In-Band Radar Cross Section Reduction of Slot Array Antenna

A slot array antenna is proposed for both in-band and out-of-band radar cross section (RCS) reduction. The presented slot array antenna is covered by the superstrate consisting of a polarization rotation reflective surface (PRRS). Four different configurations of the PRRS supersrtate are proposed and their effects on radiation and scattering performances of the slot array antenna have been investigated. By optimizing the arrangement of the unit cells of the PRRS, a good RCS reduction in an ultra-wide frequency band from 7 to 40 GHz is achieved. Besides, the in-band RCS of the proposed antenna is reduced by 12.4 dB compared with that of the reference antenna. Moreover, the 10 dB impedance bandwidth of the proposed antenna is enhanced from 3.5% to 14.2% and the gain remains nearly the same. Good agreement between the simulations and experiments is obtained.