This project was carried out jointly between the Department of Electronic and Electrical Engineering (DEEE) at University of Sheffield and the Advanced Textiles Research Group (ATRG) at Nottingham Trent University over a period of six months.  DEEE provided expertise in electromagnetic design and measurement and the ATRG provided the textile manufacturing expertise. The work focused on the design and manufacture of textile electromagnetic structures using computerised flat-bed knitting machines and conducting yarns.  Initially, the knitting process was used to manufacture single layer textile materials with conducting surface patterns to form structures such as frequency selective surfaces (FSS). Further work investigated advanced knitting techniques to enable 3-D spacer structures to be manufactured.  The 3-D structures consisted of a knitted conducting back-plane, an integrated dielectric spacer layer (knitted from polyester yarn), and a surface layer with a conducting patch pattern. The project also investigated and prototyped a new knitting technique that enabled conducting vias to be incorporated into the 3-D knitting process to connect the conducting surface patches to the ground-plane. The 3-D knitting technique represents a major advance in the development of integrated functional electromagnetic textiles and provides a new area for future research. The textile samples were tested at the DEEE and characterised the free-space reflectivity performance of both the single layer and 3-D planar textile surfaces.

This research project was funded by the Defence Science and Technology Laboratory under contract number DSTLX1000065500.

Details of this innovation are available in the following articles:

Knitted, textile, high impedance surface with integrated conducting vias

Experimental knitted, textile frequency selective surfaces