Case Study: Designing a Custom High-Flex Medical Coaxial Cable for Next-Gen Diagnostic Imaging

1. The Challenge & Application Scope

The coaxial cable serves as the data lifeline between the ultrasound transducer array and the imaging system. For this advanced probe aimed at point-of-care diagnostics, the requirements were exceptionally stringent:

• Application: High-frequency signal transmission in a compact, handheld ultrasound transducer.

• Key Demands:

  1. Superior Flexibility: The cable must withstand >50,000 tight bend cycles without performance degradation, allowing for natural clinician movement.

  2. Signal Integrity: Maintain precise 50Ω impedance with >90 dB shielding effectiveness (SE) to ensure crystal-clear imaging free from internal or external noise.

  3. Patient/User Safety: Require a bio-compatible, non-toxic, and easily cleanable jacket material.

  4. Manufacturing Feasibility: The design needed to be reliably produced at scale with consistent performance.

2. The Material Selection: A Data-Driven Breakdown

The core of the solution lay in selecting the right combination of materials for each layer, balancing electrical, mechanical, and regulatory needs.

• Insulation & Jacket Material Analysis for Medical Coaxial Cables

  Material	Typical Shore A Hardness	Temperature Range	Key Advantages	Limitations & Best For...
  PVC	80 - 95	-10°C to 105°C	Low cost, good durability.	Stiffens in cold, contains plasticizers (leaching risk), not ideal for high-flex or intimate patient contact.
  Thermoplastic Polyurethane (TPU)	70 - 90	-40°C to 125°C	Excellent abrasion & chemical resistance.	Can be heavier, less "silky" feel than silicone, good for robust cable bodies.
  Silicone Rubber (Our Choice)	40 - 60	-60°C to 200°C	Unmatched softness/flexibility, superior bio-compatibility (ISO 10993), odorless, sterilizable (autoclave/EtO).	Lower cut/abrasion resistance (requires careful design). The premier choice for patient-facing, high-flex applications.

Why Silicone Was Uniquely Suited: With a Shore A hardness of 50 in our formulation, the silicone jacket provided a "silky" feel that reduced hand fatigue for clinicians. Its extreme temperature range ensured it could withstand repeated cleaning and accidental autoclaving without cracking or hardening, directly contributing to the >50,000 flex cycle target.

• Shielding Configuration & Color Options for Medical Devices

  A. Shielding Performance Comparison
  Shield Type	Structure	Shielding Effectiveness (Typical) & Application
  Single Braid	One layer of tinned copper braid.	~70-80 dB. Suitable for general-purpose medical devices with moderate EMI.
  Dual Shield (Our Choice)	AL Foil (100% coverage) + Tinned Copper Braid (≥90% coverage). or double braiding optional	>90 dB. Provides complete coverage for critical, high-frequency applications like ultrasound.
  Premium Dual Shield	AL Foil + Silver-Plated Copper Braid.	>95 dB & Non-Magnetic. Essential for MRI-conditional or MRI-safe devices, preventing image artifacts.

  

  B. Jacket Color Standardization
  Color	Industry Convention & Purpose	Visual & Practical Benefit
  White	Universal for patient-connected cables.	Easy to visually inspect for cleanliness and contamination. Associated with cleanliness and sterility.
  Blue	Common for non-patient-facing cables or specific departmental coding (e.g., ultrasound).	Provides contrast in the clinical environment, aids in quick equipment identification and inventory management.
  Custom Colors	For brand differentiation or proprietary system coding.	Allows device manufacturers to integrate cables seamlessly into their product ecosystem.

3. The Engineered Solution & Measured Outcomes

We delivered a fully customized, miniaturized coaxial cable with the following specification stack:

• Electrical Core: Precision-engineered to maintain 50Ω ±2Ω impedance up to 6 GHz, ensuring flawless signal transmission for high-resolution imaging.

• Shielding: Dual-shield structure with AL foil and a high-density tinned copper braid, achieving a tested 92 dB shielding effectiveness, eliminating noise.

• Flexibility Jacket: Medical-grade white silicone formulated to a 50 Shore A hardness, providing the required drape and softness.

• Performance Validation: The cable passed >60,000 flex cycles (IPC-620 test standard) with no electrical discontinuities and maintained signal integrity after 50 repeated autoclave cycles.

The Result: The OEM integrated our cable into their probe, achieving a product that was lauded for its ergonomic design and exceptionally reliable, artifact-free imaging performance, directly contributing to successful market adoption.

Your Partner in Medical Cable Innovation

This case study exemplifies our approach at Shanghai Dingzun Electric & Cable Co., Ltd.. With over 20 years of experience, we specialize in turning complex application challenges into reliable, high-performance cable solutions. Our extreme customizability covers every aspect—from specialized shielding like non-magnetic silver-plated braids to formulating silicone compounds for specific feel and durability.

We engage in direct, professional collaboration with your engineering team. Our expert technical staff guides you from concept to validation, ensuring your cable component meets all electrical, mechanical, and regulatory requirements.

Ready to solve your medical device cabling challenge?

[Contact our specialist team for a confidential engineering consultation].