A novel dual-band dual-sense circulalry polarized antenna based on simple printed dipole structure

A new method to achieve dual-band dual-sense circularly polarized (CP) antenna is studied in this paper. This antenna is evolved from a simple linear polarized bow-tie dipole antenna, and the dual-band dual-sense CP waves are generated by rotational symmetry geometry. The measured impedance bandwidth (IBW) for S
₁₁
>-10 dB is 97.4% (1.96~5.68 GHz). The measured 3-dB axial ratio bandwidths (ARBWs) are 9.2% (2.29~2.51 GHz) with right-hand circular polarization (RHCP) and 12.3% (4.96~5.61 GHz) with left-hand circular polarization (LHCP). Furthermore, the radiation patterns perform very well, and the antenna peak gain within the lower and upper ARBWs are 2.0 and 4.6 dBic, respectively.