Multi-Conductor Coaxial Cable Layout for Dense Test Connections

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Solution Overview

Problem

The limited space in the motherboard housing of semiconductor device testing apparatuses restricts the increase in the number of coaxial cables required for simultaneous measurements, hindering the scalability of the testing capacity.

Innovation Solution

A coaxial cable design featuring multiple inner conductors arranged in a tubular insulator with arc-shaped cross-sections, allowing for high-density arrangement and reduced rigidity, which includes a shared outer conductor and insulator structure to minimize crosstalk and mechanical stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the number of coaxial cables is increased to support more simultaneous measurements, then the testing capacity increases, but the available space in the motherboard housing is exceeded

Engineering Contradiction:

Improvetesting capacityVSAvoidmotherboard housing space

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

Multiple inner conductors (three or more) are integrated within a single coaxial cable structure that shares a common outer conductor and insulator, effectively merging multiple signal paths into one compact unit. This reduces the total number of separate coaxial cables needed while maintaining the capability to support multiple simultaneous measurements, thereby increasing testing capacity without exceeding housing space limits.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent implements a nested structure where multiple inner conductors are positioned concentrically within the insulator, which is itself surrounded by the outer conductor. This nested arrangement maximizes space utilization within each cable cross-section, allowing more conductors to be packed into a smaller overall diameter, thus enabling higher cable density in the motherboard housing.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Quantity of substance

If multiple inner conductors are disposed close together to increase density, then space efficiency improves, but mechanical stress and crosstalk increase

Engineering Contradiction:

Improvecable densityVSAvoidconnection reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The insulator material is specifically selected and positioned to provide localized electrical isolation between adjacent inner conductors. The insulator's dielectric properties are optimized to prevent crosstalk while maintaining compact spacing. Additionally, the outer conductor provides a grounded shield that locally contains electromagnetic fields, preventing interference between neighboring cables and ensuring connection reliability despite high density.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The insulator acts as an intermediary element between the multiple inner conductors, physically separating them and providing electrical isolation. This intermediary structure allows the conductors to be disposed close together for high density while preventing direct electrical interaction that would cause crosstalk and mechanical stress, thereby maintaining connection reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS20250322982A1Coaxial cable and device testing apparatus

Publication Date: 2025.10.16 ADVANTEST CORP

AI summary

A coaxial cable includes a tubular outer conductor, an insulator covered with the tubular outer conductor, and inner conductors disposed in the insulator.