Wideband high-gain circularly-polarized low RCS dipole antenna with a frequency selective surface

Abstract

A low radar cross-section (RCS) wideband circularly-polarized (CP) dipole antenna using a frequency selective surface (FSS) is presented in this paper. A planar dipole antenna consists of a pair of slotted patches fabricated on top and bottom sides of the substrate is designed. The slotted patches are connected through a circular ring, which acts as a delay line to achieve circular polarization. In the proposed configuration, a band-stop FSS is employed for the antenna reflector, which improves the radiation performance and reduces the RCS of the dipole antenna. The impedance bandwidth (S11 ≤-10 dB) of the proposed antenna is 0.95 to 3.1 GHz and 3-dB axial ratio bandwidth (ARBW) is 1.9 to 2.35 GHz. The proposed antenna shows the maximum and average RCS reduction of 20 dB and 6.9 dB, respectively, in the frequency range of 3.7 to 18 GHz. The simulated and measured results show that the maximum gain of the antenna increases by 5.9 dB by using FSS.