International Journal of Interdisciplinary Research
Table 1 Comparison of different manufacturing techniques for the fabrication of textile antennas and their advantages and disadvantages
Reference | Manufacturing technique | Advantages | Disadvantages | Possibilities | Fabricated samples |
|---|---|---|---|---|---|
Embroidered Antennas | Mechanical flexability No problems related to cracks and deformations due to mechanical stress Remarkable RF performance No compromis on antenna performance and efficiency Sheet resistance can be adjusted Controlling stitch spacing, stitch length, stitch direction and/or stitch pattern Avoiding additional assembling process Pattern can be directly transferred onto the fabric | Affects geometry accuracy and geometry resolution Especially at corners and edges Separate assembly process required to manufacture patch antennas Avoid sewing needle breakage from mechanical fatigue Especially challenging for denser or multi-layer embroideries | RFID Personal protective clothing IoT networks |
Wearable embroidered dipole-type ultra high frequency (UHF) RFID tag antennas (\(\copyright\) [2012] IEEE. Reprinted, with permission, from Moradi et al. (2012))
Microwave antenna-based sensor for in vitro experiments for monitoring blood glucose levels (Gharbi et al. 2021) | |
Bulathsinghala (2022) | Knitted Antennas | Sufficient elasticity for stretchable antenna systems One-step integration process of conductive and non-conductive yarns Eliminates the degradation in antenna performance due to bulkiness and electrical losses (only for planar antennas like dipoles, manufactured in a one-step knitting process) 3D spatial fabrication technique possible Entire antenna design—the radiating patch, ground plane, and dielectric substrate—can be knitted in a single process | Inconsistent loop geometry within the structure Depends on a combination of several parameters, such as take-down tension, feeding tension, knit structure, loop density, linear yarn density, etc. Significant fluctuations in sheet resistance/conduction due to the stretching effect Stretch on both axis possible: y-axis and x-axis Increased conduction losses, due to non-uniform conductivity Point connection of adjacent loops Mechanical stabilization is essential To maintain geometric accuracy | Applications with a higher level of stretching and bending, such as sportswear Knitting geometry imparts the required elasticity for mobility and comfort Single jersey structures Enables to fabricate planar complex topologies with minimal bulkiness and fewer heterogeneities (e.g. radiating patches and ground planes) |
Strain sensor consisting of a folded, knitted dipole antenna equipped with an inductively coupled RFID tag (\(\copyright\) [2016] IEEE. Reprinted, with permission, from Patron et al. (2016)) |
Printed Antennas | Additive process Does not require environmentally harmful etching chemicals Excellent resolution Leads to a high degree of reproducibility Minimum material consumption Cost-effective method of creating conductive patterns on different textile substrates | Difficult to create continuous highly conductive traces Rough, porous surface structure of textiles Lower wash resistance Ink can wear off over time Low resistance to stretching and self-motion Resilience to high temperatures Ink has a high percentage (\(\approx\) 85%) of non-conductive solvent to ensure inkjet printability—for this requirement this must be removed from the ink Difficult to achieve high antenna efficiency | Structural and health monitoring systems Wireless monitoring of vital functions |
Screen-printed coplanar keyhole antenna on fabric (Nylon/Spandex) substrate (Hasni et al. 2021)
Inkjet-printed \(2.4\,\hbox {GHz}\) Dipole antenna on polyurethane coated stretchable textile (Li et al. 2012) |
