A dualband WLAN access point antenna

In this paper, the simulation results of a dual band access point antenna for WLAN applications have been presented. As shown in the results, the input impedances at the center of both bands are about 50 ohms. Therefore, an additional matching network is not necessary. This means there is no efficiency loss due to adding matching networks. The radiation patterns are basically omnidirectional. Although the 2.4 GHz and 5 GHz bands are used here, similar results can be obtained for the GSM and DCS band, and 900 MHz and 2.4 GHz ISM bands. The grounded monopoles with the same length are used in the analysis. However, different lengths can be used for radiation pattern control, especially to reduce the gain variations in the 5 GHz band. Furthermore the design ideas presented here can be used for tri-band applications if the grounded monopoles with different lengths are used.