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Chapter 5 197

Introduction

Look around, and you discover that antennas became the vital part of our everyday life being
practically everywhere. They are in our pocket cell phones, Wi-Fi connected smart home
devices, broadcast, and wireless communication systems, radars, garage door openers, RFID
tags, remote baby monitors, missiles and smart bombs, etc. Nevertheless, by today probably 99
% of devices, systems, and services worldwide are still not interconnected, and we are
confronted with a daunting task of developing a broad range of antennas that enable wireless
communications on a truly massive scale.

There is a wide diversity of antenna realizations depending on increasingly complex and
dynamic EM signal environment, frequency band, weight-cost requirements, etc. Sometimes
the antenna design is so immense or complicated that we do not know how to start. Our advice
is to follow the old Latin proverb “Divide et Impera” or “Divide and Conquer” in English and
try the magic of decomposition. The central idea of decomposition or factoring methodology is
to break down a complex task into several smaller, simpler and more manageable, sub-tasks
that are easier to conceive, understand, program, solve, cheaper to produce. After that, using
an appropriate and efficient iterative algorithm, you can properly interconnect these solutions
and make progress toward the original problem. There are always various ways in which the
same problem can be cut apart and then reconstructed, which opens up plenty of room for
optimization and engineering creativity.

According to Encyclopedia Britannica, an antenna is the “…component of radio, television,
and radar systems that direct incoming and outgoing radio waves.” If so, the starting point of
any antenna design is the rigorous analysis of system specification describing the role of the
antenna in system performance. First of all, notice that any antenna is designated to convert the
energy of electric signals carrying the information into the energy of EM waves able to
propagate in free space. Subsequently, all the information must be delivered with minimal loss
and distortion to the receiving part of the system where the inverse transformation, EM waves
into electric signals, takes place. Therefore, an antenna as a device is the part of information
channel and must not limit the system information capacity. The use of proper antennas, with
appropriate radiation pattern, can improve the system performance, eliminate some unwanted
interfering signals and increase the quality of the signal reception and its processing. The typical
but not exhaustive set of antenna characteristics is listed in Table 5.1 and grouped into two
broad categories: electrical and provisionally named environment. The term “Depends” means
that the referred parameter may not play the primary role in some cases. Note that the comments
in this table reflects the authors’ opinion only and cannot be considered as a standard.
Table 5.1
Electrical Parameters Comments Environment Requirements Comments
System designation Operation temperature,
Critical humidity range, ocean salt Critical
water, etc.
Frequency of operation and Critical Mass Critical
EM spectrum compatibility