Electromagnetic interference (EMI) shielding is a fundamental requirement in the design and qualification of modern electronic systems. From avionics and defense electronics to medical instrumentation and industrial controls, EMI control ensures that systems operate reliably in the presence of radiated and conducted electromagnetic energy. Compliance with electromagnetic compatibility (EMC) standards such as MIL-STD-461, RTCA DO-160, IEC 60601-1-2, CISPR 25, and NATO STANAG 4370 (AECTP 500 series) is essential to guarantee performance, safety, and security across critical applications.

In high-reliability environments, EMI shielding does more than prevent display flicker or signal degradation, protects mission integrity, ensures data confidentiality (as defined in NSTISSAM TEMPEST/1-92), and enables qualification under harsh environmental and electromagnetic stress conditions.

Applications Of EMI Shielding

  • Aerospace and Aviation: Compliance with RTCA DO-160 Sections 20 C21 for radiated and conducted susceptibility; shielding required for flight displays, flight control systems, and avionics LRUs to prevent RF coupling in aircraft bus systems.
  • Military and Defense: Designs qualified per MIL-STD-461G (CE101/CE102 conducted emissions, RE102 radiated emissions, RS103 susceptibility) and TEMPEST-controlled systems per NSA 94-106 to prevent electromagnetic eavesdropping or compromise.
  • Industrial Equipment: Ensures compliance with IEC 61000-6-4 and CISPR 11 for emissions and immunity, minimizing crosstalk between power conversion, control, and communication circuits.
  • Medical Devices: Shielding per IEC 60601-1-2 (4th Edition) to ensure patient safety and prevent interference with life-critical monitoring or imaging systems.
  • Telecommunications: Conformance with ETSI EN 300 386 and FCC Part 15 Class B limits to maintain signal integrity and network reliability.
  • Consumer Electronics: Compliance with CISPR 25, ISO 11452, and SAE J1113 to protect infotainment, ADAS, and vehicle communication systems.

Risks of Not Implementing EMI Shielding

Failure to implement proper EMI shielding can result in a range of performance and security issues. For example, LCD displays may exhibit distortion, flickering, or discoloration due to interference. In more critical applications, unshielded electromagnetic emissions can be exploited to detect and track military assets or intercept sensitive data, posing significant security risks.

Omitting proper EMI shielding exposes electronic systems to:

  • Functional Degradation: LCD or OLED displays exhibiting flicker, image distortion, or transient color shifts due to coupling with nearby RF fields.
  • Data Compromise: Radiated emissions from unshielded systems can be intercepted, revealing sensitive or classified information, violating TEMPEST or NATO security standards.
  • System Instability: Induced currents on signal lines can cause false triggering, data corruption, or complete operational failure under high-field environments (up to 200 V/m as tested in RS103).
  • Non-Compliance and Certification Failure: Products unable to meet CE, FCC, or military EMC requirements face rejection in qualification testing or field deployment.

Benefits of EMI Shielding

  • Reliability: Enhances operational consistency and mean-time-between-failure (MTBF) by reducing noise coupling into critical circuits.
  • Regulatory Compliance: Enables qualification to military and aerospace EMC requirements such as MIL-STD-461G, DO-160G, and EC60601 for medical use.
  • Safety: Reduces electromagnetic exposure to operators, aligning with occupational RF exposure limits (IEEE C95.1).
  • Signal Integrity: Preserves timing, reduces jitter, and ensures data fidelity across high-speed digital buses (e.g., LVDS, MIPI DSI, or DisplayPort).
  • Security: Limits unintentional radiated emissions (EMSEC compliance) and supports TEMPEST Level A/B containment for secure systems.

Cevians EMI Shielding Strategies and Solutions

At Cevians, electromagnetic compatibility is engineered at every level of the system from power entry to optical output. By leveraging its From Molecules to Systems integration philosophy, Cevians applies EMI control principles through three primary domains:

1. Power-Supply Filtering and Input Conditioning: Cevians integrates multi-stage LC filters and common-mode chokes designed per MIL-STD-1275E and DO-160 Section 16 requirements. These input networks attenuate conducted emissions (CE101/CE102) and protect against transient spikes and ripple currents. Precision-engineered ground returns and filter layouts minimize loop area and ensure compliance with 28 Vdc and 270 Vdc aircraft or vehicle power standards.

2. Circuit Card and System-Level Design

Printed circuit boards incorporate:

Controlled-impedance traces and ground-plane segmentation to isolate analog, digital, and power domains. Shielded enclosures and conductive gaskets that meet MIL-DTL-83528 elastomeric shielding requirements. Filtering at signal interfaces using feed-through capacitors and Pi filters to suppress conducted susceptibility (CS101/CS114). Differential pair routing and decoupling networks tuned for high-frequency performance up to 1 GHz+ in compliance with RS103 radiated susceptibility thresholds.

3. Optical Stack EMI Attenuation:

Unique to Cevians’ vertically integrated display manufacturing, EMI mitigation extends into the optical stack:

ITO (Indium Tin Oxide) Transparent Conductive Layers: Thin films deposited via sputtering provide uniform sheet resistivity without compromising optical transmission or color neutrality.

Micro-Mesh Conductors: Cevians employs high-precision stainless or copper micro-mesh patterns (60 to 200 OPI) laminated within the optical stack, achieving shielding effectiveness exceeding 40 to 60 dB across 10 MHz to 10 GHz.

Optical Optimization: Proprietary patterning geometries and refractive index matching minimize Moiré and Newton interference, ensuring high contrast and low reflectance.

Integrated Grounding: Optical EMI layers are bonded through conductive busbars and grounding tabs, enabling continuous shielding paths to chassis reference is essential for TEMPEST-controlled environments and NATO SDIP-27 Level A applications.

Conclusion

Cevians’ comprehensive EMI design philosophy covering power, circuitry, and optics ensures compliance with the most stringent global EMC standards. From MIL-STD-461G qualification to TEMPEST and DO-160G environmental testing, Cevians delivers display and embedded electronic systems engineered for mission-critical reliability, security, and electromagnetic integrity.

Discover how Cevians can help support the success of your next mission and contact us today.