Design of dual-frequency broadband planar antenna for high-speed wireless LAN systems

Recently, high-speed wireless LAN has been used as a communications system for portable information terminals such as notebook computers. Presently, two frequency bands-2.4 and 5 GHz are used for wireless LANs. There is a tendency for wireless LANs to be embedded on personal computers as a standard setup. Hence, small, low-profile antennas containable in portable information terminals have been studied extensively. In the present paper, a dualfrequency broadband planar antenna operating at 2.4 and 5 GHz is proposed for use with wireless LANs contained in a portable information terminal. By means of the HFSS three-dimensional electromagnetic field simulator, the operating mechanism of the proposed planar antenna is found. The impedance characteristics and directivities in each band are simulated. It is confirmed that the results almost entirely agree with the measured data. Based on this result, an antenna is designed that can use wireless LAN not only in Japan but also in Europe and North America. Hence, it is shown that the proposed antenna is effective. (c) 2005 Wiley Periodicals, Inc.