Wireless Systems Design

Antenna Aims To Improve In-Building Coverage

Mobile subscribers are quickly catching on to the convenience of wireless-local-area networks (WLANs). They revel in being able to open up their laptops and access the Internet at airports, coffeshops, and many other locations. In response to this user increase, the locations that have already implemented 802.11b voice and data networks—like airports and hospitals—are now upgrading their networks to provide even more functionality and coverage. Many locations are planning a move to IEEE 802.11a.

To help them upgrade their networks and guarantee better performance, Centurion Wireless Technologies, Inc. (www.centurion.com) has released the 5-GHz Sphere antenna. This offering is specifically geared toward in-building wireless communications. It works to overcome many of the problems faced in indoor environments. For instance, network signals must permeate walls, wiring, furniture, equipment, and more. In addition, the user's mobility must be taken into account.

To combat these issues, this low-profile, omnidirectional antenna provides wide-angle coverage. It therefore promises to provide reliable, widespread coverage for broadband-Internet and other IEEE 802.11a applications in public spaces, such as hospitals and office buildings.

Compared to traditional dipole antennas, the omnidirectional Sphere claims a significant gain improvement. In crowded wireless environments, this improved gain leads to more widespread indoor coverage. The 5-GHz Sphere also boasts high performance. It has a peak gain of 5 dBi and an impedance of 50 Ohms. The antenna contains a linear polarization and operates at a temperature range of −40° to 70°C.

This antenna also caters to the cosmetic requirements of an indoor environment. It's practical to think that an indoor WLAN antenna must be small, as it should not get in the way of anything. However, it also should refrain from being an eyesore. To blend into virtually any public environment, the Sphere comes enclosed in a small case. It easily attaches to a ceiling-tile grid with a standard metal clip.

Antenna developments like the Sphere pose minimal interference on the building's interior. Yet they have a huge impact on the users who want to access higher-data-rate applications. Thanks to innovations from companies like Centurion, a data-heavy WLAN experience may soon be within reach.

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