Ultrawideband and Omnidirectional RCS Reduction by Using Symmetrical Coded Structures

In this letter, a planar structure for ultrawideband and omnidirectional radar cross section (RCS) reduction is designed. The means of omnidirectional is the capability of RCS reduction in all of phi(i) in certain theta(i). To achieve this, the theory of diffraction in periodic structures as well as symmetrical pixelated geometry of unit cell are employed. According to this theory, the dimension of unit cell is larger than one wavelength, which induces multiple Floquet harmonics each in certain direction and causes diffusion in scattering. Addition of symmetry to the geometry of unit cell causes the omnidirectional RCS reduction; besides, pixelating of geometry is optimized with the goal of wideband RCS reduction. Finally, a 2 x 2 array of this unit cell is simulated and fabricated.