Wideband microstrip-line-fed circularly polarized slot antenna with open slot structure

Abstract

A new wideband circularly polarized (CP) slot antenna with open slot structure using a microstrip-line for feeding is presented. The proposed antenna consists of an open C-slot with a straight slit on the ground plane, and a microstripline with a semi-circle-shaped patch on the other side of the substrate. The antenna size is reduced by about 35% compared with the circular slot antenna. By using the semi-circle-shaped patch to disturb the magnetic current distribution on the open C-slot, a wider CP bandwidth can be achieved. The measured results show that the proposed antenna can provide a 3 dB axial ratio (AR) bandwidth of 40% (4.1-6.2 GHz) and a 10 dB return loss impedance bandwidth of 107% (2.3-7.6 GHz).