A CPW-Fed Dual-Band Slot Antenna with Circular Polarization

In this paper, a coplanar waveguide (CPW)-fed dual-band slot antenna with circular polarization (CP) is presented. In order to achieve CP characteristic, an asymmetric slot and F-shaped end patch are introduced to a conventional rectangular slot antenna. Moreover, by cutting a T-shaped notch on the ground plane, the axial ratio (AR) bandwidth (ARBW) can be extended. The antenna shows left-hand CP (LHCP) radiation in the boresight direction (i. e., + Z direction) at both ARBWs. The proposed antenna is fabricated and measured. The measured results have a good agreement with the simulated ones. The measured impedance bandwidths (vertical bar S-11 vertical bar < -10 dB) are 1.08 GHz (2.02 to 3.10 GHz, 40% at 2.70 GHz) and 2.31GHz (4.57 to 6.88GHz, 39.8% at 5.8GHz). The two measured ARBWs are 600 MHz (2.60 to 3.20 GHz, 22.2% at 2.70 GHz) and at least 1.15 GHz (4.85 to 6.0GHz, 19.8% at 5.8GHz) at the lower and upper bands, respectively.