Page 20 - Antennas for Base Stations in Wireless Communications

Introduction xix

GSM, CDMA, GPRS, EDGE,
UMTS, HSDPA/HSUPA, LTE

WiMAX

WiFi
UWB, ZigBee
Bluetooth
RFID
NFC

WPAN (Wireless personal area network)
WLAN (Wireless local area network)

WMAN (Wireless metropolitan area network)

WWAN (Wireless wide area network)

Figure 1 Coverage of modern personal wireless networks

Our lifestyle has changed significantly compared to 20 years ago.
Besides the proliferation of mobile phones, wireless communication
technologies have penetrated many aspects of life from business to
social networks to healthcare and medical applications. A variety of
wireless communication systems are now available to connect almost
all people and premises, as shown in Figure 1.
In these systems, antennas play a vital role as one of the key compo-
nents or subsystems. The rapid proposal of new applications has also
spurred strong demands for new high-performance antennas. Although
the fundamental physical principles of antennas have not changed,
antenna engineers have been experiencing the rapid advancement of
antenna technologies. For example, antenna technologies for the ter-
minals and base stations in mobile communications have changed
remarkably since the first mobile phones, which had long whip anten-
nas, appeared in the market, as detailed in Table 1.
Conventionally, an antenna or array is designed as a radiating RF
component. By optimizing the radiators’ shapes or configurations, or
by combining different radiating elements, the antenna or array will
achieve the performance needed to meet system requirements. Such a
methodology has been used for a long time in the design of commercial