What Is EMI Testing? A Complete Guide to Electromagnetic Interference Testing
Electromagnetic Interference (EMI) occurs when unwanted electromagnetic energy disrupts electronic devices, circuits, or systems. This interference manifests as noise, signal degradation, data corruption, or complete device failure—threatening reliability across aerospace, medical, automotive, and telecommunications applications.
EMI testing measures how much electromagnetic energy a device emits and how well it withstands external electromagnetic interference. This critical validation ensures electronic products operate reliably in their intended electromagnetic environment while meeting regulatory compliance requirements. Understanding the differences between EMI and EMC helps manufacturers develop compliant products from the start.
Proper shielding design is essential for passing EMI testing—devices with inadequate electromagnetic protection face costly redesigns and delayed market access.
Why EMI Testing is Crucial for Modern Electronics
EMI testing plays a critical role in identifying electromagnetic interference issues before products are deployed in real-world environments, where failures are far more costly and dangerous. By revealing emissions and susceptibility problems early, testing allows engineers to correct design flaws prior to production and field use.
Beyond failure detection, EMI testing helps optimize designs so products are neither over-shielded nor under-shielded, balancing performance, weight, cost, and manufacturability. It also verifies that devices meet stringent regulatory requirements necessary for market access across aerospace, medical, automotive, and telecommunications sectors.
Regulatory mandates make EMI testing non-negotiable:
- FCC Part 15 (US) – Limits unintentional radiators and computing devices
- CE/EMC Directive (EU) – Required for European market access
- IEC 61000 – International electromagnetic compatibility standards
- MIL-STD-461 (Military) – Defense systems emissions and susceptibility
- DO-160 (Aerospace) – Avionics environmental test procedures
Non-compliance consequences include product recalls, market access denial, legal liability, regulatory fines, and long-term reputation damage. The most effective way to prevent field failures is to combine robust EMI shielding with adequate testing during initial design phases.
Radiated Emissions Testing
Radiated emissions testing measures unwanted electromagnetic energy radiating from products into the surrounding space, validating that devices aren’t emitting excessive RF energy that would interfere with nearby electronics.
Test setup requirements:
- Open Area Test Site (OATS) or anechoic chambers
- Measurement antennas at specified distances (3 or 10 meters)
- EMI receivers or spectrum analyzers to capture emissions
Applicable standards: FCC Part 15 (150 kHz – 40 GHz), CISPR 22/32 (information technology equipment), EN 55022/55032 (European harmonized standards).
Effective shielding enclosures reduce radiated emissions at the source, providing 60-90+ dB attenuation and making compliance straightforward (rather than iterative and costly).
Conducted Emissions Testing
Conducted emissions testing measures unwanted electromagnetic energy traveling along power cables and signal lines. While devices may shield radiated emissions effectively, conducted interference propagates through cables and jeopardizes other equipment that shares the power network.
Test setup components:
- LISN (Line Impedance Stabilization Network) – Provides defined impedance blocking external noise
- Spectrum analyzers – Measure emissions 150 kHz to 30 MHz
- Shielded enclosures – Eliminate ambient RF
Vacuum-metallized conductive coatings on plastic enclosures, combined with proper filtering, reduce conducted emissions and improve the odds of passing conducted emissions testing.
Radiated Immunity Testing
Radiated immunity testing simulates real-world RF interference and indicates how powerful external electromagnetic fields will need to be to cause malfunction. Products must operate reliably despite exposure to nearby transmitters, radar systems, and wireless communications.
Required equipment: Signal generators, RF power amplifiers (creating 1-200 V/m field strengths), transmit antennas, and anechoic chambers providing controlled test environments.
Military applications that require passing MIL-STD-461 are tested with field strengths exceeding 200 V/m to simulate high-power radar and jamming scenarios. Comprehensive shielding ensures equipment survives these extreme electromagnetic environments.
Conducted Immunity Testing
Conducted immunity evaluates device resistance to interference injected directly onto power and signal cables. Real-world environments contain electrical fast transients, voltage surges, and RF noise coupled onto cables from external sources.
