How EMI Shielding Protects Cell Phones

How EMI Shielding Protects Cell Phones

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’s EMI?

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 of 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.






Tips for Reducing EMI in PCB Designs

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.









What To Know About Metalizing Plastic

Ever wondered what the best ways to metalize plastic are, or if metalizing your plastic is worth it? Here’s what to know about metalizing plastic, including its benefits and the most effective methods and processes for coating it.

The Benefits of Metalizing Plastic

Plastic can be metalized for both aesthetic and mechanical purposes. Vacuum metalizing plastic has several benefits. When metalized, plastic takes on a glossy, reflective appearance along with practical qualities, such as abrasion resistance and electric conductivity. Metal-coated plastic is used in similar applications as metal parts. It tends to have a lower weight, a higher resistance to corrosion, controllable conductivity levels, and a lower manufacturing cost. There are several common methods of metalizing plastic, two of which are arc and flame spraying and vacuum metalization.

Metalization Processes

Another important thing to know about metalizing plastic is how it’s done. Let’s look at some of the most common methods and processes used to metalize plastic.

Arc and Flame Spraying

In basic flame spraying, a hand-held device is used to spray a layer of metallic coating on the substrate. A metallic powder is heated and melted by an oxygen and gas-fueled combustion flame. The mixture is accelerated and released as a spray, which coats the plastic component. This method of metalizing has a high deposition rate and thick, durable coatings, but tends to produce results that are porous and rough. Flame spraying can be used to apply metalized coatings to a specific area, which is useful when working with complex or unusually shaped parts. Arc spraying is, at its core, flame spraying, but with a different power source. Instead of depending on a combustion flame, arc spraying derives its energy from an electric arc.

Vacuum Metalizing

Vacuum metalizing is another efficient process for metalizing plastic. Before vacuum metalizing occurs, the plastic undergoes a pretreatment. This can be done chemically, mechanically, or with low-energy plasma. Since metals tend to bond poorly with polymers, the pretreatment ensures the metal properly adheres to the plastic. Next, a metal, typically aluminum, is evaporated. The vapor from the metal condenses onto the substrate, leaving a thin layer of metal coating. To prevent oxidation, the entire process takes place within a vacuum chamber. Vacuum metalized plastic is used in a wide range of applications—from automotive interior parts to certain types of foils.

Deep Coat’s innovative vacuum metalizing process makes coating your materials—plastic or otherwise—quick, simple, and efficient. If you’re thinking about vacuum metalizing plastic components, get in touch with us so we can discuss and plan your next metalizing project. We can also provide additional services such as surface pretreatment and decorative overcoating, so don’t hesitate to reach out.








The History and Uses of Metalizing

Metalizing is a general term referring to the technique of coating metal onto an object’s surface, whether for decorative, environmental, or electronic purposes. It’s an extremely reliable method of protecting parts, components, machinery, products, and more. To learn more about the history and uses of metalizing, keep on reading.

Origin of Metalizing

In 1835, Justus von Liebig succeeded in coating a metallic silver over the surface of glass. This marked one of the earliest uses of metalizing. When ABS plastic was introduced and made widely accessible, the coating of other non-metallic objects became commonplace.

How Objects Are Metalized

Non-metallic objects have poor conductivity. To overcome that limitation, a conductive surface needs to be created and applied. There’s more than one method for metalizing objects. Two common methods of metalizing include chemical vapor deposition and physical vapor deposition (or, more specifically, vacuum metalizing).

The Two Methods of Metalizing (CVD and PVD)

There are two common methods of metalizing: chemical vapor deposition and physical vapor deposition.

CVD, or chemical vapor deposition, is a vacuum deposition method used to create solid, high-quality and high-performance materials. To prepare for CVD, the non-metallic components of an object are chemically etched. The part is dipped into a hot mixture of sulfuric acid-chromic acid. Afterwards, it’s temporarily submerged into a tin chloride and palladium fluoride solution, which activates and sensitizes it. Nickel or electroless copper is used to coat the processed surface, and from there, the object can be properly metalized. During the metalizing process, the substrate is exposed to volatile precursors. These react and/or decompose on the surface, forming the necessary deposits.

PVD, or physical vapor deposition, is a term used to describe a variety of vacuum deposition methods, including sputtering and evaporation. In PVD, the metal goes back-and-forth between a condensed and vapor phase until a thin film is formed. Normally, the surface undergoes a pre-treatment. This can involve the use of acid etching, plasma, and more. Instead of being chemically bonded, evaporated atoms of metal are deposited physically onto the substrate’s surface.

During the vacuum metalizing process, a metal, usually aluminum, is evaporated in a vacuum chamber. The vapor that forms from the metal’s evaporation radiates outwards, condensing onto the surface of the substrate and creating a thin layer of metal coating. One of three methods is used to vaporize the coating metal: resistance, electron beam, or plasma heating.

Vacuum metalizing is well known as the process used to deposit aluminum on the glass mirrors of reflecting telescopes (such as the Hale telescope.)

The history and uses of metalizing are vast. The technology used to metalize objects has evolved over time, making the process not just easier, but more effective.

Having trouble with EMI? Deep Coat Industries can help. Our innovative approach to the vacuum metalizing process makes metalizing simple, and delivers high-quality, long-lasting results. We can also offer additional services to complement our vacuum metalizing core competencies, so contact us today.



The Differences Between EMI and EMC

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.


A Glossary of EMI Shielding Terms

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 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 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.


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.


How to Protect Your PCB From EMI

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.

PVD vs. CVD: The Differences and How To Choose

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.

Common Materials Used for Vacuum Metalizing

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.


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 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.

EMI Shielding Compounds vs. Coatings

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.