Impact of Terahertz Electromagnetic Devices on Human Tissue: A Review of SAR and Safety Considerations

Abstract

Terahertz (THz) technology, operating in the 0.1–10 THz band, has gained increasing relevance in wireless communications, biomedical diagnostics, and wearable systems. Its ability to provide high‐resolution imaging and non‐invasive sensing has made it a promising tool in healthcare. However, strong absorption of THz waves by water‐rich biological tissues raises critical concerns regarding biological safety. A key metric for evaluating electromagnetic exposure is the Specific Absorption Rate (SAR), which quantifies the rate of energy deposition in tissues. This review examines the role of THz antennas, sensors, and absorbers in shaping electromagnetic field distributions and their implications on SAR. While flexible and compact THz antennas and sensors demonstrate potential for applications such as COVID‐19 detection, fall monitoring, and biosensing, most studies rely on simplified phantoms or simulations, limiting biological realism. Similarly, metamaterial absorbers enhance device sensitivity and control field localization but may inadvertently introduce resonant hotspots that increase localized SAR. Current research highlights a trade‐off between device performance and biological safety, further constrained by incomplete dielectric data sets and lack of standardized measurement techniques. This review underscores the urgent need for experimental validation, localized SAR metrics, and updated safety frameworks to ensure the safe deployment of THz‐enabled biomedical technologies.