TechBlog

Applied scientists at Harvard University in collaboration with researchers from the German universities of Jena, Gottingen, and Bremen, have developed a new technique for fabricating nanowire photonic and electronic integrated circuits that may one day be suitable for high-volume commercial production.

Fabrication technique could yield low-cost, scalable nanowire photonic and electronic circuits

Spearheaded by graduate student Mariano Zimmler and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, both of Harvard’s School of Engineering and Applied Sciences (SEAS), and Prof. Carsten Ronning of the University of Jena, the findings will be published in Nano Letters. The researchers have filed for U.S. patents covering their invention.

Continue reading ‘Scientists Demonstrate Method for Integrating Nanowire Devices Directly onto Silicon’ »

Lab-on-a-Chip

Color coding: This prototype of a new paper diagnostic test from Harvard University analyzes the glucose (left well) and protein (right well) content of urine; the top well is a control for the glucose assay. The beige part of the test paper has been treated with a hydrophobic polymer that channels the liquid into the wells. In this test, the paper was dipped in an artificial urine solution that contained glucose and a protein extracted from cow blood.

By taking advantage of the natural movement of liquid through paper, researchers at Harvard’s Whitesides Research Group may have found a way to make microfluidics technology much cheaper. The result could be disposable diagnostic tests simple and abundant enough for use in the developing world.

The field of microfluidics deals with the precise manipulation of tiny quantities of liquid. One of its most promising applications is the so-called lab-on-a-chip, which can work with much smaller fluid samples than larger devices require, potentially allowing for more portable diagnostic tools. But existing microfluidic chips are generally made from comparatively expensive materials like silicon, glass, or plastic and have tiny pumps and valves that can be difficult to manufacture.

Continue reading ‘Lab-on-a-Chip Made of Paper’ »

Antennas serve as transducers between electromagnetic waves traveling in free space and guided electromagnetic signals in circuits. As such, they play a critical role in the performance of wireless communication systems. With the proliferation of mobile wireless services that deliver voice and/or data in smaller and smaller devices, the task to design an antenna for a portable unit that meets not only operational requirements but also aesthetic and packaging restrictions is becoming more and more challenging. As result, engineers rely on a combination of theory, simulation, and experimental investigation to arrive at a design that meets all the demands of a particular application.

Basic Antenna Parameters

The basic parameters of antenna are impedence, mismatch and ohmic efficiency, radiation pattern and polarization, directivity, gain and equivalent isotropically radiated power, and effective height and aperture. In addition, celebrated Friis equation is and equations for the signal to noise ratio (SNR) of an antenna and source-field relationships are also important.For a more detailed treatment of the material pointed out here, the reader is referred to “A HANDBOOK OF ANTENNA IN WIRELESS COMMUNICATION” OF CRC Press by Lal Chand Godara.

Continue reading ‘Future Antennas Will be Flat’ »

The U.S. Air Force Research Laboratory has authorized Raytheon Company to demonstrate target recognition technology designed to increase protection for ground forces without compounding risk to an aircraft stalking enemies who threaten those forces.

First in a laboratory and then aloft, the company expects to show how its Air-to-Ground Radar Imaging II program would permit aircraft at a safe distance to detect, track and target hostile forces in motion on the ground.

The laboratory demonstration is expected in autumn 2008, followed by a flight next spring aboard a Raytheon test aircraft.

Continue reading ‘Raytheon Develops Technology To Help Aircraft Protect Ground Forces’ »

In the wake of personal navigation devices’ success, cellular carriers have started to offer on-board and off-board navigation solutions, as well as a range of LBS (Location Based Services) such as friend finder and local search on GPS handsets. Community and social-networking-related functionality, such as the sharing of POIs (Points of Interest) and geo-tagged pictures, is also becoming popular and is expected to boost GPS-enabled handset uptake as carriers, handsets manufacturers, and service providers look to capitalize on the LBS trend.

“While most CDMA handsets are already GPS-enabled and GPS is set to become a standard feature in GSM smartphones, GSM feature phones are next on the agenda to be equipped with GPS technology,” says ABI Research principal analyst Dominique Bonte. “GPS chipset vendors increasingly target handsets, looking for new markets and spurred on by the recent dramatic growth of personal navigation devices.”

