In this paper, a novel wideband circularly polarized (CP) slot antenna and its array are presented.The antenna element consists of a C-shaped slot Foot Cream and a 50-Ω microstrip-fed port to achieve left-hand circular polarization.Both the impedance bandwidth (IBW) and the 3-dB axial ratio bandwidth (ARBW) are greatly broadened by off-center microstrip-fed sword-shaped structure.A 2 × 2 array prototype based on the proposed CP element is also designed.
Sequential rotation microstrip-feeding structure is used to excite four antennas and to realize good symmetric unidirectional radiation.To verify this Darkroom Equipment design, both the CP antenna element and 2×2 array are fabricated and measured.The measured results of the antenna element exhibit an IBW of 132% (0.85-4.
15 GHz) and an ARBW of 95.7%(1.20-3.40 GHz).
The measured ARBW and IBW of the 2×2 antenna array are about 108.3% (1.10-3.70 GHz) and 100%(1.
15-3.45 GHz), respectively.And the measured peak gain of the antenna array reaches 13.4 dBic.
The proposed antenna is very suitable for CP applications in L/S bands.