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The authors proposed analytical models applicable to monolayer and multilayer mantle cloaks for suppressing the scattering fields of electrically large conducting objects using printed ultrathin metasurfaces. To analyse the proposed structure, the two‐sided impedance surface method is used and the scattering cross section (SCS) is obtained using Mie theory. It is shown that using surface impedance expression obtained from the analytical model for monolayer mantle cloak they can design a proper unit cell of a metasurface to reduce significantly total scattering from the cylinder. The proposed mantle cloaks in this work are mainly designed to minimise simultaneously several scattering multi‐poles of a relatively large object around considerably broad bandwidth. Numerical results and full‐wave simulation show good cloaking performance in designed frequency. The simulated results using their analytical models as well as the full‐wave results show that the multilayer mantle cloak is an optimised candidate for cloaking of electrically large objects. The proposed multilayer mantle cloak confirms 3.6 dB SCS gain to cancel the scattering fields of a perfect electric conductor cylinder with a radius of 1.425λ0 at the designed frequency. Finally, they consider a cluster of closely spaced and overlapping three cloaked cylinders for suppression of electromagnetic fields. [ABSTRACT FROM AUTHOR]

An analytic solution is presented to the scattering of a left circularly polarized (LCP) plane wave from a chiral elliptic cylinder placed in another infinite chiral medium, using the method of separation of variables. The incident, scattered, as well as the transmitted electromagnetic fields are expressed using appropriate angular and radial Mathieu functions and expansion coefficients. The unknown scattered and transmitted field expansion coefficients are subsequently determined by imposing proper boundary conditions at the surface of the elliptic cylinder. Numerical results are presented graphically as normalized scattering widths for elliptic cylinders of different sizes and chiral materials, to show the effects of these on the scattering widths. [ABSTRACT FROM AUTHOR]

In this communication, a parabolic shaped complementary cloak is proposed which makes the object invisible by reducing its scattering under different incidence angles of electromagnetic wave. The proposed design is based on transforming a line segment into an enclosed space that is surrounded by the core region. The enclosed space is symmetrically divided into two regions, namely, cloaked region and complementary region. The shifted parabolic coordinate system introduced in the present work enhances the area of cloaked region and provides diagonally anisotropic but optimized homogeneous material properties in the core region. The cloaked region is mapped onto the complementary region using a simple one directional folding transformation, which yields homogeneous and isotropic material properties in the complementary region and also eases the creation of antiobject. Numerical results confirm the cloaking effect of the proposed approximate complementary cloak. The metamaterial unit cell designs are also presented for realizing the proposed material properties of core and complementary regions. [ABSTRACT FROM AUTHOR]

Abstract: The expansions of the incident arbitrary beam shape in spherical, spheroidal and cylindrical coordinates in the general case of oblique illumination are presented. The scattered electromagnetic fields of typical particles of arbitrary orientation illuminated with a beam shape are provided. The numerical results of the normalized scattering cross section are evaluated. [Copyright &y& Elsevier]

Abstract: We present measurements and simulations of a transmission-line network that has been designed for cloaking applications in the microwave region. Here the network is not used for cloaking but for channelling electromagnetic fields through an electrically dense array of metal objects, which alone is basically impenetrable to the impinging electromagnetic radiation. With the designed transmission-line network the waves emitted by a source placed in an air-filled waveguide are coupled into the network and guided through the array of metallic objects. Our goal is to illustrate the simple manufacturing, assembly, and the general feasibility of cloaking devices based on the transmission-line approach. Most importantly, we demonstrate both with measurements and with numerical simulations the excellent coupling of waves between the network and the surrounding medium. [Copyright &y& Elsevier]

Reverberation chambers are now common test facilities used in electromagnetic compatibility. Objects loaded in the chambers, such as antennas and reflectors, can affect the measurement because they absorb and scatter the diffuse field. Thus, it is important to know the scattering and absorbing cross sections of these objects. In this paper, we propose a new technique to measure the scattering cross sections averaged over all angles of incidence and both polarizations in a reverberation chamber. It is based on stacking time-dependent fields generated by a repetitive pulsed source while the objects are moving. The fields recorded by wire antennas are averaged over the object positions. The square of the averaged field is shown to decrease exponentially with the time spent by the wave in the chamber. The cross section is deduced from the exponential factor. The technique has been experimentally validated in a 1-m³ reverberation chamber at 2.45 GHz with metallic spheres of several radii. The experimental cross sections are found to be in agreement with the theoretical ones. [ABSTRACT FROM AUTHOR]