Constraints and performances of various antenna types in commercial mobile terminals

Although feature phones are less sophisticated than nowadays smart phones, it could be a footstone to explore the constraints and performances of various antenna types in a commercial mobile terminal. From the era of analog system to the age of digital world, a wide variety of services are embedded into a mobile terminal including text messaging, multi-media services, email, internet access, short-range wireless communications, gaming and photography. However, the handset has dramatically reduced in size and invisible antennas become a standard feature resulting in a challenging environment for antenna design. In addition, the interaction between mobile terminals and human bodies is another current issue in which mobile phone manufacturers have to account for. The antenna performance can be influenced severely when the phone is in contact with the human head and hand, whereas certain antenna designs may fail the standard of Specific Absorption Rates (SAR) though they can meet other requirements.