Low RCS Spiral Antenna Array Based on Frequency Selective Surface Radome

In the paper, a planar frequency selective surface(FSS) radome is proposed. The radome consists of a resistive absorbing structure and a conventional frequency selective part. In the operating band from 4GHz to 10GHz, the FSS plays the role of frequency selection, and it also acts as the ground of the resistive absorbing structure to absorb out-of-band electromagnetic waves. We design a 1*8 Archimedean spiral antenna array and load the FSS radome 120mm above the array to get a low RCS array. When compared with the reference spiral antenna array, the overall radiation performance of the low-RCS array remains good. In the vertical incidence electromagnetic waves case, there is more than 8dBsm RCS reduction in the operating band. In the case of 30 deg oblique incidence electromagnetic waves, it still maintains an average RCS reduction of 8.21dBsm, with a reduction bandwidth of 85.7%.