Broadband Low RCS Based on Polarization- Dependent Artificial Magnetic Conductor Metasurface

The reduction of radar cross-section (RCS) becomes an essential requirement for many military and civilian applications. One of the ways to achieve this is by using artificial magnetic conductors (AMCs) as electromagnetic surfaces. In this research, the reduction of the RCS is realized by adding a novel single layer AMC based metasurface unit cells that depend on polarization to cancel backscattering for Ka applications. The proposed AMC unit cell consists of a rectangular patch with open ended microstrip stubs. This unit cell exhibits a wide band phase difference about
$\mathrm {180^{\circ }\pm 38^{\circ }}$
between the two reflected orthogonal field components in the frequency range from 27 to
$\mathrm {56.5 GHz}$
(about
$\mathrm {71\%}$
relative bandwidth). Four AMC block arrays perpendicular to each other are combined in a chessboard configuration. To validate the capability of achieving a good RCS reduction, a substrate integrated wave guide (SIW) cavity-backed slot antenna is placed in the center of the AMC sheet. Simulation results show that the proposed AMC unit cell significantly reduces backscattered energy from
$\mathrm {29.5 GHz to 50 GHz}$
and from 28.5 GHz to 48.5 GHz in both
$y-$
and
$x-$
polarization, respectively, and covers a
$\mathrm {-10 dB}$
backscattering reduction at antenna working band (
$\mathrm {32.2-34 GHz}$
). The antenna’s bistatic performance at different frequencies is also presented. The fabricated design’s measurements and simulations match well, verifying and validating the proposed design.