A CPW-fed L-shaped monopole antenna for triple-band operations

Over the decade, the broadband and multi-band planar antennas have attracted considerable interest in antenna community for the design applications in multi-function and multimode wireless communication systems. The budding users market demands high functionality and multiple services within a single terminal unit. For instance, a cell-phone supports multiple cellular voice standards: GSM/PCS/3G, and data communication standards: GPS, WiFi, FM radio and digital TV as well. In recent years, the worldwide interoperability for microwave access, known as WiMAX, employs microwave to enable the last mile delivery for wireless data transfer. There is a tendency WiMAX standard is also to be included into the cell-phones design. Therefore, when design a broadband or multi-band antenna for mobile terminals, one needs to include those allocated WiMAX frequency bands: 2.5GHz band (2.5-2.69 GHz), 3.5 GHz band (3.4-3.69 GHz) and 5.5 GHz band (5.25-5.85 GHz). Amongst the number of techniques reported in the literature for achieving dual-band or multi-band operation [1]-[6], coplanar waveguide (CPW)-fed planar monopole antenna received much more interest [2]-[5] than others because of its small size, simple structure and the low fabrication cost. However, these multi-band planar monopole antennas are usually addressed to the multi-mode voice standards and/or WLAN/WiFi applications [1]-[5]. There is scant literature covering the planar antenna for the WiFi and WiMAX applications. In this paper, we present a novel triple-band CPW-fed L-shaped monopole antenna in a simple structure. The aim of the present design is to address the need of WLAN and WiMAX bands. The CPW-fed L-shaped monopole antenna exhibits not only three distinct bandwidths but also have very good omnidirectional radiation characteristics