Test methodologies:
- CDN (Coupling/Decoupling Network) – Injects RF interference onto cables
- Direct RF injection – Applies interference to specific conductors
- Bulk current injection – Uses current probes to inject RF currents into cable bundles
Standards include IEC 61000-4-6 (RF conducted disturbances) and IEC 61000-4-4 (electrical fast transient/burst). Proper grounding and shielding prevent conducted immunity failures.
Key Test Standards and Regulatory Bodies
FCC Part 15 is a United States regulation that governs unintentional radiators—devices using digital circuits that generate RF energy. Class B limits (residential) are approximately 10 dB more stringent than Class A (industrial).
CE Marking requires compliance with EMC Directive (2014/30/EU) and Radio Equipment Directive (RED 2014/53/EU) for European market access. Harmonized standards include EN 55032 (emissions) and EN 55035 (immunity).
MIL-STD-461 specifies electromagnetic emissions and susceptibility for defense systems. Current revision 461G covers conducted emissions (CE101/102), radiated emissions (RE101/102), conducted susceptibility (CS101-118), and radiated susceptibility (RS103/105).
DO-160 (RTCA/DO-160G) establishes environmental test procedures for airborne equipment, including EMC, lightning protection, and HIRF (High-Intensity Radiated Fields) resistance.
Pre-Compliance vs Full Compliance Testing
Pre-compliance testing occurs during development and uses simplified setups to identify potential EMI issues before formal certification. This approach enables design optimization—particularly shielding improvements—and reduces the likelihood of costly failures during final compliance testing.
Benefits: Lower cost, rapid feedback during design iterations, early identification of major shielding deficiencies, reduced risk of compliance failures.
Full compliance testing occurs in accredited laboratories meeting ISO/IEC 17025 requirements. Accredited reports satisfy regulatory authorities and provide legal documentation for market access.
Conduct multiple pre-compliance evaluations throughout development to optimize shielding effectiveness before formal testing. Reserve full compliance testing for production-ready designs with validated electromagnetic protection.
EMI Receivers and Spectrum Analyzers
EMI receivers are specialized instruments designed for compliance testing that meet CISPR 16-1-1 requirements. They provide six standard IF bandwidths, peak/quasi-peak/average detectors per regulatory standards, high dynamic range, and automated scanning.
Spectrum analyzers offer real-time spectrum monitoring and faster measurements but lack quasi-peak detectors required for full compliance. Modern real-time analyzers capture transient emissions missed by swept measurements.
Pre-compliance work uses spectrum analyzers at a lower cost to identify shielding weaknesses. Final compliance requires true EMI receivers or spectrum analyzers with EMI measurement options.
Antennas, LISNs, and Test Facilities
Antennas must cover the required frequency ranges with calibrated antenna factors. Common types: biconical (30-300 MHz), log-periodic (200 MHz – 2 GHz), broadband horn (1-40 GHz).
LISNs provide a defined 50-ohm impedance to devices under test while blocking external conducted noise, enabling repeatable measurements.
Shielded rooms use conductive materials in their walls, thereby turning the entire testing room into a Faraday cage. Anechoic chambers add RF-absorbing foam to eliminate reflections of electromagnetic noise and simulate open-area conditions indoors. Semi-anechoic chambers feature reflective floors with absorber-covered walls and ceilings.
Pre-Compliance Tools for In-House Testing
Budget-friendly setups enable rapid design iteration and shielding validation. USB spectrum analyzers ($1,000-$5,000) identify major EMI issues and shielding deficiencies during development.
Near-field probes ($200-$2,000) enable PCB-level troubleshooting by identifying specific noise sources on circuit boards. These magnetic and electric field probes pinpoint problematic components or traces that require localized shielding.
Software like EMCVu provides simplified automated testing. Pre-compliance doesn’t require accredited calibrations or full anechoic chambers—tabletop shielding and basic antenna sets suffice for validating shielding improvements.
Aerospace & Defense EMI Testing
Military and aerospace systems face intentional high-power electromagnetic threats. MIL-STD-461 validates equipment survivability in contested environments that may concern jamming, radar, and nuclear electromagnetic pulses (NEMP). Shielding effectiveness requirements may exceed 100 dB of attenuation for mission-critical electronics.
DO-160 Section 22 addresses lightning-induced transient susceptibility. Aircraft must withstand direct and indirect lightning strikes without critical failures—this requires comprehensive enclosure shielding.
