Multiband and Wideband Antennas for Mobile Communication Systems

摘要: The popularity of mobile communication systems has increased remarkably during the last decade and market demand still continues to increase. As a fundamental part these systems, antenna is one most important design issues in modern units. Although there are several similar definitions, an can be mainly described as device, which transforms electromagnetic waves radiating unbounded medium such air transmitting mode vice versa receiving mode. Because antennas dependent on frequency, they designed operate for certain frequency bands. rapid growth forced use novel base station applications (mobile phone, notebook computer, personal digital assistants (PDA), etc.). Earlier, were bands 2G (second generation) Digital Cellular System (DCS), Personal Communications Service (PCS) Global Mobile (GSM) networks. Currently, many GSM 900/1800/1900 (890-960 MHz 1710-1990 MHz); Universal Telecommunication Systems (UMTS) UMTS 3G expansion (1900-2200 2500-2700 Wi-Fi (Wireless Fidelity)/Wireless Local Area Networks (WLAN) (2400-2500 5100-5800 MHz) where list frequently used given Table 1 (Best, 2008). Conventionally, because single not at all communication, multiple different covering separately should used. However, usage usually limited by volume cost constraints applications. Therefore, multiband wideband essential provide multifunctional operations communication. A system defined operating distinct bands, but intermediate frequencies between For example, triple band cover 890-960 (Ali et al., 2003); however, it does properly 1200 or 2500 MHz. On other hand, operates every points within band. UMTS, extended WLAN 2400 functions