UWB antenna built into 3G smartphones

In recent years, ultra-wideband (UWB) technology has received considerable attention as a promising technology for realizing ubiquitous networks. In comparison with conventional narrowband antennas, it is more difficult to construct a broadband antenna in electronic equipment because it is necessary to ensure antenna performance over the entire UWB frequency band. In this study, we investigated an unbalanced dipole antenna with semicircular and trapezoidal elements, known for its excellent, broadband performance, in 3G smartphones. Further, we proposed and investigated an antenna configuration that serves both the 2-GHz band for 3G smartphones and the 3.1-10.6-GHz UWB. As a result, we designed and developed an antenna configuration with a VSWR of less than 2.1 in both the 3G and UWB frequency bands, which was adequate for practical use.