tested in a continuing effort to develop high-speed switches for a variety of stationary and portable electronic equipment. As explained below, these devices offer advantages over electrostatically actuated micro- electromechanical switches, which, heretofore, have represented the state of the art of rapid, highly miniaturized electromechanical switches. Potential applications for these devices include computer memories, cellular telephones, communication networks, scientific instrumentation, and general radiation-hard electronic equipment.

Posted in: Briefs, Electronics & Computers, Electronic equipment, Microelectromechanical devices, Switches, Nanotechnology


Architecture for a High-to-Medium-Voltage Power Converter

High input voltage would be divided evenly among many converter blocks. A power converter now undergoing development is required to operate at a DC input potential ranging between 5.5 and 10 kV and a DC output potential of 400 V at a current up to 25 A. This power converter is also required to be sufficiently compact and reliable to fit and operate within the confines of a high-pressure case to be lowered to several miles (≈5 km) below the surface of the ocean. The architecture chosen to satisfy these requirements calls for a series/parallel arrangement of 48 high-frequency, pulse-width-modulation (PWM), transformer-isolation DC-to-DC power converter blocks.

Posted in: Briefs, TSP, Electronics & Computers, Architecture, Voltage regulators, Marine vehicles and equipment


24-Way Radial Power Combiner/Divider for 31 to 36 GHz

A unique design affords high bandwidth with high order of combining. The figure shows a prototype radial power-combining waveguide structure, capable of operation at frequencies from 31 to 36 GHz, that features an unusually large number (N = 24) of combining (input) ports. The combination of wide-band operation and large N is achieved by incorporating several enhancements over a basic radial power-combiner design. In addition, the structure can be operated as a power divider by reversing the roles of the input and output ports.

Posted in: Briefs, TSP, Electronics & Computers, Waveguides, Product development


Three-Stage InP Submillimeter-Wave MMIC Amplifier

Submillimeter-wave amplifiers can enable more sensitive receivers for earth science, planetary remote sensing, and astrophysics telescopes. A submillimeter-wave monolithic integrated- circuit (S-MMIC) amplifier has been designed and fabricated using an indium phosphide (InP) 35-nm gate-length high electron mobility transistor (HEMT) device, developed at Northrop Grumman Corporation. The HEMT device employs two fingers each 15 micrometers wide. The HEMT wafers are grown by molecular beam epitaxy (MBE) and make use of a pseudomorphic In0.75Ga0.25As channel, a silicon delta-doping layer as the electron supply, an In0.52Al0.48As buffer layer, and an InP substrate. The three-stage design uses coplanar waveguide topology with a very narrow ground-to-ground spacing of 14 micrometers. Quarter-wave matching transmission lines, on-chip metal-insulator-metal shunt capacitors, series thin-film resistors, and matching stubs were used in the design. Series resistors in the shunt branch arm provide the basic circuit stabilization. The S-MMIC amplifier was measured for S-parameters and found to be centered at 320 GHz with 13–15-dB gain from 300–345 GHz.

Posted in: Briefs, TSP, Electronics & Computers


Solid-State High-Temperature Power Cells

These cells can be used in batteries for high-temperature applications. All-solid-state electrochemical power cells have been fabricated and tested in a continuing effort to develop batteries for instruments for use in environments as hot as 500 °C. Batteries of this type are needed for exploration of Venus, and could be used on Earth for such applications as measuring physical and chemical conditions in geothermal and oil wells, processing furnaces, and combustion engines.

Posted in: Briefs, TSP, Electronics & Computers


Direct Metal Laser-Sintering of Titanium

DMLS titanium parts can be used in aerospace and medical applications. During the first decade of direct metal laser-sintering (DMLS), the metals employed were generally ones developed specifically for DMLS, rather than those used in traditional metalforming methods. But in recent years, the range of available powder metals and the production quality of DMLS parts have advanced considerably, driving new interest in rapid manufacturing.

Posted in: Briefs, Manufacturing & Prototyping, Lasers, Powder metallurgy, Titanium


Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

A new fabrication strategy for valve manifolds uses flexible, durable materials. A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013.

Posted in: Briefs, Manufacturing & Prototyping


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