A novel broadband circularly polarized planar antenna based on off-centered coplanar waveguide feeding method

摘要

A novel broadband circularly polarized (CP) planar antenna based on off-centered coplanar waveguide (CPW) feeding method is proposed. To obtain circular polarization, traditional methods are mainly by employing external polarizer or by introducing perturbation segments into radiator. Different from traditional methods, off-centered CPW feeding provides 90° phase difference between the two orthogonal modes without any phase shift circuits or perturbation segments. The CP characteristic is good, and the 3 dB axial ratio (AR) bandwidth is 33.5% (from 1.96 GHz to 2.75 GHz), among which -6 dB impedance matching is satisfied. Also, the normalized size of the planar antenna is 0.417λ0 ×0.417λ0 ×0.013λ0, relatively small among the CP microstrip antennas.