In today’s high-tech era, digital media has quietly turned out to be the hidden power that rules our lives. A common source of such interference is Radiofrequency radiation (RF) coming from devices that, in addition to keeping us occupied and entertained, also make life more convenient. All these devices are responsible for the generation of electromagnetic fields. These fields can harm other electronic gadgets, cause data loss, and even affect our bodies to the extent of compromising our health.
With more and more activities being wireless, there is a rise in EMI radiation, thus, it is necessary to understand the dangers it entails and take steps to reduce its influence.
What is Electromagnetic Interference?
The ever-present and hidden danger of Electromagnetic Interference (EMI) is an uninvited guest in our modern era, which has infected everything and everyone to the core. It is a kind of energy released by electronically operated things, from the humblest of mobile phones to the most complicated industrial machines. This energy, which comes in electromagnetic waves, can greatly affect the performance and reliability of nearby electronic systems.
Imagine a busy city street that is filled with people; they are from different social classes and walk in a hurry everywhere. Visualize from now that every human being is giving off a specific variation of energy, just like a radio station signal. The thicker the crowd the noise of the signals increases, and thus their interference disrupts the harmoniousness of the environment.
Electromagnetic interference or RF interference is the phenomenon of disturbance caused by the interaction of undesired electromagnetic waves from neighboring devices or sometimes the system itself. In any active communication system or transmitting device, electromagnetic interference is a significant characteristic that determines the quality of the device and system.
RF interference is a common phenomenon in any system that operates at the radio frequency (RF) range. Due to the increasing number of transmitting devices, the co-existence of an efficient wireless ecosystem is significant. More wireless transmission techniques are emerging to support a wide range of applications, and all of them use radio frequency waves for communication.
Types of Electromagnetic Interference
EMI radiation can be divided mainly into four types, which feature different characteristics, frequencies, and exposure effects on devices and systems.
Conducted EMI: undesired signals using a conductor medium such as a wire or transmission cable to cause interference in another system, which is the transmission that goes through the conductive medium, including wire or cable. Such a form of EMI, in turn, can be adamant, leading to voltage drops, noises, and more.
Inductive EMI: It occurs when two transmitting cables are close to each other, and the varying electromagnetic field of these transmission media influences each other. It happens due to the phenomenon of electromagnetic induction.
Capacitive EMI: Capacitive EMI occurs when two conductors are parallel to each other, and if there is a medium to store charges between the conductors. It happens only when two conductors are very close to each other.
Radiated EMI: undesired signals use a wireless medium (like radio waves), which causes interference in other devices or systems. Radio Frequency Interference (RFI) is the most common type of EMI as the electromagnetic radiation emitted from radio waves, microwaves, or other electromagnetic radiation waves is emitted into the air through the air. Such a type of EMI is referred to as a cause of major headaches since it can potentially propagate far and at the same time afflict multiple systems.
It is necessary to strictly follow guidelines to make sure that any device will not create any disturbance to other devices, and the intensity of the signal is safer for humans and other living organisms.
Sources of Electromagnetic Interference
In our daily lives, we get exposed to EMI radiation from different sources in varying conditions. Such radiation is often stigmatized as the humming of the fluorescent lights above our heads, the motors of household appliances, and the wireless signals generated from the routers and modems.
1. Intentional Sources
Devices purposely meant to radiate energy in the radio frequency range include Wi-Fi routers, mobile phones, Bluetooth headsets, radios, etc. They are important to communications, but bad design, improper frequency planning, or close physical proximity could lead to mutual interference. Co-located antennas on a cell tower must be carefully isolated and filtered to prevent them from stepping on each other’s signals, for example.
2. Unintentional Sources
Most of the electronic devices (computers, LED lights, or even power supplies) radiate RF energy unintentionally. The type of radiated RF energy is generally very weak. However, poorly shielded or defective devices could cause interference, particularly in areas such as hospitals or even with aircraft.
3. Industrial Equipment
Motors, generators, welding machines, and HVAC systems can generate strong electromagnetic fields. These electromagnetic fields often come within the vicinity or well into the RF spectrum, radiating noise into nearby wireless systems. Such systems turn chronic offenders with poor grounding or shielding.
4. Power Lines and Electrical Grids
Power lines are of moderate to average size. This happens especially for power lines that are aged, causing the carrying wires to sometimes be closer than expected and act like giant antennas. They produce and broadcast a good amount of RF noise when there is an arcing insulator or loose connection, which can be radiated across wide frequency ranges and is usually difficult to isolate.
5. Natural Sources
Of course, not all interference is caused by technology invented by humans. There are bursts of RF energy among lightning, solar flares, and cosmic radiation. Although these bursts are rarer and tend to last a shorter duration, they can indeed prove devastating to satellite communication, aviation, and high-frequency (HF) radios.
All transmitting electronic devices can potentially become a source of EMI.
How is Electromagnetic Interference generated?
Generally, all electronic devices use electrical power, creating a small electromagnetic interference. In wireless transmission systems, the power of the signals received at the antenna is much lower. The lower level of EM interference is not harmful to other surrounding equipment, but stronger noise could affect the quality of the signals, especially devices receiving signals from transmitters far away from the receiver.
