T-Waves May Offer Just Right Choice

By Peter Coffee  |  Posted 2002-05-20 Print this article Print

Wireless communication forces us to bridge the "goldilocks gap": the expensive territory that lies between two inexpensive but unattractive extremes.

Wireless communication forces us to bridge the "goldilocks gap": the expensive territory that lies between two inexpensive but unattractive extremes.

With this months reported successful tests, in Italy, of the first microscopic, solid-state, terahertz laser, we can hope that we may soon be offered a wireless menu that includes the choice "just right."

At one extreme, radio has long used wavelengths of tens or hundreds of meters, including the bands below 30MHz (longer than about 10 meters), ironically called short waves and once thought to be above the frequency range of value for practical communications.

After all, at wavelengths of 200 meters or more, stations could count on ground-wave propagation to follow the curve of the earth; short-wave experimenters, in contrast, exposed themselves to the vagaries of "skip" propagation that relied on the ionosphere to bounce transmitted waves back to the surface.

Unfortunately, these debates took place when a symphony orchestra concert represented high-bandwidth content. Even FM-quality audio demands only the equivalent of about 100,000 bits per second, which we can easily squeeze even into a channel width of only tens of kilohertz. The problem is that there are only several dozen such channels in the wavelength range from 200 meters to infinity—even one Ethernet channel is out of the question.

Microwaves, with much more bandwidth to spare at their centimeter wavelengths, might seem to be at the other extreme, but theyre still on the near side of the gap—and all the wavelengths from short wave up through microwave are hotly contested territories, even if microwaves do perform better for cooking than for bad-weather communication. Think about energy absorption by water molecules.

The far side of the Goldilocks gap lies in the infrared and visible-light wavelengths, a few hundred nanometers or shorter. Infrared and light waves are really cheap to produce, but theyre readily blocked by even a sheet of paper.

Wouldnt it be nice to have something thats just right?

Thats why people are so excited about terahertz waves (T-waves for short), which readily penetrate even concrete. Expect to hear more about this next generation of wireless technologies.

Tell me about your wireless plans at peter_coffee@ziffdavis.com.

Peter Coffee is Director of Platform Research at salesforce.com, where he serves as a liaison with the developer community to define the opportunity and clarify developers' technical requirements on the company's evolving Apex Platform. Peter previously spent 18 years with eWEEK (formerly PC Week), the national news magazine of enterprise technology practice, where he reviewed software development tools and methods and wrote regular columns on emerging technologies and professional community issues.Before he began writing full-time in 1989, Peter spent eleven years in technical and management positions at Exxon and The Aerospace Corporation, including management of the latter company's first desktop computing planning team and applied research in applications of artificial intelligence techniques. He holds an engineering degree from MIT and an MBA from Pepperdine University, he has held teaching appointments in computer science, business analytics and information systems management at Pepperdine, UCLA, and Chapman College.

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