- RF exposure testing
- Four different methods to show RF exposure compliance
- How to prepare for the RF exposure evaluation?
- Additional information
RF exposure testing
The RF radiation of all wireless devices must be evaluated to ensure a safe and reliable use of radio devices. There are international and regional RF exposure requirements that are defined based on scientifically established health effects. RF exposure testing or calculations must be performed to ensure that the RF exposure characteristics of the device are within the required safety limits.
The limits for RF exposure depend on the region where the device is being sold. The council of European Union determines the limits for EU, Innovation, Science and Economic Development Canada (ISED) for Canada and Federal Communications Commission (FCC) for USA. RF exposure compliance of electronic and electrical equipment with the basic restrictions usually is determined by measurements and, in some cases, calculations of the exposure level.
Four different methods to show RF exposure compliance
There are four different evaluation techniques to show RF exposure compliance of a device:
- Specific Absorption Rate (SAR) testing
- Electromagnetic Field (EMF) Measurements
- Power density calculations
- Assessment of low power equipment
Two of the methods require testing (SAR and EMF testing) and two of the methods are done by calculations (power density calculations and assessment of low power equipment). Read our four ways to show RF exposure compliance -article to get a better understanding what is the best way to show RF exposure compliance of your device. If you are unsure what is the best method for you to show RF exposure compliance of your device, contact our sales and we will help you.
How to prepare for the RF exposure testing or calculations?
There are some things that are good to know before the RF exposure evaluation. Depending on the selected RF exposure evaluation method, there are a list of things that should be done and ensured before the evaluation. Below you will instructions what to do when you need a RF exposure evaluation performed on your device. We will start with SAR testing, move on to EMF testing and lastly go through the processes of RF exposure evaluation calculations.
Specific Absorption Rate (SAR) is a measure which explains how much radio frequency energy is absorbed by the user’s or bystander’s body or head. SAR testing is required for the devices that are used closer than 20 cm to the human head or body. We offer compliance SAR testing and pre-compliance SAR testing.
- Pre-compliance SAR testing. SAR testing during the product development phase is called pre-compliance SAR testing. Pre-compliance SAR test gives an indication if the product will pass the mandatory SAR testing when the product is otherwise ready. SAR testing during the product development phase helps to locate possible issues already in the R&D stage and gives an indication of the SAR level for the final product. Locating the possible problems in an early phase, costly design errors can be avoided, and the product design can be developed towards the right direction from the beginning. It can save some serious costs from the future. Resolving the observed SAR issues in an early phase ensures more predictable certification costs and early access to the market.
- Compliance SAR testing . Compliance SAR testing is required for all the radio devices that are used closer than 20 cm to the human head or body to have a permission to sell them on markets. Verkotan SAR test laboratories are accredited by FINAS and by having FINAS accreditation, Verkotan is ILAC recognized test laboratory. We have the capability to perform SAR testing for example for CE, FCC, ISED certifications.
How to prepare for SAR testing at Verkotan?
Another way to demonstrate RF exposure compliance is by electromagnetic field (EMF) measurements. Electromagnetic field consists of electric fields (typically called E-field) and magnetic fields (typically called H-field). Electrical devices emit electromagnetic fields when being used. Typically, EMF testing is done when SAR testing is challenging to perform; EMF measurements are typically performed on low frequency devices. For example, wireless chargers require EMF testing.
There are different regional limits set by regulatory bodies for exposure to EMF, similar way as with SAR testing. EMF testing is used to assess the levels of exposure and compare them to reference levels. Compliance with EMF requirements is obligatory in most markets including Europe, the US, and Canada. Verkotan is equipped for EMF testing for various different products.
How to prepare for EMF testing process at Verkotan
Power density calculations & assessment of low power equipment
There are two methods to show RF exposure compliance by calculations, without any testing. These two methods are assessment of low power equipment and power density calculations. For these two methods the RF exposure compliance process for the device manufacturer is the same. Read more detailed information about RF exposure calculations from our When to show RF exposure compliance with calculations -article.
Assessment of low power equipment
Assessment of low power equipment is possible to be performed on low power devices. The standard EN 62479 defines the assessment methods for low-power electronic and electrical equipment, whereas the standard EN 50663 defines maximum power levels, called PMAX exclusion levels for low power equipment. PMAX exclusion level means that if a device has lower or equal power levels as PMAX exclusion level, the RF exposure value of a device can be calculated instead of testing. Standard EN 50663 defines maximum power levels to be 20 mW over the 10 MHz to 300 GHz frequency range for the general public exposure. Below you see the PMAX exclusion levels defined by EN 50663:
Power density calculations
Power density calculations can be used to show the RF evaluation compliance when a device has radiating parts farther than 20 cm from a human body or head, or when operating at frequencies over 6 GHz frequency. For example, a wireless security camera could be a device to which power density calculations were performed.
In short, there are two possible cases when power density calculations are possible to perform:
- When the device has radiating parts further away than 20 cm from a human body or head
- It operates over 6 GHz frequency.
How to prepare for RF exposure calculations at Verkotan
RF exposure calculations and measurements require a great level of knowledge from the test engineers to be able to follow the rapidly changing standards and get reliable evaluation and accurate measurements. Let a professional test laboratory take care of the measurements, and you can focus on the processes most relevant for you. We are happy to help you with your RF exposure compliance needs.
If you have any further questions do not hesitate to contact us! We are always ready to help you.
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