# Shielding effectiveness by Karen Burnham

**URL:** <https://sierraconnect.protoexpress.com/t/shielding-effectiveness-by-karen-burnham/2878>\
**Category:** EMC and EMI\
**Tags:** emi, shielding, karen-burnham\
**Created:** [February 3, 2025, 4:55pm UTC](https://sierraconnect.protoexpress.com/t/shielding-effectiveness-by-karen-burnham/2878 "2025-02-03T16:55:36Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![lucy.sierracircuits](https://sea2.discourse-cdn.com/sierraconnect/user_avatar/sierraconnect.protoexpress.com/lucy.sierracircuits/32/8_2.png) [@lucy.sierracircuits](https://sierraconnect.protoexpress.com/u/lucy.sierracircuits)\
**Post date:** [February 3, 2025, 4:55pm UTC](https://sierraconnect.protoexpress.com/t/shielding-effectiveness-by-karen-burnham/2878/1 "2025-02-03T16:55:36Z")

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https://fast.wistia.net/embed/iframe/7iw947ve0r

Effective shielding is essential for ensuring proper EMC performance, but measuring it correctly can be tricky. @karen.burnham recently highlighted critical concepts for measuring shielding effectiveness, offering practical advice and insights for engineers during a webinar with Sierra.

Here’s what she had to say:

- **Fundamental measurement concept:** Compare the energy or power picked up in unshielded versus shielded configurations. Shielding effectiveness is always a positive number—bigger is better!
- **dB makes math easy:** “EMC engineers love working in decibels—just kindergarten math: addition and subtraction!”
- **Reverb chamber benefits:**
  - Covers large frequency areas quickly
  - Illuminates the target from multiple angles
  - Ideal for real-world simulations

However, reverb chamber testing has its limitations, especially on the lower frequency side where it struggles to provide statistically meaningful data.

**Measurement methods:**  
Karen emphasized the importance of measuring shielding effectiveness using **unshielded vs. shielded configurations of the same cable assembly** instead of relying on comparisons with reference antennas, which can overstate the shielding effect.

What’s your experience with shielding effectiveness measurements? Do you have a preferred method or any tips for accurate results?

Watch the full webinar [here](https://www.protoexpress.com/webinars/how-good-is-my-shield/?utm_source=sierraconnect&utm_medium=display&utm_campaign=shielding%2Beffectiveness%2Bthread%2Bfeb%2B2025).