There are many reasons for electromagnetic interference such as high power wires running close to other transmitting cables, poor connection and joints in a power transmission system, harmonics generated in an active semiconductor switch and power amplifiers, intermodulation due to mixing of two or more signals and its harmonics, faulty couplers, splitters, malfunctioning accessories in high power applications, etc…
Read how intermodulation distortion is generated
Malfunctions of low-power transmitting devices like mobile phones, household appliances like microwave ovens, switch-mode power supply units inside personal computers, and aircraft flying at lower altitudes are some of the common sources of electromagnetic interference.
How to Avoid RF Interference?
Although RF interference can never be fully eliminated, it is certainly manageable. The following measures have been tried and proved effective:
Frequency Planning: Careful assignment of frequencies so there is no overlap or problems due to crowding should avoid adverse effects, particularly in multi-transmitter environments.
Correct Shielding: Proper shielding is applied to cables, enclosures, and especially sensitive components so that they emit or absorb stray RF energy.
Grounding and Bonding: grounding of all systems on a proper basis. A good ground will always provide safe dissipation of unwanted signals.
Filter and Isolate: the use of filters to suppress unwanted frequencies and isolation techniques for cross-talk prevention between instruments.
Compliance: EMC (Electromagnetic compatibility) and EMI (Electromagnetic interference) standards assure you that your creations are far less likely to cause or be afflicted by interference.
How does EMI Radiation Affect Our Health?
The hidden harm of Electromagnetic Interference (EMI) radiation that is undetectable affects everyone, as we lead a more tech-related lifestyle. Even though it is invisible to the human eye, the health hazards that it poses can be alarming. Permanent exposure to EMI radiation leads to the problem of complex health conditions that include, for example, headaches, fatigue, and even brain tumors.
The human body is a highly complicated and susceptible system, and EMI radiation may interfere with its normal operation. Exposure to electromagnetic waves induces our cells to absorb them and routinely causes them to vibrate with an unfamiliar frequency. Due to this lowered immunity, we have a higher risk of getting ill and developing diseases.
Moreover, there is evidence that the harmful rays can disrupt brain activities, leading to problems in concentration, memory, and mood. The wide-ranging effects of radiation from EMI are alarming, and we need to act to come up with remedial measures that can help us avert the catastrophic consequences on our health. Through the recognition of the risks of EMI radiation, we may choose to undertake measures that will protect our friends and family from this danger that they can’t see or perceive.
The 5G Boom and the Growth of RF Interference
With the rollout of 5G, IoT (the Internet of Things) has exploded, thereby making RF interference more and more of a challenge. When new spectrum bands are particularly mid-band (like 3.5 GHz) and millimeter-wave (24 GHz+), are used nearer to or overlapping existing systems.
Smart homes, self-driving vehicles, wearables, and industrial automation are adding transmitters to the environment, each of possible interference and a possible victim. Increasing device density means that interference management is no longer optional; it is now a design priority.
Effects of electromagnetic interference
- Generally, performance degradation of devices and equipment is one of the troubling effects of electromagnetic interference.
- Wrong readings in test equipment due to high levels of noise
- Malfunctioning wireless sensors and total disruption in connectivity
- Failure of radio communication in emergency services and aviation could lead to unexpected situations
- Long-term exposure to high-intensity electromagnetic radiation could cause health issues like skin diseases, affecting brain cells, vision, hearing, and even cancer
How to avoid interference in EMC?
Shielding, Earthing, and filtering are known as the three principles of electromagnetic compatibility. In order to fulfill the EMC standard requirement, engineers have to follow best practices during design stages, testing, and product implementation. Periodic verification according to specifications may also be required in some cases to make sure every component of the system works within allowed limits.
Shielding: Proper shielding of printed circuit boards and power modules will prevent signals from radiating out and into the system. Metallic shielding is often used in complex circuit boards and amplifiers.
Find more about Electromagnetic Shielding
Earthing: Earthing, also known as grounding, is a method of adding a proper signal ground connection to prevent undesired signal interference. Surge arresters and decoupling capacitors are used in high-power applications.
Filtering: filtering of undesired signal components is another effective method in electromagnetic compatibility. Passive and active filters are used to filter out noise components.
Electromagnetic Compatibility – Standards and Guidelines
Electromagnetic compatibility (EMC) is a standard for many countries that qualifies a product whether it meets certain requirements in the guideline. Basically, EMC is a product qualifying factor that ensures a particular product doesn’t interfere with other devices via electromagnetic radiation. If the product emits radiation above the allowed level, it will not be qualified for the EMC standard.
Organizations like the International Committee on Radio Interference (CISPR), the Federal Committee for Communication (FCC) in the United States, and European Norms (EN) in the European Union have strict standards for any products sold in each country. These guidelines ensure the safety of people and restrict any violations like harmful radiation from devices.
How is EMC tested?
Electromagnetic compatibility is tested with a highly sensitive antenna within a Faraday cage known as a test chamber. The device under test will be placed on a wooden table and rotated 360 degrees during the test. Radiated signals from the DUT will be absorbed at the antenna, and the radiation pattern and strength will be calculated using sophisticated equipment.
EMC test chamber
Radiated emission tests, conducted emission tests, and radiated immunity tests are conducted to determine the product qualification for electromagnetic compatibility. EMC is a compulsory standard for all electronic devices, toys, drones, automobiles, aircraft, and military equipment.
The size and capacity of the test chamber depend on the application in which the system is used.
Source: Inductive EMI
Please share your feedback, leave a comment