Metasurface base on uneven layered fractal elements for ultra-wideband RCS reduction

Jianxun Su,Yueyang Cui,Zengrui Li,Hongcheng Yin,Yaoqing (Lamar) Yang,Yongxing Che

doi:10.1063/1.5013106

Abstract

A novel metasurface based on uneven layered fractal elements is designed and fabricated for ultra-wideband radar cross section (RCS) reduction in this paper. The proposed metasurface consists of two fractal subwavelength elements with different layer thickness. The reflection phase difference of 180° (±37°) between two unit cells covers an ultra-wide frequency range. Ultra-wideband RCS reduction results from the phase cancellation between two local waves produced by these two unit cells. The diffuse scattering of electromagnetic (EM) waves is caused by the randomized phase distribution, leading to a low monostatic and bistatic RCS simultaneously. This metasurface can achieve -10dB RCS reduction in an ultra-wide frequency range from 6.6 to 23.9 GHz with a ratio bandwidth (fH/fL) of 3.62:1 under normal incidences for both x- and y-polarized waves. Both the simulation and the measurement results are consistent to verify this excellent RCS reduction performance of the proposed metasurface.

Highlights

With the rapid development of the contemporary radio technology and the military electronic technology, the ability of the combat defence systems search and track the target have been enhanced at a great extent.[1]
Different techniques have been proposed in the previous literatures to reduce the Radar cross section (RCS), such as applying radar absorbing materials (RAM) which transforms the electromagnetic energy into heat,[2] the RAM often operate in the vicinity of the resonance frequency
A kind of polarization rotation reflection surface (PRCS) based on the unit cell consists of a square and L-shaped patches is applied to achieve a 10 dB reduction over frequency bandwidth of 98%

Summary

INTRODUCTION

With the rapid development of the contemporary radio technology and the military electronic technology, the ability of the combat defence systems search and track the target have been enhanced at a great extent.[1]. Different techniques have been proposed in the previous literatures to reduce the RCS, such as applying radar absorbing materials (RAM) which transforms the electromagnetic energy into heat,[2] the RAM often operate in the vicinity of the resonance frequency Another technique is altering the appearance of the target (Shaping) to redirect the scattered field to more directions, but that increases the complexity of the design.[3]. A chessboard-like meaturface is designed and fabricated in Ref. 14, by applying a binary optimization algorithm and linking it to a full-wave simulation package, it works over an ultra-wide band of frequency from 3.8 to 10.7 GHz. In addition, Ref. 15 proposed a coding phase gradient metasurface (CPGM) made of the N-shape metallic pattern, which could come true 10 dB RCS reduction in frequency bands of 7.8-13.5 GHz with a radio bandwidth of 1.95:1. The simulated and the measured results validate effectively the capacity of the proposed metasurface for reducing the monostatic and bistatic RCS of the target and significantly extending frequency bandwidth

Unit cell designs

Simulated result

Measured result

Findings

CONCLUSION