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This paper will review the evolution of wearable textile antennas over the last couple of decades. Particular emphasis will be given to the process of embroidery. This technique is advantageous for the following reasons: (i) bespoke or mass produced designs can be manufactured using digitized embroidery machines; (ii) glue is not required and (iii) the designs are aesthetic and are integrated into clothing rather than being attached to it. The embroidery technique will be compared to alternative manufacturing processes. The challenges facing the industrial and public acceptance of this technology will be assessed. Hence, the key opportunities will be highlighted.

This paper is a critical review of metasurfaces, which are planar metamaterials. Metamaterials offer bespoke electromagnetic applications and novel properties which are not found in naturally occurring materials. However, owing to their 3D-nature and resonant characteristics, they suffer from manufacturing complexity, losses and are highly dispersive. The 2-dimensional nature of metasurfaces allows ease of fabrication and integration into devices. The phase discontinuity across the metasurface offers anomalous refraction, thereby conserving the good metamaterial properties while still offering the low-loss characteristics. The paper discusses salient features and applications of metasurfaces; wavefront shaping; phase jumps; non-linear metasurfaces; and their use as frequency selective surfaces (FSS).

This paper presents an inkjet printed textile antenna realised using a novel fabrication methodology. Conventionally, it is very difficult to inkjet print onto textiles due to surface roughness. This paper demonstrates how this can be overcome by developing an interface coated layer which bonds to a standard polyester cotton fabric, creating a smooth surface. A planar dipole antenna has been fabricated, simulated and measured. This paper includes DC resistance, RF reflection coefficient results and antenna radiation patterns.Efficiencies of greater than 60% have been achieved with only one layer of conducting ink.The paper demonstrates that the interface layer saves considerable time and cost in terms of the number of inkjet layers needed whilst also improving the printing resolution.

Abstract:We introduce two flat graded-index (GRIN) lens designs in this paper. First of these is a thick lens which was designed and fabricated by using the 3D-printing technique. Second, a thin Dial-aDielectric (DaD) lens which uses state-of-the-art artificially engineered dielectric materials for design and will be fabricated in future. Both designs overcome the difficulties faced in finding desired commercial off-the-shelf (COTS) materials for 3D-printing lenses. The lenses comprise of several concentric dielectric rings with bespoke relative permittivities for transforming spherical waves into plane waves and vice versa. The 3D-printed thick flat lens is low-cost and light-weight, but provides broadband and high gain performance. Measurement results show that the realized gain of the thick lens is 9-11 dB over the frequency band of 12-18 GHz. The designed DaD lens has the desirable characteristics of low loss, low reflection and broadband properties.