A planar dipole antenna with wideband characteristics for UWB and wireless LAN

In recent years, attention has focused on UWB (Ultra Wideband), which is suitable for high-speed, large-capacity near-distance wireless communication systems. Since UWB uses the 3.1- to 10.6-GHz bands, research and development into antennas capable of obtaining wideband characteristics has become active. Research has also accelerated on antennas that can be shared with wireless LAN and other wireless communication systems. In this paper, we propose a wideband characteristics method that uses trapezoidal conductors for planar dipole antennas that satisfy the ultrawide bandwidths required for UWB, and for planar asymmetric dipole antennas that can be used for both IEEE802.11b/g, a wireless LAN in the 2.4-GHz band, and UWB. We performed analysis and measurement of impedance characteristics, and of directionality in each frequency band, and confirmed that the analysis results and measurement results virtually match. We also performed measurement to study group delay characteristics. We used the proposed method to achieve an antenna that is effective for both UWB and the 2.4-GHz-band wireless LAN, and showed the validity of the wideband characteristics method. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(12): 22–30, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20395