HIRF testing exposes equipment to field strengths exceeding 7,200 V/m, simulating proximity to ground-based radar during airport operations. Only properly shielded equipment survives these extreme field intensities.
Medical Device EMI Requirements
IEC 60601-1-2 establishes EMC requirements for medical electrical equipment. The standard specifies immunity levels based on electromagnetic environments—professional healthcare facilities versus home healthcare settings.
Low EMI tolerance in operating rooms and intensive care units demands robust shielding to mitigate interference from RF-generating surgical equipment, MRI systems, and wireless communications. Inadequate shielding causes life-threatening malfunctions in patient monitoring and treatment delivery systems.
Automotive & Consumer Electronics Testing
CISPR 25 establishes vehicle component emissions and immunity limits. Testing validates that infotainment systems, ADAS sensors, powertrain controllers, and body electronics maintain electromagnetic compatibility through comprehensive shielding.
ISO 7637 addresses electrical transients on power supply lines. Voltage spikes from load dumps, switching transients, and inductive coupling must not disrupt vehicle electronics.
Modern vehicles integrate dozens of electronic systems that create electromagnetically dense environments. Hybrid and electric vehicles add high-power inverters and wireless charging, both of which generate strong electromagnetic fields that require robust EMI testing methods to verify roadworthiness.
Design for EMC from the Start
Early EMC consideration dramatically reduces testing failures and redesign costs. PCB layout fundamentals:
- Solid ground planes providing low-impedance return paths
- Minimized loop areas, reducing magnetic field coupling
- Strategic component placement separating noisy and sensitive circuits
- Controlled impedance traces for high-speed signals
Proper tips for reducing EMI in PCB designs implement these strategies during initial development rather than after testing failures.
Shielding enclosures are critical: Vacuum-metallized conductive coatings on thermoformed plastics provide lightweight electromagnetic protection with 60-90+ dB effectiveness. Understanding how to measure EMI shielding effectiveness empowers you to validate design decisions before formal testing.
Pre-Testing Checklist
Standards selection – Identify applicable regulations for target markets (FCC, CE, military, industry-specific)
Equipment calibration – Verify test instruments maintain valid calibrations traceable to national standards
Shielding validation – Confirm enclosure shielding effectiveness meets design targets through pre-compliance measurements
Device preparation – Ensure representative production configuration – including final enclosures, cables, and accessories – is used in the test.
Common mistakes to avoid:
- Testing development prototypes without production-equivalent shielding
- Inadequate cable management that results in unintentional antennas
- Missing required operating modes during immunity testing
- Insufficient enclosure shielding that allows electromagnetic fields to penetrate the device
What Happens If You Fail EMI Testing?
EMI test failures are common during initial compliance attempts when shielding proves inadequate. Diagnostic methods:
- Near-field scanning localizes emission sources that require enhanced shielding
- Frequency analysis correlates emissions to clock frequencies or switching regulators
- Time-domain analysis captures transient emissions
Iterative troubleshooting:
- Identify dominant emission frequencies and leakage paths
- Correlate frequencies to circuit functions and enclosure openings
- Implement targeted fixes—enhanced shielding, improved gaskets, better grounding
- Retest verifying shielding improvements
- Address remaining issues until full compliance is achieved
Common design revisions: Enhanced enclosure shielding effectiveness, improved conductive gaskets to seal joints, additional localized shielding over high-emission components, PCB layout modifications to improve grounding.
Choosing the Right EMI Testing Partner
Accredited laboratories hold ISO/IEC 17025 accreditation from recognized bodies (A2LA, NVLAP). Accreditation verifies that laboratories maintain qualified personnel, calibrated equipment, and documented quality systems.
Key selection criteria:
- Accreditation scope covering the required standards
- Industry-specific expertise (aerospace, medical, automotive)
- Chamber capabilities match device size and frequency ranges
- Engineering support for troubleshooting and shielding recommendations
Shielding preparation: Before engaging test labs, validate shielding effectiveness through pre-compliance testing. Well-shielded products pass compliance testing on first attempts, avoiding expensive retest cycles.
What is the Difference Between EMI and EMC?
