Intelligent Machines

From the Labs: Information Technology

New publications, experiments and breakthroughs in information technology–and what they mean.

Filtering Terahertz Frequencies
A new type of filter could make extremely fast wireless ­communication devices possible

The spacing between the holes in this metal film determines the wavelength of terahertz radiation that passes through.

Source: “Transmission Resonances through Aperiodic Arrays of ­Subwavelength Apertures”
Tatsunosuke Matsui et al.
Nature 446: 517-521

This story is part of our July/August 2007 Issue
See the rest of the issue

Results: Researchers at the University of Utah have designed a perforated stainless-steel film that restricts the frequencies of terahertz radiation passing through it. In effect, the film is a simple terahertz filter, a potential precursor to terahertz communication devices.

Why it matters: The filter could provide a way to control terahertz radiation in future wireless devices. Though still years from commerciali­zation, wireless networks that use this radiation–which technically ranges from about 100 gigahertz to 10 terahertz–could carry much more data than existing networks, speeding up wireless Internet links by a factor of a thousand. Terahertz transmission would be most useful for relatively short-range communication–between devices in a room, for example.

Methods: The new filter is made of stainless steel with arrays of holes in it. When terahertz radiation passes through the holes, it propagates as a terahertz wave with a few narrow frequency bands; the frequencies emitted depend on the spacing of the holes. Where previous studies had assumed that uniform arrays were necessary for terahertz filtration, the Utah researchers used irregular arrays of perforations, allowing several different frequencies of radiation to pass through the filter at the same time.

Next steps: The researchers will now try to build terahertz communication devices based on the principles demonstrated by their work thus far.

Touch Screens That Vibrate
A touch screen that offers tactile feedback could help people type more accurately on PDAs

Source: “Tactile Feedback for Mobile Interactions”
Stephen Brewster et al.
CHI 2007, April 28-May 3, 2007, San Jose, CA

Results: Researchers at the University of Glasgow, Scotland, have found that mobile phones and PDAs whose touch screens vibrate when touched promote better typing and are easier to use than nonvibrating devices. In the lab, subjects made 22 percent fewer typing errors and were able to correct 48 percent more of their errors when they used vibrating PDAs. Those bene­fits diminished somewhat when subjects were tested on a moving train.

Why it matters: More and more phones are being designed to let users enter numbers and letters using touch screens. But virtual buttons on a flat display simply don’t feel like buttons, and people using them are prone to errors. Some researchers suspect that adding tactile cues–such as vibrations when a screen is touched–will improve the interface.

Methods: To the backs of several PDAs, the researchers attached actuators that caused the gadgets to vibrate when their touch screens were tapped. The vibration was smooth when a subject pressed a button correctly but rougher if the subject made a mistake, such as tapping a button twice. Twelve study participants, who had never used PDAs before, were given poems to type into the devices as accurately and quickly as possible, both in the lab and on a moving train.

Next steps: The group is exploring additional ways of using actuators in mobile devices. For example, actuators at the four corners of a device could denote the progress of a file download: the actuators would vibrate in sequence until the download was complete.

Become an MIT Technology Review Insider for in-depth analysis and unparalleled perspective.

Subscribe today

Uh oh–you've read all of your free articles for this month.

Insider Premium
$179.95/yr US PRICE

More from Intelligent Machines

Artificial intelligence and robots are transforming how we work and live.

Want more award-winning journalism? Subscribe to Insider Premium.
  • Insider Premium {! insider.prices.premium !}*

    {! insider.display.menuOptionsLabel !}

    Our award winning magazine, unlimited access to our story archive, special discounts to MIT Technology Review Events, and exclusive content.

    See details+

    What's Included

    Bimonthly magazine delivery and unlimited 24/7 access to MIT Technology Review’s website

    The Download: our daily newsletter of what's important in technology and innovation

    Access to the magazine PDF archive—thousands of articles going back to 1899 at your fingertips

    Special discounts to select partner offerings

    Discount to MIT Technology Review events

    Ad-free web experience

    First Look: exclusive early access to important stories, before they’re available to anyone else

    Insider Conversations: listen in on in-depth calls between our editors and today’s thought leaders

You've read all of your free articles this month. This is your last free article this month. You've read of free articles this month. or  for unlimited online access.