Pushing the Boundaries: New Connectors Engineered for Harsh Aerospace and Defense Environments

December 2023, By Cameron Foley-Molovinsky

Aerospace and defense applications withstand some of the harshest environmental conditions for high-performance electronics technologies. The mission-critical RF systems within these applications serve as the backbone for a range of vital technologies, including satellite communication, electronic warfare, intelligence, missile guidance, radar, hypersonic systems, and more. An ongoing evolution of hardware components and interconnection solutions is needed to meet the rigorous demands imposed by cutting-edge technologies and ensure their flawless operation in harsh and variable environments.

The effectiveness of RF systems fundamentally depends on the integrity of those hardware components and how they come together. While some installations can make do with fairly standard products, others necessitate custom-designed solutions tailored to unique specifications. In the ever-changing landscape of the aerospace and defense industries, there is a growing demand for high-performance connectors that can withstand harsh conditions, severe vibrations, and extreme temperatures while still delivering consistent performance.

However, legacy connector designs, such as SMP/SMPM, are no longer sufficient to meet the requirements of advancing technology. They are susceptible to issues like electromagnetic interference (EMI) and electromagnetic compatibility (EMC), lack environmental sealing, and have the potential to disengage upon impact, such as during a hard landing. This has spurred the development of innovative RF interconnect designs to address these challenges more effectively.

Among these, locking miniature push-on and locking miniature blind mate connectors have emerged as the new industry standard, specifically tailored to rectify the shortcomings of legacy technologies.

These advancements in connector designs also drive the development of a new generation of aerospace and defense applications that continually push the boundaries of power handling and performance. These novel connector types are engineered to excel in high peak power situations at high altitudes. They are crucial in the next wave of military communication systems designed for harsh environments.

This article will detail how these advanced technologies are ushering in the modern era of reliable high performance in demanding, variable, and extremely harsh environments and will further explore the RF interconnect designs required to handle these challenges. Additionally, it will offer insights into emerging applications that demand multifaceted connectivity solutions.

The New Industry Standard

Evidence of this shift can be seen in the rising popularity of smaller-sized, O-ring sealed connector solutions that surpass their SMP/SMPM predecessors, delivering enhanced shielding, environmental protection, and mechanical retention. This includes the introduction of cutting-edge locking miniature push-on and locking miniature blind mate connectors, specifically designed to address EMI concerns for applications that require an environmentally sealed and shielded connector. The locking miniature push-on connector type is also ideal for high-vibration environments such as a carrier landing, weapons launch, or similar harsh platform issues.

This modern class of connectors maintains the small form factor dimensions of SMPs while introducing advancements such as improved shielding, environmental, and power capabilities, spanning a frequency range from DC to 60 GHz. The mating component effectively covers the connector’s slots, preventing signal leakage. This capability enables these connectors to effectively address performance challenges from EMI and EMC interference as well as liquid and salt ingress. Furthermore, the sealed, rugged design enhances their resilience to withstand harsh conditions and severe environments. At the same time, the overlapping insulators cut off a direct path to the ground from the center conductor to the outer shield, enabling higher-voltage functionality.

In addition, the connectors incorporate a latching mechanism, improving their mating retention capabilities and making them a more suitable choice than threaded body alternatives. A visual verification feature with red (unlocked) and green (locked) color coding provides visual confirmation that the connectors are fully mated and locked. Finally, the locking blind mate version is equipped with an additional outer sleeve, ensuring complete protection of tines for blind mate applications.

Examples of these connector types include the Times Locking Miniature Push-On (TLMP) and the Times Locking Miniature Blind Mate (TLMB) connectors offered by Times Microwave Systems. These connectors are rapidly gaining traction as the industry standard for the new integrated antennas used in modern aerospace configurations.

Trusted Designs Enable the Next Leap Forward

As harsh environment applications continue to advance, the need for new connector solutions for high-density, high-power applications also grows. For example, locking miniature push-on and blind mate connectors are evolving to accommodate higher CW power and frequencies above 18 GHz.

These new connector types are critical when it comes to ensuring the reliability of communication systems. They are well-suited for a wide range of applications, including densely packed signal intelligence, electronics intelligence, and electronic warfare systems that operate in harsh environments. While these connectors preserve the previously mentioned attributes, including the overlapping design, environmental sealing, and enhanced EMI performance, they also incorporate new capabilities to efficiently manage high power at altitude.

The Times Locking Connector (TLC) is an example of technological advancement in this field. It was engineered with a 40-mil line size design and was built to handle higher transmit powers aboard aircraft. This connector utilizes dielectric materials to strengthen its thermal dissipation by adopting Fluoroloy-H™ instead of Teflon. Fluoroloy-H dielectrics possess eight times the thermal dissipation capacity of Teflon, making this connector type specifically tailored for effective heat dissipation of high continuous wave (CW) power at higher altitudes. It is exceptionally well-suited for applications up to 23 GHz.

In cases where a design like the TLC connector is too large for a particular system, alternative technologies like the Times Locking Push-on Connector (TLPC) have been developed to manage high power levels while maintaining a considerably smaller form factor. It features a 30-mil line size and is available in multiple versions, including card edge and various edge launch configurations. It is designed for easy integration, whether threading through the wall of a box or soldering to the ground plane and the center pin or trace on the board, making it suitable for applications requiring a frequency range of up to 32 GHz.

