Semi fractal three leaf clover-shaped CPW antenna for triple band operation

This article presents a unique and compact coplanar waveguide CPW antenna that exhibits triband operation with circular polarization. The single antenna was designed to operate simultaneously in the following bands: WiMAX 3.3-3.6 GHz, wireless local area network WLAN 5.15-5.825 GHz, ITS 5.795-6.400 GHz, and ITU-R 7.725-8.5 GHz. The realization of the triband antenna was achieved by using two semi fractal ring patches resembling the shape of a three leaf clover, and by introducing a pair of symmetrical L-shaped slits in its ground plane. The antenna's physical parameters were investigated to fully understand their affect on the antenna's performance. The salient parameters obtained from this analysis enabled the optimization of the antenna's overall characteristics. The design concept was confirmed by fabricating the antenna prototype and measuring its characteristics. The proposed antenna has dimensions of 20 × 20 × 1 mm3. Measured results show the antenna exhibits circular polarization in WiMAX and ITU-R bands, and linear polarization in the WLAN band. The antenna radiates omnidirectionally in the H-plane, and approximately bidirectionally in the E-plane. In addition, the antenna presents stable gain over the triband. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:413-418, 2015.