Automated Fabric Circuit and Antenna Fabrication

electrical and electronics
Automated Fabric Circuit and Antenna Fabrication (MSC-TOPS-92)
Improves performance of e-textiles through automation
Innovators at NASA Johnson Space Center have developed a cost-effective method to create fabric-based circuits and antennas by combining conventional embroidery with automated milling. The technology allows for higher surface conductivity, improved impedance control, expanded design and application potential, and greater choice of materials for optimized performance. Previous efforts to automate fabric circuit and antenna fabrication have faltered on either the complexity of the manufacturing hardware and associated costs, or design and application limitations of the resulting e-textiles. This fabrication method offers benefits in cost and labor savings and provides opportunities for the development of design patterns with higher geometric complexity and performance improvements.

The Technology
Modern production of e-textiles utilizes an embroidery technique called e-broidery that directly stitches circuit patterns with conductive thread onto textiles. This automated manufacturing process combines steps of e-broidery and milling to expand the application of e-textiles to high-current and high-speed uses. Manufacturing begins with two layouts of the desired conductive pattern. After assembling the layers of conductive and nonconductive materials, e-broidery is performed with the second layout and nonconductive thread to secure the layers together and designate the pattern for the conductive material. The secured assembly is transferred to an automated milling or laser cutting machine, which cuts the desired conductive pattern and releases the unneeded portions of the conductive material. The resulting e-textiles are tightly woven together, providing higher surface conductivity and impedance control. Initial comparison tests assessing the performance of fabric-based spiral antennas developed with this method, compared to conventional antennas, indicated no loss in performance across multiple metrics, including voltage standing wave ratio (VSWR), radiation pattern, and axial ratio performance. The Method and Apparatus for Fabric Circuits and Antennas is a technology readiness level (TRL) 6 (system/subsystem prototype demonstration in a relevant environment). The innovation is now available for your company to license. Please note that NASA does not manufacture products itself for commercial sale.
Fabric spiral antennas using this method performed similarly to conventional copper antennas across multiple metrics, including VSWR.
  • Mirrors methods used for fabrication of conventional rigid PCBs and printed antennas
  • Permits use of materials that enable traces characterized by high surface conductivity
  • Allows control of line characteristic impedance for applications over a wide range of the electromagnetic spectrum
  • Actualizes complex single and multi-layered circuits with high degrees of geometric complexity
  • Setup costs comparable to wet-etch process commonly used for flexible and conventional rigid PCBs

  • Aerospace: lightweight fabric antennas for fabric skin aircraft and unmanned autonomous vehicles (UAVs); advanced sensors/antennas for spacesuits
  • Military: digital battlefield apparel can be embedded with stealth and flexible electronics and antennas
  • Textiles/wearables: wireless or cellular networking, RFID, sensors, GPS
Technology Details