Beyond single interconnects, as aircraft increasingly incorporate numerous boxes and highly densified antennas, the demand for more cables and connectors per square inch also continues to grow. The innovative connector designs detailed above go beyond single interconnects and can be incorporated into multi-ported versions, eliminating conventional coupling nut schemes. This enhances space utilization and operational efficiency. In this configuration, the interfaces are integrated into male and female shells, effectively serving as bulkhead disconnects, enabling significantly higher interface densities.

Navigating New Connectivity Challenges in Harsh Environments: Application Examples

The blend of advanced signal processing and sensing capabilities, combined with integrated hardware, helps unlock critical insights from very large data sets. This empowers military aircraft with more accurate and comprehensive systems and enhances functionality and safety. As this innovation accelerates, connectors must rise to the challenge of handling higher frequencies, faster data transmission speeds, and increased power demands while enduring the same harsh operating environments as their predecessors.

For instance, current systems operate within the 23 to 60 GHz range and beyond, enabling quicker target detection and more precise tracking. These expanding frequency ranges necessitate faster data transmission rates for processing incoming signals. Onboard processors quickly filter and analyze this data to identify threats and facilitate rapid responses. Printed circuit boards (PCBs) are pivotal in establishing rapid connections between components or among PCBs in this sophisticated network. Connectors such as the TLMP, TLMB, TLP, and TLC series have been precisely designed to deliver high-performance connections in such applications, minimizing signal loss and interference.

Moreover, as aircraft continually push the boundaries of speed and altitude, connectors must be able to handle elevated power levels while maintaining a delicate balance between weight, size, and power transmission capacity. For instance, the radar processor box within an airframe orchestrates a complex symphony of technologies, including phased array radar systems that utilize multiple small antennas to electronically steer radar beams. Connectors such as the TLP and TLC are engineered to effectively tackle the inherent challenges in this demanding environment. Furthermore, as boundaries are pushed further in hypersonic flight, connector designs fortified with materials like boron nitride dielectrics capable of withstanding extreme temperatures are emerging.

Finally, modern systems increasingly incorporate integrated antenna elements into the aircraft’s structural framework rather than large standalone antennas. This requires numerous small antennas and connections within a confined space. High-density connectors, such as the TLP and TLC, are ideal solutions for these demanding applications.

Innovative New Strategies Require Collaborative Partnerships

Collaborating with experienced suppliers with deep expertise and trusted heritage of engineering development in mission-critical industries is paramount when designing applications that demand the highest-performing connectors for the harshest environments. The chosen partner must thoroughly understand material technologies and possess in-depth knowledge of the specific applications, encompassing the aircraft, environmental factors, and underlying physics. This holistic approach ensures the development of optimal solutions.

The RF supplier should be an integrated extension of the project’s design team. Given the highly complex nature of aerospace and defense systems, which rarely incorporate standardized solutions, the technical team must ask the right questions to gain insight into the application’s unique requirements. This collaborative effort is instrumental in creating solutions that offer superior electrical, mechanical, and environmental performance.

Consider the following factors when choosing the optimal RF interconnect supplier to ensure the highest possible performance for demanding aerospace and defense applications:

Heritage and qualifications: Many RF suppliers offer a decent list of standard capabilities, but aerospace and defense requirements are unique. Search for a partner with a wealth of relevant experience to help develop RF systems that can withstand the rigors of aerospace and defense environments, deliver reliable performance, and adhere to stringent safety requirements.

Dedicated technical experts: Avoid partnering with a supplier focused on mass-market products—offering the same product they sell to everyone else. Always request to engage with their technical experts. Additionally, the supplier should assist you in understanding the electrical and mechanical trade-offs specific to your application.

A large breadth of products:  A supplier with an extensive product portfolio is better positioned to offer the ideal system for your specific application. When selecting the appropriate materials, it’s advantageous to have a variety of options, including different cable constructions, various connector designs (ranging from low power to high power), and diverse assembly techniques, all available from a single supplier.

Meeting the stringent technical standards required for products deployed in challenging military environments, which mandate the use of acceptable materials and Mil-spec constructions, is essential. However, there isn’t a universally applicable standard for applying these materials to construct a consistently reliable RF solution. This is where your supplier’s expertise and access to a comprehensive range of product options become invaluable.

Manufacturing execution: In an ideal scenario, the RF supplier possesses both the full spectrum of technology and products required and understands how to integrate them into a finished product. The following qualification to evaluate is the supplier’s manufacturing operations. Does the company have robust facilities and well-defined processes that ensure seamless execution? Cleanroom manufacturing capabilities are essential, as well as traceability in managing all the parts that make complicated assemblies. It is also important to know which quality standards the supplier adheres to, as well as any extended services offered.

Agility: Finally, be sure to select an RF partner that is strong enough operationally and financially to not only deliver results but also endure turbulent times.

Looking Forward

To adapt to the ever-changing demands of aerospace and defense systems that operate in harsh environments, evolving connector designs that offer substantial reductions in physical footprint, available in single-mount or multi-ported versions that support higher densities and power thresholds of modern applications while solving the EMI issues and environmental issues of the previous generation of RF connectors, are required. These advanced designs are ushering in a new era of consistently high performance, even in the most demanding, variable, and extremely harsh environments. Regardless of the end product used in building a high-performance application, collaborating with an experienced partner with deep engineering expertise and a trusted legacy of development in mission-critical industries is critical to ensure the continued excellence of high-performance aerospace and defense systems.