A High Gain Broadband Circularly Polarized Antenna with Sector Dipole

A sector dipole circularly polarized antenna is proposed in this paper. The antenna is fed by a semi-rigid coaxial line and the antenna structure is fed by multiple sections of microstrip line of unequal width and λg/4 length. The structure achieves four equal divisions of power and four 90° degrees of phase differences. For the array element, the conventional rectangular dipole is modified to a sector dipole, while the sector dipole is slotted for better matching. The improved sector dipole structure effectively extends the bandwidth of the antenna. The simulation results show that the impedance bandwidth of the antenna is 64.9% (1.55GHz-3.04GHz), the 3-dB axial ratio bandwidth is about 32.9% (1.70GHz-2.37GHz), the gain is 6.44dBic-7.52dBic, and the antenna is RHCP in the AR bandwidth. The proposed antenna is able to achieve high gain circular polarization in a wide frequency band.