AN FRANCISCO, Nov. 3 — A start-up company plans to announce new antenna technology on Monday that it says can expand the limits of a popular wireless Internet format, providing access to hundreds or even thousands of portable computer users at distances of more than 2,000 feet within buildings and about four miles outdoors.
The antenna uses the 802.11 technical standard, also known as Wi-Fi, which is currently limited to providing wireless Internet access to several dozen users within a few hundred feet of the transmitter. Wi-Fi is increasingly common in offices, airports, places like Starbucks shops and even in a growing number of households.
Executives for the start-up company, Vivato, based here, said they expected their technology to be especially suited to office buildings because it would enable so many more people to use a single Wi-Fi Internet connection simultaneously.
"We will change the way people think about the physics of Wi-Fi," said Ken Beba, the chairman and chief executive of Vivato, which is across from the Pac Bell Park baseball stadium.
The company does not plan to formally introduce its product or discuss pricing until the first quarter of next year. The announcement on Monday, instead, will be devoted to discussing the technology, which employs an antenna shaped like a large picture frame, about three feet by four feet and about three inches thick.
The Vivato technology, which stems from 1950's research for so-called phased-array antennas for military applications, makes it possible to electronically steer numerous radio beams from a single point. Focusing the beams increases their signal strength, and using large numbers of them greatly increases the antenna's traffic capacity.
"Most people don't understand it, but the antenna is the most important part of any radio," said Craig Mathias, president of the Farpoint Group, a wireless industry technical consultant.
Analysts who were briefed on Vivato's plans said that the technology was intriguing, but they warned that it had yet to be proved commercially —particularly in the corporate, or enterprise, settings that the company sees as its main targets.
"The entire market is scrambling to get some traction with the enterprise customers," said Sara Kim, a wireless industry analyst at the Yankee Group in Boston.
The idea of adding capabilities to antenna systems is not new for either wireless data or voice communications. Silicon Valley companies now pursuing such ideas include ArrayComm and SkyPilot.
But analysts say Vivato is the most aggressive in making use of the inexpensive Wi-Fi capabilities that are already part of many desktop and portable computers, as well has hand-held Palm and other devices. Most other more advanced systems in use today require adding a special networking device to the user's computer.
"The key magic here is our ability to talk to the standard 802.11 clients," Mr. Beba said.
Vivato's antenna is meant to be placed in the corner of a large office and used to provide wireless service throughout a building. In contrast to many other companies that are trying to extend the range of 802.11 by creating meshes of access points, Vivato takes a more centralized approach by transmitting a series of beams from the antenna.
Until now, many corporations have shied away from Wi-Fi technology because it can be vulnerable to eavesdropping. Silicon Valley is awash in stories of "war driving" — the practice by hackers or joy riders who travel about detecting wireless networks that have not been protected with encryption software that scrambles the signals.
The Wi-Fi industry plans to introduce a new security design next week that it says will solve the most critical flaws in the existing format. And Vivato executives said that the sensitivity of their antenna technology would make the system ideal for detecting potential intruders.
The company's initial audience is corporate buyers, but extending the geographic range of wireless Internet networks could potentially open the market to Internet service providers looking for alternatives to high-speed cable modems and telephone-line DSL connections.
So far, many attempts by Internet service providers to use wireless connections have failed because of the high cost of the equipment and the need to pay for costly installation for end users.
But Vivato said that its antenna technology would be a viable alternative to the first generation of wireless systems deployed by service providers like Sprint, as well as a second generation of technologies now being introduced by ArrayComm, Beamreach Networks, Nokia, Navini, Flarion, Malibu Networks, MeshNetworks, Motorola, NextNet Wireless and others.
