Abstract
The 2.4GHz ISM band has become very popular and is now widely used for several wireless communication standards. As an example, many laptops incorporate Bluetooth technology as a cable replacement to connect portable and/or fixed electronic devices and IEEE 802.11b/g technology for WLAN [1-2], 802.11b devices can provide data rates up to 11Mbps. For much higher data rates, 802.11a devices in the 5GHz band (5.15-5,35 GHz) are required. Such devices have data rates up to 54Mbps. Many new portable devices, such as laptop computers, will be equipped with radio cards supporting both 802.11a and 802.1 lb/g standards. As a result, the demand for an antenna operating at both bands is increasing. For world-wide applications, an antenna covering the 2.4-2.5 GHz and 5.15-5.85 GHz ranges is needed. Dual-band antennas with one feed point are of special interest due to low cost on feeding cables and in some applications tight cable rout requirement. There are many articles discussing dualband antenna designs for the portable devices [3-7], For the portable device, antenna size and low cost are crucial design requirements, so the antenna performance has been compromised for those applications. In this paper, a dualband antenna based on sleeve or closely coupled antennas [3] [8-9] for access point (AP) is studied.