scholarly journals Evaluation of Nano-Antenna Directivity Contributions for EM Propagation in WBANs

2019 ◽  
Vol 5 (2) ◽  
Author(s):  
Hussein Sarah ◽  
Falou Abdul Rahman El ◽  
Sahyoun Walaa ◽  
Ziade Youmni ◽  
Shubair Raed M.
Keyword(s):  
Antenna Directivity

scholarly journals Study of Antenna Superstrates Using Metamaterials for Directivity Enhancement Based on Fabry-Perot Resonant Cavity

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Haixia Liu ◽  
Shuo Lei ◽  
Xiaowei Shi ◽  
Long Li
Keyword(s):  
Reflection Coefficient ◽  
Resonant Cavity ◽  
Frequency Selective Surface ◽  
Lens Model ◽  
Optimum Location ◽  
Electromagnetic Bandgap ◽  
Left Handed ◽  
Antenna Directivity ◽  
Fabry Perot ◽  
Refractive Lens

Metamaterial superstrate is a significant method to obtain high directivity of one or a few antennas. In this paper, the characteristics of directivity enhancement using different metamaterial structures as antenna superstrates, such as electromagnetic bandgap (EBG) structures, frequency selective surface (FSS), and left-handed material (LHM), are unifiedly studied by applying the theory of Fabry-Perot (F-P) resonant cavity. Focusing on the analysis of reflection phase and magnitude of superstrates in presently proposed designs, the essential reason for high-directivity antenna with different superstrates can be revealed in terms of the F-P resonant theory. Furthermore, a new design of the optimum reflection coefficient of superstrates for the maximum antenna directivity is proposed and validated. The optimum location of the LHM superstrate which is based on a refractive lens model can be determined by the F-P resonant distance.

Directivity enhancement by layered radomes

1995 ◽  
Vol 73 (7-8) ◽  
pp. 444-451
Author(s):  
R. Zhou ◽  
L. Shafai
Keyword(s):  
Ground Plane ◽  
Single Layer ◽  
Image Theory ◽  
Antenna Design ◽  
Optimum Length ◽  
Integral Equation Methods ◽  
Antenna Directivity ◽  
Layered Dielectrics ◽  
The Moment ◽  
Low Permittivity

Single and layered radomes are often used to protect radiating elements. A two-dimensional analysis is used to investigate their influence on the antenna directivity and radiation patterns. Image-theory and integral-equation methods are used to formulate the problem for a line source and layered dielectrics of finite length over a ground plane, and solved numerically using the moment method. It is shown that, for a sufficiently long single-layer slab, the directivity enhancement is approximately equal to the square root of its relative permittivity. Properly truncating the slab can even improve the directivity. The optimum length of a finite dielectric slab is determined to maximize the directivity. For multilayer slabs, the directivity enhancement is much greater and they can be used with low-permittivity dielectrics to simulate a single-layer one of higher permittivity. Frequency dependency of the enhanced gain is also studied. Useful information for how to incorporate the radome parameters into the antenna design and use it for gain or directivity enhancement is provided.

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