By Gina Roos, editor-in-chief
Technological advancements in applications such as aircraft, soldier communications, unmanned aerial vehicles (UAVs), and NewSpace applications are creating new challenges for connector and cable manufacturers. Not only do they need to meet higher performance requirements, they also need to enable lighter and smaller designs more cost-effectively.
One of the new challenges is that as devices get smaller, they still need to meet the same rugged requirements. Cable assemblies must be able to operate in tough environmental conditions, including temperature, shock, and vibration — all factors that impact product reliability and life cycle — as well as meet stringent safety and security requirements.
Military/aerospace OEMs are also under pressure to keep costs down while still maintaining safety and performance. Plus, they need assemblies to meet tough compliance requirements.
Cables for military and aerospace range from high-speed data cables and RF assemblies to power-distribution cables. High-performance materials are behind a lot of advances in the cable assembly market, enabling small, light, and flexible interconnections.
High-speed communications
With the tremendous amount of data being transmitted and received, cable assemblies now need to deliver high-speed connectivity for more demanding military communications. At the same time, they still need to be rugged and operate in harsh conditions.
One example is the Raychem CANbus (controller area network) cable line from TE Connectivity (TE) that is offered in several flavors for harsh-environment applications. The high-speed ruggedized copper cables can transmit data at speeds up to 1 Mbits/s for military ground systems, marine, and aerospace applications.
Variations of the 20-Ω twisted-pair cables meet SAE J1939 and SAE J1939-11 and -15 requirements for use in military ground vehicles. With operating temperatures ranging from −65°C to 200°C (depending on construction), Raychem CANBus cables are also available in constructions for aerospace and marine uses.
TE offers a variety of material choices to meet application-specific needs and environmental conditions “instead of a one-size-fits-all solution.” These cables can be used in military ground systems, flight controls, aircraft galleys, and military and commercial aerospace. Custom-designed cables are also available upon request.
For 10GBASE-T, IEEE 802.3n, and 10/100/1,000/10,000 communications, L-com, an Infinite Electronics brand, recently released a new line of Category 7 cables with low-smoke zero-halogen (LSZH) jackets for shipboard, aerospace, and defense applications or any tight space that calls for protection from toxic and corrosive gases in case of a fire. It delivers requirements for high-speed connectivity with low-smoke zero-halogen jackets.
These Cat 7 cables support high-speed voice, video, and data traffic and are fully compatible with Cat 6a couplers and adapters. The LSZH Category 7 cables feature an overall braid shield covering individually shielded twisted pairs (S/FTP) and 26 AWG stranded conductors for greater flexibility. The low-smoke zero-halogen jackets comply with IEC 60332-1-2 flame ratings, IEC 60754-2 corrosive gas ratings, and IEC 61034-1 and -2 smoke emission ratings.
L-com also released a new line of high-temperature−rated Ethernet cables specifically designed for aerospace and demanding high-temperature environments. Applications include cabin management, in-flight systems, backbone avionics, ground vehicle trunks, high-temp testing, and general military, avionics, or aerospace use.
These new cable assemblies feature special FEP jackets that are rated for a wide temperature range of −55°C to 150°C, along with double cable shielding with both 100% foil and 85% braid shields that provide maximum electromagnetic interference (EMI) and radio frequency interference (RFI) protection.
The cables are available in Cat 6a, Cat 5e, and Cat 5e slim construction variants. They meet all RoHS directives and Federal Aviation Regulation (FAR), Airbus, and Boeing requirements.
RF cable configurations
More choices, along with cost-effective options, are becoming a bigger issue for mil/aero OEMs. More customers are requiring cables that meet their specific needs faster and at a lower cost. This means more commercial off-the-shelf (COTS) cable assemblies available for same-day shipping. Providing higher frequency ranges is also becoming a bigger requirement.
Pasternack, an Infinite Electronics brand, as an example, offers a new line of military-grade MIL-DTL-17 RF cable assemblies that come in 124 basic configurations for six cable types, for a total of more than 700 part numbers. These COTS cable assemblies are 100% tested and include a test report as well as material lot traceability when shipped. They can operate in a range of avionics, military electronics, satellite ground stations, and autonomous vehicles.
