A perfectly designed Printed Circuit Board (PCB) definitely improves the performance and efficiency of electronic equipment. Due to continuous technological advancement, the complexity of electronic design is increasing and PCB designers need to design boards carefully, so the board can perform well without any failures. As compared to traditional electronics, big-sized wiring-based products nowadays, we are utilizing smart, reduced size and multifunctional electronics devices which are faster, user-friendly and easier to operate.
To fulfil the demands of the new generation in terms of advanced technology-based electronic devices, Electromagnetic Interference-related (EMI) concerns need to be handled carefully while designing the PCB. A PCB must be designed with perfect planning and execution while considering the EMI issues. EMI can create unwanted noise in signals, damage sensitive electronic components, cause cross-talk between traces, power supply stability-related issues and affect badly on the operation and working of electronic devices. Due to EMI issues, electronic devices face failure and do not work at all. By applying better shielding techniques in PCB design we can solve the EMI issues and achieve better-functioning electronic devices.
What is Electromagnetic Interference and Electromagnetic Compatibility?
EMI – Electromagnetic interference as the name indicates Electromagnetic Interference means disturbances generated by external sources which affect the surrounding different devices as well as the device’s own performance.
The different EMI and how it is generated are shown below.
- Conducted EMI – Noise transmitted via wires and cables
- Common Mode EMI – Currents flowing through ground loops
- Electrostatic Discharge – Short high voltage spikes
- Radiated EMI – Radio waves emitted and collected via devices
EMC – one of the most crucial components of a printed circuit board (PCB) layout is electromagnetic compatibility (EMC). It refers to the potential of electronic products to characteristic without being affected by electromagnetic fields or other gadgets.
EMC troubles can create critical demanding situations, together with signal interference, statistics loss, and even system failure. However, these EMC problems may be decreased by using the right grounding and shielding procedures. Also, EMC compliance must be taken into account by designers at every stage of the design process, from component selection to routing and layout, for a smooth function.
What is PCB Shielding?
In general, in electronic circuits, the signals are influenced by various kinds of interferences that come in the form of EMI, RFI and neighbouring components. PCB shielding means guards which protect the electronic circuits from different types of electromagnetic enemies, saving and extending the life of electronic devices.
Electromagnetic interference is PCB’s enemies which injure the electronic components, affect their working functions, reduce the signal quality and overall make the device useless for any application. So to avoid EMI issues shielding needs to be implemented in the PCB it provides safety to electronic components from EMI interference and avoids the signal’s interference with each other. Depending on the application requirement and criticality of the circuit, shielding needs to be applied on the entire PCB board or in specific sections of the electronic circuit section. This shield prevents loss of information and also covers the signal transmission from interference from the outside world.
Shielding Material
Shields are utilized for protection purposes from EMI so it should be made of a material which can work under environmental conditions. Below is the list of shielding materials.
- Aluminum
- Stainless steel
- Tin
- Brass
- Copper Alloys
- Silver
- Nickel
What is the Purpose of PCB Shielding?
A PCB may have conducted as well as radiated EMI generated from switching devices, switching pulses, high-speed digital signals, wireless signals and clock signals. Metals used in developing heat sinks present themselves as antennas when in high-frequency operation and cause emission of electromagnetic radiation. Whenever EMI gets into a PCB, it could hamper the normal working of the circuit, thus causing errors, signal degradation or complete failure of the device.
Shielding is useful for avoiding short-circuit situations by covering the PCB so that it will not be in contact with other parts or platforms. It also shields the devices from dust, moisture and debris by which one can develop shorts. Furthermore, it also shields circuits from electromagnetic noise from the use of radios, motors and any other source. The main purpose of shielding is to improve product life, avoid the effect of electromagnetic interference and provide a better functional product for the customers.
What Are the Main Types of PCB Shields?
- PCB RF Shielding / EMI shielding
- Conductive Enclosures
- Ground Plane Shielding
- Arduino Shielding
Benefits of Shielding in PCB Design
- Improved Signal Integrity
Shielding improves signal integrity by avoiding cross-talk-related issues between the traces on the PCB. Shielding helps in preserving the shape, time and quality of the information passed in the signal, thereby decreasing the bit error ratio on digital applications and noise on analog applications. High-speed digital signal applications require perfect signals with minimal interference in their paths.
- Enhanced Product Reliability and Improved Performance
Shielded PCB performs better as compared to unshielded PCB and by implementing shielding on PCB the product works efficiently for a longer amount of time. Known industries such as aerospace, automotive, and medical industries cannot afford anything less than reliability. Shielding helps in this regard because it basically guarantees consistent performance. Thus, by reducing interferences arising from electromagnetic fields, PCB shielding improves the efficiency of electronic devices, which function faster and with high precision.
- Extended Component Life
Shielding prevents components from being exposed to EMI stress. Shielding is good for extending the lifespan of PCBs. The shield also helps to minimise the possibility of shorting of some elements or tracks on the PCB by accident. Shielding works as a protection sheet for PCB components and enables them to work properly without any failure due to any operating conditions.
- Reduce EMI
The effects of interference can be internal when devices on the same PCB are interfering with other devices on it. For instance, where the high-frequency signal is in one section, it can produce interference with the analog signal in the other section, which creates operational issues. Electronic devices are always in interaction with EMI and RFI originating from other devices or a power supply and wireless signals. These interferences can even make the circuit on a PCB not function as expected or even impact some delicate components on the circuit. The advantage of the shield is that it reduces the possibility of the electromagnetic field spreading from the PCB to affect other parts of the board or devices external to the board.
- Noise Reduction
PCB shielding helps to maintain the integrity of signals by reducing noise and preventing crosstalk between different traces and components. This is crucial for ensuring accurate and reliable signal transmission.
- EMC Standards Compliance
Once PCB designing, manufacturing and assembly work is done, the PCB needs to clear standard compliance tests except the Electromagnetic Compatibility (EMC) test and get compliance approval. This makes it easier for manufacturers if compliance is controlled, and their products are prepared for the market and sold worldwide. Compliance with these standards requires electronics to be properly shielded from interfering with other electrical systems and to maintain high electromagnetic compatibility.
Applications of PCB Shielding
- Network and Server Systems
- Medical Electronics
- Aerospace and Defence Industry
- Consumer Electronics
- Mobile and Computing Systems
- Telecommunications Industry
- Industrial Automotive Electronics
- Automation and Energy Systems
Conclusion
Electronic product designing and development is a challenging and time-consuming process. Engineering team members invest their time, energy and money in understanding the product application from the beginning to the development of the complete product and launching it onto the market. But after PCB designing, manufacturing and assembly of components, if the product fails in the compliance test it will be a big loss in terms of time, money and disappointment faced by all team members. By implementing proper shielding techniques in PCB design, and by avoiding EMI issues, devices function efficiently and chances of device failure in compliance tests can be reduced.
To meet the demand for modern electronic devices, shielding is compulsory. Shielding provides multiple benefits that improve the device’s performance, and efficiency, reduce EMI, ensure compliance with electronic devices and meet the customers’ expectations.
