- Electrical Performance Degradation Analysis
A. Insertion Loss and Return Loss Monitoring
Baseline vs. Aged Comparison:
Frequency (GHz) New Cable (dB/m) Aged (5 years, 10k cycles)
10 0.42 0.68 (+62%)
30 1.15 2.10 (+83%)
60 2.40 4.50 (+88%)
Aging causes dielectric breakdown and conductor oxidation, increasing loss.
Tool: Vector Network Analyzer (VNA) with ±0.05 dB accuracy (e.g., Keysight PNA).
B. Time-Domain Reflectometry (TDR)
Fault Localization: Detects impedance mismatches from shield corrosion or connector wear.
Case Study: A 0.8mm cable in a radar module showed a 15% impedance drop at 12cm, indicating cracked dielectric after thermal shock testing.
- Material Property Evaluation
A. Dielectric Spectroscopy
Key Metrics:
Dissipation Factor (tan δ): Increases from 0.0003 to 0.0015 in PTFE after UV exposure.
Permittivity Drift: ±2% variation in εᵣ accelerates phase instability.
Method: LCR meters (e.g., Hioki IM3536) measure dielectric response at 1 MHz–1 GHz.
B. Thermogravimetric Analysis (TGA)
Degradation Temperature:
Virgin FEP Insulation: 380°C.
Aged FEP (500 thermal cycles): 345°C (-9.2%).
Application: Identifies polymer chain scission due to overheating.
- Mechanical Stress Testing
A. Flexure Endurance
Test Protocol: IEC 61196-1 dynamic bending (radius = 5× diameter).
Cable Diameter Cycles to Failure (20% ΔZ)
0.32mm 8,000
1.2mm 25,000
Smaller cables fatigue faster due to higher stress per bend.
B. Tensile Strength Measurement
Failure Threshold:
New: 50N (braided shield).
Corroded (salt fog test): 28N (-44%).
Tool: Instron 5967 dual-column tester.
- Environmental Aging Simulations
A. Thermal Cycling
Condition: -55°C ↔ +125°C, 1,000 cycles (MIL-STD-883H).
Result: Microcracks in ETFE jackets reduce shielding effectiveness (SE) from 90 dB to 65 dB.
B. Humidity Exposure
Test: 85°C/85% RH, 1,000 hours (JESD22-A101).
Consequence: Silver-plated conductors show >50% tarnish (Ag₂S), raising resistance by 30%.
- Advanced Non-Destructive Techniques
A. Terahertz Imaging
Resolution: 10μm defects in dielectric layers.
Case Study: THz scans detected delamination in 0.47mm cables used for 5G mmWave arrays before electrical failure.
B. AI-Powered Predictive Maintenance
Model Inputs: Historical loss data, bend cycles, thermal profiles.
Output: Predicts remaining useful life (RUL) with >90% accuracy (Siemens Senseye®).
- Industry-Specific Standards
Standard Focus Area Acceptable Aging Threshold
IEC 61196-1 Flexure and RF performance <15% insertion loss increase
MIL-DTL-87104 Thermal/chemical resistance No visible jacket cracks
Automotive USCAR 2 Vibration durability <10% impedance drift
- Case Study: Aerospace Cable Aging Mitigation
Problem: Shield braid fractures in 0.5mm cables caused intermittent CAN bus errors in satellites.
Solution:
TDR identified fracture locations.
Replaced with Au-plated cables (MIL-DTL-17 qualification).
Implemented 6-monthly VNA-based screening.
Outcome: Zero aging-related failures in 3 years.
