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Interconnections are often regarded as “patches” or “weak links” in military electronic systems. In truth, they are essential components in those systems, required to provide dependable transfers of power, analog signals, and digital signals from one part of the equipment to another. Military and aerospace interconnections must provide mechanical and electrical integrity, performing over wide temperature ranges, and often as part of environments that must endure high levels of shock and vibration.

With the complex mix of different signals in modern military electronic systems, the cables and connectors found in those systems range from basic signal and power cables to exotic, multiple-conductor collections that carry every type of energy used by the system. In many cases, if these interconnections fail, the system will fail. Consequently, the reliability of the cables and connectors is extremely important, and the performance can impose a limit on the rest of the system.

The variety of cables and connectors used in military and aerospace systems is as large as the types of signals carried through those systems. The quality of the dielectric material wrapping a cable, for example, can impact the electrical performance of the cable, especially when required to minimize signal losses at higher frequencies. Connector dimensions must be tightly controlled at higher frequencies to minimize losses and signal reflections, and also to provide smooth transitions. The size, weight, and power (SWaP) requirements of modern systems impact interconnections for most aerospace and defense applications and, with the growing use of unmanned ground vehicles (UGVs) and unmanned aerial vehicles (UAVs) in these applications, the interconnections are being subjected to increasingly hostile operating environments.

Cables And Connectors Tie Systems Together, Fig. 1

Interconnections in military and aerospace systems are formed of many different types of cables and connectors, depending upon the mechanical and electrical requirements. Parameters guiding a choice of cable assembly in an airborne application include data rate, frequency, signal power, tolerable loss, and even the weight of the assembly. Whether for analog, digital, or a mix of signals, cables and connectors for military electronic systems must weather (pun intended) different types of storms, maintaining consistent performance under the best and worst operating conditions. New interconnect solutions are constantly emerging for military applications due to the broad uses and environments for those applications.

Amphenol, for example, offers a wide range of interconnects for aerospace/military applications, including connectors qualified to MIL-DTL-38999 requirements and MIL-C-26500 connectors (with bayonet or threaded coupling and aluminum or stainless-steel shells). The firm also manufactures the MIL-STD-1760 Stores Management Connector System for use on aircraft that carry rail-launched missiles or are designed for MIL-STD-1760 Weapons Release type quick-disconnect connectors. 

Cables And Connectors Tie Systems Together, Fig. 2The KVPX family of ruggedized connectors from Smiths Connectors, for example, are VITA 63 type connectors that are compatible with popular OpenVPX™ interconnection systems but constructed with the high reliability needed for military and aerospace use. This shielded, high-density, modular interconnect system (Fig. 1), available from the firm’s Hypertronics company, has been optimized for differential pair architectures in extremely tight connector/cable grids.

The connectors can handle data rates from 80 Mb/s to 6.25 Gb/s. They are scalable to work at data rates of more than 10 Gb/s and fit into backplane grids as tight as 1.8 × 1.8 mm for creating compact circuit-card solutions for military systems. They are footprint compatible with VITA 46 and VITA 48 connector standards and feature integrated electrostatic-discharge (ESD) protection.

These connectors typify the needs of military and aerospace applications, with low required insertion and extraction forces and rated for a high number of insertions without degradation in performance. In addition, they are constructed with insulators that exceed NASA’s requirements for deep-space outgassing, and they feature a contact system with low contact resistance for repeatable electrical performance.

Another novel connector design, the Dualok Interconnect System from Amphenol Aerospace, was designed for use in harsh environments across multiple markets, including in commercial and military aircraft. The compact interconnect (Fig. 2) employs an anti-decoupling mechanism that can be used on almost any cylindrical plug connector and backshell. It is designed to improve electrical performance in harsh environments, additionally providing a savings in size and weight compared to standard electrical connectors.

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