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Proceedings Paper

Materials and techniques for controllable microwave surfaces
Author(s): Alan Barnes; Kenneth Lee Ford; Peter Victor Wright; Barry Chambers; Christopher D. Smith; Denise A. Thompson; Francis Pavri
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Paper Abstract

Discs and waveguide samples of polymeric mixed conductor nanocomposite materials comprising a conducting polymer and redox active switching agent in a polymer electrolyte have been prepared and studied. These novel materials have been shown to exhibit large, rapid and reversible changes in their microwave impedance when small d.c. electric fields are applied across them from the edges. The results of simultaneous cyclic voltammetry or potential square waves and microwave transmission measurements have shown that the changes are apparantly instantaneous with the application or removal of the applied field. Analysis of the microwave results has shown that the impedance of the materials changes by a factor of up to almost 50 with the imposition or removal of the fields. Nanocomposite materials having either poly(pyrrole) or poly(aniline) as the conducting polymer component and either silver/silver tetrafluoroborate or copper/copper(II) tetrafluoroborate as the redox active components have been investigated. The results of the nanocomposite materials are compared with those of microparticulate composities of similar composition. A new configuration of single layer tunable microwave absorber using only resistive control has been investigated and shown to exhibit wideband, low reflectivity performance combined with reduced thickness. A major advantage of the new topology is the requirement for only a 3:1 change in controllable resistance.

Paper Details

Date Published: 24 August 2000
PDF: 12 pages
Proc. SPIE 4073, Fifth European Conference on Smart Structures and Materials, (24 August 2000); doi: 10.1117/12.396389
Show Author Affiliations
Alan Barnes, Univ. of Sheffield (United Kingdom)
Kenneth Lee Ford, Univ. of Sheffield (United Kingdom)
Peter Victor Wright, Univ. of Sheffield (United Kingdom)
Barry Chambers, Univ. of Sheffield (United Kingdom)
Christopher D. Smith, Univ. of Sheffield (United Kingdom)
Denise A. Thompson, Univ. of Sheffield (United Kingdom)
Francis Pavri, Univ. of Sheffield (United Kingdom)


Published in SPIE Proceedings Vol. 4073:
Fifth European Conference on Smart Structures and Materials
Pierre Francois Gobin; Clifford M. Friend, Editor(s)

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