Effects of SAR Improvement Using Anisotropic Magneto-Dielectric Sheets

Since the beginning of the 21st century, mobile technology has become a core infrastructure across various industries, such as healthcare, manufacturing, military, and home appliances. Microwave and RF electromagnetic waves are essential for mobile devices such as smartphones; however, they can cause tissue damage when absorbed by human tissues. Thus, countries worldwide have established regulations on specific absorption rate (SAR) based on international standards and legally require disclosure of SAR values for devices. Various technologies have been developed to reduce SAR, mainly by increasing the distance between the antenna and the head using RF shielding materials, or considering antenna structure in the early stages of product design. However, these methods can degrade antenna efficiency, which directly affects communication performance. This study investigated the conditions under which an anisotropic magneto-dielectric sheet can be placed between a mobile device and the human head to effectively reduce SAR without degrading antenna performance. The material properties of the anisotropic magneto-dielectric sheet were varied through simulations to derive the optimal combinations for SAR reduction.