When developing an electronic circuit, you will want to protect it against electromagnetic interference. Otherwise, it will experience unusual problems, leading to performance degradation and failure. Not only that, but it may also affect other sensitive electronics due to signal leakage. For this reason, we recommend installing PCB shields onto your system. This technology ensures circuit board longevity and safety while also blocking electromagnetic radiation.
By reading this article, you will understand the benefits of PCB shielding and the types available on the market. So let’s get started!
What is EMC Shielding?
RF shielding enclosure
Electromagnetic Compatibility (EMC) shielding generally involves protecting sensitive signals against outside electromagnetic signals. It also helps to ensure that stronger signals cannot escape, which could disrupt neighboring devices. In this case, electromagnetic frequencies may produce a communication line or interrupt a safety-critical signal. Overall, this safeguard will work with ICs, sensitive components, and wires connected to each PCB.
As a result, circuits designed with this technology will prevent signal disruption via the shielding features.
Consequences of unshielded electronics
Unshielded electronics may eventually disrupt wireless devices.
Interference such as crosstalk, power supply noises, and ground bounce can significantly affect electronics, leading to performance issues. However, electromagnetic interference (EMI) poses a more significant threat because it can devastate an electronic device’s functionality. Not only that, but it may also result in catastrophic and expensive consequences. For example, EMIs can also cause medical devices to fail, resulting in dire consequences.
If you fail to control the EMI in an electronic device, the following problems may arise.
- Communication disruptions
- Interference with wireless devices
- Results in corrupted sensor data
- Electronic component failure
- Software errors or defects
Electromagnetic interference can corrupt sensor data.
A poor circuit board layout will usually produce electromagnetic interference. Unsolved issues relating to the generated EMI will result in poor board performance, causing it to eventually malfunction. You can prevent this from happening by improving PCB design techniques.
Implementing EMI Shielding in Your PCB Layout
A PCB layout may feature any shielding material.
Electromagnetic shielding materials exist on the market, many of which provide practical and straightforward solutions. Sometimes traditional methods involving filters and best layout practices may not work as expected. In that case, you should mount any of these mechanisms in your PCB layout:
- Metal shielding cans: You can wrap a custom-made metal shield (metal box) around noise-generated circuits to restrict excessive electromagnetic radiation.
- Elastomer electromagnetic shielding materials: This material on specific components and connectors will help limit electromagnetic radiation.
- Ferrite beads, rods, and plates: If traditional filter circuits malfunction, then ferrite beads, rods, and leaves can work like an EMI filter.
- High conductivity mesh materials: Rather than rigid shielding cans, you can install mesh materials, Ideal for flexible or rigid-flex boards.
- Separated/star ground replacements: Uniform ground planes will supply several grounding points. Plus, you can easily ground conductive shielding materials.
You will also need to follow best practices when installing the shielding to your PCB layout. Doing so will allow your design to pass EMC tests.
Types of PCB Shielding
Two main PCB shielding types exist today: PCB RF shielding and Arduino shielding.
PCB RF Shielding
RF shielding blocks electromagnetic radiation and radio frequencies by lowering the coupling of electromagnetic fields, electrostatic, and radio waves. These shields may also feature a Faraday cage, which impedes electrostatic fields.
RF shielding enclosure
Arduino’s EMI PCB shield features shield pins down the sides, allowing you to mount it atop an Arduino PCB. As a result, the circuit’s functionality will increase. More importantly, you should also pay special attention to any reserved pins. If a sensor utilizes the I2C or SPI bus, it cannot operate as the input and output on another shield. You can purchase a wide selection of securities from Arduino.
Why Are Arduino Shields Better than Others?
Overall, an Arduino shield is easier to handle and cost-friendly than other types. It also features a library with sample, editable code, allowing you to develop and assemble a project. Plus, you can stack a shield board atop an Arduino, creating a complete system.
Arduino shield boards stacked atop each other.
Source: Wikimedia Commons
The typical features of PCB level shield cans
A PCB level shield typically offers the following features in its design:
- Small footprints
- Low-profile configurations
- Two-piece security: fence and cover
- Through-hole or surface mount
- Multi-cavity patterns
- Unlimited design possibilities
- I/O holes
- Connector cutouts
- Ventilation holes
- Removable covers to easily access components
- Extended shielding with RF absorbers
- Secure locking mechanisms to protect against shock and vibration
- ESD protection featuring insulation padding
Typical Shielding Materials
Electronic PCB shielding material for electromagnetic compatibility solutions.
Typically, shielding comes with the following materials:
- Tin plated cold rolled steel
- Tin plated copper
- Nickel silver
- Stainless steel
- Tin plated phosphorous bronze
We recommend selecting the tin-plated steel if you need to shield below 100 MHz on a circuit. Meanwhile, tin-plated copper will protect against ratings higher than 200 MHz for your printed circuit board. Tin plating makes it easier to solder the shield. On the other hand, aluminum has heat-sinking properties, so it cannot shield it.
Overall, PCB shields provide the necessary protection for your custom circuits. Of course, you will need to ensure that the circuit meets the criteria. It achieves this through specially designed material that works best for a specific frequency range. For example, you can utilize tin-plated steel for a device below the 100 MHz ratings. Additionally, RF shields help to block out radio frequencies and electromagnetic radiation. At the same time, other affordable options exist on the market today, especially the Arduino boards.
Do you have any questions regarding PCB shields? Feel free to contact us!