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Reference Guide
Cisco Aironet Antennas and Accessories
Overview
Executive Overview
This antenna reference guide explains issues and concerns about antennas used with a Cisco
®
Aironet
®
wireless
LAN system or wireless bridge system. It details deployment and design, limitations and capabilities, and basic
theories of antennas. This document also contains information about the Cisco antennas and accessories, as well
as installation scenarios, regulatory information, and technical specifications and diagrams of the available
antennas.
Overview of Antennas
Each Cisco Aironet radio product is designed to perform in a variety of environments. Implementing the antenna
system can greatly improve coverage and performance.
To optimize the overall performance of a Cisco wireless LAN, it is important to understand how to maximize radio
coverage with the appropriate antenna selection and placement. An antenna system comprises numerous
components, including the antenna, mounting hardware, connectors, antenna cabling, and in some cases, a
lightning arrestor. For a consultation, please contact a Cisco Aironet partner at:
http://tools.cisco.com/WWChannels/LOCATR/jsp/partner_locator.jsp.
Cisco partners can provide onsite engineering assistance for complex requirements.
Radio Technologies
In the mid-1980s, the U.S. Federal Communications Commission (FCC) modified Part 15 of the radio spectrum
regulation, which governs unlicensed devices. The modification authorized wireless network products to operate in
the industrial, scientific, and medical (ISM) bands using spread spectrum modulation. This type of modulation had
formerly been classified and permitted only in military products. The ISM frequencies are in three different bands,
located at 900 MHz, 2.4 GHz, and 5 GHz. This document covers both the 2.4- and 5-GHz bands.
The ISM bands typically allow users to operate wireless products without requiring specific licenses, but this will
vary in some countries. In the United States, there is no requirement for FCC licenses. The products themselves
must meet certain requirements to be certified for sale, such as operation under 1-watt transmitter output power (in
the United States) and maximum antenna gain or effective isotropic radiated power (EIRP) ratings.
The Cisco Aironet product lines utilize both the 2.4- and 5-GHz bands. In the United States, three bands are
defined as unlicensed and known as the ISM bands. The ISM bands are as follows:
●
900 MHz (902-928 MHz)
●
2.4 GHz (2.4-2.4835 GHz) - IEEE 802.11b
●
5 GHz (5.15-5.35 and 5.725-5.825 GHz) - IEEE 802.11a, HIPERLAN/1 and HIPERLAN/2. This band is also
known as the UNII band, and has three subbands: UNII1 (5.150-5.250 GHz), UNII2 (5.250-5.350 GHz), and
UNII3 (5.725-5.825 GHz)