Page 58 - Antennas for Base Stations in Wireless Communications

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Chapter

Base Station Antennas for

Mobile Radio Systems

Brian Collins
BSC Associates Ltd. and Queen Mary, University of London

As well as their obvious function of providing a link between a base sta-
tion and a mobile station, base station antennas provide an essential
and increasingly important tool for the control of frequency re-use and
the optimization of channel capacity in a mobile radio network. In this
chapter, we examine the way in which these considerations contribute
to the specification of the performance parameters required and the
engineering means by which these parameters can be provided.
The descriptions are of general application to many frequency bands,
so to avoid tedious repetition, the following bands will be defined and
usually referred to by the short names shown. In the context of multi-
band arrays, 850-MHz and 900-MHz bands will be referred to as the
low band and 1710–2170-MHz as the high band. The nomenclature for
base stations and mobile stations differs between air interface specifica-
tions, but for convenience the terms base station (BS) and mobile station
(MS) will be used here without implying reference to any particular air
interface. To avoid repetition, the following comments apply throughout
this chapter:
■ Reciprocity The principle of reciprocity applies to most of the per-
formance parameters of an antenna. Gain, radiation pattern, effi-
ciency, and many other characteristics have the same value whether
an antenna is transmitting or receiving a signal, so in the discussion
that follows the direction of transmission is chosen to suit the simplest
understanding of the phenomena described.

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