Associate Professor, Kun Li, Advanced Wireless Communication Research Center (AWCC), University of Electro-Communications (UEC), Tokyo.

How do wireless systems interact with the human body? Can wearable and implantable devices be both powerful and safe? At the University of Electro-Communications, Associate Professor Kun Li explores these questions through his research in body-centric wireless communication—a field at the intersection of radio engineering, biology, and human health.

Invisible Waves and Early Curiosity
Li’s fascination with radio waves began in childhood. “I loved watching movies about aliens and outer space,” he recalls. “When I learned that deep-space observation relies not on optical telescopes but on radio telescopes, I was amazed that invisible waves could carry so much information.”
This early curiosity led him to major in communication engineering. His undergraduate research on antennas and electromagnetic fields became the foundation for his lifelong focus on how radio frequency (RF) waves interact with the human body.

Ensuring Safety in a Connected World
With mobile phones, Wi-Fi, and wearable devices now ubiquitous, humans are surrounded by electromagnetic fields (EMF) almost constantly. “Over the past 20 years, our electromagnetic environment has changed dramatically,” Li explains. His recent studies investigate how EMF exposure affects human health, how to establish regulations for EMF-emitting devices, and how to balance safety with high-performance communication.
“Our goal is to integrate safety and efficiency,” he says. “We want wireless systems that work better while ensuring that human exposure remains within safe limits.”

The Body as Part of the System
In conventional wireless systems, antennas transmit and receive signals in open air. In body-centric systems, the human body itself becomes part of the electromagnetic environment.
“The body has dielectric properties—it absorbs, reflects, and scatters electromagnetic waves,” Li explains. “This affects antenna performance and signal propagation, especially at high frequencies like millimeter and terahertz waves.”
Understanding these interactions is critical for designing next-generation wearable and implantable devices, from smart health monitors to advanced medical sensors.

Bridging Engineering and Life Sciences
One of the major challenges in this research is understanding the biological impact of electromagnetic exposure. “As a microwave engineer, I realized that physics alone cannot explain how EMFs influence biological tissues,” Li says. “We need knowledge from medicine and biology to interpret experimental results properly.”
To address this, his group collaborates closely with medical and biological researchers across Japan. In a MIC-funded project, engineers and physicians jointly investigate the thermal and physiological effects of millimeter-wave exposure. “The medical perspective has greatly strengthened our studies,” Li notes. “It helps us evaluate safety scientifically, not just theoretically.”

Toward Safer, Smarter Wearables
Li sees the next wave of innovation in high-speed communication for wearable devices. Today’s wearables mainly transmit low-data-rate health information, but future devices will integrate AI, cloud connectivity, and big data analytics.
“Such systems will require faster, more reliable links—and stricter safety standards,” he says. “Designing networks that meet both demands is our next big challenge.”

Looking Ahead
Li’s long-term vision is to create body-centric wireless systems that combine communication efficiency with biological safety. “If we can achieve that balance,” he says, “we will enable a safer, smarter, and more connected society.”
By merging insights from engineering and life sciences, Li’s work ensures that the invisible networks surrounding us will remain not only fast and powerful—but also safe for every human body they touch.

Kun Li’s research spans body-centric wireless systems, electromagnetic field exposure safety, and next-generation wearable communication technologies.