On the Practical Design of Small Terminal Antennas for Mobile Applications

Mobile communication have become an important part of telecommunications. Original applications like paging, mobile phones or GPS have shown a tremendous growth, and new applications are emerging every day: tagging, wireless computer links, wireless microphones, remote control, wireless multimedia links, satellite mobile phones, wireless internet. Mobile means light, small, with low energy consumption and appealing designs. Technology has evolved very fast to satisfy these needs in rapidly growing markeds: chips are becoming smaller, consume less current, are more efficient and perform more complex operations. The antennas however have not experienced the same evolution, as the size of an antenna is mainly dictated by the frequency band it has to transmit or receive. Thus, the art of antenna miniaturization is an art of compromise: one has to design the smallest possible antenna, which is still suitable for a given application regarding its radiation characteristics. Or in other words, one looks for the best compromise between volume, bandwidth and efficiency. In this paper, we will go through classical design techniques, starting from ultra small antennas and going UWB antennas over multiband designs. key words: small terminal antennas, miniaturization, multifrequency antennas, ultra WideBand