EMI (Electromagnetic Interference) refers to unwanted electromagnetic energy that may disrupt device operation. EMC (Electromagnetic Compatibility) encompasses both emissions control and immunity—the complete ability of equipment to function properly without causing or experiencing interference.
EMC includes emissions testing (ensuring devices don’t generate excessive EMI through proper shielding) and immunity testing (verifying devices withstand external EMI through adequate protection).
How Long Does EMI Testing Take?
Full compliance testing typically requires 3-5 days for straightforward products with effective shielding. Complex devices with multiple configurations may require 1-2 weeks.
Testing duration depends on: number of required standards, device complexity, configuration options, number of ports requiring testing, and frequency of failures that require shielding modifications to be developed and additional testing to occur.
Well-shielded products pass initial testing quickly. Poorly-shielded products face multiple retest cycles, dramatically extending timelines and costs.
Can EMI Be Eliminated Completely?
Complete EMI elimination is impossible—all electronic circuits generate some electromagnetic energy. However, proper shielding design reduces emissions to negligible levels that meet regulatory limits with a substantial margin.
Multi-faceted approaches combining good PCB layout, comprehensive filtering, and effective enclosure shielding achieve excellent EMI attenuation. Vacuum-metallized conductive coatings on plastic enclosures provide 60-90+ dB shielding effectiveness—reducing emissions to tiny fractions of regulatory limits and ensuring straightforward compliance testing.
What’s the Cost Range for EMI Testing?
Full compliance testing costs:
- Simple products: $3,000-$8,000
- Moderate complexity: $8,000-$15,000
- Complex products: $15,000-$50,000+
Pre-compliance testing runs $500-$2,000 per day. In-house pre-compliance capabilities cost $10,000-$50,000 for basic equipment.
However, the biggest cost isn’t testing—it’s failure. Products with inadequate shielding fail testing, requiring expensive redesigns, new shielding tooling, and multiple retest cycles. Each retest cycle costs $3,000-$15,000 plus weeks of schedule delay.
Investment in proper shielding design and pre-compliance validation dramatically reduces expensive compliance test failures.
Prepare Your Products for EMI Testing Success
Deep Coat Industries provides custom EMI shielding solutions to help manufacturers pass EMI testing on first attempts. Our vacuum-metallized conductive coatings deliver 60-90+ dB shielding effectiveness on thermoformed plastic enclosures, injection molded housings, and 3D printed components—providing lightweight electromagnetic protection that meets the most stringent regulatory requirements across aerospace, defense, medical, and commercial electronics.
With over 45 years of electromagnetic shielding expertise, we help product developers design effective enclosure shielding before compliance testing begins. Our dual-fire and quad-fire vacuum metallizing processes create multi-layer conductive coatings optimized for specific frequency ranges, which reduces the costly design-test-fail-redesign cycle plaguing products with inadequate electromagnetic protection.
Contact Deep Coat Industries for shielding design consultation before your compliance testing. Our engineering team provides material recommendations, shielding effectiveness predictions, and custom coating solutions, ensuring your products achieve electromagnetic compatibility requirements—passing EMI testing the first time and reaching market faster.
Electromagnetic interference (EMI) can affect any type of electronic device, including your cell phone. EMI is the reason your cell phone will garble conversations and drop calls, and, in extreme circumstances, it can lead to a loss of data and system failure. To function in this technology-filled world, your phone needs a solid defense against electromagnetism. In this guide, we’ll explain how electromagnetic interference works and how EMI shielding protects cell phones against unwanted interference.
What is EMI (Electromagnetic Interference)?
Your electronic devices depend on the routing of electrons around circuits to operate. For routing to occur, the electrons need to be accelerated. Whenever charged particles like electrons are accelerated, electromagnetic fields are generated. “EMI” describes what happens when an electromagnetic field or another external source disrupts or adversely affects the normal functioning of an electronic circuit or device. There are national and international standards that regulate how much electromagnetic energy a device can emit. The easiest way to ensure compliance with these standards is to build devices with EMI shielding.
How Can I Protect My Cell Phone Against EMI?
Most smartphones are built with EMI shielding. EMI shielding protects cell phones by reducing the amount of electromagnetic waves coming from the phone and blocking incoming interference. This way, your phone is less likely to affect surrounding devices, and surrounding devices are less likely to affect your phone.
