Compact CPW-Fed Dual-Band Linearly and Circularly Polarized Monopole Antenna for Wimax/WLAN Applications

A novel compact dual-band linearly and circularly polarized monopole antenna is designed and fabricated, which employs an inverted-L shape monopole and the asymmetric ground plane which are fed by coplanar waveguide (CPW). The inverted-L shape strip and a slit embedded on the ground plane providing an orthogonal phase difference were designed to generate circularly polarized radiation. The measured results demonstrate that a 10-dB impedance bandwidth of 92.7 %(3.3-9 GHz) and a 3-dB axial-ratio bandwidth (ARBW) of 57.1 %(5–9 GHz) could be achieved which could completely cover the WLAN (5.725-5.85 GHz) band. Meanwhile, a linear polarization is also obtained which could completely cover the WiMAX (3.3-3.7 GHz) bands.