Beyond Rigidity: High-Performance Flexible Cables for Aerospace & Defense

Originally published with EverythingRF

For decades, semi-rigid coaxial cable assemblies were the gold standard in demanding aerospace, defense, and telecommunications due to their outstanding electrical performance, phase stability, and shielding. They’re designed to last in harsh environments. However, their inherent rigidity has always presented major design and installation headaches. As systems grow more intricate and space is at a premium, the industry urgently needs a more adaptable option that doesn’t sacrifice the crucial electrical integrity of semi-rigid cables.

The Constraints of Semi-Rigid Cable

Historically, semi-rigid coaxial cable assemblies were preferred for their high-fidelity electrical characteristics. Their construction, featuring a solid copper outer conductor, yields exceptional electromagnetic interference (EMI) mitigation and robust phase stability across diverse environmental conditions. These properties are paramount for preserving signal integrity in critical high-frequency applications like radar and advanced telecommunications infrastructure.

However, these performance advantages come with significant practical limitations. The inflexible nature of semi-rigid cables necessitates complex 3D bend configurations during installation, severely restricts on-site modifications, and requires manual shaping or specialized tools. This rigidity also elevates the risk of damage during the installation process and reduces adaptability to subsequent design changes.

The difficulties posed by traditional semi-rigid cables often translate into lengthy development timelines, escalated installation expenses, and restricted design agility for engineers and system integrators. As systems evolve to be more intricate and compact, these limitations push the industry towards solutions that can match electrical performance while providing greater mechanical adaptability.

The Shift to Flexibility: A New Era in RF

Flexible alternatives to semi-rigid assemblies are a significant advancement in RF transmission. Their core purpose is to match the electrical prowess of semi-rigid assemblies while being significantly easier to install.

For system designers, the capacity to maintain these robust performance characteristics while gaining superior installation flexibility is a major step forward. This innovation empowers engineers, eliminating the previous trade-off between critical electrical performance and essential mechanical flexibility.

Application-Specific Advantages

A key benefit of advanced flexible alternatives is their seamless compatibility with existing systems. Utilizing standard solder-on connectors allows for integration into established designs without needing a complete overhaul. This extends the advantages of flexible construction even to legacy systems. When it comes to new designs, flexible alternatives provide significant advantages for compact and efficient layouts, which semi-rigid assemblies can’t achieve. This means engineers can easily route cables through complex configurations without the precise, time-consuming bend planning previously required.

For aircraft and satellite systems, cutting weight and simplifying installation are top priorities. Flexible solutions address these by removing the need for precise pre-forming, which in turn cuts installation time and the risk of assembly damage.

With telecommunications infrastructure becoming increasingly dense, the capability to route cables efficiently through confined spaces without performance degradation is highly prized. Flexible alternatives streamline installation within crowded equipment tracks and enclosures, significantly cutting assembly time while preserving the crucial integrity vital for high-bandwidth applications.

Aerospace and defense applications demand uncompromising performance stability in harsh conditions. Flexible cable options need to consistently deliver stable loss, phase, and VSWR characteristics despite flexing. This is essential for systems where signal integrity directly determines operational effectiveness.

Military applications demand highly resilient solutions that maintain consistent performance through extreme conditions. Flexible assemblies must rise to this challenge with durable construction and excellent protection in corrosive environments. A significant benefit of flexible assemblies for deployed systems is the capacity for field modifications, a task that is difficult or even impossible with traditional semi-rigid assemblies, thereby greatly enhancing serviceability.

TFlex^®: Redefining Flexible RF Performance

A key player in this flexible revolution is TFlex^® cable, a high-performance microwave cable from Times Microwave Systems explicitly designed to serve as a direct, drop-in substitute for semi-rigid coaxial assemblies. This advanced flexible cable stands apart from traditional options, which often sacrifice electrical performance. It delivers consistently low insertion loss, excellent shielding effectiveness, and stable phase performance, even when bent or flexed. This makes TFlex coaxial cables an ideal solution for aerospace, defense, and telecommunications, serving as a direct and flexible replacement for semi-rigid cables without requiring intricate 3D bend configurations.

How TFlex Cable Delivers Unmatched Flexibility and Performance

The innovative construction of TFlex assemblies showcase how far flexible alternatives to semi-rigid cables have come. It meets MIL-DTL-17 standards while offering significantly simpler installation. This breakthrough is due to its unique combination of performance-enhancing features:

The silver-plated copper center conductor helps maximize signal transmission efficiency.
An inner layer of solid PTFE dielectric material ensures excellent electrical performance and consistent stability across varying temperatures.
Superior EMI protection comes from a double-layer shield, combining a helical wrap of silver-plated copper tape with an outer braid.
An FEP (Fluorinated Ethylene Propylene) outer jacket provides robust environmental protection, especially in corrosive conditions.

The innovative construction strikes a crucial balance between mechanical flexibility and electrical performance. The unique helical wrap and braided shield design enables the cable to bend easily without specialized tools while preserving the electrical characteristics typically found in semi-rigid assemblies.

It provides excellent shielding effectiveness, actively protecting sensitive components from external interference. The cable also exhibits low passive intermodulation (PIM), which is essential for maintaining signal clarity in complex multi-channel systems. Furthermore, TFlex ensures stable loss, phase, and VSWR characteristics even when flexed, a testament to its robust design. Its compatibility with standard solder-on semi-rigid connectors greatly simplifies integration with existing systems. Finally, a UV-resistant, flame-retardant outer jacket makes it durable enough for a wide range of installation environments.

Choosing the Right TFlex Cable

TFlex cable assemblies are available in three sizes to suit different application needs, each engineered for optimal performance and flexibility:

TFlex 405 (Cable Size 100): Balance flexibility and low-loss signal transmission, making them the perfect choice for high-frequency applications in aerospace, defense, and telecom industries.
TFlex 402 (Cable Size 160): Excellent RF performance with the flexibility needed for easy installation in tight spaces. Engineered as a direct replacement for semi-rigid cables, they maintain low loss and excellent shielding while eliminating the challenges of complex routing.
TFlex 401 (Cable Size 270): A high-performance, flexible coaxial cable designed for aerospace, defense, and telecommunications applications, offering low insertion loss and excellent phase stability.

Flexible Future of RF

TFlex assemblies broaden design horizons and cuts down on complexity and costs by seamlessly merging the electrical prowess of semi-rigid cables with the ease of flexible installation. A major advantage of TFlex over traditional semi-rigid options is its immediate availability: you can get raw cables, connectors, and full assemblies quickly through distributors. This eliminates the need for the extensive design time and specialized bending equipment usually required for semi-rigid setups. Additionally, TFlex coaxial cable assemblies are stocked by authorized distributor partners, ensuring you get fast access to high-performance RF solutions when you need them.

The continuous advancement of aerospace, defense, and telecommunications systems is driving a growing need for components that are both high-performing and easy to integrate. Flexible solutions like TFlex address this dual requirement by preserving essential performance characteristics while also offering a full ecosystem of compatible products easily accessible via standard distribution channels.

In applications requiring both high signal integrity and easy integration, flexibility is an advantage. It’s a forward-looking solution that delivers on performance while simplifying installations for future innovations.

TFlex^® is a registered trademark of Times Microwave Systems.