256-Core Coaxial Cable Bundle | Phase-Matched Ultrasound & PAUT

256-Core Coaxial Cable Bundle

256-core coaxial bundle cable— 42 AWG (9.6 mm OD) or 44 AWG (7.8 mm OD), phase-matched ±1% (±0.5% available). 50 Ω, ePTFE dielectric, 7-strand conductor. For 3D/4D ultrasound probes and 256-element PAUT inspection. Concentric layer geometry, per-element TDR certification.
Ultra-Fine Gauge × Ultra-High Core Density
ePTFE Low-Loss Dielectric Technology
Dual-Layer Shielding — Channel Isolation >40 dB
High-Flex — 1M Flex / 5M Torsion Cycles
ISO 9001 Certified · Fast Turnaround · Full Customization
Phase Matching ±1% — 100% TDR Verified
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The 256-core coaxial cable bundle is the most demanding standard configuration in micro coaxial manufacturing. 256 individually shielded 50 Ω elements — each with its own foil and braid shielding — must be precisely arranged in concentric layers, phase-matched within ±1% propagation delay, and enclosed in a flexible jacket that allows over 500,000 flex cycles. At 42 AWG, this produces a 9.6 mm OD bundle; at 44 AWG, 7.8 mm.

256-core bundles serve two primary markets: 3D/4D ultrasound probe manufacturers (cardiac and OB volumetric imaging) and NDT PAUT equipment builders (256-element high-resolution inspection systems).

We have manufactured 256-core phase-matched bundles since 2008, with cumulative production exceeding 15,000 assemblies. This is our most technically demanding standard product and our highest demonstration of phase-matching manufacturing capability.

Specifications — 256-Core Bundle Coaxial

Parameter 42 AWG Configuration 44 AWG Configuration
Core count 256 256
Element OD 0.48 mm 0.38 mm
Bundle OD (jacketed) 9.6 mm ± 0.3 mm 7.8 mm ± 0.3 mm
Impedance 50 Ω ± 2 Ω per element 50 Ω ± 2 Ω per element
Phase matching ±1.0% (std) / ±0.5% (prem) ±0.5% standard
Dielectric ePTFE (Dk ≈ 1.45) ePTFE (Dk ≈ 1.45)
Conductor Ag-plated CuAg, 7-strand Ag-plated CuAg, 7-strand
Capacitance ≤ 95 pF/m per element ≤ 110 pF/m per element
VoP ≥ 78% ≥ 78%
Flex life (7-strand) > 500K at 30 mm radius > 500K at 25 mm radius
Jacket PUR / PFA PUR / PFA
Cable length range 1.5–3.0 m 1.5–2.5 m
Weight per meter ~85 g/m ~55 g/m

Concentric Layer Geometry

256 elements are arranged in concentric hexagonal close-pack layers:

Layer Element Count Cumulative Total Layer OD (42 AWG) Layer OD (44 AWG)
Core 1 1 0.48 mm 0.38 mm
1 6 7 1.44 mm 1.14 mm
2 12 19 2.40 mm 1.90 mm
3 18 37 3.36 mm 2.66 mm
4 24 61 4.32 mm 3.42 mm
5 30 91 5.28 mm 4.18 mm
6 36 127 6.24 mm 4.94 mm
7 42 169 7.20 mm 5.70 mm
8 48 217 8.16 mm 6.46 mm
9 39 (partial) 256 9.12 mm 7.22 mm
Jacket — — 9.6 mm 7.8 mm

The 9th layer is partially filled (39 of maximum 54 positions), creating an asymmetric outer layer. Our assembly process positions these 39 elements symmetrically around the circumference with spacer elements (non-active fillers) in the remaining 15 positions to maintain round cable geometry and prevent bundle distortion during flexing.

Phase Matching at 256 Channels — Manufacturing Challenge

Phase matching 256 channels to ±1.0% is significantly more difficult than matching 128 channels. The statistical challenge: with 256 elements drawn from a production lot, the probability of finding 256 elements within ±0.25% of the lot mean decreases exponentially with channel count. Our process addresses this through:

Large production lot sizes: We extrude ePTFE dielectric in continuous runs of 50,000+ meters to maximize lot uniformity. Larger lots produce tighter natural distribution of Dk values.

Tight Dk control: ePTFE wall thickness controlled to ±0.005 mm. At this tolerance, propagation velocity variation across a production lot is typically ±0.15% (1σ) — well within the ±0.25% bin tolerance.

Bin inventory management: We maintain rolling inventory of measured and binned cable elements. For a 256-channel order, we draw from the center of the distribution — the largest bin — to maximize the probability of finding 256 matched elements.

Bundle verification: Every channel in the completed 256-core bundle is TDR-verified. Any channel outside tolerance is replaced and the bundle re-verified. Typical replacement rate: 2–5 elements per 256-core bundle (< 2%).

