When most people think of wireless charging systems, the devices that first come to mind are probably smartphones, tablets, or smartwatches. As wireless charging has become more popular, its use is expanding to other contexts like medical devices. The application of wireless charging in medical settings is making it easier than ever for patients to get the treatment and monitoring they need at all times. However, this means that these devices need to be safe for consumer use. Keep reading to learn more about these wireless charging systems, wireless charging for medical devices, and SAR testing regulations for these devices.    

What Are Wireless Charging Systems

Most people are probably familiar with wireless charging systems used to charge a smartwatch, phone, or laptop. These devices function through wireless power transfer (WPT) and are able to transfer electrical energy without physical wires connecting the charger to the device.

This provides users of these devices with significantly more mobility and convenience, especially when used to charge medical devices.

How This Technology Works

These charging systems work using technology invented by Nikola Tesla in the late 1800s. Using a process known as resonant-inductive coupling, Tesla was able to create a magnetic field between a transmitter and receiver to power light bulbs in his laboratory wirelessly. This led to him patenting the Tesla coil some years later, which was a tower with a coil at the top that emitted bolts of electricity.

Using Tesla’s invention as a foundation, the principle of inductive charging can be used to charge devices wirelessly using an electromagnetic coil. When placed in a charging base, this coil creates a magnetic field that transmits energy. A second coil in the device that will be charged, such as a phone or medical device, receives the energy and uses it for its battery.

Wireless Charging for Medical Devices

As mentioned, phones, laptops, and tablets aren’t the only devices that can use wireless charging systems. Medical devices and implants like pacemakers, hearing aids, insulin pumps, defibrillators, and more are also being charged wirelessly.

This has made the lives of the patients that need implanted devices much safer and more convenient. Without wireless charging capability, the only way to replace batteries in these devices is through surgery or a wire known as a driveline, used to connect an implanted device to a battery outside of the body. However, neither of these options is particularly convenient, and both have great potential for complications like infections. 

Even for patients that use medical devices that aren’t implanted, wireless power transfer goes a long way in improving their user experience and quality of life. It also allows medical teams to work without cables so they can do their jobs more quickly, efficiently, and safely.  

SAR Testing for Wireless Charging Systems

Wireless charging systems, like most electronic devices, emit electromagnetic radiation during use. Because of this, they must prove compliance with governing bodies’ regulations for RF exposure and are required to do so through SAR testing.

SAR evaluation for wireless charging devices is usually performed on low-frequency devices that operate below 13.567 MHz and are designed to be used within 20 cm of the body. During SAR testing, electric field (E) and magnetic field (H) values from the device are measured to ensure that it complies with regulations. These measurements are taken in reactive near field, radiating near field, and far field. Most wireless charging systems are meant to be used in reactive near field. The strength of these E- and H-fields is measured using probes or sensors.

International Wireless Power Transfer Standards

Because wireless charging systems may be sold in a variety of countries, they must be compliant with SAR regulations set by the governing bodies of these various countries. In the European Union, these regulations are set by the European Telecommunications Standards Institute (ETSI), the Federal Communications Commission (FCC) in the USA, Innovation, Science and Economic Development (ISED) in Canada, as well as many other governing bodies in other countries.

At RF Exposure Lab, we have both the accreditation and experience to efficiently and cost-effectively perform SAR testing for a variety of countries. You can see our full list of worldwide compliance testing standards here. If you manufacture devices that must undergo SAR testing and will be sold in multiple countries, the importance of working with an experienced, A2LA accredited testing lab cannot be overstated.

Get SAR Testing for Wireless Charging Systems at RF Exposure Lab

Our team’s expertise comes from RF Exposure Lab’s Owner, Vice President, and Chief Engineer, Jay Moulton. An authority in SAR testing with a background in manufacturing and the regulatory side of SAR testing, Jay Moulton has more than 25 years of experience. He is unique in his ability, experience, and knowledge of SAR. It’s this distinctive expertise and knowledge that allows us to guarantee our clients accurate SAR testing results and solutions.

In addition to this expertise, our team always works hard to go above and beyond, making sure that our clients understand how we are testing their devices and how SAR standards affect this. We strive to be as communicative and transparent as possible throughout the testing process so our clients are always up to date on the status of their testing.

We offer SAR 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 SAR testing help that is provided with expertise, speed, accuracy, and integrity, contact us to learn more about our services or to get a quote.