Compliant Cable Termination for Impedance Matching
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Solution Overview
Problem
Existing controlled-impedance cable terminations suffer from impedance mismatches and limited density capabilities due to the use of conventional connectors and soldering methods, leading to high-frequency signal attenuation and reduced cable density.
Innovation Solution
A compliant contact element is used at the termination point, allowing for a compression-based attachment system with compliant signal and ground contacts that compensate for noncoplanarities and provide precise impedance matching, enabling higher cable density without the need for through-hole mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connectors (e.g., SMA) are used for cable termination, then the impedance environment is generally matched, but impedance mismatches occur at the interface points causing high-frequency attenuation
Solution Approach 1:
The invention extracts the problematic conventional connector interface from the system and replaces it with a direct cable-to-PCB trace connection. By eliminating the SMA connector and its associated impedance mismatches at interface points, the patent achieves continuous controlled impedance from cable to destination without the energy loss that occurs at conventional connector boundaries.
Solution Approach 2:
The patent applies local quality control by creating a specialized termination structure where the cable center conductor connects directly to a PCB trace and the shield connects to a ground plane, maintaining consistent impedance characteristics (e.g., 50 ohms) throughout the entire signal path. This localized controlled-impedance design ensures uniform electrical properties without the discontinuities introduced by conventional connectors.
2Ease of manufacture
If through-hole mounting is used for cable termination, then mechanical connection is achieved, but PCB area is substantially increased decreasing density capability
Solution Approach 1:
The invention replaces the mechanical through-hole mounting system with a surface-mount approach where the cable termination structure is mounted directly onto the PCB surface. The anchor block with embedded cable connections is positioned on the PCB surface and secured without requiring holes through the board, thereby maintaining mechanical connection while dramatically reducing the area consumed on the PCB.
3Ease of operation
If conventional cable termination systems are used, then single cable connection is achieved, but a substantial amount of PCB area is required reducing connection density
Solution Approach 1:
The patent creates a universal termination structure that can accommodate multiple cables in a compact footprint. The anchor block design with integrated cable management allows multiple cables to be terminated in close proximity, and the system can handle various cable types and configurations, thereby increasing connection density while maintaining ease of operation for cable connections.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution minimizes detrimental electrical effects, enhances high-frequency signal transmission, and increases cable density by reducing impedance mismatches and eliminating the need for through-hole mounting, allowing for more efficient use of space in electronic equipment.
Implementation Method 1
compliant contact element at the point of termination minimizes detrimental electrical effects of the termination
Implementation Method 2
The assembly is removably attached to the electrical device by a compression force in a direction of compression
Data Source
AI summary
An apparatus for terminating a controlled-impedance cable using compliant electrical contacts to provide an interface to another device. The terminator includes an anchor block for securing the cable. Optionally, the anchor block is electrically non-conductive. A conductive ferrule is installed on the cable shield and the cable end is dressed. The ferrule/cable assembly is installed in a through hole in the anchor block so the cable end is flush with the anchor block face. An insulating or conductive plate mounted to the anchor block holds the signal contact that electrically connects the center conductor to the device and optional ground contacts that electrically connect the ferrule to the device. The ground contacts surround the signal contact in a pattern that closely mimics the impedance environment of the cable. When using a conductive plate, the signal contact is insulated from the plate by an insulating centering plug or a non-conductive coating.An apparatus for terminating a controlled-impedance cable using compliant electrical contacts to provide an interface to another device. The terminator includes an anchor block for securing the cable. An electrically-conductive ferrule is installed on the cable shield and the cable end is dressed. The ferrule/cable assembly is installed in a through hole in the anchor block so that the cable end is flush with the anchor block face. An electrically-conductive plate mounted to the anchor block face holds the signal contact that electrically connects the center conductor to the device and optional ground contacts that electrically connect the ferrule to the device. The signal contact is insulated from the plate by an insulating plug. The ground contacts surround the signal contact in a pattern that closely mimics the impedance environment of the cable.