Ultra-wideband bi-static RCS reduction with full angular stability using diffraction periodic symmetrical structures

Abstract

In this paper, a planar, two-layer, and symmetrical structure is presented to obtain ultra-wideband bi-static RCS reduction with angular stability in azimuth and elevation directions. The proposed structure is composed of two layers. The bottom layer contains a periodic surface with periodicity larger than one wavelength to scatter multiple Floquet harmonic and thus bi-static RCS reduction. To achieve angular stability for the azimuth direction, the geometry of the unit cell is optimized with symmetry to its center. The top layer contains a substrate with high relative permittivity, which, according to refraction Snell’s law, increases the bandwidth of RCS reduction and contributes to angular stability regarding the elevation direction. The results show the RCS reduction by 10 dB over a wide frequency range from 4.2 GHz to 22.9 GHz (137%) at the normal incidence, and more than 80% for oblique incident waves within the ${50}^{\circ }$ elevation angle range.

KEYWORDS:

• Bi-static RCS reduction
• diffraction periodic structure
• refraction Snell’s law
• angular stability

Disclosure statement

No potential conflict of interest was reported by the author(s).