A Miniaturized Dual-band Dipole Antenna with a Modified Meander Line for Laptop Computer Application in the 2.5 and 5.25 GHz WLAN band

摘要

Small balanced antennas with multi-band operation are highly desired for multi-radio mobile wireless laptop computer application. The upper rim of the laptop lid is a promising candidate location for the antenna, but the space available for antenna installation is very limited. At present most laptop computers employ unbalanced antennas such as PIFA (Planar Inverted F-shaped Antenna) which incorporates the laptop skin as a ground plane of the antenna. However, the unbalanced antenna causes high conductive coupling between antennas through the common ground formed by the skin of the laptop devices and may increases platform noise generated from surface current flowing through unbalanced feed cables. Balanced dipole antennas have the potential to reduce the antenna to antenna coupling and reduce the platform noise problems arising from the unbalanced antenna systems. However, the size of the balanced dipole antenna is typically 0.5λ{sub}0 which is double the size of the unbalanced antenna. Typical antenna size of the unbalanced PIFA antenna is about 0.25λ{sub}0. In this paper, a reduced size dual-band balanced antenna is presented and tested in a lid of laptop computer. The antenna size is only 0.28λ{sub}0, which is 44% smaller than the conventional dipole antenna and is comparable to the size of unbalanced antenna. A modified meander line technology [1] is used in the particular antenna configuration to achieve dual-band operation in the 2.5 and 5.25 GHz WLAN bands.