Antenna Hocus Pocus

When Kerry Greer talks to vendors, he gets some quizzical looks. He's trying to sell a new handset antenna his company developed, but most vendors aren't having any of it. And why should they? The antenna essentially hasn't changed since Guglielmo Marconi invented the first transmitter in the attic of his parents' Italian villa over a hundred years ago, and it's worked just fine ever since.

Greer is trying to convince customers that it's time to rethink the antenna, the only component of the cell phone not to undergo a major overhaul. He's no snake-oil salesman, though: He's an RF engineer, just like the people he's trying to reach. In fact, his name is on five of the 15 patents for the meander-line technology that Greer's company, Melbourne, Fla.-based SkyCross, is developing. Such technology enables handset antennas to operate in multiple wireless modes and at much greater efficiencies than current designs.

But as vice president of business development for SkyCross, Greer is spending less time in a lab coat and more time in a sportcoat, trying to explain to vendors how his company's 20-square-millimeter tablet will handle carriers' growing demands for greater power, efficiency and coverage.

“Vendors are very skeptical,” Greer said. “Phone manufacturers don't want to buy 60¢ antennas when they're getting by fine with 50¢ antennas. Ten cents doesn't seem like much — but when you're talking about millions of handsets, it adds up.”

Greer's gray AT&T Wireless phone looks like any other standard Nokia handset design of recent vintage — until he turns it over.

Then Nokia's trademark airbrushed contours give way to a clunky black box at the head of the phone. Greer has jury-rigged it with one of SkyCross' own antennas, and inside that tiny box is an array of copper squiggles attached to a ground plane, all of which looks more like the heating coils of a toaster than a complex piece of communications equipment.

The device essentially works like a tiny loop antenna, except the curvature and length of each meander line is precisely tuned to cellular frequencies. The end result is a compact, embedded antenna much more powerful than your standard di-pole.

“It's really all black magic,” Greer said with a grin. “The bottom line is we've created a very small, very efficient high-gain antenna using standard circuit board material.”

In fact, the antenna has improved gain on the order of 2.5 dB, which translates into almost twice the standard signal power. Higher signal strength translates into a stronger connection and fewer dropped calls; it also translates into greater range from the base station, which means more space between cell sites. And on CDMA-based systems, it translates into more users per cell: While TDMA-based networks transmit on fixed power levels, CDMA base stations dynamically control the transmit power of all handsets on the network. The higher the gain from an antenna, the more individual calls each base station can handle. And the antenna manages to boost signal power without any additional drain on battery power, Greer said.

Meander-line technology is nothing new itself; it's been used in military communications for years. In fact, SkyCross's patents are based upon original military designs for powerful non-protruding antennas designed for military vehicles and aircraft.

Venture capital firm Milcom launched SkyCross in May of 2000 to find commercial applications for these kinds of military innovations, and late last year Milcom executive Chris Morton took over as SkyCross' CEO to guide the company from its R&D phase to sales.

“If there's a whip antenna on a tank, after two hours in rough terrain you probably won't find an antenna there anymore,” Morton said. “While the commercial public's requirements for antennas may not be as stringent as the military's, we saw a lot of potential uses for the technology. The most obvious of those advantages is that standard antennas break off.”

SkyCross is not alone in its pursuit to revolutionize the antenna. Companies like Fractus are developing high-power antennas using fractal designs printed directly into circuit boards; this design has a theoretically infinite number of peaks and valleys in its structure, creating an infinite number of radiating surfaces and therefore a very powerful signal. Other firms are exploring ceramic technologies to create powerful miniature technologies for narrowband devices.

While admitting that such technologies have their merits, Greer said SkyCross believes its meander-line technology has an edge. While most ceramic and fractal technologies are narrowband and focus on specific frequencies, a single meander-line antenna can be tuned to multiple bands, Greer said.

SkyCross' antennas are now designed to work on the multiple bands in the U.S. and European wireless markets, picking up PCS and cellular signals with equal precision. There is technically no physical limitation on how many bands the antennas can accommodate if size is not a constraint — Greer said SkyCross has designed an ultra-wideband transmitter for PCMCIA cards that runs the entire gamut of frequencies between cellular (824 MHz) to Wi-Fi (2400 MHz), incorporating GPS and XM Satellite Radio and virtually everything in between.

Greer isn't discarding fractal and ceramic technologies, however, and SkyCross is exploring ways to incorporate aspects of both technologies in its antenna design. Ceramic processes could allow SkyCross to incorporate other components such as signal filters and diplexers into the antenna itself, and the company is looking into the possibility of printing its antennas directly into circuit boards.

So far, SkyCross has managed to bring a Wi-Fi product to market, capitalizing on the technology's high signal strength to boost network capacity and range. The company is still trying to make it in the wide-area world, though. And because vendors may be slow to realize the technology's advantages, Greer has begun taking his road show directly to carriers, whose ears perk up when he starts talking about increased capacity and network range.

If Greer can successfully make his case to the service providers who are writing the checks, vendors will follow. Already, SkyCross has entered into a joint development agreement with Korea's SK Telecom to create a CDMA/GPS antenna for SK Telecom's 3G networks. Greer hopes more of these relationships will follow.

“Antennas have not been seen as an important component in the design of wireless phones since they were created,” he said. “The industry believes there's just one type of design, which amounts to a coat hanger sticking out of the top of the phone. We're trying to overcome that mentality.”