Page 122 - Antennas for Base Stations in Wireless Communications

3
Chapter

Antennas for Mobile

Communications: CDMA,

GSM, and WCDMA

Ka-Leung Lau and Kwai-Man Luk

City University of Hong Kong

3.1 Introduction
The operating frequencies for 2G and 3G mobile communications fall
into the 820–960 MHz and the 1710–2170 MHz frequency bands. In
these lower microwave frequency ranges, antenna size is an issue for
both base station antennas and handset antennas. In general, we prefer
base station antennas that have a low profile and a streamlined struc-
ture. Otherwise, our living environment would be crowded with the
huge number of antennas for different systems and operators. Also for
aesthetic reasons, we prefer that a handset antenna be embedded in
the mobile phone cover.
Designing base station antennas is more challenging and interesting
than designing handset antennas, since more stringent requirements
are imposed on the performance of different base station antennas for
indoor and outdoor coverage.

3.1.1 Requirements for Indoor
Base Station Antennas
In indoor environments, such as shopping malls, parking garages, or air-
ports, integrated networks serving all mobile phone operators are com-
monly installed. For this implementation, very wideband or multiband
antennas are required. The gains of these antennas need not be too high.
In wall-mounted cases, the radiation pattern should be unidirectional

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