Application of Transformation Electromagnetics to Cloak Design and Reduction of Radar Cross Section

Abstract

In this paper we present an alternative approach to addressing the problem of designing cloaks for radar targets, which have been dealt with in the past by using the transformation optics (TO) algorithm. The present design utilizes realistic materials, which can be fabricated in the laboratory, and are wideband as well as relatively insensitive to polarization and incident angle of the incoming wave. The design strategy, presented herein, circumvents the need to use metamaterials for cloak designs that are inherently narrowband, dispersive and highly sensitive to polarization and incident angle. A new interpretation of the TO algorithm is presented and is employed for the design of radar cross section-reducing absorbers for arbitrary targets, and not just for canonical shapes, e.g., cylinders. The topic of performance enhancement of the absorbers by using graphene materials and embedded frequency structure surfaces is briefly mentioned. The design procedure for planar absorbing covers is presented and their performance as wrappers of general objects is discussed. 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.

A new look at the transformation electromagnetics approach for some real-world applications

“…Some examples of such realistic blanket designs based on the FT strategy can be found in [5,7,[16][17][18] and are omitted here for the sake of brevity. The above work also shows how to design the blankets for arbitrary targets by borrowing some ideas from the TO algorithm to improve their design.…”

“…These materials are often commercial off-the-shelf (COTS) type, or slight modifications thereof, realized by using the diala-dielectric (DaD) approach as mentioned below in this paper in the context of flat lens design. For the RCS-reduction problem, the materials can be fabricated in the laboratory, as has been adequately demonstrated in [5], for instance. It is important to recognize that, unlike MTMs, the materials called for in the present FT design have many desirable features, namely broad bandwidth; desirable loss and dispersion characteristics; and desirable levels of insensitivity to angle of incidence and polarization, as shown below in this paper.…”