Development trends of small antennas for mobile terminals

This paper gives a brief overview on some typical development trends of the small antennas used in multi-system mobile communications terminals. The main challenge in this development has been and will be to fit all the antennas needed for up to over 10 radio systems into a small, thin handheld terminal, whose total volume should in many cases stay below 100 cm3. The increasing complexity of the mechanical structure of the terminal and addition of low-frequency UHF radio systems like DVB-H to the terminal have set additional challenges for the antenna development. However, new approaches have been found during the recent years for the implementation of mobile antennas through in-depth studies of the radiation mechanisms available in the terminals. This has made it possible to introduce antenna solutions that meet the strict size and performance requirements of the new devices. Below these new antenna solutions, which are based on the so-called non-resonant coupling elements to excite currents on the chassis of the terminal, are discussed and several application examples are presented.