Vivaldi Array Antenna With Low In-band RCS and Low Cross-polarization Properties by Loading Spoof Surface Plasmon Polariton Absorber

A Vivaldi antenna array with low in-band radar cross section (RCS) and low cross-polarization properties is proposed in this paper. The proposed antenna array consists of 4 $\times 4$ Vivaldi antennas and an orthogonally oriented spoof surface plasmon polariton (SSPP) absorber. Since the electromagnetic waves whose polarization direction is parallel to the SSPP absorber can be absorbed, the in-band cross-polarization RCS and the cross-polarization level of the antenna array can be reduced. The antenna array works in the frequency band of 3.7-15.0 GHz. Compared with the antenna array without SSPP absorber, the proposed antenna array can achieve a 10-dB RCS reduction from 6.2 to 13.5 GHz and a 10-dB in-band cross-polarization reduction from 6.2 to 11.5 GHz, while the radiation performance of co-polarization remains unchanged.