A Wideband Dual-Cavity-Backed Circularly Polarized Crossed Dipole Antenna

A novel wideband dual-cavity-backed circularly polarized (CP) crossed dipole antenna is presented in this letter. The exciter of the antenna comprises two classical orthogonal straight dipoles for a simple design. Dual-cavity structure is employed to achieve unidirectional radiation and improve the broadside gain. In particular, the rim edges of the cavity act as secondary radiators, which contribute to significantly enhance the overall CP performance of the antenna. The final design with an overall size of 0.57λ
_o
× 0.57λ
_o
× 0.24λ
_o
where λ
_o
is the free-space wavelength at the lowest CP operating frequency of 2.0 GHzb yields a measured -10 dB impedance bandwidth (BW) of 79.4% and 3 dB axial-ratio BW of 66.7%. The proposed antenna exhibits right-handed circular polarization with a maximum broadside gain of about 9.7 dBic.