What to Know About SAR Requirements for Wearable Technology

What to Know About SAR Requirements for Wearable Technology

Wearable technology has become more and more popular over the past decade, and this market is only growing, thanks to the development of 5G technology. In fact, shipments of wearable technology reached almost half a billion in 2020. However, because these devices are connected to WiFi and 5G technology, they emit radiofrequency (RF) energy. This makes these devices subject to SAR testing and SAR requirements.

In this article, we’ll be discussing what this means for manufacturers of wearable technology and how working with a reputable SAR testing lab can help.

The Basics of Wearable Technology

First of all, what is wearable technology and why does it emit RF energy?

Wearable technology is a device that’s designed to be worn, whether in clothing or directly against the body, such as in the form of a smartwatch. Devices like these can be used for a variety of tasks like entertainment or monitoring physical activity.

In order to send or receive this information to and from a smartphone, the internet, or some other device, these devices require the use of low-powered RF transmitters. These transmitters emit radio waves, which are a type of radiation. This exposes wearers to a level of RF radiation and requires that these devices undergo SAR testing to ensure they meet SAR requirements and RF exposure limits in order to be sold in the U.S. and many other countries

Types of Wearable Technology

We know that wearable technology must meet SAR requirements set by the FCC and other regulatory agencies around the world, but what devices fall under the umbrella of wearable technology?

Smartwatches. These devices are the most popular of all wearable technology. Smartwatches are worn on the wrist and connect to a mobile phone or computer. They notify their user of calls, emails, social media alerts, and track fitness and health. Some of these devices are specifically designed to only monitor health and fitness. 

Fitness trackers are devices designed specifically to track the user’s health and fitness. This includes your heart rate, calories you burn, steps taken, blood pressure, and even the user’s sleep. When users have specific health goals, these devices are very useful in helping reach them. While some versions of these devices are worn on the wrist, there are now other versions that can be worn around the neck, clipped to clothes or a belt, and more.

Sports watches differ from fitness trackers in that they are usually used by more serious athletes with a significant dedication to sports like running, swimming, or cycling. Although they’re designed to track fitness goals, these devices typically include GPS capabilities as well.

Head-mounted displays. This includes virtual reality (VR) and augmented reality (AR) headsets and smart glasses. Currently, these devices are mostly used for entertainment purposes, but may eventually be used for communication.

Smart clothing. This is a more recent addition to wearable technology and refers to garments that include electronics to increase their functionality. Examples of smart clothing include smart compression shirts that can track the user’s heart rate and are equipped with GPS and swimwear with a built-in sensor that alerts the user if they’ve spent too much time in the sun.

Smart jewelry. Based on the idea of smartwatches, smart jewelry is a device that is fashionable, practical, and useful. They are mostly used to notify users about emails, texts, or calls.

sar requirements

Portable Products and SAR Requirements

The FCC classifies wireless devices as either fixed, mobile, or portable depending on how they are installed and used. Wearable technology, of course, falls under the portable product category. This means that the device is used in close proximity to the body.

The FCC’s SAR requirements demand that portable products undergo SAR testing to prove that they meet RF exposure limits. This is because when a wireless device is used within 20 cm (about 8 in) of a user’s body, the body will absorb RF energy. The FCC’s SAR requirements ensure that the level of RF energy emitted by the product is safe.

In order to determine that a device complies with the regulations set forth by the FCC and other regulatory bodies, SAR testing is required. SAR is a unit of measurement for the quantity of RF energy absorbed by the body when a wireless device is used. In order to measure this, a “SAM (Specific Anthropomorphic Mannequin) phantom” is used to simulate the human head and a “flat phantom” simulates the human body. During testing, the wireless device is operated at its highest power levels while mimicking the way a human user would use the product. While in this configuration, a probe mounted on a robotic arm measures the RF energy that is absorbed in the simulated tissue in the SAM phantom and/or flat phantom.

Ensure Your Wearable Technology Meets SAR Requirements With Help From RF Exposure Lab

It’s important for manufacturers of wearable devices to understand SAR requirements and how they affect their products. This is helpful knowledge to have even in the design process of the product, as its design can affect whether or not it will pass SAR testing. The testing process can be complicated, so it’s best to work with a reputable SAR testing lab.

At RF Exposure Lab, we go above and beyond to make sure our clients understand what we do and assist them in understanding how FCC regulations affect the testing required for their products. We strive to be as communicative and transparent as possible throughout SAR testing so you always know what’s going on with your product and are never left in the dark.

We offer testing services for a variety of devices including wearable technology, cell phones, laptops and tablets, medical products, survey equipment, wireless modems, and soon, near field charging devices. If you’re looking for SAR testing help or have any questions about SAR testing for wearable devices, please contact us.