The growth of IoT among multiple verticals has led to the surge in demand for cutout and customized PCB assemblies. These PCB assemblies have complex and intricate design with multiple components and layers, which poses the risk of EMI and noise. This aspect has further driven the demand for good quality and flexible PCB shields. PCB shields used in IoT devices must be precise and meet specifications in terms of thickness, bendability, ventilation, and many other aspects. There are many factors to consider for board level shields in IoT devices. This post throws some light on IoT devices, their PCB assemblies, and the EMI shielding aspect.
What Are IoT Devices?
The concept of Internet of Things is facilitating inter-device communication and making systems autonomous with minimal remote monitoring. These are basically devices with sensors, improved memory and processing ability. They encompass computers, cameras, various electrical appliances, smartphones, consumer electronic goods, and so on, which are “smart” and can communicate with each other.
Quintessential Requirements in IoT Devices
IoT is a part of everyday tech in our daily lives. Here are some pointers that reflect on how the requirements of IoT devices are different from others in terms of PCB design, EMI shielding solutions, network type, communication technologies, and many other aspects.
- The key requirement is the right selection and optimal utilization of sensors, software, and communication technologies as well as advanced technology to manufacture these devices.
- The compatibility of these devices in a network and hence inter-device communication as well as their linking process to your smartphone via an application software are core aspects of consideration when making IoT devices.
- The network they are connected to must be robust, seamless, and offer high speed connectivity over long distances and remotely.
- The printed circuit boards are the components, which actually make them functional. These circuits ensure power to run the device. Most commonly, a combination of flex and HDI boards are used to make IOT device PCBs.
- Most of these devices such as smart watches, fitness trackers, smartphones, meters, smart televisions, and so on are small-sized or fitted in compact spaces, and hence there is a huge demand for small-sized, lightweight, flex boards that can accommodate multiple components.
- IoT devices come under high-frequency applications which involve heat generation and multiple signals crossing each other. These high-frequency applications pose the risk of electromagnetic interference which must be mitigated or suppressed for the device to function normally. Hence, these boards need to be protected from cross talks and signal clashes via EMI shields.
- The EMI shields need to be carefully designed and customized based on the PCB design and layout. Also, they must be made from flexible materials such as thermoplastics with a conductive layer on the outer side. They must rightly fit the board shape considering all the components, wires, vias, cavities, and so on.
- So, while all the above factors are essential in any IoT device, the right type of PCB shield goes a long way in ensuring the device is functional with all the required features, and there are no disruptions at board level due to EMI or RFI. Hence, selecting the PCB shield and customizing it based on the board size, shape, thickness, and so on is crucial.
Factors to Consider for Selecting PCB Shields in IoT Devices
Here are some factors that you may want to consider when selecting PCB shields in IOT devices.
- Materials: While it is common to use copper or other conductive metals to create PCB shields. However, they may not be suitable for IoT devices as they do not offer the required bendability. The best possible option of PCB shield materials for IoT devices is plasticized metal. A thermoplastic film made of polyetherimide with a tin coating on the outerside would offer the right amount of conductivity and flexibility.
- Frequency range: The frequency range of PCBs would differ across boards, and usually IoT devices have frequencies in the higher range. Hence, it is essential to determine the frequency range in which your IoT device operates. The shield must also be designed to suit the specified frequency range. This is because the clashing EMI signals would attenuate in these frequency ranges, and the shield would further suppress any internal EMI that may occur.
- Heat dissipation and ventilation: This is crucial aspect as IoT devices are heat-generating applications. Hence, the board must be designed with enough ventilation, heat sinks, and gaps between wiring. The shields can be designed exactly according to the board design with enough holes and thermal pads wherever required.
- Application environment: This is the most important aspect as all the features of the PCB shields must be weighed according to the application requirements and operating environment. This also includes the budget.
- Scalability: The PCB shields must be designed to be scalable and removable. At times, the PCBs may need rework or upgrade. In such cases, the engineer must be able to remove the shield, rework, and put it back with ease. The shield must be scalable to suit the upgrades done to the board.
- Shielding effectiveness: This is measured in decibels (dB) and is the ability of the shield to effectively attenuate EMI signals. This factor can be increased with the right amount of thickness, especially for sensitive components. To enhance shielding effectiveness, PCB design plays a crucial role in terms of component placement, as well as the distance between wires.
If you are an electronics contract manufacturer (ECM), you will need PCB shields that not only mitigate EMI but also suit small boards with complex layouts. XGR Technologies offers SnapShot™ as a product that can be customized to make lightweight and flexible EMI shields. These shields offer isolation across a wide frequency range from below 1 GHz to 12 GHz. The company offers a high level of customization. You can contact the XGR Technologies team today if you are interested in knowing more about the board level shielding solutions they offer for IoT devices.
