Novel design of printed monopole antenna for WLAN/WiMAX applications

In recent years, wireless communications have progressed very rapidly. Wide-band antenna and multi-band antenna designs have become very important for wireless communications. Several promising monopole antennas for WLAN and WiMax applications have been reported recently. According to the WiMax protocol, there is three bands have been allocated for WiMax application: the lower band is 2.5-2.69 GHz, the middle band is 3.3-3.8 GHz, and the higher band covers from 5.25 GHz to 5.85 GHz. In practical use of WiMax applications, the lower band and the middle band are very close to each other, which lead to cause large effects of coupling and interference. To reduce the coupling and interference between the lower and middle bands, filters must be attached to the antenna to suppress the dispensable bands. However, the cost and the overall antenna size are increased due to the attached filters. In this paper, a CPW-fed printed monopole antenna for dual-band operation of 2.3-4.15 GHz and 4.93-5.83 GHz are proposed. Furthermore, by etching a pair of slits on the proposed monopole antenna, band rejection of frequency range from 2.93 GHz to 3.12 GHz can be achieved. Results show that, this novel design of CPW-fed monopole antenna is suitable for both WLAN and WiMax applications.