The shielding isn’t applied to the entire phone. An array of digital chips inside the phone is shielded instead, which allows the phone to function normally while still receiving adequate protection. The shielding protects the parts of your phone that control wireless LAN, radio frequency, and Bluetooth. An overlooked benefit of EMI shielding is that it helps create space inside the phone without compromising the device’s performance. While most modern smartphones come equipped with EMI shielding, older devices with worn-out or no EMI shielding materials at all might still be susceptible to electromagnetic interference.
Deep Coat specializes in EMI coating and shielding for a wide range of industries and devices. Connect with one of our team members to discuss how our innovative coating and shielding processes can help protect your devices.
EMI is everywhere. Without the proper precautions, it can wreak havoc on your devices, including your PCB. EMI, or electromagnetic interference, is electromagnetic energy that disrupts the signaling in an electronic device through radiation or induction. It doesn’t take much to create EMI. All you need is energy and an antenna. All electronic devices create EMI, and all electronic devices can be affected by it—but there are ways to mitigate its effects. Mitigating EMI starts with the design of your PCB. Let’s check out some tips for reducing EMI in PCB designs, so you can stop EMI in its tracks.
The Ground Plane
A ground plane is an electrically conductive surface that connects to electrical ground. In PCBs, the ground plane is an area of copper foil. It connects to the power supply ground terminal and acts as a return path for current from different components on the board. The bigger the ground plane, the less you’ll have to deal with electrical noise, interference through ground loops, and crosstalk. When the digital circuits switch state, current pulses will flow from the active devices into the ground circuit. A high impedance will lead to a voltage drop, which can result in significant noise. By providing a larger conducting area, you can cut down on interference. Other methods for optimizing your ground plane include:
- Using a multi-layer board
- Using split grounds cautiously
- Connecting split ground planes at a single point
- Connecting bypass or decoupling capacitors to the ground plane
The Trace Layout
Another tip for reducing EMI in PCB designs is to focus on the trace layout. A trace is a conductive path. When a circuit is active, it contains flowing electrons. Crossing or bending the trace layout could lead to the formation of an antenna. When you’re designing your trace layout, make sure to:
- Avoid sharp right-angle bends
- Keep your signals separate
- Keep return paths short
- Isolate high-speed components
- Keep analog circuits separate from digital circuits
EMI Shielding
Most devices produce EMI. To cut down on the negative effects, you’ll want to focus on electromagnetic compatibility, or designing your circuit to prevent disruption by shielding it. By shielding your devices, you can protect your receivers from external electromagnetic signals, or prevent a stronger signal from escaping and interfering with other electronics. An EMI shielding coating can cover vulnerable PCB elements, along with connectors and cables between PCBs.
Using dual-fire or our patented quad-fire vacuum metalization process, Deep Coat can create precise, effective PCB shield designs. If you’re looking for a way to protect your devices against EMI, contact us to discuss our custom PCB EMI shielding services.
Electromagnetic interference and electromagnetic compatibility are terms used when referring to the regulatory testing of electronics. But despite their similar-sounding names, they are not completely alike. Curious about the differences between EMI and EMC? Find out the advantages and disadvantages of EMI versus EMC.
Electromagnetic Interference (EMI)
EMI is energy or radiation that disrupts the operation of surrounding electrical devices.
Usually, energy is contained by a device’s plastic, rubber, or metal casing. Inevitably, some of it will escape and travel through the air. This escaped energy impedes the functions of other devices. For example, a blaring radio might impact a nearby television’s ability to project images or sound. Devices that produce high levels of interference interact poorly with surrounding machines and can render an entire system virtually useless.
EMI can originate from either natural or manmade sources. Lightning and solar radiation are two examples of natural interference.
To an extent, all man-made devices can cause EMI; cellphones, microwaves, and radios are some common sources. Generators, voltage regulators, oscillators, computing devices, sonar equipment, and high-tech medical equipment, like MRI machines and X-rays, account for other potential causes. Thankfully, Deep Coat Industries has many capabilities, from EMI shielding to vacuum metalizing, for all your equipment protection needs.
Emission testing measures the amount of EMI generated by a particular device. This is used to gauge its potential impact on surrounding devices and, as a result, prevent mass malfunction.
