Compact size triple-band monopole antenna with parasitic element for WLAN/WiMAX applications

A compact size (20 × 38.5 × 0.8 mm³) coplanar waveguide (CPW) fed monopole antenna design with triple-band operation for WLAN (Wireless Local Area Network) and WiMax (Worldwide Interoperability for Microwave Access) applications is proposed. The monopole design is a modified symmetrical U-shaped printed structure, and a parasitic element is attached behind this printed monopole. Good impedance matching is attained by loading two dissimilar notches separately into the two CPW ground planes. From the measured results, the 10-dB impedance bandwidths of the three operating bands (f_L, f_M, and f_H) are 17.6% (2.105-2.495 GHz), 28.7% (3.22-4.30 GHz), and 23.3% (4.895-6.125 GHz), respectively. Furthermore, the three operating bands have also yielded peak gain and radiation efficiency of more than 2.7 dBi and 65%.