The Pasternack cables provide operating frequencies of up to 12.4 GHz and VSWR as low as 1.3:1 per connector. They are made from MIL-DTL-17−qualified cable, MIL-PRF-39012−qualified connectors, AS23053 heat shrink, and J-STD soldering. They are available for same-day shipping.
Similarly, Fairview Microwave Inc., also an Infinite Electronics brand, announced RF cable assemblies with numerous options available for same-day shipping. Released earlier this year, the new series of military-grade MIL-DTL-17 RF cable assemblies with lot traceability targets military electronics, electronic countermeasures (ECM), avionics, unmanned systems, IFF systems, GPS, and satcom.
The cable assemblies are offered in a variety of options. It offers a selection of six cable types in 124 basic configurations, for a total of more than 1,200 part numbers.
The military-grade cable assemblies feature operating frequencies of up to 12.4 GHz and VSWR as low as 1.3:1 per connector. The cables are constructed of MIL-C-17−qualified cable, MIL-PRF-39012−qualified connectors, J-STD soldering, and AS23053 heat shrink.
These COTS cable assemblies are 100% tested and shipped with test data, test report, and material lot traceability. Applications include aerospace, defense, transportation, and telecommunications industries or other applications in which there is a high cost of failure. These assemblies are available with same-day shipping.
Expanding its RF portfolio, Amphenol RF recently added ruggedized fixed-length cable assemblies to its existing line of ARC connectors. The ARC line consists of coaxial connectors and RF cable assemblies engineered specifically for superior performance in harsh conditions. They are designed to operate in less-than-optimal environments, such as military, transportation, and construction.
The ARC cable assemblies include N-Type and TNC configurations and feature adhesive-lined, multi-layer heat-shrink tubing. Amphenol RF said that this construction offers better resistance against shock and vibration, which prevents distortion, and reinforces connector termination retention and cable flex rigidity. All ARC products are IP67-rated in both the mated and unmated condition and offer a threaded interface.
New requirements for NewSpace
NewSpace applications, an emerging commercial space industry, also call for their own set of requirements that center on lower cost as well as smaller and more frequent designs for space programs often spanning one to five years.
One manufacturer targeting these new applications is W. L. Gore & Associates (Gore) . The company recently announced a new collection of high-speed data cables and high-frequency microwave/RF assemblies for NewSpace. “Leading the way are innovative companies such as SpaceX that use smaller, sleeker, lower-cost satellites and vehicles with fast-paced designs and frequent, inexpensive launch capabilities,” said Gore. “As a result, customers want qualified, reliable cables and assemblies at a reduced price delivered quickly for NewSpace applications to help bring connectivity to the world in a way that has never been done in the past.”
Leveraging its expertise in traditional spaceflight program experience, Gore has released a series of robust space cables and assemblies, focusing on size and weight reductions while offering flexible designs for Low Earth Orbit (LEO) and Medium Earth Orbit (MEO) applications. These products are qualified according to NASA EEE-INST-002 Level 2, ESA ECSS-Q-ST-60-13C Class 3, and Technology Readiness Level (TRL) 6+.
These new solutions are chemically inert and thermally resistant against extreme temperatures, shock, vibration, radiation, atomic oxygen, and outgassing. One product example is the Gore hook-up wires that ensure that power is delivered up to 600 V safely and reliably in demanding orbit environments.
Gore also offers high-speed data cables that improve signal quality and transmit critical information. They meet and exceed standard protocols such as Ethernet Cat6 a, XAIU, USB, and HDMI.
The Gore spaceflight microwave/RF assemblies are said to offer the smallest diameter sizes and operate reliably from DC to 40 GHz with low loss for high-density, high-frequency, and high-power applications. A variety of connector systems are available to meet the performance of each assembly type, which minimizes loss and reflection for optimized signal transmission.
Lighter and smaller designs that are critical for ever-growing space-constrained military/aerospace applications, coupled with stringent safety, compliance, and environmental requirements, will continue to drive interconnect manufacturers to make advances in design and processes. Growing new applications such as UAVs (drones), soldier communications, and private sector satellite programs will also drive interconnect manufacturers to develop new cable assemblies and connectors that deliver ruggedness in a smaller footprint and at a lower cost.
This article was originally published at EET’s Military & Aerospace Designline .
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Military connector designs address size, weight, and environment
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