Electromagnetic Compatibility (EMC)
EMC refers to a device’s ability to block EMI, or function under its effects. To withstand EMI, devices are often outfitted with a metal, rubber, or fabric shielding.
The process of evaluating a device’s tolerance is called susceptibility or immunity testing. Electronics with a strong electromagnetic compatibility function better under EMI than those without. Testing for EMC is essential for products like pacemakers and hard drives, where interference could prove damaging, if not outright fatal.
Testing for EMI and EMC
There are plenty of differences between EMI and EMC, but both do have to be tested.
EMI and EMC compliance standards are not uniform and can be the deciding factor when comparing EMI versus EMC. Military-grade equipment has stricter standards than most, and commercial standards can vary from industry to industry.
To ensure efficiency, safety, and compliance of your products, you should test for both electromagnetic interference and compatibility. A failure to test for either could lead to dangerous, costly problems down the road.
If you need reliable, long-lasting EMI shielding coating for your devices, Deep Coat Industries is the best place to search. We’re here to help if you find you need to enhance your product’s EMC or protect your hardware from EMI. Contact us with any inquiries.
Particularly if you’re a device engineer unfamiliar with the field, understanding electromagnetic interference (EMI) and how it affects the devices you make is difficult yet vital. Consider this glossary of EMI shielding terms a reference tool you can use throughout the design process.
Attenuation
Attenuation is the reduction of electromagnetic energy. It occurs through many mediums, though shield structures are intentionally placed attenuators. You communicate the degree of attenuation in decibels (dB), which is a logarithmic measure of electrical power.
Conducted Emissions
This refers to the electromagnetic signals that pass from one material to another via a shared plane or cable. The degree to which emissions conduct depends on the medium’s conductance. See radiated emissions to learn about another form.
Crosstalk
Crosstalk is EMI that occurs between two, often parallel, wires in a circuit. To clarify how crosstalk happens, engineers refer to the source of the signal that bleeds into another field the aggressor whereas the suppressed recipient is the victim.
Electromagnetic Compatibility (EMC)
EMC is a device’s general ability, given its existing structure and shielding or lack thereof, to operate despite the presence of electromagnetic signals. Its compatibility is not an absolute—it varies according to what environment it enters.
Faraday Shield
Named after inventor Michael Faraday, a Faraday shield or cage constitutes a consistent conductive structure that encapsulates a machine. An outside electrical signal cannot easily penetrate and disrupt electronics’ function with this or similar shields in place.
Grounding
A conductor or other conductive medium that returns electrical signals to the earth or another substantial, usually large, substance. Grounding allows devices such as circuit boards to maintain their function by redirecting harmful EMI.
Radiated Emissions
Whereas conducted emissions travel through a nongaseous material, radiated emissions travel into space. Many radiated emissions serve constructive purposes, but others interfere with existing waves or otherwise impair electronics’ functionality.
Shielding Effectiveness
Shielding effectiveness is the environment-specific ability of a shield to attenuate EMI. Not to be confused with electromagnetic compatibility, shielding effectiveness expressly relates to the shield, not the whole device. Total effectiveness is the incoming signal strength divided by the strength of the signal that penetrates the shield.
Shielding Gasket
Our final term, shielding gasket, refers to the crucial element that protects against EMI at the point the enclosure material ends or creates a gap. A flexible material such as wire mesh works well when making up a gasket.
These nine terms in our glossary of EMI shielding don’t encompass the totality of the field. To learn more about EMI shielding or to ask about our vacuum metalizing services, contact Deep Coat Industries. We have decades of experience to draw from and offer unique multi-stack coatings that keep EMI away from your products.
A circuit board is similar to a brain. It sends and receives electrical signals to specific locations so a larger structure can do its work. While you are the structure your brain powers, printed circuit boards give life to any number of different electronics.
As you produce PCBs, this integral part must not have defects that expose it to electromagnetic interference. If you are curious how to protect your PCB from EMI, here are a few facets to pay attention to.
Electromagnetic Capability Basics
First, a word on electromagnetic capability. EMC is a device’s readiness to operate in an electromagnetic environment without falling prey to interference. In the event of a design flaw or shielding deficit, EMC drops and EMI, whether internal or external, inhibits PCB functionality. Often, the edges of a circuit board are the most at risk of creating an EMI-emitting antenna.
