Just like technology, RF testing and SAR regulations are always changing. It can be difficult to keep up with, but it doesn’t have to be. Although we can’t say for sure what the future holds for RF technology, we discuss where we think things are headed.

An Overview of RF Testing & Modern Technology

We’ll start by explaining radio frequency (RF) testing. This testing is used to confirm that wireless devices comply with federal regulatory requirements. RF testing is mandatory for any electronic product that can oscillate above 9 kHz. There are some exceptions to this, but they are few. 

RF compliance testing is required to sell most wireless devices and it proves that your wireless products are safe for consumer use. This testing is also an essential part of demonstrating that any radio and telecommunications products are efficiently using the radio spectrum and are not interfering with other products that use this spectrum.

Testing should be done during the early stages of your product’s development to avoid product redesigns or issues that may arise from finding out that your product has failed testing after mass production has started. Ensuring that your product meets compliance testing requirements early in the process will reduce your time to market and avoid costly redesigns.

But what is RF and how is it used to power wireless technology? Today, most devices use RF energy to send and receive data. Most of these devices use single-frequency or spread-spectrum technology to send data. Single-frequency technology uses one frequency to transmit data, while spread spectrum uses multiple frequencies simultaneously to send data.

Devices that use RF energy are used for broadcasting, communications, medicine, and wireless power. Medical devices typically use VHF frequencies because they do not cause harm to the human body, but UHF frequencies may also be used. These frequencies allow medical professionals to monitor internal organs. Telecommunications devices can use both VHF and UHF frequencies.

Other applications of RF energy include:

• RFID tags, chip cards, and contactless smart cards
• 3G, 4G, 5G, WiFi, and Bluetooth devices
• Medical devices
• Wireless remotes for home appliances and cars as well as some wireless toys
• Wearable medical devices such as medical bracelets or sensor patches
• Implanted medical devices, including pacemakers, insulin pumps, neural chips, etc.

Advancements and Changes in Wireless Technology

Wireless technology is constantly evolving, which means that RF testing needs to keep up with these changes. Expectations for faster communication speeds and larger data capacities with lower latency require higher frequencies and changes to the wireless devices we use.

This also requires changes to how RF compliance testing is conducted and even changes in the equipment used. For example, as millimeter wave and near-field charging devices have become more popular, SAR regulations regarding their compliance have changed and labs like ours have acquired new equipment to conduct testing. Upcoming changes, like technology for 6G communications will continue to require changes to regulations and equipment. 

Emerging Technologies and Devices

5G networks are quickly becoming the new normal for wireless communication, and we can assume that consumers will eventually demand faster mobile speeds and even better reliability. Even the military, government, and private sectors are working toward developing the next generation of RF technology.

All of this proves that demand for RF technology is high and shows no signs of stopping or even slowing down. In the following sections, we’ll discuss some of these emerging technologies and how they may affect RF testing.

Higher Frequencies and Bandwidths 

Higher frequency bands will allow devices to have higher network capacity and data rates, which is why new technologies and solutions are being sought for the next generation of wireless devices.

Different generations of technology have operated in different bandwidths, such as 2G technology, which operated at 200 kHz with frequencies below 2 GHz. 3G technology operated at 5 MHz with frequencies up to 2.6 GHz. 4G had a more flexible bandwidth ranging from 1.4 MHz – 20 MHz, with frequencies up to 3.6 GHz. 5G, the most recent generation, is similar to 4G in that its bandwidths are flexible and can reach a hundred megahertz.

High Data Rates at Lower Frequencies

As mobile technology and generations advance into higher frequencies, wider channel bandwidths become available. This technology is now being developed to utilize frequency bands near 100 GHz and beyond.

Higher frequencies also allow for smaller antenna elements due to the short wavelengths of these frequencies. Smaller antennas also make it possible for the beam to be controlled by properly phasing the antenna elements of the array.

Unfortunately, higher frequencies also have greater atmospheric attenuation and pathlosses. To make up for this, highly directive antenna rays are often used. This makes beam steering antennas a crucial part of millimeter wave technology. 

Another important challenge of high frequencies affects the specific absorption rate of devices using these frequencies. Because the beams produced by the antennas used may be able to penetrate tissue, these devices may exceed SAR limits. This makes taking SAR measurements during the development phase very important.

5G and Beyond 

As network iterations evolve, there will be new challenges in RF  testing. Although it may seem like 5G is simply an incremental update of 4G and so on, new networks actually involve major changes to technology.

For example, 5G uses higher frequencies for increased data carrying capacity, but this is at the cost of coverage because high frequencies have greater pathloss. This means that 5G devices need to be close to transmitters for them to receive a signal.

As we move to 6G, there will be another set of challenges. In addition to this, it’s very likely that artificial intelligence and edge processing will be integrated into the network. This will be used for collecting, aggregating, and analyzing data. Of course, this will also change testing for these devices.

Over-the-Air (OTA) Testing 

Over-the-air (OTA) testing is a method used to forecast the performance and reliability of wireless devices in the real world. To conduct OTA testing, the wireless device is placed in a free-space environment within a test chamber, where real-life situations will be simulated. Within this environment, the device is subjected to multiple test conditions and how it responds to each situation is closely monitored.

OTA testing measures the device’s signal path and antenna performance to ensure that it will be able to perform as intended in real-world environments.

This form of testing is preferred for devices that use 5G technology. These products may include phased antenna arrays of 4-by-4 or 8-by-8, which makes it necessary to determine how to conduct SAR testing for these devices based on OTA testing.

There are three different distances for OTA testing known as near-field reactive, near-field radiative, and far-field.

• Near-field reactive testing is close enough that physical obstructions could affect the signal.
• Near-field radiative is testing in which an obstacle may still be able to distort the signal
• Far-field is testing in which the device’s signal simply radiates out with a square-law power decay.

But why is OTA testing so important for 5G, MIMO, and other wireless devices? There are a few different reasons, but the most important is that the operation of these devices may degrade when used in the real world. OTA testing is a key part of making sure that devices like phones, tablets, and other wireless devices are ready to enter the market.

OTA tests also certify some products according to the standards of the test and most IoT and M2M device manufacturers require that products are OTA certified in order to reduce compliance complexity, avoid potentially costly design errors, and meet manufacturing schedules.

RF Testing Help From the Experts at RF Exposure Lab

When you need RF or SAR testing for a project, come to the experts here at RF Exposure Lab. The importance of working with an experienced, A2LA accredited testing lab can’t be overstated. 

Working with an experienced testing lab as early as possible in the manufacturing process will help you successfully get through the maze of regulations and ensure that your product is compliant. We offer RF exposure testing services for a variety of wireless devices, such as

• Millimeter wave devices
• Near field charging devices
• Cell phones, laptops, and tablets
• Medical devices
• Modems

As well as many more devices! 

If you’re looking for compliance testing help that is provided with expertise, speed, accuracy, and integrity, contact us to learn more about our services or to get a quote.