A Compact Quad-Band Sickle-Shaped Monopole Antenna for燝SM�00/WiMax/WLAN Applications

In this paper a novel, compact, microstrip-fed, quad-band monopole antenna is presented for the application of Global System for Mobile communication (GSM 900), Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN). The proposed antenna comprises of a sickle-shaped structure with four circular arc strips, and a modified rectangular ground plane. The four strips of the antenna are independently responsible for the four different resonant frequencies of the operating bands and can be tuned separately to control the radiation performance. The proposed quad-band antenna is designed to resonate at 940 MHz for GSM 900, 2.5 and 3.5 GHz for WiMAX and 5.85 GHz for WLAN applications. At the four intended operating bands, the antenna exhibits impedance bandwidth of 60 MHz (905–965 MHz), 80 MHz (2.45–2.53 GHz), 110 MHz (3.48–3.59 GHz) and 2.39 GHz (4.82–7.21 GHz), respectively. At the resonance frequency of the four bands, the gain of the proposed antenna is obtained as 4.2, 2.5, 1.7 and 1.9 dBi, respectively. A prototype of the designed antenna is fabricated and a good agreement between simulated and measured results is observed. Furthermore, the proposed antenna shows good radiation characteristics and gains at all the four operating bands.