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Explained: Shielding Effectiveness Ratings and What They Mean for You
The Shocking Truth Behind EMI Shielding (And Why Ratings Matter More Than You Think)
Let’s set the scene:
You’ve designed a cutting-edge device. It works perfectly in the lab. But once deployed in the real world—BOOM! Glitches. Signal loss. Total interference.
What went wrong? Most likely: poor EMI shielding. And more specifically: you didn’t check the Shielding Effectiveness Rating.
In today’s hyper-connected world, electromagnetic interference (EMI) is no joke. Your electronics are constantly bombarded by external signals—Wi-Fi, 5G, radar, even microwaves.
If you don’t have the right shielding in place—rated correctly—your product’s performance, safety, and compliance go out the window. Let’s break it all down.
What is Shielding Effectiveness?
Shielding Effectiveness (SE) measures how well a material can block, reflect, or absorb electromagnetic energy. It’s expressed in decibels (dB) and determines the reduction of EMI inside or outside a shielded enclosure.
- Higher dB = Better Shielding
| SE Rating (dB) | Reduction in EMI | Common Usage |
| 20 dB | 90% | Minimal protection – basic consumer devices |
| 40 dB | 99% | Mid-level industrial & medical |
| 60 dB | 99.9% | Mission-critical electronics |
| 80+ dB | 99.99% | Aerospace, defense, and RF-sensitive areas |
Why Shielding Effectiveness Ratings Matter
✅ Signal Integrity
High-speed circuits are sensitive. EMI causes data loss, latency, and random errors. Shielding protects your signal lines.
✅ Product Reliability
Without proper SE, even minor surges or radio signals can damage components. Result? Frequent failures.
✅ Compliance & Certification
Regulations like FCC, CE, or MIL-STD-461 demand certain EMI performance. You won’t pass testing without the right SE.
✅ Safety
In critical sectors like medical, aerospace, and defense—shielding can be the difference between life and death.
Key Insights on EMI Shielding Effectiveness
1.Electromagnetic Interference (EMI) is a pervasive threat to modern electronics. If not properly controlled, EMI can severely disrupt functionality—or worse, render devices completely inoperable.
2. Shielding Effectiveness refers to a material’s or component’s ability to reduce EMI. It is calculated as the difference in signal strength (in decibels, dB) before and after applying shielding—higher dB means better protection.
3. EMI can be caused by both man-made sources (like computer circuits, power lines, and cellular networks) and natural sources (such as lightning or solar flares). These interferences occur via conduction or radiation, making effective shielding a must.
4. The attenuation level, measured in decibels (dB), quantifies how much interference is blocked. For instance, a 60 dB shield reduces interference by 99.9%, making it suitable for most industrial applications.
5. Material selection plays a critical role in shielding performance. Common conductive fillers include silver, silver-aluminum, silver-nickel, silver-copper, and nickel-graphite, each chosen based on conductivity, cost, and corrosion resistance.
6. Military and defense electronics must meet stringent EMI shielding requirements. Standards like MIL-STD-285 mandate shielding effectiveness of at least 100 dB across frequencies from 20 Hz to 10,000 Hz for maximum protection.
7. EMI shielding is not optional—it’s essential for protecting critical systems in industries like medical, military, aerospace, transportation, and industrial automation.
8. For designs requiring both EMI shielding and environmental sealing, using dual-material strategies or specialized products—like Nolato’s Compashield™ Extrusions—ensures optimal performance on both fronts.
Understanding the Ratings: A Closer Look
The Shielding Effectiveness Rating depends on:
1. Material Type
- Copper: High conductivity = excellent SE.
- Nickel Alloys: Used for corrosion resistance and strength.
- DOMADIA™ Shielding Fabrics: Engineered for flexible yet high-performance EMI protection.
2. Frequency Range
A material might shield well at 30 MHz but fail at 10 GHz. Always match your frequency spectrum.
3. Construction
The shielding quality changes with:
- Number of layers
- Gaskets and seals
- Aperture sizes
- Grounding
DOMADIA™ Shielding Materials: What Makes Them Special
At DOMADIA™, we don’t just sell shielding materials—we engineer EMI solutions.
