2.1.1 Technologies in Mobile Communications[1]

Throughout the history of mobile communication systems, various kinds of mobile systems have been developed and commercialized. Among them, the largest and the most complex system is the mobile phone systems. Deployment of new systems other than the mobile phone systems is rapid in this decade. These systems aim mainly at data applications rather than telephone applications. The typical systems are wireless access systems (WAS) such as mobile wireless local area network (WLAN) and mobile worldwide interoperability microwave access (WiMAX) systems, which operate in the middle and long ranges. Other systems are mobile wireless systems (MWS) such as Bluetooth, near field communication (NFC) systems, including radio frequency identification (RFID; refer to Chapter 13) and ultra wide band (UWB; refer to Chapter 12), which generally operate in the short ranges. Whichever mobile systems are constructed, complete understanding of wave propagation, radio transmission, modulation/demodulation systems, channel control, and hardware device is essential. Extensive study of these concepts have been conducted. Since the onset of mobile phone services, the technologies concerned with mobile communications have matured enough to construct sophisticated and multifunctional systems, and the experience acquired through the operation of mobile phone systems for more than 40 years continues to enable engineers to effectively design and develop mobile systems other than mobile phones into commonly useful technology and experiences although every system, of course, needs particular considerations on its design, depending on specific requirements.

In designing antenna hardware, we must...