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Cellphone Safety – Too Close for Comfort?

News, PerSe Smart Sensing, ESG

David Wong

David Wong

Cellphone Safety – Too Close for Comfort?An independent investigation recently conducted by The Chicago Tribune revealed that some of the most popular cellphones might come with radio frequency (RF) radiation levels well above the legal safety limit. This finding has drawn public attention to cellphone RF safety and also prompted a follow up investigation by the Federal Communications Commission (FCC) in the United States.

What is SAR?

Specific Absorption Rate (SAR) is a measure of the amount of RF energy absorbed by the human body when using a mobile device, and is currently the industry safety standard for measuring the RF emissions of many wireless devices. In the U.S., the FCC allows RF exposure from cellphones up to a SAR level of 1.6 W/kg (over 1g of tissue) with a maximum separation distance of 25mm, while the European standard is 2 W/kg (over 10g of tissue) with a recently updated separation distance limited to 5mm from the body.

Since the introduction of these standards over four decades ago, wireless devices have advanced the levels of RF power with increasingly widespread use; thus, it is important to have standards reviewed and revised regularly in order to maintain an optimal balance of connectivity and RF safety. Not only should we focus on monitoring and enforcing these legal restrictions for human health – particularly for those generations that have been exposed to smartphones for longer durations – we also need to simplify the classification system while increasing public awareness of such regulations.

The Evolution of Smartphones

The popularity of smartphones has increased dramatically since the 1990s, becoming the most readily adopted consumer device in recent history. From 1G – which is a voice-only device, to the new 5G – promising high bandwidth and extremely fast data throughput, the innovation and advancement of wireless technology is introducing many new benefits to consumers. At the same time, the transition to the 5G era is also bringing more complexity in the latest smartphone designs.

To enable ultra-high speed, 5G phones are designed with high-performance RF devices often containing an increased number of antennas to support the demand for more reliable connectivity and greater bandwidth. However, the increase in RF power also introduces added challenges for smartphone original equipment manufacturers (OEMs) to maintain compliance with the worldwide RF codifications.


One way to ensure compliance with exposure guidelines is to reduce the maximum RF power permanently, however, very few OEMs use this method as it has a very negative effect on exactly the type of user experiences targeted by higher bandwidth network technologies like 4G and 5G. A much more effective approach to addressing the potential health risks of prolonged RF exposure is to implement a SAR sensor in the phone that manages the power output of the phone dynamically based on proximity to the user, delivering a vastly superior customer experience.

As a market leader in smart sensing devices including SAR, Semtech has seen a significant increase in the number of leading smartphone OEMs utilizing SAR sensors for this exact reason. Instead of compromising the performance that consumers are expecting from 5G, the use of SAR sensors provides OEMs an effective solution to manage their device RF system output while ensuring a good customer experience and complying with safety standards.

As mobile technology continues to evolve to support ever higher bandwidth and throughput requirements, Semtech expects a similar evolution in safety management standards and best practices fueled by an increase in public awareness of RF safety concerns. In turn this will drive a need for smartphone OEMs to continue to focus new product development on phones which combine the best customer experience with RF safety for end users.

A Call to Action for Industry

In an increasingly competitive smartphone industry, the time to act is now. Staying at the leading edge of RF safety standards will increasingly become a differentiator for smartphone OEMs across both premium and value sectors of the market.

We believe there are three key areas where OEMs can gain competitive advantage, specifically:

  • Driving increased public awareness of RF safety standards by adopting a simpler evaluation system that consumers can more easily understand to determine which smartphones and other wireless products are best in class
  • Continually evaluating global safety regulations and standards to ensure that the OEMs’ products keep pace with the latest technology advancements and the new use cases such advancements enable
  • Integrating SAR sensors into all future designs to deliver the combination of performance and safety that consumers demand

Over the past two decades, as network and device technologies have rapidly evolved, we’ve seen massive shifts in market share across device OEMs. The evolution of this market shows no signs of slowing as we enter a world where high bandwidth connectivity is ubiquitous.

The battleground for device OEMs going forward is in delivering solutions which leverage the best available technologies to deliver both high performance and user safety. The winners in this new world may well be the OEMs who innovate and lead (rather than follow) the development of safer solutions.

Learn More About SAR Sensors

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