A novel compact slot antenna for broadband circularly polarized radiation

A novel design of broadband circularly polarized slot antenna fed by a coplanar waveguide (CPW) is proposed and fabricated. The proposed antenna has a compact size of 0.328λ×0.328λ×0.004λ. Circularly polarization is achieved by the slots around two opposite corners of the square slot. A circular tuning stub protruded into the slot from the narrowed strip at the end of the signal strip of the CPW is used to obtain good impedance matching. For the optimized antenna prototype, the obtained results show that the frequency of minimum axial-ratio (AR) and the 3dB AR bandwidth are 1.64GHz and 14.6% (1.54GHz-1.78GHz), respectively. And the VSWR(<;2) impedance bandwidth is larger than 57.9%.