Cable Shielding Effectiveness Measurement

Cable interconnects which allow cables inside the cage to connect to cables outside may undergo modification for additional connectors that damage the shielding integrity.

Cable shielding effectiveness measurement.

This method is effective for frequencies less than 500 megahertz. Ventilation is another example and one that is usually problematic with regards to shielding effectiveness. A plot of the chamber s dynamic range is shown in figure 2. A shielding unit is inserted through the box s opening.

The method is offered as a standard technique for measuring the shielding effectiveness of shielded cables. Our most common request is to measure se for connectors and cables. It involves the use of a sealed box with an opening. An efficient and repeatable measurement method for determining shielding effectiveness of cable feedthroughs based on the use of nested reverberation chambers is presented.

For these products we primarily use two techniques the triaxial fixture method and the mode stirred method. To verify the periodic calibration two gold standards are employed. This is a typical margin recommended by various industry specifications. There could also be changes in compliance standards.

The shielding effectiveness is measured by comparing the reading of reference and the load devices. When a cable specification calls for 90 db of rf shielding the 100 db dynamic range allows a 10 db margin in the measurement range. For example housings connectors or cables all use shields and each application requires a unique test fixture to ensure accurate and repeatable se measurements. Measurement method for determining shielding effectiveness of cable feedthroughs.

The measurement method is validated by comparing measurements on an isolated conductor penetrating the shield with a simple theory based on basic circuit theory in combination with antenna theory.