electrical and electronics
Similar Results
James Webb Space Telescope deployed
Thin-Films with Integrated Structural and Functional Elements
The technology uses additive print manufacturing to produce hierarchical and integrated structural and functional elements into large-area thin-film structures. Adding these structural and functional elements has the potential to enable very lightweight, large-scale thin-films with improved damage tolerance, self-deployment capability, flexibility, and multifunctional (optical, thermal, electrical) connectivity and interrogation capabilities. Based on simple and proven additive manufacturing concepts, advanced geometrical, biomimetic (insect wing), and hierarchical structures could be applied to, or eventually with further development integrated within the bulk of large-area thin films using roll-to-roll processing techniques for a potentially low-cost manufacturing approach. The subject technology potentially addresses many of the disadvantages of current large-scale membrane material systems, which are prone to damage or require extensive deployment and support structures.
Figure 1.  Antenna Design.
Multi-and Wide-Band Single-Feed Patch Antenna
NASA's patch antenna technology exhibits higher operational bandwidth (on the order of 20%) than typical patch antennas (less than 10%) and can operate across integer-multiple frequency bands (e.g. S/X, C/X, S/C). Testing of the antenna design has demonstrated &#62 6dB of gain on both S and X bands (boresight), with an axial ratio of &#60 6dB and voltage standing wave ratio (VSWR) &#60 3:1 throughout the entire near-Earth network (NEN) operating bands (22.4GHz and 88.4GHz) with hemispherical coverage. The patch size is on the order of 10 x 10 cm and with associated electronics, is about 1 cm in height.
Lightweight, Self-Deployable Helical Antenna
NASA's newly developed antenna is lightweight (at or below 2 grams), low volume (at or below 1.2 cm3), and low stowage thickness (approx. 0.7 mm), all while delivering high performance (at or above 10 dBi gain). The antenna includes a novel design-material combination in a helical coil conformation. The design allows the antenna to compress for stowage (e.g., satellite launch), then self-deploy at the desired time in orbit. NASA's lightweight, self-deployable helical antenna can be integrated into a thin-film solar array (or other large deployable structures). Integrating antenna elements into deployable structures such as power generation arrays allows spacecraft designers to maximize the inherently limited resources (e.g., mass, volume, surface area) available in a small spacecraft. When used as a standalone (i.e., single antenna) setup, the the invention offers moderate advantages in terms of stowage thickness, volume, and mass. However, in applications that require antenna arrays, these advantages become multiplicative, resulting in the system offering the same or higher data rate performance while possessing a significantly reduced form factor. Prototypes of NASA's self-deployable, helical antenna have been fabricated in S-band, X-band, and Ka-band, all of which exhibited high performance. The antenna may find application in SmallSat communications (in deep space and LEO), as well as cases where low mass and stowage volume are valued and high antenna gain is required.
Rocket Nozzles
Silicon Carbide Fiber Tows
SiC fiber tows and preform materials are commonly used as reinforcements in CMCs, to make parts for use in harsh, high-temperature environments such as aircraft engines. These materials are desirable for numerous high-temperature applications because of their very low weight and outstanding thermo-chemical inertness. However, the multiple-step process using electric furnaces to produce these materials have numerous drawbacks: they are very expensive ($10,000 to $25,000 per spool); they involve high temperatures (greater than 2000°C); they require high power (more than 700 watts); and they produce much wasted material. Glenn innovators have discovered an efficient way to improve the quality and strength of SiC fiber tows using a unique microwave-furnace design that induces molecular heating. Glenn's innovation relies on microwave sintering to convert a polymer to ceramic fibers/tows/yarns, or to manipulate commercially available SiC fibers to increase strength and improve other qualities. Not only can higher quality tows be produced, but also - for the first time - old, damaged, or otherwise unusable fibers can be improved and recycled, thereby saving significant costs by increasing yield. Even entire engine components can be placed in the furnace and restored. The desired results can be achieved in minutes rather than the usual hours or even days. Glenn's low-temperature microwave process provides greater control with less power, while also eliminating plasma generation and minimizing arcing events. Because this method also facilitates the shaping of the SiC fiber after initial processing, fabricating preforms with 2D or 3D architectures becomes simpler. Glenn's creative processing method makes producing SiC tows and preforms much less expensive, opening them up for increased use in a broad range of applications.
TOP Front Image
Novel Overhang Support Designs for Powder-Based Electron Beam Additive Manufacturing (EBAM)
EBAM technology is capable of making full-density, functional metallic components for numerous engineering applications; the technology is particularly advantageous in the aerospace, automotive, and biomedical industries where high-value, low-volume, custom-design productions are required. A key challenge in EBAM is overcoming deformation of overhangs that are the result of severe thermal gradients generated by the poor thermal conductivity of metallic powders used in the fabrication process. Conventional support structures (Figure 1a) address the deformation challenge; however, they are bonded to the component and need to be removed in post- processing using a mechanical tool. This process is laborious, time consuming, and degrades the surface quality of the product. The invented support design (Figure 1b) fabricates a support underneath an overhang by building the support up from the build plate and placing a support surface underneath an overhang with a certain gap (no contact with overhang). The technology deposits one or more layers of un-melted metallic powder in an elongate gap between an upper horizontal surface of the support structure and a lower surface of the overhang geometry. The support structure acts as a heat sink to enhance heat transfer and reduce the temperature and thermal gradients. Because the support structure is not connected to the part, the support structure can be removed freely without any post-processing step. Future work will compare experimental data with simulation results in order to validate process models as well as to study process parameter effects on the thermal characteristics of the EBAM process.
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