Whether it’s flexible conductive tapes, metal mesh, EMI gaskets, or copper foil rolls, every DOMADIA™ product is tested and rated to meet global standards.
✔ Certified per MIL-STD, ASTM & IEEE benchmarks
✔ Frequency coverage from kHz to GHz
✔ Performance up to 120 dB SE for extreme applications
✔ Available in various forms: sheets, rolls, tapes, enclosures
Applications That Demand High Shielding Effectiveness
1. 5G Infrastructure
With ultra-high frequencies and dense signal environments, 5G networks are highly vulnerable to EMI. Even minor interference can lead to latency, signal loss, or dropped connections. High SE shielding ensures stable data transmission and performance reliability in base stations, antennas, and routers.
2. Military & Defense Electronics
From communication systems to radar and weapons control, defense electronics demand the highest shielding standards. Operating in hostile EMI conditions, these systems require SE ratings of 80–120 dB for mission-critical reliability and national security. DOMADIA™ offers MIL-STD-compliant materials trusted in the defense sector.
3. Medical Devices (MRI, ECG, Ultrasound)
Precision is everything in medical technology. EMI can lead to inaccurate readings or device malfunction—putting lives at risk. Shielding with high SE ratings protects both patients and equipment, ensuring accurate diagnostics and uninterrupted device function in sensitive hospital environments.
4. Automotive Control Units (EVs, ADAS, ECU)
Modern vehicles are loaded with electronic control systems, especially EVs and autonomous cars. EMI can disrupt crucial safety systems like braking, steering, or navigation. High-performance EMI shielding helps protect critical functions and ensures safety, reliability, and compliance with automotive standards.
5. Satellite & Aerospace Communication Systems
In aerospace and satellite tech, there’s no room for EMI errors. From avionics to ground communication, high SE-rated shielding is essential to ensure signal integrity, data accuracy, and mission success—often under extreme temperature and pressure conditions. DOMADIA™ provides lightweight, high-SE aerospace-grade solutions.
6. Consumer Electronics (Wi-Fi, Bluetooth, Smart Devices)
Everyday devices like smartphones, laptops, and routers are exposed to constant electromagnetic noise. EMI shielding with 20–50 dB SE ratings protects internal circuits, maintains wireless performance, and prevents frustrating connectivity issues—ensuring a smooth user experience in compact, tech-heavy environments.
In any of these sectors, guessing the rating = gambling with performance.
How to Choose the Right Shielding Rating?
Ask yourself:
✅ What frequencies need shielding?
✅ How sensitive is your circuitry?
✅ What are the compliance requirements?
✅ What form factor fits the enclosure?
Pro Tip: For critical performance, always go for 60+ dB rated materials, preferably tested by certified labs.
Need help? DOMADIA™’s team of experts can guide you.
Conclusion: Shielding Effectiveness = Performance Insurance
Shielding is no longer optional. It’s an essential insurance policy for every electronic product.
And like insurance, the policy only works if it’s the right one.
So, the next time you shop for EMI shielding, don’t just ask “Is it conductive?”
Ask: “What’s the Shielding Effectiveness Rating?”
Because with the right rating, your electronics stay safer, faster, and smarter.
Trust DOMADIA™ for tested, certified, and reliable shielding materials.
Frequently Asked Questions (FAQs)
Q1: What’s a good SE rating for consumer devices?
A: 20–40 dB is usually sufficient, depending on signal sensitivity.
Q2: How is SE tested?
A: Using standardized test methods like IEEE 299 or MIL-STD-285 in shielded environments.
Q3: Can I improve SE after the product is built?
A: Yes, with add-on shields, conductive paints, gaskets, or retrofitting with DOMADIA™ tapes and foils.
Ready to safeguard your electronics with certified EMI solutions?
Explore DOMADIA™’s full range of high-performance shielding materials today.
Talk to us: Kairav Domadia | Aadil Domadia | Er.Pankaj Domadia | Pragati Sanap | Pooja N N
