Showing papers by "Constantine A. Balanis published in 2015"
TL;DR: In this article, the authors applied this unique reflection phase property to alter the direction of the fields scattered by a radar target to reduce its radar cross section (RCS), which results in a wider frequency band RCS reduction.
Abstract: Electromagnetic band-gap (EBG) structures have noteworthy electromagnetic characteristics that include their reflection phase variations with frequency. This paper applies this unique reflection phase property to alter the direction of the fields scattered by a radar target to reduce its radar cross section (RCS). This redirecting of the scattered fields occurs when a surface is covered with a checkerboard of alternating EBG structures, and results in a wider frequency band RCS reduction. RCS reduction compared to a PEC surface of 10 dB can be realized over 60% frequency bandwidth. Simulations of monostatic and bistatic RCSs of two dual EBG checkerboard surfaces, square and hexagonal, are compared with those of equal-sized PEC ground planes. The simulated monostatic RCS is also compared with measurements. Both $\bf{TE}^{\bf{z}}$ and $\bf{TM}^{\bf{z}}$ polarizations for oblique incidence are considered. Excellent agreement is obtained between simulated and measured patterns, for both the square and the hexagonal EBG checkerboard surfaces. An approximate analytical expression is provided as a guideline for a 10-dB RCS reduction of a dual EBG checkerboard surface compared to that of a PEC.
350 citations
TL;DR: In this paper, a planar scalar impedance holographic metasurface is designed at a dominant TM surface wave mode frequency, which is capable of beam forming with a desired electric field polarization and high gain.
Abstract: This paper presents the design of a novel planar scalar impedance holographic metasurface, which is capable of beam forming with a desired electric field polarization and high gain. It is demonstrated that the surface can be constructed with patches of simple geometry and design. A detailed analysis of the mechanism of scalar impedance holographic metasurfaces is discussed. The scalar impedance holographic metasurface is designed at a dominant TM surface wave mode frequency. It is observed that the TM surface wave mode has an impurity of TE polarized electric fields of small magnitude. The presence of this impurity is exploited to design a holographic metasurface for beam forming with a desired polarization. This modified-HAIS is capable of forming a beam at a nonphase crossover frequency, unlike the conventional HAIS. The design procedure of the surface, with simulation and measurement results, is presented.
126 citations
TL;DR: In this article, the impact of finite dielectric-covered groundplane edge diffraction on the amplitude patterns of circular apertures is investigated based on the Geometrical Optics and the Uniform Theory of Diffraction (UTD) for an impedance wedge.
Abstract: The impact of finite dielectric-covered ground-plane edge diffractions on the amplitude patterns of circular apertures is investigated. The model is based on the Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD) for an impedance wedge. The circular aperture antenna is mounted on square and circular finite ground planes that are coated with a thin lossy dielectric layer. The predictions based on the GO/UTD model are validated by comparisons to experimental results and simulated data.
6 citations
01 Oct 2015
TL;DR: The reflection variation property of Electromagnetic Band-Gap structures can be utilized to reduce the Radar Cross Section (RCS) of ground planes by combining PEC and EBG structures on the same ground plane.
Abstract: The reflection variation property of Electromagnetic Band-Gap (EBG) structures can be utilized to reduce the Radar Cross Section (RCS) of ground planes. Combining PEC and EBG structures on the same ground plane forms checkerboard surfaces which can achieve a RCS reduction in a narrow frequency band. However, a wider band RCS reduction can be realized by combining two different EBG structures. It can realize 60% frequency bandwidth for the 10-dB RCS reduction. The scattered fields for square checkerboard surfaces are re-directed toward four quadrants, while the scattering for hexagonal checkerboard surfaces are toward six directions. The maxima of the RCS for checkerboard surfaces in the four quadrants are 10 dB less than those of the PEC ground plane, and more than 19 dB RCS reduction is obtained along the principal planes. Both bistatic and monostatic RCS are compared with those of the equal-sized PEC ground planes.
3 citations
01 Oct 2015
TL;DR: A planar sinusoidally modulated reactive metasurface is excited through an aperture and a parametric analysis on the variation of its radiation properties is performed due to the variation in coupling coefficient of the aperture.
Abstract: A planar sinusoidally modulated reactive metasurface is excited through an aperture and a parametric analysis on the variation of its radiation properties is performed due to the variation in coupling coefficient of the aperture. The aperture coupling varies with the position and size of the aperture, the properties of the dielectric substrates and the propagating leaky-wave modes. The propagation of the fundamental leaky-wave mode is considered for this study.
1 citations
01 Oct 2015
TL;DR: A wideband semi-periodic circular high impedance surface for loop antenna applications is designed and a loop antenna is placed above the surface afterwards to find the operational bandwidth of the structure.
Abstract: A wideband semi-periodic circular high impedance surface for loop antenna applications is designed. The surface is illuminated with a plane wavw whose electric field is of phi component. A loop antenna is placed above the surface afterwards to find the operational bandwidth of the structure.
1 citations