Tri-band planar monopole antenna with dual band circular polarization

A tri-band planar monopole antenna with dual band circular polarization for 3G, WiMAX and WLAN applications is presented. The antenna consists of monopole arms on one side of an FR4 substrate attached to a slotted feedline and a slotted ground plane on the other side of the same substrate. The antenna has a total size of 25 × 35 × 1.6 mm3. Measured results show that the antenna has a −10 dB impedance bandwidth of 9.7% (2.05–2.26 GHz) for the lower band, 11.3% (3.41–3.82 GHz) for the middle band and 60.2% (4.89–9.11 GHz) for the upper band. The simulated axial ratio (AR) bandwidths are 4.4% (3.55–3.71 GHz) and 57.9% GHz (4.69–8.52 GHz).