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- 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.
SAR testing
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?
1. Contact us
If you are unsure what is the best way to show the RF exposure compliance of your device, we will help you.
If SAR testing is the right method to show the RF exposure compliance of your device, follow the instructions below.
2. Provide the lab with the information about your device
- Are you looking for pre-compliance SAR testing or compliance SAR testing?
- General description about the device
- Size
- Weight
- Intended use case
- What modules are used in the device?
- How many TX antennas there are used per module?
- Is carrier aggregation (CA) supported by the device?
- Which certification you are looking for? (if you are)
- CE, FCC, ISED, ACMA, MIC
- The maximum output power + production tolerance information for each band of the product needs to be provided.
- Maximum duty cycle
Or alternatively request a quote using the form below
3. We will send you an estimate about the price of the RF exposure testing
4. Let’s book a suitable testing slot for testing.
Our SAR testing laboratory has a good capacity and tests are possible to be performed even in a short time frame.
5. Consider these things before sending the device for us
- To control transmission for cellular devices, the device under test (DUT) needs to have a slot for SIM (to able to connect to tester) or have a control SW to establish the transmission. If the product has E-SIM, it needs to be configured as a test SIM or an external SIM slot needs to be added to the DUT.
- A control software needs to be provided with a DUT in order to establish a connection to e.g., WLAN, BT, RFID. For testing of WLAN, a control SW that enables the selection of channel, output power, the data rate is needed. Also, the duty cycle needs to be adjusted close to 100%.
- The DUT needs to be able to transmit continuously on full power during the whole test, for a minimum of 20 minutes. The testing time might be longer, depending on DUT size since larger DUTs require longer testing times.
- During the testing the device will not have access to real network so it should be configured accordingly
6. Deliver your equipment to us.
- Sample for conducted output power measurements, i.e., where antenna is bypassed by a coaxial cable
- Unmodified samples for SAR testing with test mode enabled if possible. If the sample runs out power quickly, then more samples are needed as samples need to be charged often.
- Charger/device for charging
- Batteries
- Accessories (body-worn accessories, any changeable parts, e.g., different straps, covers, etc.)
- User instructions for the testing, e.g., how to use the control software, how to get the device to transmit
7. Testing time!
We will test your device. After testing we will send you a drafted report and answer any possible questions you may have. After your approval, we will sign the test report. If we notice something unusual or non-conformance on your device during the testing, we will notify you immediately to save your time and costs.
Below you can download an example of SAR test report.
Download the Example SAR Test Report
EMF measurements
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
1. Contact us
If you are unsure what is the best way to show the RF exposure compliance of your device, contact us and we will help you.
If EMF testing is the right method to show the RF exposure compliance of your device, follow the instructions below.
2. Provide the lab with the information about your device
- Are you looking for pre-compliance or compliance testing?
- General description about the device
- Size
- Weight
- Intended use case
- What transmitters are included
- Which certifications you are looking for? (if you are)
- CE, FCC, ISED, ACMA, MIC
- The maximum output power
Or alternatively request a quote using the form below
3. We will send you an estimate about the price of the RF exposure testing
4. Let’s book a suitable testing slot for testing.
Our SAR testing laboratory has a good capacity and tests are possible to be performed even in a short time frame.
5. Consider these things before sending the device for us
- To control transmission Verkotan will need a control software
- The DUT needs to be able to transmit continuously on full power during the whole tests
6. Send your equipment to us.
- Sample for conducted output power measurements
- User instructions for the testing, e.g., how to use the control software, how to get the device to transmit
7. Testing time!
We will test your device. After testing we will send you a drafted report and answer any possible questions you may have. After your approval, we will sign the test report.If we notice something unusual or non-conformance on your device during the testing, we will notify you immediately to save your time and costs.
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
1. Contact us
If you are unsure what is the best way to show the RF exposure compliance of your device, contact us and we will help you.
If RF exposure calculations is the right method to show the RF exposure compliance of your device, follow the instructions below.
2. Provide the lab with information about your device
Here is a list about the information you need to provide us. You will find all these questions from our RF exposure evaluation template that you need to fill in before the calculations.
- Product name
- Manufacturer
- Model
- Use case
- What certifications you are looking for?
- FCC, CE, ISED, ACMA, MIC
- SW version
- HW version
- Description of the Device Under Test
- Module/SoC model(s)
- Minimum separation distance to body or head [mm]
- FCC ID (if available)
- IC ID (if available)
- Does the device support for Simultaneous Transmission?
- Possible Simultaneous Transmission Combinations? (e.g., WLAN + LTE)
- Product datasheet, Module specification, Photos of the DUT
- Fill in the following table
| Radio Access Technology | Frequency Bands | Maximum Specified Output Power [dBm] | Maximum Duty Cycle | Maximum Antenna Gain [dBi] |
|---|---|---|---|---|
Typically RF exposure calculations do not require shipping a sample to us.
3. We will send you an estimate about the price of the RF exposure calculations
4. Let’s schedule a suitable time for calculations
Our laboratory has a good capacity and calculations are possible to be performed even in a short time frame.
5. Time to perform the calculations
- We will do the calculations based on the filled form you send to us and provide you with reliable results. After evaluation we will send you a drafted report and answer any possible questions you may have. After your approval, we will sign the report.
Additional information
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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