A Broadband Low-RCS Metasurface for CP Patch Antennas

A novel metasurface (MS)-based method for broadband radar cross section (RCS) reduction of circularly polarized (CP) patch antennas is proposed. The RCS reduction is achieved in a much broader band than the openly al band of the antenna. The simple technique is based on MS units on a grounded substrate in a checkerboard-like configuration. The broadband RCS reduction is achieved by combining two different destructive interference principles. In the high-frequency region, for a normal incident wave, the RCS is reduced by the phase cancellation generated by the MSs and the grounded substrate. In the low-frequency region, the RCS is reduced by the polarization conversion property of the MS. In this case, the fields reflected by two MS sections are in counter phase for a normal incident wave. The MS is combined with a CP patch antenna. It concerns a traditional corner-truncated square patch and four sequentially rotated surrounding MS cells. This dedicated MS allows two things: an additional resonant mode is excited resulting in a 3 dB AR bandwidth extension from 4.2% to 15.9% and a broadband RCS reduction of over 6 dB from 4.95 to 15.73 GHz (104.25% bandwidth) for both x- and y-polarized incident waves.

Automated summary

A novel metasurface-based method is proposed for broadband radar cross section reduction of circularly polarized patch antennas, achieving a much broader band than the antenna's operating band. By combining two different destructive interference principles, the broadband RCS reduction is achieved through phase cancellation generated by the metasurfaces and grounded substrate, as well as the polarization conversion property of the metasurfaces.