Authors: Raj Mittra and Yuda Zhou
Source: FERMAT, Volume 9, Article 2, May_Jun, 2015
Abstract: In this paper we present an alternative approach to addressing the problem of scattering reduction for radar targets, which have recently been dealt with by using the Transformation Optics (TO) algorithm which calls for the use of Metamaterials (MTMs) that are inherently narrowband, dispersive and highly sensitive to polarization as well as to the incident angle. The present design utilizes realistic lossy materials that can be conveniently fabricated in the laboratory, and are wideband as well as relatively insensitive to polarization and incident angle of the incoming wave. A modified interpretation of the TO algorithm is presented and is employed to design of RCS-reducing absorbers for arbitrarily shaped targets, and not just for canonical shapes, e.g., cylinders, for which cloaks have been designed by using the TO. The paper also briefly examines the topic of performance enhancement of absorbers by using graphene materials and embedded Frequency Structure Surfaces (FSSs).
We begin by presenting the design procedure for planar absorbers, and then examine how well those designs perform for general-shaped objects. Finally, we discuss how the planar design can be modified by tailoring the material parameters of the coating for specific object shapes. A number of test cases are included as examples to illustrate the application of the proposed design methodology, which is a modification of the classical TO paradigm.
Index Terms: Transformation Optics (TO), cloaking, RCS reduction, RFI, microwave absorber, EMI.
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Design of Absorptive Coatings for Arbitrarily Shaped Targets for Reduction of Radar Cross Section (RCS) using an Alternative to the Transformation Optics (TO) Algorithm