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Conformal Antennas for Mobile Terminals
Published in Shiban Kishen Koul, G. S. Karthikeya, Millimetre Wave Antennas for 5G Mobile Terminals and Base Stations, 2020
Shiban Kishen Koul, G. S. Karthikeya
Several techniques could be incorporated for reduction of the back lobe: a localized ground plane could be designed which would essentially be effective for a narrowband. An absorber such as a Salisbury screen could be placed a quarter-wavelength away from the radiating aperture, but there the gain would be reduced. The third technique is to place a wideband reflector for back-lobe reduction leading to gain enhancement in the forward direction. Since this architecture would provide relatively higher gain for a wider band compared to other methods, the reflector design is investigated.
Electromagnetic Specifications and Prototype Designs of Software-Defined Surfaces
Published in Christos Liaskos, The Internet of Materials, 2020
Fu Liu, Xuchen Wang, Mohammad Sajjad Mirmoosa, Sergei Tretyakov, Odysseas Tsilipakos, Anna C. Tasolamprou, Maria Kafesaki, Alexandros Pitilakis, Nikolaos V. Kantartzis, Do-Hoon Kwon
In this chapter we explain how to use auxiliary metasurface structures to improve absorption in graphene and realize strong tunability of absorption. First of all, we need to understand the exact physical reason for the low absorption in graphene. We start from the simplest absorptive structure, a graphene-Salisbury screen, where graphene is mounted on a dielectric substrate and the transmission is totally blocked by the ground plane, as shown in Fig. 3.28(a). The equivalent circuit of the structure in Fig. 3.28(a) is shown in Fig. 3.28(b).
A design methodology for an EM wave absorber with a sub-skin depth periodic pattern using Ni deposition
Published in Advanced Composite Materials, 2023
Sang Min Baek, Won Jun Lee, Sangyong Kim, Jeongin Go, Jongkwang Lee
Various types of wave absorber have been developed [9]. The Salisbury screen-type is the simplest, which absorbs EM waves using resonant characteristics by impedance matching at the target frequency through the resistive screen and the gap between the screen and the ground [10,11]. It is characterized by a narrow absorption bandwidth and it must have a fairly thick multi-layered structure in order to overcome this [12]. In the case of the Dallenbach-type absorber, materials with EM loss characteristics are structured in a multi-layered approach [13,14]. The mechanical properties, however, could be degraded because the conductive material (such as carbon nanotubes, carbon black, or graphite) is impregnated in the absorbing material to obtain appropriate dielectric constants [15,16].