PCB Design Tips
The first way to protect your PCB from EMI is through smart design. Ensure you have a sufficiently grounded plane that touches every single component as a foundation.
Meanwhile, plan effective trace paths so they don’t radiate EMI. To do so, don’t bend traces more than 45 degrees at one point—opt for gradual turns instead. In addition, properly space traces to cut down on disruptive “cross-talk” between like-speed paths.
EMI Shielding Solutions
Though there are design strategies for stopping EMI at the source, it’s impossible to completely eradicate. For that reason, PCBs require protective shields to counteract and ground existing EMI. Shields encapsulate a circuit board or individual components with conductive materials to attenuate radiating signals.
Deep Coat’s unique dual-fire or quad-fire vacuum metalizing services deposit several layers of conductive metals onto a shield. To maximize shields’ flexibility, we also partner with plastic molding, 3-D printing, and thermoforming specialists to match your exact PCB shield specifications. When in place, these shields eliminate weak points and regulate device function so your customers can trust your products for years of use.
If left unprotected, electronics of all sorts would fall prey to electromagnetic interference (EMI). Nearby waves would contact their circuitry and disrupt their function. This interference might be annoying for a casual smartphone user, but it would be downright dangerous for an overseas military member unable to communicate with their team.
In response to the need for EMI protection, many companies developed efficient and effective shielding methods. Deep Coat utilizes vapor deposition, but even within that subset, there are options. If you want more information on the differences between PVD and CVD and how to choose between them, read this simple guide to both.
Chemical Vapor Deposition
Chemical vapor deposition (CVD) is the process by which a deposition material mixes with a precursor substance and then bonds with a substrate. This deposition material can vary by project, while the precursor—often a halide or hydride—is the medium that prepares and transports the deposition material to the substrate or intended surface. This combination enters a vacuum chamber, the deposition material forms a uniform layer on the substrate, and the precursor breaks down and exits via diffusion.
This process requires extremely high temperatures. While this necessitates a substantial heat source, the more significant disadvantage is that some substrates cannot withstand heat upwards of 900 degrees Celsius. In addition, the chemicals involved are toxic. Companies must find safe ways to handle and dispose of them to protect workers and the environment.
Physical Vapor Deposition
Meanwhile, physical vapor deposition (PVD) is—unsurprising, given its name—deposition by physical rather than chemical means. One of the more popular physical methods, the one Deep Coat uses when vacuum metalizing plastic, is evaporation. This process involves heating the deposition metals until they convert to a gas, then feeding them into a vacuum chamber where they form a layer of metal capable of attenuating EMI.
While transitioning metals into gases requires high temperatures, the difference between evaporation and chemical deposition is that this variation doesn’t require heating the substrate itself. Also, because PVD doesn’t rely on chemicals, the handling and disposal process is safer and easier.
If you have further questions regarding the differences between PVD and CVD and how to choose one for shielding purposes, get in touch with our knowledgeable Deep Coat team to learn about our extensive capabilities.
The vacuum metalizing process is an innovative technology that lends metal-like qualities—such as conductivity—to a non-metallic surface—such as plastic—via cost-effective and environmentally responsible means. These metalized surfaces mitigate electromagnetic interference and can also serve an aesthetic purpose. When vacuum metalizing plastic, there are several metals capable of lending effective conductivity. Here is a brief guide to common materials used for vacuum metalizing and their differences from one another so that you can further understand the process.
Aluminum
First, aluminum is a reasonably conductive and regularly used metal. In fact, aluminum is the most common of all metals for vacuum metalizing for several reasons. Due to its prevalence—aluminum is the most plentiful metal on the planet—aluminum is a cost-efficient material for metalizing. Also, this metal is particularly corrosion-resistant and retains the metalized surface’s integrity well. In some applications, aluminum’s high reflectivity is another plus.
Copper
Copper is a second common material used for vacuum metalizing. Copper is a bit better than aluminum at providing a conductive surface capable of mitigating surrounding EMI. That said, aluminum is the most common metal used in part due to copper’s propensity to corrode and tarnish. The Statue of Liberty is a good example—over time, Lady Liberty shifted from a reflective brown color to its present-day blue-green color. This illustrates copper’s general tendency to oxidize, which negatively impacts a vacuum-metalized surface.
