A Dual-CP Slot Antenna Based on the Inherent Coupling with 90° Phase Difference

A dual circularly polarized (CP) slot antenna is proposed. In this design, based on the original CP antenna with only one axial ratio (AR) pole using two orthogonal slots, an identical slot is additionally introduced, thus forming up an extra inductive coupling with 90° phase difference. By doing this, a pair of orthogonal polarization with different rotations compared with the original counterpart is thus constructed. Therefore, a dual-CP slot antenna with both right-hand CP (RHCP) and lefthand CP (LHCP) is successfully achieved. Simulation results indicate that this proposed antenna exhibits good stability within 2.14-2.94 GHz frequency band. Two minimum AR poles located at 2.2 GHz and 2.5 GHz and stable gain of about 4.3 dB within the passband band are obtained.