A Compact Size and Small Frequency Ratio CPW-Fed Circular Slot Antenna for GPS/WLAN Dual-Band and Circular Polarizations

This paper presents a novel dual-band circularly polarized CPW-fed circular slot antenna with two open-ground rings. The proposed antenna is constructed with two opened-ground rings facing in opposite directions and embedded in the circular slot and the enhanced feed strip of CPW. By way of adjusting the relevant parameters, we can obtain the dualband at 1.57GHz and 2.46GHz respectively. A smaller frequency ratio of 1.56 is presented. The measured i10dB return loss impedance bandwidth are 380MHz (24.68%) for 1.57GHz band and 210MHz (8.33%) for 2.46GHz band. The measured i3dB axial ratio bandwidth for 1.57GHz and 2.46GHz bands are 13.38% and 8.13%, the polarization of radiation patterns are RHCP and LHCP for each band and the antenna gain are 3.72 and 3.21dBic respectively.