Abstracts - Dipartimento di Elettronica Applicata

Meta 2010 & FEM 2010 – Rome, 13-15 December 2010
Finite Element Design of
CNT-based Multilayer Absorbers
Ugo d’Elia (1) , Giuseppe Pelosi (2) , Stefano Selleri (2) , Ruggero Taddei (2)
(1) MBDA Italia, via Tiburtina km. 12,400, 00131
Roma, Italy – E-mail: ugo.delia@mbda.it
(2) University of Florence, Electronics and Telecommunications Department
Via C. Lombroso 6/17 – 50134
Florence, Italy E-mail: [giuseppe.pelosi, stefano.selleri, ruggero.taddei]@unifi.it
Absorbing materials are of relevant industrial interest both for radar cloaking and
anechoic chambers. For the former problem, lightweight, compact, durable materials
adequate to be layered on the vehicle hull are at a premium.
In the radar cloaking context frequency selective surfaces (FSS) comprising regular
lattices of lossy elements are an interesting possibility. FSS elements constituted of
conductive rings loaded with lumped resistors are a possibility investigated in
literature [1], yet they are difficult to manufacture; an FSS exploiting ring resonators
with inherent high losses would be more interesting. To this aim, in this contribution,
a very recently developed carbon nanotubes paper-like material is exploited [2]. This
material exhibits relatively high losses and consequently - for the frequencies at which
the rings resonates - a very high absorption.
A design for multi-layer absorbers based on this FSS is here studied. The FSS if
analyzed via finite element (FE) analysis over a single periodic cell by exploiting
Floquet theory [3]. Analyses are carried out for different polarization and different
values of the incident plane wave angle over a single layer FSS. A genetic algorithm
(GA) based optimization is then performed to design multiple layer FSS satisfying
specific set of bandwidths and absorption requirements.
Design is finally validated via full wave FEM simulations.
References
[1] B.A. Munk, P. Munk, J. Pryor, “On designing Jaumann and circuit analog absorbers (CA
absorbers) for oblique angle of incidence,” IEEE Trans. Antennas Propag., 55, 186–193, 2007.
[2] L. Wang, R. Zhou, H. Xin, “Microwave (8-50GHz Characterization of Multiwalled Carbon
Nanotube Papers Using Rectangular Waveguides,” IEEE Trans. Microwave Theory Tech., 56,
499-506, 2008.
[3] G. Pelosi, R. Coccioli, S. Selleri, Quick Finite Elements for Electromagnetic Waves, 2nd Edition,
Artech House, London (UK), 2009.
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