A compact low-profile C-band dual circularly polarized sub-array antenna

A compact low-profile cavity-backed dual circularly polarized (CP) sub-array antenna is proposed in this paper. The proposed C-band antenna array has a 2×2-element microstrip patch antenna. The operating bandwidth of the proposed antenna is ranging from 0.89f
₀
to 1.11f
₀
(about 22%) with the voltage standing wave ratio (VSWR) less than 2, where the f
₀
is center frequency of the target band. Moreover, the axial ratio (AR) is less than 3 dB for the entire desired band. The highlight of this proposed antenna is that it can realize dual circularly polarized radiation with a compact structure. In addition, the depth of the cavity is only about λ
₀
/8. The detailed structure and simulated results of the proposed dual CP sub-array antenna will be presented.