Application

3D/4D Cardiac Ultrasound Probes
256-element matrix arrays for real-time volumetric cardiac imaging. Phase matching ±0.5% at 44 AWG (7.8 mm bundle OD) enables ergonomic probe design. The highest-value application for 256-core bundles.

3D OB/GYN Ultrasound Probes
256-element convex matrix arrays for fetal volumetric imaging. 42 AWG standard (9.6 mm OD acceptable for convex probe form factor). Phase matching ±1.0%.

High-Resolution PAUT Inspection
256-element phased-array probes for aerospace composite inspection, nuclear plant weld examination, and high-resolution pipeline ILI. LEMO EPL or Hypertac multi-pin connectors. ASME/ASTM documentation.

Research Ultrasound Platforms
Custom 256-channel research probe cables for universities and R&D institutions developing novel imaging algorithms, contrast agent techniques, or experimental transducer architectures.

256-Core vs. 128-Core vs. 512-Core

Factor 128-Core 256-Core 512-Core
Bundle OD (42 AWG) 7.2 mm 9.6 mm 13.7 mm
Bundle OD (44 AWG) 5.8 mm 7.8 mm 11.2 mm
Phase match cost Baseline +35–50% vs 128 +80–120% vs 128
Lead time 3–5 weeks 3–5 weeks 4–6 weeks
Application Standard 2D imaging 3D/4D volumetric Next-gen matrix
Market status Established Growing rapidly Emerging

Frequently Asked Questions

Why choose 42 AWG vs. 44 AWG for a 256-core bundle?

42 AWG (9.6 mm OD) when bundle diameter is not the constraining factor — lower cost (40–60% less), lower attenuation, faster delivery. 44 AWG (7.8 mm OD) when the probe handle or form factor cannot accommodate 9.6 mm — typically 3D cardiac probes and compact portable devices. The 1.8 mm OD savings of 44 AWG is significant for ergonomic probe design.

Can 256 channels be phase-matched to ±0.5%?

3–5 weeks for prototype (5 assemblies). 2–4 weeks for repeat production orders where cable elements are pre-stocked. Emergency: 2–3 weeks with surcharge.

What is the delivery time for a 256-core bundle?

Yes. Send the probe (or failed cable) and we reverse-engineer via TDR, optical measurement, and material analysis. Turnaround: 3–5 business days to specification. Engineering fee credited against first production order of 50+ assemblies.

Do you map element positions in the bundle?

Yes. Every 256-core phase-matched bundle ships with a position map showing which cable serial number occupies which position in the concentric layer arrangement. This enables your connector termination team to maintain the known position → pin-out mapping.

Need a 256-core phase-matched bundle for ultrasound or PAUT? Share AWG preference, phase tolerance, and connector — quote within 48 hours.

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Related Words: 256 core coaxial cable, 256 channel coaxial bundle, 256 element cable, 256 core micro coaxial, 256 channel ultrasound cable, 256 element PAUT cable, high channel count coaxial bundle

Applications

Ultrasound Probe & Transducer

Modern 3D ultrasound probes contain 128–512 piezoelectric elements requiring precisely matched electrical path lengths for accurate beamforming. Multi-core micro coaxial cable provides per-channel shielding with phase-matched construction, serving as the core interconnect for GE, Philips, Siemens, and Mindray platforms.

Medical Endoscope Camera

Endoscope insertion tubes of 2–4 mm diameter must transmit HD/4K video while enduring 1M+ flex cycles. Using 42–46 AWG stranded conductors, OD achieves as small as 1.2 mm, supporting HD-SDI and 4K LVDS signals while meeting ISO 10993 biocompatibility requirements.

Robotic Surgery Cable

Robotic surgery arms must carry imaging signals, electrosurgical RF power, motor drive currents, and fiber optic illumination through ±270° articulating joints — all within a single hybrid assembly. Micro coaxial elements serve as the signal core, qualified to 5 million torsional flex cycles.

NDT Ultrasonic Testing (PAUT / TOFD)

Weld inspection and corrosion mapping in petrochemical, nuclear, and aerospace industries use PAUT and TOFD — requiring 16–256 core, phase-matched ±1%, 50 Ω micro coaxial bundles with industrial PUR/FEP/PTFE jackets, compliant with ASME V and EN 583-2 standards.

MRI-Compatible Device Cables

The MRI bore presents three electromagnetic environments requiring all metals to pass ASTM F2503 ferromagnetic assessment. Non-magnetic silver-plated copper alloy conductors meet 1.5T/3T MRI safety requirements for MRI-guided interventions, coil connections, and CT detector array interconnects.

Semiconductor / Industrial Robotics / Aerospace

Semiconductor wafer AOI inspection, industrial robot joint routing, and aerospace sensor arrays all demand high-density, fine-gauge cables with tight impedance control and signal integrity — areas where micro coaxial cable delivers unmatched performance in high-frequency transmission, channel isolation, and compact construction.

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