Abstract

This paper presents a two-way comparison between a stitched transmission line constructed with a copper wire and conductive thread, and a stitched transmission line constructed with conductive threads only from Light Stitches®. The stitched transmission lines which are both 150 mm long consist of a copper inner conductor surrounded by a tubular insulating layer made up of polyethylene. For shielding purpose, the structure is stitched onto a 150 mm × 150 mm denim material first with a copper wire and a conductive thread and secondly with conductive threads only, with stitch lengths, thread tension and stitch width at 2, 4 and 2 mm, respectively. The direct current (DC) resistances of the stitched transmission lines were measured to compare DC losses, while the scattering parameters were investigated through simulation and experiments within a frequency range of 0.04 to 4 GHz with results demonstrating an improved transmission characteristic and less DC loss with the stitched transmission line with copper wire and conductive thread.

Key words: Stitched transmission line, conductive thread, copper wire, direct current (DC) resistance, S-parameters, stitch length, thread tension, stitch width.