7 Tips and PCB Design Guidelines for EMI and EMC

Electromagnetic interference (EMI) is associated with every electronic device we use nowadays. If you turn on your radio set and TV simultaneously, you will experience the noisy disturbance from TV interfering with the radio signal and vice-versa. We can also experience this when we board a plane and are asked to switch off the electronic devices by the crew. This is to avoid interference of mobile and electronic device signals with the plane’s navigational signals. As consumer electronics is on high demand, the effects of EMI must be taken into consideration. It would be very irking if a person walking down the sidewalk talking on their cell phone caused interference to someone else’s audio device. It is not possible to get rid of EMI/EMC completely, but we can surely curate our PCB design services to make them less vulnerable to EMI/EMC effects.

An electronic system consists of printed circuit boards (PCBs), integrated chips, interconnect, and I/O cables. At high frequencies depending on the length of the interconnects and the current carried by the conductors, the interconnects tend to act as antennas, resulting in EMI. These EMI radiations interfere with other devices present in the vicinity. There are international standards that limit the level of emissions. Thus, it is highly important to measure electromagnetic radiation and control these radiations.
So, any product having wires/traces and operating at high-frequency has the tendency to radiate radio waves. This is the reason why EMI/EMC study and analysis is important. Does your product’s radiation disturb other devices present nearby? Whether it is within the set standards? Are the relevant EMI standards such as IPC CISPR standards achieved? In this article, we will cover the PCB design guidelines using which EMI and EMC can be controlled/avoided.  

What are EMI and EMC in a PCB?
EMC compliant PCB design
What are the Sources of EMI?
Design guidelines for EMI and EMC reduction in a PCB
Testing EMI/EMC in a PCB design
What are the EMI/EMC Standards? (CISPR)

What are EMI and EMC in a PCB?
Electromagnetic compatibility (EMC) is the ability of an electronic system to operate within an electromagnetic environment satisfactorily without generating intolerable EMI (electromagnetic interference) in nearby devices/systems. EMC ensures that the system must perform as intended under the defined safety measures.
EMI is an electromagnetic disturbance, where energy is transmitted through radiation/conduction from one electronic device to another and corrupts the signal quality causing malfunctioning. EMI focuses on the testing requirements and interference between the neighboring equipment. It can occur in any frequency range, say anything more than DC. Typically, it happens above 50MHz. 
Whenever a device deviates from the defined standards,...