What Key Characteristics Should You Consider in a Cable Assembly Solution?

Cable assemblies are essential interconnects that serve as a signal’s primary pathway between various components in RF and microwave systems. Other solutions in the interconnect family play complementary roles for efficient and reliable signal transmission. For instance, adapters and attenuators enable optimal signal control and management by facilitating connections and adjusting signal strength to appropriate levels. Components such as torque wrenches and connector gage kits are important maintenance tools for ensuring secure, high-integrity connections over time.

This blog post will explore the role of the cable assembly in RF and microwave systems, reviewing critical performance parameters to consider when selecting the most suitable cable for your specific objectives.

Cable Assemblies: Key Characteristics

Cables are constructed of several layers that enable signal transmission and provide protection. The RF signal travels along a center conductor, which is surrounded by several layers of material that provide  various benefits, such as electromagnetic interference (EMI) shielding and mechanical protection. Armored cables, such as the Maury Microwave StabilityPlus^TM Phase Stable Cable Assemblies (SP-series) pictured below, incorporate additional protective layers to enhance durability compared to standard cables.

Achieving high-quality measurements and optimal system performance relies on several cable assembly features, including amplitude stability, phase stability, flexibility, and durability.

Amplitude stability

Ideally, cables should maintain the power level of a signal between various devices. Signal amplitudes that degrade or fluctuate can introduce errors during testing, making it difficult to distinguish whether inaccuracies were introduced by the device under test (DUT) or the cables themselves. This can compromise both measurement accuracy (the degree to which the measured value reflects the true value) and repeatability (obtaining reliable, stable results under the same conditions). Further, unstable signal strength can significantly affect overall system performance. Communications systems, for example, can experience misinterpreted data, transmission failures, and reduced quality. Since mechanical stresses, such as bending or flexing, can cause these variations, it’s vital to choose cable assembles that provide excellent amplitude stability even after flexure.

Phase stability

A phase-stable cable assembly can maintain a signal’s phase relative to a reference signal as it travels from the source to its destination, even if the cable is manipulated, bent, or flexed. Similar to the effects of amplitude instability, shifts in phase compromise measurement accuracy, leading to erroneous data, reduced repeatability, and low confidence in the validity of test results. From a performance perspective, signal drift can cause synchronization issues in systems that rely on precise timing, increase bit errors and the potential for interference, and reduce signal quality.

Durability

Oftentimes cable assemblies require a high level of durability, especially when used in harsh environments that heighten the likelihood of physical stress, such as bending, flexing, and heavy impacts. When used on a test bench or inside an electromagnetic compatibility (EMC) chamber, cables are susceptible to being damaged, compressed, or stepped on, especially if placed along the floor over long distances. In these cases, cables are ultimately left in harm’s way, increasing the importance of selecting highly durable cables that protect against damage, extend the lifespan to minimize replacement costs, and ensure consistent performance under challenging conditions.

Flexibility

Cable flexibility simplifies installation, saving time and effort by easily maneuvering within tight, space-constrained environments or complex test setups. In addition, flexible cables can withstand repeated bending and twisting without the risk of damage, fatigue, or a reduction in signal quality.

StabilityPlus Phase Stable Cable Assemblies

Combining these key features into an everyday test cable is the ruggedized, phase-stable, and amplitude-stable SP-series cable assembly from Maury Microwave. The SP-series is an ideal choice for daily use in dynamic environments that demand frequent use, significant flexure, and high rates of mating and demating. This solution is well-suited for various test environments and applications, including VNA testing, remote testing, production testing, and situations requiring long cable lengths.

The ColorConnect™ color-coding system follows the proposed IEEE high-frequency connector/adapter color convention. With this system, users can quickly and clearly identify whether the cable assembly is in fact compatible. Clear indications of compatibility and intermatability significantly reduce the risk of damaging both the assembly and system, which ensures equipment reliability, maintains high performance standards, and minimizes lengthy maintenance times associated with improperly mating incompatible interconnects.

Cable assemblies are critical components that hold great influence over the integrity and repeatability of measurements in RF and microwave systems. Setting the standard for high-performance ruggedized cable assemblies, the SP-series is your preferred interconnect of choice to enhance your daily testing needs.