Experimental Fabrication and Characterisation of Textile Metamaterial Structures for Microwave Applications
Abstract
This thesis presents an investigation of fabrication technologies and electromagnetic
characterisation of textile metamaterials in the microwave frequency range.
Interdisciplinary in nature, the work bridges textile design practice and electromagnetic
engineering. The particular ambition was to explore a number of surface techniques
prevalent in the textile design field, and map their suitability for the construction of
metatextiles for microwave operation.
Two different classes of metatextiles, all-dielectric and dielectric with electrically
conductive patterns, were examined.
First, five structures of all-dielectric textiles and papers are reported; three textiles with
graded embroidered and screen printed patterns, and two papers embellished with
regular and irregular laser cut patterns. Permittivities for these materials were measured
in a purpose-built test chamber and shown to be similar to permittivity ranges exhibited
by solid discrete metamaterial cells previously reported in the scientific literature.
Importantly these metatextiles were realised within one textile surface and one
fabrication process, bypassing the need to assemble large numbers of isotropic material
cells. This reveals the potential for rapid and low-cost manufacture of graded textile
materials to produce anisotropic ground plane cloaks.
Secondly, three studies are presented that examine the use of electrically conductive
patterned textile materials in the design of metatextiles which exhibit negative
refractive index over a narrow frequency band. A range of e-textile (electronic textile)
fabrication technologies were explored to assess their suitability for prototyping splitring
and wire arrays, resonating in a narrow region between 3 - 10 GHz. Designs
utilised a repeated unit cell pattern on a two-dimensional textile surface and were
subsequently pleated into the required three-dimensional structure. A small negative
refractive index was achieved for an embroidered prototype at
4.9 GHz, and two ‘printed and plated’ prototypes at, 7.5 GHz and 9.5 GHz respectively.
In summary the thesis demonstrates a set of guidelines for the fabrication of textile
metamaterials for microwave frequencies, derived through a practice-led and
interdisciplinary method based on material experimentation.
Authors
Greinke, BeritCollections
- Theses [4125]