The short answer is yes—but coaxial cable assemblies require specialized design, material selection, and mechanical optimization to maintain performance and reliability in high-vibration environments (e.g., aerospace, industrial automation, automotive powertrains, or marine systems). Without these safeguards, vibration can cause signal degradation, mechanical failure, or premature wear. Below is a detailed breakdown of key considerations to ensure suitability:
1. The Risks of Vibration to Standard Coaxial Assemblies
Before exploring solutions, it is critical to understand how vibration harms conventional coaxial designs:
- Mechanical damage: Repeated vibration can loosen connector interfaces, crack insulation, or break stranded conductors (via metal fatigue). For example, a standard BNC connector without a locking mechanism may decouple under 50Hz+ vibration.
- Signal integrity loss: Vibration-induced micro-movement between the inner conductor and dielectric can shift characteristic impedance (target: 50Ω/75Ω for most applications), leading to reflection, insertion loss, or crosstalk.
- Shielding failure: If the outer shield (e.g., aluminum foil or braided copper) becomes detached from the connector or develops gaps, electromagnetic interference (EMI) immunity drops—critical in industrial or aerospace settings.
2. Design & Material Solutions for High-Vibration Use
To mitigate these risks, coaxial assemblies must be engineered for vibration resistance. Key technical choices include:
A. Conductor Design: Prioritize Flexibility & Fatigue Resistance
- Stranded inner conductors: Replace single solid conductors with multi-stranded (e.g., 7×32 AWG) copper or copper-clad steel. Stranded designs absorb vibration energy better and resist fatigue—solid conductors are prone to snapping after 10,000+ vibration cycles.
- Tinned or silver-plated conductors: Plating reduces oxidation (a common issue in humid/vibrating environments) and maintains electrical conductivity over time.
B. Dielectric (Insulation): Stability Under Stress
- PTFE or PFA dielectrics: These fluoropolymer materials offer low dielectric constant (εr ≈ 2.1) for impedance stability, plus resistance to temperature extremes (-200°C to 260°C) and vibration-induced creep. Avoid foam dielectric for high-vibration use—its porous structure can compress or crack.
- Uniform wall thickness: Extruded dielectrics with ±0.001” thickness tolerance prevent impedance fluctuations caused by vibration.
C. Shielding: Robust EMI Protection
- Dual-shield constructions: Combine a tinned copper braid (90%+ coverage) with an aluminum mylar foil. The braid resists mechanical stress from vibration, while the foil blocks low-frequency EMI. For extreme environments (e.g., jet engines), add a third layer of copper tape.
- Shield-to-connector bonding: Use solder or crimped interfaces (instead of adhesive) to attach the shield to the connector backshell. This prevents shield detachment during vibration.
D. Connectors: Secure Locking & Reinforcement
- Threaded or bayonet locks: Choose connectors like SMA (threaded), TNC (threaded), or MS3456 (military bayonet) over push-on designs (e.g., BNC). Threaded locks provide 5–10x more retention force under vibration.
- Metal backshells: Plastic backshells crack under repeated stress—opt for nickel-plated brass or stainless steel. Add O-rings for environmental sealing (IP67/IP68) to prevent moisture ingress (worsened by vibration).
E. Strain Relief: Absorb Vibration Energy
- Integrated strain relief boots: Use heat-shrinkable polyurethane (PU) or silicone boots at the connector-cable junction. These boots distribute stress away from the conductor/dielectric interface, reducing fatigue.
- Cable clamps or brackets: For fixed installations (e.g., industrial machinery), use metal clamps to secure the cable at 6–12” intervals. This limits cable movement and prevents excessive vibration transfer.
3. Testing: Validate Performance in Vibration
Even with optimized design, coaxial assemblies must pass industry vibration tests to ensure reliability. Common standards include:
- MIL-STD-883H Method 2007: Tests vibration resistance across 10–2000Hz (10g acceleration) for 1 hour per axis (x, y, z). Assemblies must show <0.1dB insertion loss change and no mechanical damage.
- IEC 60068-2-6: For industrial use, tests 10–500Hz (5g acceleration) for 2–24 hours.
- Automotive EIA-364-28: Tests 10–2000Hz (20g acceleration) for automotive powertrain applications.
Post-test, inspect for connector tightness, conductor continuity, and impedance stability (using a network analyzer) to confirm performance.
4. Typical High-Vibration Applications
Optimized coaxial assemblies are widely used in:
- Aerospace: In-flight entertainment systems, radar, and engine sensors (vibrations up to 20g).
- Industrial automation: Robot arms, CNC machines, and conveyor systems (10–15g, 50–500Hz).
- Automotive: ADAS (Advanced Driver-Assistance Systems) and EV battery management (vibrations from road surfaces, 5–10g).
- Marine: Shipboard communication systems (vibrations from engines, 5–8g).
Why FRS Coaxial Assemblies Excel in High-Vibration Environments
When reliability in high-vibration settings matters, FRS’s factory-designed coaxial assemblies deliver. Built to address the exact challenges outlined above, FRS uses:
- Stranded, silver-plated copper conductors for fatigue resistance;
- PTFE dielectrics for impedance stability;
- Dual-shield (braid + foil) constructions with soldered shield-to-connector bonding;
- MIL-grade threaded connectors (SMA/TNC) with metal backshells;
- Integrated PU strain relief and IP67 sealing.
Every FRS assembly undergoes MIL-STD-883H vibration testing and 100% post-production inspection (insertion loss, impedance, continuity) to ensure it performs in the harshest environments—from aerospace to industrial automation. For custom solutions tailored to your specific vibration requirements, FRS’s engineering team works closely with you to deliver reliable, long-lasting coaxial assemblies.
