Subject: [NEXTEL-1] The Black Magician of Antenna Design

From: NEXTEL-1
Date: Sun, 27 Jun 2004 13:34:34 -0400

The Black Magician of Antenna Design

By David Pescovitz
 Thursday June 24, 2004

Ham radio head Rob Vincent couldn't find an
antenna that fit outside his new house. Ten
years later, he's patenting a revolutionary new
antenna design with applications from AM radio
to cellular telephony

Rob Vincent couldn't let anything interfere with love, even interference
itself. In 1995, the ham radio buff moved in to his girlfriend's small
Rhode Island house to live happily ever after. But there was a hitch.
Her
small piece of property wasn't big enough for Vincent, his significant
other, and the 140-foot antenna he needed to reach his wireless buddies
around the world.

Dedicated to both his future wife and his hobby, Vincent spent nearly a
decade designing the antenna now standing in his backyard. The
40-foot-high
pole bests conventional antennas three times taller. This week, the
60-year-old inventor and his employer, the University of Rhode Island,
are
filing a patent on the technology. It's not just amateur radio
enthusiasts
that stand to gain, though. According to Vincent, his approach could
also
be used to double the range of walkie-talkies used by emergency crews,
free
our cityscapes of 300-foot AM radio towers, and perhaps even lead to a
"Dick Tracy wrist radio, with all the features."

"A small antenna with high efficiency and wide bandwidth is the Holy
Grail
of antenna design," says Vincent, a technician in the university's
physics
department. "According to current theory, you have to give up one of
those
to achieve the other two."

The theories may be due for an upgrade. As revolutionary as the work
claims
to be, it has the university's seal of approval. After Vincent showed
some
of his early results to several professors, the physics department
provided
him with office space and time to conduct his research. This year, he
received the university's 2004 Outstanding Intellectual Property Award.

However, not everyone is a believer. Threads of mostly polite inquiries
on
the TowerTalk amateur radio mailing list and other online discussion
boards
are punctuated with highly technical critiques of Vincent's claims and
even
a bit of downright mockery.

Vincent isn't phased though. The numbers don't lie, he says. He's
already
built dozens of antennas at one-third to one-ninth the size of their
traditional counterparts. He and his friends in the local ham radio
community tested designs in various locations, from rocky ground that's
brutal on performance to a salt marsh, ideal for transmission and
reception. Time and again, there was hardly any difference in efficiency
-- 
the ratio of the radiated power to the total input power -- between
Vincent's small prototypes and conventional full-size antennas at the
same
location.

"The people saying that I'm a snake oil salesman... will have to order a
great big plate of crow very soon," Vincent says.

For Vincent, the patent is the culmination of more than 40 years
twisting
dials. He was 14 when he earned his amateur radio license.

"I was always tinkering in the basement," he says. "I can still remember
my
poor father driving up after a hard day's work to see wires wrapped
around
the house."

Eventually, Vincent transformed his love for the wireless world into a
career. He worked for several decades in the radar division of Raytheon,
developing an acuity for electronics that fed his after-hours obsession.

Still, antenna design is very much a black art. Engineers draw from
well-established theories but ultimately success usually comes from a
methodology of build, test, repeat. With the birth of the personal
computer
came modeling programs that took out some, but not nearly all, of the
guesswork. Indeed, Vincent used one of these applications to design an
early prototype 21MHz-band antenna out of Plexiglass and copper. Just 18
inches tall, the antenna was 16 times smaller than commercial models
built
for that band.

On just five to ten watts of power, far less than the average amateur
operating power of 100 watts, the antenna enabled Vincent to connect
with a
station in Chile. He slowly cranked the power, unaware that outside the
antenna was melting. The minor setback proved to be a springboard in the
design process. His patent-pending approach uses a conventional
component
known as a load coil to spread the current more evenly along the antenna
mast.

"The technology is completely scalable," Vincent was quoted as saying in
a
technical article on the new design in EE Times
 (See
http://www.eetimes.com/at/news/showArticle.jhtml?articleID=21401977).
"Take the component values and divide them by two, and you get twice the
frequency; take all the component values and multiply them by two, and
you
are at half the frequency."

Now that the proof-of-concept is completed and patent is in process,
Vincent is designing models specifically-suited for the GHz bands of
cellular phones and radio frequency identification (RFID) systems. While
he
has no plans to start a company based on his innovation, he's eager to
consult with firms that license the technology.

"When I first started this project, the work was based on about 10
percent
theory and 90 percent black magic," Vincent says. "Now it's the other
way
around."

http://www.thefeature.com/article?articleid=100798&ref=1563669

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