Compact CPW-fed tri-band stepped monopole antenna with inverted-L strip for WLAN/WiMAX applications

A compact coplanar waveguide (CPW)-fed tri-band stepped monopole antenna with inverted-L strip for WLAN/WiMAX applications is proposed and investigated in this paper. The proposed antenna is composed of a stepped monopole and an inverted-L strip, which occupies a very compact size of 23 × 16 mm² including the ground plane. By adjusting the dimensions of the stepped monopole, inverted-L strip and ground plane, three desired resonant frequencies can be achieved and tuned independently. The antenna exhibits three resonances covering the 2.4/5.2/5.8 GHz WLAN bands and 3.5/5.5 GHz WiMAX bands. Details of the antenna design, simulation, and measurement results are presented and discussed. The proposed antenna shows nearly omnidirectional radiation characteristics and reasonable gains in the operating bands. The simple structure, compactness and uniplanar design make it easy to be integrated within the portable device for wireless communication.