Isolated Antenna Gets the Range

By Eric Griffith

June 10, 2002

Ethertronics' new embedded antenna can reduce client PC Card size and may increase the range of an 802.11-based client by 30%.

PHILADELPHIA, PA -- Today at the 802.11 Planet Conference & Expo , wireless client-antenna maker Ethertronics of San Diego will announce the company's GY embedded antenna, a low profile, multi-band antenna suitable for cell phones, Bluetooth adapters, and 802.11-based client PC Cards.

Bruce Gray, CEO of Ethertronics, spoke to us at length about the company, its antennas, and the technology behind them.

"Whatever sticks out of a PC Card now, we can reduce that by a full quarter inch," Gray says. The GY antenna supports both 2.4GHz and 5GHz, making it perfect for multimode 802.11a/b clients. "We are concerned with frequency, not protocol. The money is in 802.11a/b."

The GY, along with Ethertronics' other antennas (the smaller MI blade design for cell phones, and the recently announced JI for larger form factor devices), are all isolated antennas -- they do not use the standard, non-isolated Planar Inverted-F Antenna (PIFA) found in most NICs.

Gray claims that in their tests, 802.11b network range increased from 50 to 94% using a GY antenna (depending on the direction of the signal; it's less when passing through a notebook computer), compared to the best-ranged PC Card they could find on the market. Ethertronics expects as much as a 30% increase may be available to end users with an isolated GY antenna.

"The way an antenna works, it establishes an electrical field, and every PC card on the market today makes the field between the element and the ground plan of the printed circuit board in the card," Gray explains. "That is the non-isolated antenna -- it actually interacts with the circuit board. The downside is, you are making an electromagnetic field across that board, so every component is a radiation source...half the energy is wasted by radiating the printed circuit board itself. Any radiation made in the laptop body is absorbed by the laptop and goes nowhere.

"The GY is a fully isolated antenna -- the electromagnetic field is on the antenna, and does not interact with the circuit board."

Because of its size ("double the thickness but half the diameter of a dime" or about 3mm thick), the GY is targeted at PC Cards, Mini-PCI cards, and USB/dongle-type adapters.

"We tune it to the enclosure it goes inside of. Everything we ship is semi-customized," says Gray. This customization with smaller, isolated antennas on the card means the PC Card WLAN NIC will not stick out as far from the laptop, meaning less potential to break off.

Bruce Gray, CEO of Ethertronics, will be speaking on the topic "Optimizing WLAN Coverage with High Performance Antennas" at the 802.11 Planet Conference & Expo in Philadelphia on June 11, 2002.

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