Multi-Stack Coatings
Given the strengths and weaknesses of copper, aluminum, and other metals, Deep Coat Industries commonly creates multi-stack coatings consisting of several complementary metals. This allows for maximum attenuation and mitigates shield breakdown. For instance, to prevent copper’s oxidization, our Dual-Fire solution applies highly conductive copper followed by an oxidization-resistant aluminum top layer.
Alternatively, our Quad-Fire solution sandwiches two conductive copper layers between two bookend layers of stainless steel. Beyond a merely protective substance, stainless-steel and also nickel-chrome contribute excellent low-frequency EMI attenuation due to their magnetic properties. Beyond these, you can also request nickel, tin, and other metals for your project, affording you many different options.
Physical Differences
Practically, for shielding, EMI coatings vs. compounds manifest differently from one another. Shielding compounds are conductive materials typically infused in a solvent base. Because plastic lacks conductivity, engineers must add conductive material to these plastics so these compounds can fend off EMI. This mixture forms a resin and contains conductive fibers or particles typically consisting of metals.
In contrast, when pondering EMI coatings vs. compounds, conductive coatings cover the surface of a nonconductive material such as plastic through vacuum metalization. This involves vaporizing and depositing metals onto whatever surface requires shielding. Rather than modifying the substrate’s composition with a conductive filler, conductive coatings form a cohesive layer of copper, stainless steel, nickel-chrome, or several other possible materials that attenuate potentially disruptive EMI.
Shielding Mechanism Differences
When considering the physical differences between EMI coatings vs. compounds, it’s important to recognize how these differences affect their shielding mechanisms. Because compound shielding involves the use of an integrally conductive compound, compound shields inherently have gaps between conductive particles in suspension; vacuum metalized coatings provide a complete metal layer that has less opportunity for transmission and can therefore be thinner while accomplishing the same attenuation.
These two shielding methods function in the same way but have very different impacts on the weight and structural integrity of the device you’re trying to shield.
If you have further questions about the differences between these two shielding practices, contact us at Deep Coat Industries. Also, we can discuss the EMI coating process in-depth and determine if it fits your current project’s needs.
Electromagnetic interference (EMI) disrupts device function. One shielding application to prevent EMI is vacuum metalization. The vacuum metalizing process involves treating a substrate, vaporizing a metal, and depositing it onto the surface. There are marked benefits to vacuum metalizing—read on to learn what they are and why vacuum metalizing is an innovative solution for your EMI shielding needs.
Vacuum Metalizing Is Safe and Environmentally Friendly
First, the benefits of vacuum metalizing include its safety and environmental-friendliness. Particularly when considering electroless plating and chemical-based coating in general, vacuum metalization has safety and environmental advantages. Specifically, it doesn’t give off harmful chemical fumes like electroless plating does, preserving the health of the workers while not subjecting the surrounding environment to emitted chemicals. In fact, the vacuum metalization process takes place within an enclosed space that prevents vaporized metals from reaching the outside, essentially eliminating potential health and environmental risks.
It Ensures Conductivity and EMI Shielding
Vacuum-metalized surfaces are also highly conductive and effective at shielding EMI. Vacuum-metalized devices can attenuate incoming frequencies so they don’t impact function and are a great option for several different kinds of surfaces, plastics being one notable example. Based on the metals you choose for your EMI attenuation, this shield is also quite corrosion- and rust-resistant wherever you apply it, so you can expect your metalized devices to limit electromagnetic interference for years without issue.
It Is Cost-Effective
For several reasons, vacuum metalization is also cost-effective relative to other shielding techniques. While vaporizing metal and depositing it onto a surface sounds complex, it’s a streamlined option relative to electroless plating, for example. Electroless plating involves etching a substrate with acid and then catalyzing a substance onto the surface. The precise reactions and conditions required for electroless plating make this option less cost-effective, and more intrusive to the substrate, than vacuum metalizing, which less intrusively applies a conductive metalized layer to the substrate.
If you have more questions about the benefits of vacuum metalizing, contact our knowledgeable team at Deep Coat Industries. We’re happy to advise you on effectively protecting your devices from EMI and draw from decades of experience to do so.