However, as GPS begins to penetrate lower-end phones, the cost, power consumption, and footprint of GPS chipsets will have to be further reduced. This will be made possible by single chipset technology and the emergence in 2009 of combination chips integrating GPS, Bluetooth, and Wi-Fi all on one die. Major silicon vendors such as Broadcom, NXP, and Atheros are well positioned to develop such solutions following the acquisition of GPS chipset vendors Global Locate, GloNav, and u-Nav, respectively.

Continue reading ‘More Than 550 Million GPS-Enabled Handsets Will Ship By 2012’ »

It seems size does matters after all. But for flying snakes, smaller is better, according to University of Chicago researchers. Scientists described the effects of size and behavior of flying snakes, and found that the smaller animals were better gliders.

“Despite their lack of wing-like appendages, flying snakes are skilled aerial locomotors,” said lead scientist and author Jake Socha, Ph.D., who has been studying these unique creatures for the past eight years.

Chrysopelea paradisi, commonly known as the paradise tree snake. (Copyright Jake Socha / Courtesy of University Of Chicago Medical Center

Continue reading ‘University Of Chicago Researchers Reveal Secrets Of Snake Flight’ »

Taking a page out of a science fiction story, researchers from the Woods Hole Oceanographic Institution (WHOI) and Webb Research Corporation (Falmouth, Mass.) have successfully flown the first environmentally powered robotic vehicle through the ocean. The new robotic “glider” harvests heat

WHOI associate scientist Dave Fratantoni (background) and WHOI postdoctoral scholar Benjamin Hodges prepare to lower the thermal glider into the ocean in December 2007. (John Lund, Woods Hole  Oceanographic Institution)

Continue reading ‘Environmentally Powered Robotic Vehicle’ »

A team led by Boeing has been selected by the Defense Advanced Research Projects Agency (DARPA) to demonstrate initial technologies for a new spacecraft system architecture concept.A $12,891,049 cost-plus-fixed-fee, 12-month Phase 1 contract was awarded to Boeing Advanced Systems to research, design, develop and test DARPA’s Future, Fast, Flexible, Fractionated, Free-Flying Spacecraft United by Information Exchange (System F6) space technology and demonstration program.

The DARPA System F6 is based on a concept whereby a group of spacecraft operate together wirelessly as a single unit to enable flexible data sharing and distributed processing that will allow cooperative communications among the spacecraft. This concept of multiple spacecraft operating together to perform a mission similar to that of a single larger spacecraft is known as “fractionation.”

“We believe the fractionation spacecraft concept proposed by our team can be a game-changer that could provide the high degree of flexibility needed for responsive space missions,” said Bob Friend, director for Boeing Operationally Responsive Space.

Continue reading ‘Boeing Selected To Design DARPA Space System’ »

WRIGHT-PATTERSON AIR FORCE BASE, Ohio (AFPN) — Engineers here are testing a new kind of transparent armor — stronger and lighter than traditional materials — that could stop armor-piercing weapons from penetrating vehicle windows.

The Air Force Research Laboratory’s materials and manufacturing directorate is testing aluminum oxynitride — ALONtm — as a replacement for the traditional multi-layered glass transparencies now used in existing ground and air armored vehicles.

The test is being done in conjunction with the Army Research Laboratory at Aberdeen Proving Grounds, Md., and University of Dayton Research Institute, Ohio.

Continue reading ‘US Air Force testing new transparent armor’ »

In a significant breakthrough, researchers at Northwestern University’s Center for Quantum Devices (CQD) have demonstrated visible-blind avalanche photodiodes (APDs) capable of detecting single photons in the ultraviolet region (360-200 nm).

Previously, photomultiplier tubes (PMTs) were the only available technology in the short wavelength UV portion of the spectrum capable of single photon detection sensitivity. However, these fragile vacuum tube devices are expensive and bulky, hindering true systems miniaturization.

The Northwestern team, led by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science at Northwestern’s McCormick School of Engineering, became the world’s first to demonstrate back-illuminated single photon detection from a III-nitride photodetector. These back-illuminated devices, based on GaN compound semiconductors, benefit from the larger ionization coefficient for holes in this material. The back-illumination geometry will facilitate future integration of these devices with read-out circuitry to realize unique single-photon UV cameras. Towards that end, the team has already demonstrated excellent uniformity of the breakdown characteristics and gain across the wafer.

Continue reading ‘Tiny Avalanche Photodiode Detects Single UV Photons’ »