A wideband CPW-fed monopole antenna with linear and circular polarizations

A coplanar-waveguide (CPW)-fed monopole antenna for applications of the multi-system integration has been presented in this study. The enhancement of impedance bandwidth and circular polarization in the microstrip rectangular monopole antenna using following techniques: using asymmetrical CPW feeding structure and adding three grounded sleeve strips. By tuning the width of one side of the CPW ground plane, increase of impedance bandwidth and excitation of circular polarization at 1.57 GHz are achieved. Three parasitic inverted-L conducted strips are connected to the ground plane to further extend the impedance bandwidth. The measured impedance bandwidth of a S
₁₁
<; -6 dB ranges from 0.65 to 2.85 GHz and the measured 3-dB axial-ratio bandwidth is about 150 MHz. The proposed antenna covers most of commercial wireless communication systems, such as GSM, GPS, DCS, PCS, IMT-2000, WLAN, and LTE.