Applications / EMI shielding
Galvorn® shielding takes the weight out of EMI protection.
Galvorn offers lightweight EMI shielding either as a film or overbraid. Based on NASA-funded testing, a cable shielded with this advanced carbon material can achieve a 50% reduction in the total weight of the cable.
Context
What is lightweight EMI shielding?
Electromagnetic interference (EMI) is stray noise that can corrupt a cable's signal, and shielding blocks it. Galvorn film is a thin, flexible tape made from an advanced carbon material. Wrapped around an insulated conductor, it replaces the metal braid.
The problem
Metal braid is one of the heaviest parts of a shielded cable.
A typical shielded cable wraps its inner conductor in a metal braid. Metal braids make up most of the weight of a shielded cable. That weight rides on every flight, launch, and drive, and designers of aircraft, eVTOL vehicles, UAVs, launch vehicles, satellites, and defense systems pay for it in range and payload.
Results
A much lighter cable that still meets the specification.
These results come from NASA-funded testing of prototype RG 316 coaxial cables. Each one compares Galvorn film against the commercial RG 316 cable with a standard double metal braid.
Design matters
The best shield design depends on your application.
In addition to the NASA data we report, DexMat customers exploring the use of Galvorn in EMI shielding are seeing promising results through a variety of designs and constructions. Our team will work with you to understand your specific requirements and determine the best design approach with our material, be it film, overbraid, or a combination.
Galvorn film
Wrap it on standard tape-wrapping equipment.
Cable makers already use a process called cigarette wrapping: a guide folds the tape lengthwise around the insulated conductor. In NASA-funded testing, the film ran through a commercially available guide, and a nylon braid over the top held it in place. Nylon is a dielectric, so the shielding in those tests came from the film alone.
In customer testing, continuous Galvorn film has shown improved shielding effectiveness over copper braid at GHz frequencies.
You can apply one layer or two. In testing, the double-wrapped cables averaged 5 to 10 dB more shielding attenuation than the single-wrapped ones.
Scroll to watch the film fold lengthwise around the core, the same cigarette wrap a tape guide makes.
Test results
Insertion loss meets the military specification, and shielding is comparable to commercial cable.
In prototype testing, insertion loss met the military specification for RG 316 cable, MIL-C-17, before and after flexing. Shielding effectiveness was comparable to the commercial cable with a double metal braid, and double-wrapped cables added 5 to 10 dB on average. Insertion loss changed little with film thickness. Thicker film shields better, mostly below about 300 MHz, and about 47 microns was needed to match the double metal braid from 30 MHz to 3 GHz.
Both charts come from NASA-funded testing of prototype RG 316 cables shielded with Galvorn film held in place by a nylon braid. A commercial cable assembler terminated and tested the cables. The first prototypes used film about 28 microns thick. These results apply to the tested prototype cables, and testing in stressful environments is still to come.
Galvorn braid
Use a Galvorn braided sleeve or overbraid when the application calls for it
Galvorn yarns can also be built into a braided sleeve or an overbraid, a tube of interlaced yarns that fits over a conductor, a cable, or a harness bundle. Customers are evaluating Galvorn sleeves and overbraids for shielding and harnessing, including hollow sleeves over thin cores and overbraid on harness bundles where they want a lighter alternative to metal.
A sleeve can serve as the shield, go over a film wrap, or go over another shielding layer. The NASA-funded shielding data on this page covers film wraps, not braids, so test a braid sample against your own requirements.
To start, send our engineers the diameter, length, and shielding target for your application.
Built to move
The shield keeps working after 1,000 flex cycles.
Galvorn fiber has 1,000x the flex life of copper.
In bending fatigue tests at Rice University, a fiber of this material survived more than a billion bending cycles without breaking. Copper wire in the same test rig failed before one million. That is a fiber result, so it does not by itself predict how a cable will last.
The tested cables were flexed plus or minus 90 degrees at a minimum bend radius of 0.83 cm, up to 1,000 cycles, then tested again. Insertion loss and shielding effectiveness showed no measurable change. These results apply to the tested prototype cables, so check your own cable type and bend radius with samples.
Forms and who builds with them
Lighter shielded cable, built with our partners or yours.
Galvorn comes as fiber tow, twisted yarn, braided yarn, fabric, and film. DexMat supplies the material and works with wire, cable, and harness manufacturers to produce the finished shielded cable. You can work with DexMat and one of its manufacturing partners, or bring your own partner and we supply the material.
Proof from NASA
Built on three NASA SBIR projects.
DexMat has completed three NASA Small Business Innovation Research (SBIR) projects on lightweight shielded cable and wiring for space systems. The film results on this page come from that work.
Who it is for
For teams that count grams on every shielded run.
Harness, cable, and connector manufacturers, and the engineers who specify their shielded cable, can use Galvorn where weight and flexibility decide the design. That includes launch vehicles and satellites, UAVs, eVTOL and other aircraft, defense systems, and automotive platforms.
FAQ
Questions engineers ask about Galvorn shielding.
It is a conductive layer around the inner conductor that keeps outside electromagnetic noise away from the signal. In the commercial RG 316 cable we compared against in our work with NASA, that layer is a double metal braid. Galvorn film replaces the braid.
Start with a sample.
Order Galvorn film and braided yarn samples from the store, download the data sheet for full specifications, or tell our engineers what you want to shield.