A very small broadband CPW-fed circular polarized antenna with two semicircles etched on ground plane

摘要

In this paper, a very small broadband circularly polarized planar antenna fed by coplanar waveguide is designed and fabricated. The antenna is composed of a beveled rectangular radiator patch, a square patch, two inverted L-shaped grounded strip lines, and two semicircles etched on ground. Additionally, to realize the circular polarization a new structure including two semicircles etched on ground and two inverted L-shaped grounded strip lines at the corner is introduced. The proposed antenna has a very small size of 15 × 15 mm2 that covers the measured impedance bandwidth (S11 <; -10 dB) of 113.17% from 3.31 GHz to 13.1 GHz with axial ratio bandwidth of 36.31% from 4.51 GHz to 6.55 GHz for WLAN frequency band. The average gain of the antenna is almost 3.1 dBi within the axial ratio bandwidth.